Amorphous letemovir and solid pharmaceutical formulations thereof for oral administration

Abstract

The present invention provides amorphous letemovir and orally administered solid pharmaceutical formulations thereof (immediate release formulations). The present invention relates to amorphous letemovir suitable as an immediate release formulation when separated from an organic solution by drum drying of an organic solution in a volatile organic solvent, in particular acetone, at a temperature of 30 DEG C to 60 DEG C and subsequent drying of the resulting amorphous letemovir; or separating the amorphous letemovir by precipitation from a water-miscible solvent selected from acetone or acetonitrile into excess water as an anti-solvent, and subsequently filtering or concentrating the resulting amorphous letemovir. The immediate release formulation of amorphous letemovir is intended for use in methods of prophylaxis or treatment of diseases associated with herpes virus populations, preferably associated with cytomegalovirus (CMV), even more preferably associated with human cytomegalovirus (HCMV).

Description

[0001] The present application is a divisional application of a patent application filed on June 19, 2014, with application number 201480040969.X and titled “Amorphous Letermovir and its solid pharmaceutical preparation for oral administration”. Technical Field

[0002] The technical field of the present invention is pharmaceutical chemistry / galenic formulations. The present invention relates to a new stable galenic formulation of the amorphous compound Letermovir for oral administration. The formulation is suitable as an orally administered medicament for use in a method of treating viral diseases, in particular human cytomegalovirus (hereinafter referred to as HCMV) infection. The present invention also relates to a method for isolating Letermovir in an amorphous state as an active pharmaceutical ingredient (hereinafter referred to as API). In particular, the present invention relates to an amorphous Letermovir having advantageous physicochemical properties in terms of particle size distribution, specific surface area and toxic impurity content, which allows the compound to be readily formulated into a solid pharmaceutical formulation for oral administration. Background Art

[0003] It is well known that APIs in an amorphous state present problems in the pharmaceutical industry that must be faced during their isolation and galenic formulation. In particular, zwitterionic compounds such as Letermovir, which are known to exist in different salt forms, present many challenges during synthesis and galenic formulation.

[0004] Letermovir is known to be a highly active drug for the treatment of HCMV infection and is extensively described in Lischka et al., In Vitro and In Vivo Activities of the Novel Anticytomegalovirus Compound Letermovir. Antimicrob. Agents Chemother. 2010, 54: pp. 1290-1297; and Kaul et al., First report of successful treatment of multidrug-resistant cytomegalovirus disease with the novel anti-CMV compound Letermovir. Am. J. Transplant. 2011, 11: 1079-1084; and Marschall et al., In Vitro Evaluation of the Activities of the Novel Anticytomegalovirus Compound Letermovir against Herpesviruses and Other Human Pathogenic Viruses. Pathogenic Viruses). Antimicrob. Agents Chemother. 2012, 56: 1135-1137.

[0005] HCMV is a virus species belonging to the family of viruses known as herpesviruses. It is usually abbreviated as HCMV and alternatively referred to as human herpesvirus-5 (HHV-5). Among herpesviruses, HCMV belongs to the subfamily of betaherpesviruses (Betaherpesvirinae), which also includes cytomegaloviruses from other mammals.

[0006] Although they can be present throughout the body, HCMV infection is usually associated with the salivary glands. HCMV infection is usually unnoticed in healthy people, but can be life-threatening for immunocompromised subjects such as HIV-infected persons, organ transplant recipients or newborns. In particular, HCMV remains the leading viral cause of birth defects and a life-threatening disease in transplant recipients.

[0007] Currently approved anti-HCMV drugs target viral DNA polymerase pUL54. Known compound Ganciclovir (GCV) acts as a nucleoside analog. Its antiviral activity needs to be phosphorylated by HCMV protein kinase pUL97. In this regard, Cidovir (CDV), as a nucleotide analog, has been phosphorylated and is therefore active. Foscarnet (FOS) has different modes of action. It directly inhibits polymerase function by blocking the pyrophosphate binding site of pUL54. However, it is known that the above-mentioned drugs are associated with the emergence of toxicity and drug resistance. In addition, its bioavailability can still be improved.

[0008] Attempts have been made to develop more active and less toxic oral HCMV antiviral drugs with a new mode of action by synthesizing and evaluating benzimidazole ribonucleosides. This class of drugs shows high activity against HCMV and targets the viral terminase complex. However, it has been shown that this class of compounds is metabolically unstable.

[0009] In addition, HCMV resistant to benzimidazole ribonucleosides have been described, where resistance has been mapped to viral open reading frames (hereinafter referred to as ORFs) UL89 and UL56 (see Krosky et al., Resistance of Human Cytomegalovirus to Benzimidazole Ribonucleosides-Maps to Two Open Reading Frames: UL89 and UL56, Journal of Virology, 1998, pp. 4721-4728; and Evers et al., Inhibition of Human Cytomegalovirus Replication by Benzimidazole Nucleosides Involves Three Distinct Mechanisms, Antimicrobial Agents and Chemotherapy, 2004, pp. 3918-3927).

[0010] BAY 38-4766 is another potent and selective inhibitor of HCMV replication and is a representative of the new class of non-nucleoside anti-HCMV drugs, phenylenediamine sulfonamides. It also targets the viral terminase complex. BAY 38-4766 prevents the cleavage of high molecular weight viral DNA concatemers into monomeric genome lengths. However, the development of this class of compounds has been discontinued.

[0011] In addition, compound-resistant HCMV have been described, which contain mutations in the viral ORFs UL56 and UL89, among others (see Buerger et al., A Novel Non-nucleoside Inhibitor Specifically Targets Cytomegalovirus DNA Maturation via the UL89 and UL56 Gene Products, Journal of Virology, 2001, pp. 9077-9086).

[0012] Other attempts to develop improved anti-HCMV drugs led to the identification of the small molecular weight compound Bay 82-3286 and 3,4-dihydroquinazolines such as Letermovir.

[0013]

[0014] Compared to the above compounds, 3,4-dihydroquinazoline as Letermovir blocks viral replication without inhibiting the synthesis of offspring HCMV DNA or viral proteins. In fact, it is shown that Letermovir works via a mode of action involving viral terminase. However, its interaction mode with the viral terminase complex and its chemical structure are different from all other so far characterized drugs (including BDCRB and BAY 38-4766) of known targeting HCMV terminase complex. Although all published cutting / packaging inhibitors (including BDCRB and BAY 38-4766) are described for the antiviral activity of rodent cytomegalovirus, Letermovir is only active for human cytomegalovirus and therefore has a high potential as a specific human anti-HCMV drug.

[0015] The exact chemical name of Letermovir is (S)-{8-fluoro-2-[4-(3-methoxyphenyl)-1-piperazinyl]-3-[2-methoxy-5-(trifluoromethyl)phenyl]-3,4-dihydro-4-quinazolinyl}acetic acid, which has the formula (I) shown below:

[0016] C 29 H 28F 4 N 4 O 4 .

[0017] The synthesis of Letermovir is disclosed in US2007 / 0191387 A1, Exemplary Embodiments 14 and 15, pages 40 and 41, paragraphs

[0495] to

[0505] . Letermovir exhibits excellent in vitro and in vivo anti-HCMV activity and has completed Phase IIb clinical trials.

[0018] US 2007 / 0191387 A1 is silent about the specific physicochemical properties of Letermovir in terms of particle size distribution, specific surface area and pharmaceutically acceptable impurity content, which make it suitable for orally administrable solid galenic formulations.

[0019] The preparation of Letermovir is described in WO 2006 / 133822; Example 11.

[0020] WO 2006 / 133822 is silent about the specific physicochemical properties of Letermovir in terms of particle size distribution, specific surface area and pharmaceutically acceptable impurity content which make it suitable for orally administrable solid galenic formulations.

[0021] WO 2013 / 127971 A1 describes sodium and calcium salts of Letermovir and solvates thereof, and their use as antiviral agents. WO 2013 / 127971 A1 does not mention the specific physicochemical properties of Letermovir in terms of particle size distribution, specific surface area and pharmaceutically acceptable impurity content, which make it suitable for orally administrable solid galenic formulations.

[0022] Letermovir inhibits HCMV replication through a specific antiviral mechanism that involves the viral terminase subunit, but is distinct from the antiviral mechanisms of other classes of compounds that are also known to target this enzyme complex (see Goldner et al., The Novel Anticytomegalovirus Compound AIC246 (Letermovir) Inhibits Human Cytomegalovirus Replication through a Specific Antiviral Mechanism That Involves the Viral Terminase, Journal of Virology, 2011, pp. 10884-10893).

[0023] However, zwitterionic Letermovir carries a chemical property that presents challenges in the field of medicinal chemistry. According to this, isolated Letermovir in the form of zwitterions can remain in the amorphous state, while Letermovir in the form of acidic and basic salts can crystallize under a limited number of counterions (see also German patent application 10 2012 101 673.9; German patent application 10 2012 101659.3).

[0024] Attempts to reproducibly crystallize the API Letermovir in zwitterionic form and to keep it crystallized in a stable polymorphic form have so far failed. Therefore, Letermovir must be isolated in its amorphous state with sufficient yield and purity while maintaining its physicochemical properties, which enable adequate dissolution characteristics to be achieved in a tablet / capsule formulation for oral administration.

[0025] In this regard, only solution formulations of Letermovir are known in the art. However, amorphous Letermovir for intravenously administrable formulations can be completely dissolved in water (with and without ethanol) only by adding excess arginine or lysine or by adding a combination of cyclodextrin and sodium hydroxide.

[0026] The object of the present invention is to obtain fast dissolving solid dosage forms such as tablets and / or capsules of Letermovir in an amorphous state suitable for oral administration. In this context, another object of the present invention is to obtain oral dosage forms of solid amorphous API Letermovir for oral administration with sufficient bioavailability.

[0027] However, by using both spraying and high shear granulation, wet granulation of an aqueous solution of Letermovir and excess arginine will not produce a tablet / capsule showing sufficient dissolution for immediate release (hereinafter referred to as IR). In particular, in the case of most organic solvents (including lower alcohols), problems are encountered in the separation of Letermovir in pure API form, purity and / or chemical stability. Therefore, contrary to expectation, the method for manufacturing intravenous preparations by adding arginine is not transferable to the tablet / capsule preparation of Letermovir. As shown in Example 1, arginine has no positive impact on the dissolution characteristics of Letermovir in solid dosage forms.

[0028] Solubility studies performed by the present inventors also confirmed the problematic solubility profile of amorphous Letermovir, since as shown in Example 2, the solubility of Letermovir in the pH range of 1 to 7.5 varied from 0.4 mg / ml to >1 mg / ml. Summary of the invention

[0029] Surprisingly and unexpectedly, the present invention provides pure API Letermovir in an amorphous state sufficient for further processing into a solid pharmaceutical formulation for oral administration. When tested using Ph. Eur. Method 2.9.3, Apparatus 2, at a paddle speed of 50 rpm at 37.0°C ± 0.5°C in 1000 ml 0.1 N HCl / 0.2% sodium lauryl sulfate medium and dissolution measured by reverse phase HPLC at time point 30 minutes as follows, the solid pharmaceutical formulation provided herein is able to achieve a dissolution profile of amorphous Letermovir in a granular formulation with a dissolution rate of >50% within 30 minutes:

[0030] HPLC operating conditions:

[0031]

[0032]

[0033] Therefore, a high degree of oral bioavailability can be expected based on the improved dissolution profile.

[0034] In a first main aspect, the inventors have found that amorphous Letermovir can be advantageously isolated by:

[0035] i) drum drying a solution of amorphous Letermovir in a volatile organic solvent, preferably propanol, or

[0036] ii) precipitating the amorphous Letermovir from a water-miscible solvent, preferably acetone or acetonitrile, into excess water as anti-solvent.

[0037] In principle, amorphous compounds like Letermovir can also be isolated by spray drying or evaporation of solutions in organic solvents, but in the case of Letermovir, the yield and / or purity is insufficient due to the large amounts of residual solvent remaining in the amorphous API Letermovir.

[0038] In a second main aspect, the inventors have found two preferred manufacturing methods, namely in the case of isolated Letermovir on a drum dryer, it is preferred to process the API using wet granulation, and in the case of precipitated Letermovir, it is preferred to process the API using dry granulation.

[0039] Both methods enabled the manufacture of a reproducible galenic formulation of amorphous Letermovir as API, which exhibited a dissolution profile of >50% dissolution of Letermovir in the granulated formulation within 30 minutes when tested using Ph. Eur. method 2.9.3, Apparatus 2, at a paddle speed of 50 rpm at 37.0°C ± 0.5°C in 1000 ml 0.1 N HCl / 0.2% sodium lauryl sulfate medium and dissolution measured by reverse phase HPLC at time point 30 minutes as follows:

[0040] HPLC operating conditions:

[0041]

[0042] DETAILED DESCRIPTION

[0043] The present invention relates to an improved isolation of amorphous API Letermovir and its chemically stable galenic formulation with adequate dissolution characteristics for oral administration. In addition, the present invention relates to oral dosage forms such as tablets or capsules containing solid amorphous API Letermovir or its pharmaceutically acceptable salts, solvates or hydrates and showing adequate bioavailability. In addition, the present invention relates to pharmaceutical preparations of solid amorphous API Letermovir or its pharmaceutically acceptable salts, solvates or hydrates that can be administered orally, which are used in methods of treatment of viral diseases, in particular in methods of treatment of HCMV infection.

[0044] In the context of the present invention, the problems faced by a suitable galenic formulation based on amorphous Letermovir are reflected in:

[0045] a) inevitably isolating from a solution in an organic solvent to obtain amorphous Letermovir in pure form which exhibits physicochemical properties sufficient for the preparation of an oral dosage form, and

[0046] b) To provide a suitable galenic formulation which keeps Letermovir in an amorphous state and enables granulation of IR tablets or capsules.

[0047] Regarding item a) above, Fig.12 The reaction scheme of the preferred synthetic route of Letermovir is shown, wherein the asterisk at the bottom left before step 4)-solvent switching indicates the step of starting separation according to the present invention.

[0048] In this regard, the present invention provides a solution to the above-mentioned problems underlying the present invention, namely

[0049] a) Provide appropriate separation techniques to obtain Letermovir in a pure, chemically stable and amorphous state

[0050] b) Provide a suitable tablet / capsule manufacturing process for amorphous Letermovir which enables to achieve adequate dissolution profile in IR tablet / capsule dosage form, ie >50% Letermovir dissolution within 30 minutes.

[0051] Surprisingly and unexpectedly, the present invention provides a chemically stable, orally administrable solid pharmaceutical formulation of Letermovir or a pharmaceutically acceptable salt, solvate or hydrate thereof, characterized in that the amorphous Letermovir in the granulated formulation has a dissolution rate of >50% within 30 minutes.

[0052] Furthermore, surprisingly and unexpectedly, the present invention provides a chemically stable, orally administrable solid pharmaceutical formulation of Letermovir or a pharmaceutically acceptable salt, solvate or hydrate thereof, characterized in that the absolute bioavailability (F) of the amorphous API Letermovir in the granulated formulation is 30% to 95%, preferably 50% to 95%, more preferably 60% to 95%.

[0053] In another aspect, surprisingly and unexpectedly, the present invention provides a chemically stable, orally administrable solid pharmaceutical formulation of Letermovir or a pharmaceutically acceptable salt, solvate or hydrate thereof, characterized in that the absolute bioavailability (F) of the amorphous API Letermovir in the granulated formulation is >30%, preferably >40%, more preferably >50%, even more preferably >70%, even more preferably >80%, and most preferably >90%.

[0054] Chemical stability is crucial for maintaining the activity of the medicament also in a suitable dosage form for oral use, such as tablets or capsules. The skilled person recognizes that the chemical stability of the API depends inter alia on its isolation method, in addition to the composition of its formulation itself, its mixture, its manufacturing method and its own storage conditions. In this regard, it is common knowledge that impurities may degrade from an API such as Letermovir due to increases, for example, associated with storage temperature, storage relative humidity and storage duration.

[0055] Thus, in a first main aspect of the present invention, Letermovir is isolated from an organic solvent solution in sufficient yield and purity and Letermovir remains stable in its amorphous state having conserved physicochemical properties to enable an oral tablet / capsule formulation providing adequate dissolution characteristics, i.e. amorphous Letermovir dissolution >50% within 30 minutes.

[0056] According to the present invention, in the final chemical synthesis step, Letermovir is prepared by saponification of the corresponding methyl ester, which is used to separate the two enantiomers by crystallization using (2S, 3S)-(+)-di-O-4-toluoyl-D-tartaric acid. The chiral acid is removed by extraction with aqueous bicarbonate solution from a methyl-tert-butyl-ether (hereinafter referred to as MTBE) solution, and the methyl ester of Letermovir is saponified using aqueous sodium hydroxide in a two-phase mixture.

[0057] After saponification, the zwitterionic form can be extracted into MTBE at neutral pH. Finally, the solvent is switched to acetone and the amorphous API Letermovir can be isolated by using either:

[0058] i) drum dryer, or

[0059] ii) by precipitation of amorphous API Letermovir from an acetone or acetonitrile solution into an excess of stirred water followed by drying in a conical dryer at elevated temperatures between 40-80°C.

[0060] Alternatively, precipitation can be forced by adding water as an anti-solvent to a solution of amorphous API Letermovir in acetonitrile or acetone. This process results in a viscous material that must be further processed to obtain solid amorphous API Letermovir, which can be isolated by filtration.

[0061] Thanks to the above-described isolation method, Letermovir can be isolated in an amorphous state, in chemical and chiral purity within acceptable limits of residual solvents, thereby exhibiting physicochemical properties suitable for galenic formulation without the need for further steps such as grinding or micronization.

[0062] The physicochemical properties include: when the isolated Letermovir is subjected to Brunauer-Emmett-Teller (BET) specific surface area (SSA) analysis and the following exemplary conditions are applied simultaneously, the specific surface area of ​​the amorphous Letermovir obtained according to the present invention is at least 1 m 2 / g:

[0063] Principle: Nitrogen adsorption at 77K; according to the method of Brunauer, Emmett and Teller (BET)

[0064] Method: According to USP <846> Volumetric determination method (Method II)

[0065] Instrument: Tristar 3000 / VacPrep 061 (Micromeritics)

[0066] Sample mass: about 1.5-2.5g

[0067] Sample preparation: Degassing under vacuum at 40 °C for 2 hours (final vacuum <2.7 Pa)

[0068] Pressure range p / p0: 0.05-0.15 (3 data points).

[0069] The physicochemical properties also include: when the isolated Letermovir of the present invention is subjected to a particle size distribution analysis and the following exemplary conditions are applied simultaneously, the median particle size distribution (PSD) does not exceed 10 μm:

[0070] Apparatus: Mastersizer 2000 with dry dispersion

[0071] Procedure: Fraunhofer; weighing amount: 0.3-0.4g

[0072] Measuring time: 20 seconds

[0073] Background time: 6 seconds

[0074] Shading limit: 0.5% to 6%

[0075] Sample tray: micro volume; small sieve with balls

[0076] Feed rate: 45-55%

[0077] Dispersion pressure: 2.5 bar

[0078] Four independent analyses were performed and the results had to be averaged.

[0079] The physicochemical properties also include the pharmaceutically acceptable toxic impurity content of the isolated Letermovir according to the present invention, namely:

[0080] i) the impurity content of mesityl oxide as determined by static headspace gas chromatography as described in detail in the specific embodiment with number 12 below: < / =31ppm

[0081] and / or

[0082] ii) the impurity content of 3-methoxyaniline is <20 ppm, preferably <15 ppm, more preferably <10 ppm, even more preferably <5 ppm, most preferably <1.5 ppm, when determined by gas chromatography with the following operating conditions:

[0083]

[0084]

[0085] Regarding the above situation, those skilled in the art know that the specific surface area of ​​powdered amorphous Letermovir increases as the particle size decreases. Therefore, the surface of the active pharmaceutical ingredient Letermovir increases, which improves the dissolution and reabsorption profile of Letermovir when administered orally in a solid dosage form.

[0086] A surprising and unexpected finding of the present invention is that by the separation method as disclosed herein, it is possible to obtain particles having a median particle size distribution of no more than 10 μm and / or a specific surface area of ​​at least 1 m 2 / g of amorphous Letermovir. In addition, the amorphous Letermovir obtained by the method of the present invention exhibits high purity, which makes it pharmaceutically acceptable to be easily formulated into a solid oral dosage form.

[0087] Accordingly, the present inventors have found that a galenic formulation of isolated Letermovir in an amorphous state maintains said amorphous state without affecting its pharmaceutical activity and dissolution characteristics.

[0088] Thus, in a second main aspect of the present invention, surprisingly and unexpectedly, the inventors have found that a galenic formulation of chemically stable amorphous Letermovir has a dissolution profile with >50% dissolution of amorphous Letermovir in a granulated formulation within 30 minutes.

[0089] In the context of the second main aspect of the invention, surprisingly and unexpectedly, the inventors have found that solid pharmaceutical formulations of Letermovir in an amorphous state exhibit an absolute bioavailability (F) of 30% to 95%, preferably 50% to 95%, more preferably 60% to 95%.

[0090] Therefore, the present invention combines the advantages of Letermovir in the metastable amorphous state, i.e. the improved dissolution properties, with an appropriate galenic formulation to maintain the amorphous state and thus provide an orally administrable solid dosage form such as a tablet or capsule. Furthermore, the present invention exploits the lipophilicity of Letermovir in the amorphous state to obtain a solid pharmaceutical formulation of Letermovir showing an absolute bioavailability (F) of amorphous API Letermovir in a granulated formulation of >30%, preferably >40%, more preferably >50%, even more preferably >70%, even more preferably >80% and most preferably >90%.

[0091] Although improved in terms of dissolution properties, the lipophilicity of Letermovir in the amorphous state maintained by the separation techniques and manufacturing methods according to the present invention also improves the bioavailability properties of the amorphous API Letermovir known to those skilled in the art.

[0092] Furthermore, it is generally known that the amorphous state is a metastable state, which results in a thermodynamic drive to crystallization. In the case where a predominantly crystalline drug is converted to an amorphous state to enhance solubility and dissolution properties, it is common practice to prepare, for example, a solid dispersion (or melt extrusion) of the drug using a pharmaceutically acceptable polymer to stabilize the drug-polymer aggregates from crystallization.

[0093] However, due to the separation technology according to the first main aspect of the present invention, a long-term stable solid pharmaceutical formulation of amorphous Letermovir is provided without processing into a solid dispersion or melt extrusion. In this regard, those skilled in the art know that it is not an easy task to separate amorphous Letermovir with high quality.

[0094] Isolation of Letermovir by using a drum dryer

[0095] The present inventors have found that a drum drying method is suitable for isolating Letermovir.

[0096] According to the present invention, the method starts from:

[0097] • using a solution of Letermovir in acetone applied in the form of a very thin film on a heated rotating drum (40-60° C., preferably 60° C.) installed in a vacuum chamber at a pressure of about 200 mbar,

[0098] • Letermovir was then removed from the drum using a scraping tool.

[0099] This approach has limited operating capacity and delivers Letermovir in an amorphous state, which must be

[0100] The final drying process

[0101] To meet the ICH requirements for residual solvents.

[0102] Isolation of Letermovir via precipitation from acetonitrile or acetone into excess water

[0103] The present inventors have also discovered that Letermovir can be isolated in an amorphous state when precipitated from acetonitrile or acetone into excess water.

[0104] Therefore, in another aspect, the present invention provides a precipitation method for isolating amorphous Letermovir, characterized in that it is precipitated from a water-miscible solvent acetonitrile or acetone into an excess of stirred water. Thereafter, separation is performed via filtration or centrifugation. Subsequently, a drying step is optionally performed in a vacuum.

[0105] According to the above, the present inventors have found that precipitation, filtration and drying in vacuum at elevated temperatures of 40-80°C are sufficient to isolate amorphous Letermovir with excellent purity and with appropriate physicochemical properties (particularly in terms of particle size distribution and specific surface area), which allows further formulation into tablets.

[0106] Effect of solvent on the separation of Letermovir

[0107] The present inventors have also found that isolating Letermovir is generally solvent dependent and therefore requires specific and appropriate solvents to obtain Letermovir in a pure and chemically stable amorphous state.

[0108] During chemical development and optimization studies to obtain pharmaceutical grade amorphous Letermovir, the following water-miscible solvents were investigated: ethanol, tetrahydrofuran (THF), methyl ethyl ketone (MEK, 2-butanone), methanol, and acetonitrile.

[0109] The present inventors have found that ethanol, THF and MEK are not suitable as solvents for obtaining pharmaceutical grade amorphous Letermovir for quality reasons (impurities, residual solvents) or due to the precipitation method and the precipitation itself.

[0110] Therefore, in another aspect of the present invention, ethanol, THF and MEK are specifically excluded for precipitation and precipitation of Letermovir from an organic solution, preferably an acetone solution.

[0111] In another aspect, the present inventors found that methanol is disadvantageous for isolating Letermovir and obtaining pharmaceutical grade amorphous API because potential side reactions as re-esterification may occur under stress conditions, thus limiting the scale-up of this separation process.

[0112] In contrast, the inventors have found that, contrary to expectations, only acetonitrile and acetone provide sufficient precipitation properties to obtain Letermovir in an amorphous state and pharmaceutical grade. The Letermovir thus obtained exhibits sufficient purity and yield, as well as suitable physicochemical properties and can therefore be directly used for the preparation of galenic formulations implemented in orally administrable tablet / capsule granulations.

[0113] Therefore, in another aspect of the present invention, acetonitrile and acetone are preferred as water-miscible solvents for precipitating amorphous Letermovir. In view of the residual solvent limits required by the current ICH guidelines, acetone is even more preferred as a solvent with lower toxicity.

[0114] Therefore, in another aspect of the present invention, acetone is the most preferred organic solvent for precipitating amorphous Letermovir.

[0115] Furthermore, according to the present invention, residual solvents (acetonitrile, acetone, water) can be effectively removed in vacuum at elevated temperatures (40-80° C.) without loss of purity or change in the physicochemical properties in terms of amorphous state, particle size distribution and specific surface area.

[0116] In another aspect of the invention, the isolated amorphous Letermovir has an acetone content of less than 5000 ppm (according to ICH guidelines), and a water content of <2% (internal limit).

[0117] Regarding the second main aspect of the present invention:

[0118] Tablet / capsule manufacturing

[0119] Furthermore, the subject of the present invention is also a manufacturing process based on dry granulation and wet granulation (also known as high shear or top spray granulation) to obtain IR film-coated tablets / capsules containing isolated Letermovir in an amorphous state of different dosage strengths. The inventors have furthermore developed dry granulation to obtain IR film-coated tablets containing isolated Letermovir in an amorphous state of different dosage strengths.

[0120] According to the invention, the dry granulation process can be carried out on a tablet press (slugging) or by using a roller compactor.

[0121] Therefore, another aspect of the present invention is to provide dry granulation of isolated Letermovir in an amorphous state which can be obtained by tabletting machine or by using roller compactor.

[0122] Another potential problem with Letermovir as an isolated amorphous API to be further processed in granulation is the drying process itself.

[0123] In the case of the amorphous drug Letermovir drying on the surface, a surrounding layer is created that impairs further drying. This behavior of amorphous APIs for oral drug formulations cannot be handled by classical drying techniques of the pharmaceutical industry and additionally contains inherent scale-up limitations.

[0124] According to the present invention, for dry and wet granulation of Letermovir in the amorphous state, a polymer is used as a binder which is hydrophilic in nature and thus has a beneficial effect on the dissolution properties of Letermovir, since Letermovir is a hydrophobic but lipophilic solid.

[0125] Therefore, in another aspect of the present invention, the polymer used is selected from the group including but not limited to hydroxypropyl methylcellulose (also known as hypromellose or HPMC), povidone (also known as polyvinyl pyrrolidone or PVP), starch (including pregelatinized starch), which is used as a binder in the granulated formulation according to the present invention.

[0126] Granulation methods / wet and dry granulation

[0127] The present inventors have found that in case of wet granulation after mixing the solid fraction of amorphous Letermovir with ethanol, the obtained product is very wet and not reproducible; irrespective of the ethanol content.

[0128] Therefore, in another aspect of the present invention, alcohols, in particular methanol and ethanol, as processing agents are rejected for wet granulation of Letermovir in an amorphous state.

[0129] Therefore, in another aspect of the present invention, acetone is rejected as a processing agent for wet granulation of Letermovir in an amorphous state.

[0130] Therefore, in a particular aspect of the present invention, a mixture of ethanol and acetone is also rejected as a processing agent for the wet granulation of Letermovir in an amorphous state.

[0131] To overcome the above mentioned obstacles, the present inventors have discovered that replacing the organic solvent with purified water results in an improved processing agent for wet granulation of isolated amorphous Letermer.

[0132] Thus, in one aspect of the present invention, purified water is a suitable processing agent for wet granulation of Letermovir in an amorphous state.

[0133] The present inventors have also found that amorphous Letermovir isolated by drum drying can be processed by wet granulation.

[0134] However, from a technological point of view, dry granulation of isolated amorphous Letermovir is preferred since no additional drying is required, which could also affect the physicochemical properties and stability of Letermovir.

[0135] Therefore, in another aspect of the present invention, the solid pharmaceutical formulation described herein contains amorphous Letermovir isolated by drum dryer, which is further processed by dry granulation.

[0136] However, throughout the description, for further processing in the context of the present invention, the API Letermovir obtained by precipitation is preferred in the amorphous state.

[0137] In particular, the inventors have found that precipitated Letermovir shows beneficial properties to obtain a homogenous mixture during the drying process accompanied by compaction for tableting.

[0138] Thus, in another aspect of the invention, the pharmaceutical dry granulation described herein contains precipitated Letermovir.

[0139] Galenic formulations of drum-dried and precipitated Letermovir

[0140] It is known to the person skilled in the art that the isolation process of an amorphous compound itself affects the tableting properties later during manufacturing.

[0141] In the following, some parameters may be slightly different from the solid pharmaceutical formulations described herein. However, those skilled in the art are aware of these changes. Therefore, those skilled in the art understand that the following aspects are only preferred aspects; but the present invention should not be limited to these specific aspects.

[0142] In addition to the isolated Letermovir in an amorphous state, the solid pharmaceutical formulation of the present invention contains one or more pharmaceutically acceptable ingredients known as excipients. Common excipients include fillers, diluents, binders, lubricants, glidants, disintegrants, solvents, film formers, plasticizers, pigments and antioxidants. All excipients that are part of the present invention are synthetic or plant-derived, they are not derived from animal or human sources.

[0143] All listed excipients that may be used in the manufacture of solid pharmaceutical formulations of amorphous API Letermovir provided herein are well known and widely used to manufacture pharmaceutical dosage forms (eg, compressed tablets or capsules) using conventional pharmaceutical methods including granulation and compaction.

[0144] In another aspect of the present invention, the solid pharmaceutical formulation of the present invention comprises one or more excipients or a combination thereof selected from: microcrystalline cellulose, copovidone, croscarmellose sodium, colloidal anhydrous silica, magnesium stearate, povidone (also known as polyvinyl pyrrolidone or PVP), lactose, sucrose, mannitol, starch (including pregelatinized starch), talc, hydroxypropyl cellulose, hydroxypropyl methylcellulose (also known as hypromellose or HPMC), sodium starch glycolate, calcium hydrogen phosphate dihydrate (also known as calcium hydrogen phosphate), triethyl citrate, methacrylic acid-methyl methacrylate copolymer, polyvinyl alcohol, magnesium stearate, polyethylene glycol, poly(vinyl alcohol) graft copolymer, polyvinyl acetate, and methacrylic acid / ethyl acrylate copolymer.

[0145] In a preferred aspect, the solid pharmaceutical formulation comprises Letermovir in an amorphous state as API in an amount of 20.0% to 70.0% w / w, povidone in an amount of 1.0% to 30.0% w / w, croscarmellose sodium in an amount of 1.0% to 30.0% w / w, microcrystalline cellulose in an amount of 10.0% to 90.0% w / w, colloidal anhydrous silicon dioxide in an amount of 0.1% to 10.0% w / w, and magnesium stearate in an amount of 0.01% to 10.0% w / w.

[0146] In a particularly preferred aspect, the solid pharmaceutical formulation comprises Letermovir in an amorphous state as API in an amount of 30.0% to 50.0% w / w, povidone in an amount of 2.0% to 10.0% w / w, croscarmellose sodium in an amount of 2.0% to 10.0% w / w, microcrystalline cellulose in an amount of 20.0% to 70.0% w / w, colloidal anhydrous silicon dioxide in an amount of 0.5% to 5.0% w / w, and magnesium stearate in an amount of 0.1% to 5.0% w / w.

[0147] Furthermore, in another aspect of the present invention, the solid pharmaceutical formulation comprising Letermovir in an amorphous state is obtainable by granulation, preferably wet granulation.

[0148] In another aspect of the present invention, a solid pharmaceutical formulation comprising Letermovir in an amorphous state may be obtained by roller compaction / dry granulation.

[0149] In another aspect of the present invention, a solid pharmaceutical formulation comprising Letermovir in an amorphous state is obtainable by direct compression.

[0150] Precipitated amorphous Letermovir prepared by dry granulation is a preferred embodiment of the present invention.

[0151] In particular, the inventors have found that granulation is possible using a purified water / povidone solution. The corresponding dissolution data revealed that Letermovir was dissolved >50% within 30 minutes.

[0152] Therefore, in another aspect of the present invention, a solid pharmaceutical formulation of Letermovir in an amorphous state is provided, wherein the Letermovir in an amorphous state is obtained by drum drying and further processed using a purified water / povidone mixture as a wet granulation processing agent, and has a solubility of >50% within 30 minutes, preferably a solubility of >60% within 30 minutes, more preferably a solubility of >70% within 30 minutes, even more preferably a solubility of >80% within 30 minutes, and most preferably a solubility of >90% within 30 minutes.

[0153] In another aspect of the present invention, a solid pharmaceutical formulation of Letermovir in an amorphous state is provided, wherein the Letermovir in an amorphous state is obtained by precipitation and further processed using a purified water / povidone mixture as a wet granulation processing agent, and has a solubility of >50% within 30 minutes, preferably a solubility of >60% within 30 minutes, more preferably a solubility of >70% within 30 minutes, even more preferably a solubility of >80% within 30 minutes, and most preferably a solubility of >90% within 30 minutes.

[0154] Furthermore, the present inventors have found that the dissolution of a solid pharmaceutical formulation of precipitated Letermovir in an amorphous state further prepared by dry granulation is enhanced by adding a disintegrant.

[0155] In particular, the increase of croscarmellose sodium as a disintegrant (from conventional 3% to 5%) improved the dissolution of amorphous Letermovir in the experimental tablet formulation for oral administration, enabling a dissolution of >50% within 30 minutes, preferably >60% within 30 minutes, more preferably >70% within 30 minutes, even more preferably >80% within 30 minutes, and most preferably >90% within 30 minutes.

[0156] Therefore, in another aspect of the invention, a solid pharmaceutical formulation of amorphous Letermovir containing at least 4%, preferably at least 5% croscarmellose sodium in the solid pharmaceutical formulation exhibits a dissolution of >50% within 30 minutes, preferably a dissolution of >60% within 30 minutes, more preferably a dissolution of >70% within 30 minutes, even more preferably a dissolution of >80% within 30 minutes, most preferably a dissolution of >90% within 30 minutes.

[0157] Therefore, for galenic reasons known to those skilled in the art, the filler / binder microcrystalline cellulose ratio must be reduced to accommodate the increased croscarmellose sodium.

[0158] In another aspect of the present invention, the solid pharmaceutical formulation of the present invention contains Letermovir in an amorphous state in an amount of at least 5%, preferably at least 15%, more preferably at least 30%, even more preferably at least 40%.

[0159] In general, the present inventors have found that amorphous Letermovir isolated by drum drying is more suitable for processing using wet granulation and precipitated amorphous Letermovir is more suitable for processing using dry granulation.

[0160] In another aspect of the present invention, the isolated amorphous Letermovir is contained in a solid pharmaceutical formulation for oral administration in an amount of 20 to 500 mg, preferably in an amount of 120 to 280 mg, most preferably in an amount of 240 mg or more.

[0161] Furthermore, in another aspect of the present invention, the isolated amorphous Letermovir is contained in a solid pharmaceutical formulation for oral administration in an amount of 20 to 400 mg, preferably in an amount of 120 to 280 mg, most preferably in an amount of 240 mg or more.

[0162] In another aspect, the subject of the present invention is a film-coated tablet containing different dosage strengths of amorphous Letermovir, i.e., 5 mg, or 20 mg, or 30 mg, or 60 mg, or 120 mg, or 240 mg of Letermovir, or >240 mg of Letermovir. The different dosage strengths should not be construed as limiting the dosage strength. The scope of the present invention also encompasses any other dosage strength that can be reasonably administered to a subject.

[0163] Dissolution Testing Methods

[0164] Throughout the specification, the corresponding dissolution data are based on a dissolution test performed using Ph. Eur. method 2.9.3, Apparatus 2, at a paddle speed of 50 rpm at 37.0°C ± 0.5°C in 1000 ml 0.1 N HCl / 0.2% sodium lauryl sulfate medium and measurements by reverse phase HPLC at time points 15, 30 and 45 minutes as follows:

[0165] HPLC operating conditions:

[0166]

[0167] Long-term stability

[0168] Another subject of the present invention is a long-term stable galenic formulation of amorphous Letermovir for oral administration. According to the galenic formulation of the invention, the precipitated amorphous Letermovir substance exhibits physical and chemical stability during storage at 25°C and 60% relative humidity for at least 36 months.

[0169] Thus, in the third main aspect of the present invention, isolated amorphous Letermovir is physically and chemically stable when stored at 25°C and 60% relative humidity for at least 36 months in the galenic formulation provided herein.

[0170] Oral administration in methods for treating viral infections

[0171] In a fourth main aspect of the invention, the galenic formulations containing amorphous Letermovir provided herein are intended for the manufacture of a medicament for oral administration to a subject for the prevention of viral infection or for use in a method of treating viral infection. The specific indications to be treated by the solid pharmaceutical formulations containing amorphous API Letermovir provided herein are selected from: HCMV infection in a subject, in particular HCMV infection in a subject suffering from acquired immunodeficiency syndrome (AIDS), HCMV pneumonia, HCMV encephalitis, and gastrointestinal and systemic HCMV infection, HCMV infection in newborns and children, acute HCMV infection in pregnant women, HCMV infection in immunosuppressed cancer patients and HCMV-positive cancer patients who need to treat HCMV-mediated tumor progression (see J. Cinatl et al., FEMS Microbiology Reviews, 2004, 28, 59-77).

[0172] In another aspect of the present invention, the solid pharmaceutical formulations containing the amorphous API Letermovir provided herein are intended for use in the manufacture of a medicament for oral administration to a subject for the prevention of a disease caused by a virus of the herpesvirus group or in a method of treating said disease.

[0173] In another aspect of the present invention, the solid pharmaceutical formulations containing the amorphous API Letermovir provided herein are intended to be used in combination with other antiviral active ingredients such as Valganciclovir, Ganciclovir, Valacyclovir, Acyclovir, Foscarnet, Cidofovir and their derivatives in the treatment of viral infections, in particular HCMV infections.

[0174] Another subject of the present invention is the use of a solid pharmaceutical formulation containing amorphous API Letermovir as provided herein in the prevention of viral infection or in a method of treating viral infection. The specific indications for the use of the solid pharmaceutical formulation containing amorphous API Letermovir as provided herein are selected from: HCMV infection in a subject, in particular HCMV infection in a subject suffering from AIDS, HCMV pneumonia, HCMV encephalitis, and gastrointestinal and systemic HCMV infection, HCMV infection in newborns and children, acute HCMV infection in pregnant women, HCMV infection in immunosuppressed cancer patients, HCMV infection in HCMV-positive cancer patients who need to treat HCMV-mediated tumor progression (see J. Cinatl et al., FEMS Microbiology Reviews, 2004, 28, 59-77).

[0175] Another embodiment of the present invention is the use of a solid pharmaceutical formulation containing the amorphous API Letermovir as provided herein for the prevention of diseases caused by viruses of the herpesvirus group or in a method of treating said diseases.

[0176] In the above context, particularly preferred subject matter of the present invention is provided by the following consecutively numbered and mutually related embodiments:

[0177] 1. Letermovir represented by the following formula (I),

[0178]

[0179] It is in an amorphous state and is suitable for use in solid oral dosage forms, wherein the Letermovir is characterized by

[0180] i) When BET surface area analysis is performed, the specific surface area is at least 1 m 2 / g

[0181] and / or

[0182] ii) When a particle size distribution analysis is performed, the median value of the particle size distribution does not exceed 10 μm.

[0183] 2. Letermovir according to embodiment 1, wherein under i), the BET specific surface area analysis is characterized by the following parameters:

[0184] Principle: Nitrogen adsorption at 77K; according to the method of Brunauer, Emmett and Teller

[0185] Method: Volumetric method; according to USP <846> Method II

[0186] Instrument: Tristar 3000 / VacPrep 061 (Micromeritics)

[0187] Sample mass: about 1.5-2.5g

[0188] Sample preparation: Degassing under vacuum at 40 °C for 2 hours; final vacuum <2.7 Pa

[0189] Pressure range p / p0: 0.05-0.15; 3 data points.

[0190] 3. Letermovir according to embodiment 1 or embodiment 2, wherein under item ii), the particle size distribution analysis is characterized by the following parameters:

[0191] Apparatus: Mastersizer 2000 with dry dispersion

[0192] Procedure: Fraunhofer; weighing amount: 0.3-0.4g

[0193] Measuring time: 20 seconds

[0194] Background time: 6 seconds

[0195] Shading limit: 0.5% to 6%

[0196] Sample tray: micro volume; small sieve with balls

[0197] Feed rate: 45-55%

[0198] Dispersion pressure: 2.5 bar;

[0199] Four independent analyses were thus performed and the results averaged.

[0200] 4. Letermovir according to any of the preceding embodiments, wherein the amorphous state is characterized by no detectable crystalline content / signal within a detection limit of 2% when the Letermovir is determined by any of the three standard XRPD methods i), ii) or iii);

[0201] wherein in i), a Letermovir powder sample was prepared on a rotating sample holder having an effective surface area of ​​1.9 mm (diameter); a powder diffraction pattern was recorded using a Bruker D8 Advance powder diffractometer equipped with a LynxEye PSD detector and a Niβ filter and using CuKα radiation operated at 40 kV and 30 mA; and the measurement was performed using a step size of 0.06° and a step time of 0.5 seconds;

[0202] wherein in ii), a Siemens powder diffractometer D5000 equipped with a secondary graphite monochromator and using CuKα radiation operated at 40 kV and 30 mA was used; the effective surface area was equal to 6×10 mm; and the measurement was performed using a step size of 0.02° and a step time of 2 seconds;

[0203] In iii), a Seifert X-ray tube DX-Cu8*0,4-S equipped with a Germanium (111) monochromator 616.2 and an imaging plate Guinier camera G670 from Huber and with CuKα radiation operated at 40 kV and 30 mA was used with a scanning range of 0°<2Θ<100° and a step width of Δ(2Θ)=0.005°.

[0204] 5. Letermovir according to any of the preceding embodiments, wherein the Letermovir in the amorphous state is a zwitterion with a pi of 5.55.

[0205] 6. Letermovir according to any one of the preceding embodiments, which can be obtained by the following method:

[0206] a) providing an organic solution of Letermovir, and any one of the following:

[0207] b1) isolating the Letermovir by drum drying the organic solution in a volatile organic solvent, in particular acetone, at a temperature of 30°C to 60°C, in particular 40°C to 50°C, and subsequently drying the resulting amorphous Letermovir, or

[0208] b2) Isolating amorphous Letermovir by precipitating it from a water-miscible solvent, in particular acetone or acetonitrile, into excess water as anti-solvent and subsequently filtering or centrifuging the resulting Letermovir.

[0209] 7. Letermovir according to embodiment 6, wherein the method according to step b2) has a final drying step.

[0210] 8. Letermovir according to embodiment 6 or 7, wherein the Letermovir obtained in step b1) or b2) is processed by wet granulation.

[0211] 9. Letermovir according to embodiment 6 or 7, wherein the Letermovir obtained in step b1) or b2) is processed by dry granulation.

[0212] 10. Letermovir according to any one of embodiments 6 to 9, wherein the Letermovir in an amorphous state is not isolated by spray drying or evaporation of a solution of Letermovir in an organic solvent.

[0213] 11. Letermovir according to any one of embodiments 6 to 10, wherein in step b2), the Letermovir in an amorphous state is not isolated by precipitation using alcohol, in particular methanol or ethanol, or using THF or MEK.

[0214] 12. Letermovir according to any one of the preceding embodiments, wherein the Letermovir in an amorphous state has an acetone content of less than 5000 ppm or an acetonitrile content of less than 410 ppm, and a water content of <2.0% when the acetone or acetonitrile content is determined by static headspace gas chromatography and the water content is determined according to European Pharmacopoeia 2.5.12, and the static headspace gas chromatography has the following operating conditions:

[0215]

[0216]

[0217] 13. A method for obtaining Letermovir according to any one of embodiments 1 to 5, comprising the following steps:

[0218] a) providing an organic solution of Letermovir, and any one of the following:

[0219] b1) isolating the Letermovir by drum drying the organic solution in a volatile organic solvent, in particular acetone, at a temperature of 30°C to 60°C, in particular 40°C to 50°C, and subsequently drying the resulting amorphous Letermovir, or

[0220] b2) Isolating amorphous Letermovir by precipitating it from a water-miscible solvent, in particular acetone or acetonitrile, into excess water as anti-solvent and subsequently filtering or centrifuging the resulting Letermovir.

[0221] 14. The method according to embodiment 13 further comprises a final drying step after step b2).

[0222] 15. The method according to embodiment 13 or 14, further comprising the step of processing the Letermovir obtained in step b1) or b2) by wet granulation.

[0223] 16. The method according to embodiment 13 or 14, further comprising the step of processing the Letermovir obtained in step b1) or b2) by dry granulation.

[0224] 17. The method according to any one of embodiments 13 to 16, wherein the precipitation in step b2) is not carried out using alcohol or using THF or MEK.

[0225] 18. A solid pharmaceutical formulation comprising Letermovir in an amorphous state, wherein the solid pharmaceutical formulation is orally administrable.

[0226] 19. The solid pharmaceutical formulation according to embodiment 18, comprising Letermovir in an amorphous state as described in any one of embodiments 1 to 12.

[0227] 20. The solid pharmaceutical formulation according to embodiment 18, comprising Letermovir obtained from the process according to any one of embodiments 13 to 17.

[0228] 21. A solid pharmaceutical formulation according to embodiment 20, wherein the Letermovir is isolated according to step b1) of embodiment 13 and processed according to embodiment 15.

[0229] 22. A solid pharmaceutical formulation according to embodiment 20, wherein the Letermovir is isolated according to step b2) of embodiment 13 and processed according to embodiment 16.

[0230] 23. A solid pharmaceutical formulation according to any one of embodiments 18 to 20, which is effective to achieve an absolute bioavailability of 70%±30% of Letermovir when orally administered as a formulation comprising at least 5 mg of Letermovir in an amorphous state.

[0231] 24. The solid pharmaceutical formulation according to embodiment 23 is effective to achieve an absolute bioavailability of 70%±30% of Letermovir when orally administered as the formulation comprising ≥240 mg of Letermovir in an amorphous state.

[0232] 25. The solid pharmaceutical formulation of embodiment 23 or 24, further comprising povidone, croscarmellose sodium, microcrystalline cellulose, colloidal anhydrous silicon dioxide and magnesium stearate.

[0233] 26. The solid pharmaceutical formulation according to embodiment 25, wherein the amorphous Letermovir is contained in an amount of 30.0% to 50.0% w / w, the povidone is contained in an amount of 2.0% to 10.0% w / w, the croscarmellose sodium is contained in an amount of 2.0% to 10.0% w / w, the microcrystalline cellulose is contained in an amount of 20.0% to 70.0% w / w, the colloidal anhydrous silicon dioxide is contained in an amount of 0.5% to 5.0% w / w, and the magnesium stearate is contained in an amount of 0.1% to 5.0% w / w.

[0234] 27. The solid pharmaceutical formulation according to embodiment 25 or 26, comprising croscarmellose sodium as a disintegrant in an amount of at least 4.0% w / w.

[0235] 28. The solid pharmaceutical formulation according to embodiment 27, comprising croscarmellose sodium as a disintegrant in an amount of at least 5.0% w / w.

[0236] 29. The solid pharmaceutical formulation according to any one of embodiments 18 to 28, wherein the pharmaceutical formulation does not contain an arginine solution, in particular an L-arginine solution.

[0237] 30. A solid pharmaceutical formulation according to any one of embodiments 18 to 29, comprising Letermovir in an amorphous state at a dosage strength of 5 mg, or 20 mg, or 30 mg, or 60 mg, or 120 mg, or 240 mg, or >240 mg.

[0238] 31. A solid pharmaceutical formulation according to any one of embodiments 18 to 30, wherein Letermovir in the amorphous state exhibits a dissolution of >50% within 30 minutes, preferably a dissolution of >60% within 30 minutes, more preferably a dissolution of >70% within 30 minutes, even more preferably a dissolution of >80% within 30 minutes, most preferably a dissolution of >90% within 30 minutes when tested using Ph. Eur. method 2.9.3, apparatus 2, at a paddle speed of 50 rpm at 37.0°C ± 0.5°C in 1000 ml 0.1 N HCl / 0.2% sodium lauryl sulfate medium and the dissolution of Letermovir in the amorphous state is measured by reverse phase HPLC at time point 30 minutes as follows:

[0239] HPLC operating conditions:

[0240]

[0241]

[0242] 32. A solid pharmaceutical formulation according to any one of embodiments 18 to 31, wherein the solid pharmaceutical formulation is an immediate release formulation, characterized in that not less than 85% of the amount of Letermovir in an amorphous state is dissolved within 30 minutes using USP apparatus I at 100 rpm or using USP apparatus II at 50 rpm in each of the following media with a volume of 900 ml or less:

[0243] (1) Acidic media, such as USP simulated gastric fluid without enzymes;

[0244] (2) pH 4.5 buffer; and

[0245] (3) pH 6.8 buffer or USP simulated intestinal fluid without enzymes.

[0246] 33. A solid pharmaceutical formulation according to any one of embodiments 18 to 32, wherein the Letermovir in an amorphous state exhibits a chemical stability of at least 36 months during storage at room temperature 25°C and 60% relative humidity when determined by gradient reverse phase HPLC as follows:

[0247] HPLC operating conditions:

[0248]

[0249] 34. A solid pharmaceutical formulation according to any one of embodiments 18 to 33, for use in a method for preventing or treating a disease associated with the herpes virus group, preferably associated with cytomegalovirus (CMV), even more preferably associated with human cytomegalovirus (HCMV).

[0250] 35. A solid pharmaceutical formulation according to embodiment 34, for use in a method for preventing or treating a disease selected from the following: HCMV infection in a subject, in particular HCMV infection in subjects suffering from AIDS, HCMV pneumonia, HCMV encephalitis, and gastrointestinal and systemic HCMV infection, HCMV infection in newborns and children, acute HCMV infection in pregnant women, HCMV infection in immunosuppressed cancer patients, and HCMV infection in HCMV-positive cancer patients who need to treat HCMV-mediated tumor progression.

[0251] In another aspect of the present invention, Letermovir in an amorphous state is long-term stable in maintaining the amorphous state when stored at room temperature of 25° C. and 60% humidity for at least 36 months without processing into a solid dispersion or melt extrusion.

[0252] According to the present invention, the "volatile solvent" is selected from methanol, ethanol, acetonitrile, dichloromethane and MTBE.

[0253] According to the present invention, the "anti-solvent" is water.

[0254] According to the present invention, the "organic solvent" is selected from acetonitrile and acetone.

[0255] definition

[0256] The term "amorphous" in the context of the present invention with respect to solid Letermovir refers to the property that there is no long-range order of adjacent molecular units, whereas its crystalline counterpart has a well-defined long-range order. Therefore, amorphous Letermovir has two properties: a) the mechanical, thermal, electrical and chemical properties of Letermovir are independent of the measurement direction in the substance (isotropic), and b) with increasing temperature, Letermovir softens and only gradually enters the liquid state, which means that the amorphous state has no definite melting point.

[0257] Therefore, Letermovir is in an amorphous state when it exhibits no detectable crystalline content / signal attributable to the Letermovir tested when analyzed by appropriate crystallographic methods.

[0258] Therefore, throughout the specification, the expression "amorphous, amorphous form, amorphous state" in the context of the present invention means that the material does not show an indicator of crystallinity within the 2% detection limit using the standard XRPD method, and therefore when analyzed by an appropriate crystallographic method, the material does not show a detectable crystalline content / signal. Typically, X-ray powder diffraction (XRPD) is used to determine the crystalline content of the material according to the present invention. Three exemplary analytical methods are described below, but are not limited to these methods:

[0259] a) The sample was prepared on a rotating sample holder with an effective surface area of ​​1.9 mm (diameter). The powder diffraction pattern was recorded using a Bruker D8 Advance powder diffractometer equipped with a LynxEye PSD detector and a Niβ filter and using CuKα radiation operated at 40 kV and 30 mA. The measurements were performed using a step size of 0.06° and a step time of 0.5 seconds.

[0260] b) A Siemens powder diffractometer D5000 equipped with a secondary graphite monochromator and using CuKα radiation operated at 40 kV and 30 mA was used. The effective surface area was equal to 6×10 mm. The measurements were performed using a step size of 0.02° and a step time of 2 seconds.

[0261] c) Using a Seifert X-ray tube DX-Cu8*0,4-S equipped with a Germanium (111) monochromator 616.2 and an imaging plate Guinier camera G670 from Huber and with CuKα radiation operated at 40 kV and 30 mA with a scanning range of 0°<2Θ<100° and a step width of Δ(2Θ)=0.005°.

[0262] The "isotropy" of the properties is also a characteristic of the polycrystalline state. However, it is characterized by a strictly defined melting temperature, and this fact proves that it is different from the amorphous state of Letermovir. The structural differences between the amorphous and crystalline states can be easily detected on the X-ray diagrams obtained by, for example, the above-mentioned XRPD method. The monochromatic X-rays scattered on the crystals constitute a diffraction pattern composed of different peaks, which is not a characteristic of the amorphous state.

[0263] As mentioned above, the characteristics of amorphous Letermovir arise from the absence of long-range order. In contrast, this long-range order is present in crystals, which exhibit strict periodicity in all directions of one and the same structural element (i.e., atoms, groups of atoms, molecules, etc.) over hundreds or thousands of periods. At the same time, Letermovir in an amorphous state has short-range order.

[0264] In the context of the present invention, "short-range order" means the regularity in the positions of neighboring particles of Letermovir, i.e. the order observed at a distance comparable to the size of the molecule when measured by the electric field gradient on the probe core of Letermovir. This consistency decreases as the distance increases and disappears after 0.5-1 nanometers. Short-range order is also a characteristic of liquids, but in the case of liquids, there is a strong exchange of positions between neighboring particles; however, this exchange is hindered as the viscosity of Letermovir increases. The viscosity of Letermovir according to the present invention can be measured by a viscometer and / or a rheometer known to those skilled in the art.

[0265] The expressions "zwitterionicity, zwitterionic properties and zwitterions" about the API Letermovir in the context of the present invention mean that the Letermovir molecule is a neutral molecule with positive and negative charges at different positions within the same molecule. Therefore, the API Letermovir has a charge that changes with pH when measured in an electric field. Therefore, Letermovir migrates in an electric field and the direction of migration depends on the net charge that the molecule has. The net charge is affected by the pH value. Letermovir has a fixed isoelectric point (pI) value, which is the pH value when the number of cations is equal to the number of anions. At this time (pI = 5.55), the net charge of Letermovir is always zero.

[0266] The term "dissolution, dissolution properties" refers to the process or property of a solid, liquid or gas to form a solution in a solvent. For the dissolution of a solid, the dissolution process can be explained as the breakdown of the crystal lattice into individual ions, atoms or molecules and their transport into the solvent. For net dissolution to occur, the overall free energy must be negative.

[0267] Throughout the specification, the expression "sufficiently dissolves" in the context of amorphous Letermovir according to the present invention means that a dissolution of >50% within 30 minutes, preferably a dissolution of >60% within 30 minutes, more preferably a dissolution of >70% within 30 minutes, even more preferably a dissolution of >75% within 30 minutes, even more preferably a dissolution of >80% within 30 minutes, even more preferably a dissolution of >85% within 30 minutes, most preferably a dissolution of >90% within 30 minutes, when tested using Ph. Eur. method 2.9.3, apparatus 2, at a paddle speed of 50 rpm at 37.0°C ± 0.5°C in 1000 ml 0.1 N HCl / 0.2% sodium lauryl sulfate medium and dissolution measured by reverse phase HPLC at time points 15, 30 and 45 minutes as follows:

[0268] HPLC operating conditions:

[0269]

[0270]

[0271] In contrast, "solubility" is the property of a solid, liquid, or gaseous chemical substance (called a solute) to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance depends essentially on the solvent used, as well as the temperature and pressure. The degree of solubility of a substance in a particular solvent is measured as the saturation concentration, where adding more solute does not increase the concentration of the solution. Solubility should not be confused with the ability to dissolve or liquefy a substance, as solutions can occur not only due to dissolution but also due to chemical reactions. Solubility also does not depend on particle size or other kinetic factors; even the largest particles will eventually dissolve if given enough time.

[0272] The term "bioavailability" generally refers to a subclass of absorption and is the ratio of the administered Letermovir dose that reaches the systemic circulation, which is one of the main pharmacokinetic properties of a drug. By definition, when a drug is administered intravenously, its bioavailability is 100%. However, when a drug is administered via other routes (e.g., oral), its bioavailability is generally reduced (due to incomplete absorption and first-pass metabolism) or may vary between different individuals. Bioavailability is one of the basic tools in pharmacokinetics because it must be considered when calculating the dose for non-intravenous routes of administration.

[0273] In the context of the API amorphous Letermovir of the present invention, the expression "sufficient bioavailability" means that the amorphous Letermovir in the solid pharmaceutical formulation of the present invention exhibits an absolute bioavailability (F) of 30% to 95%, preferably 50% to 95%, more preferably 60% to 95% when administered in an oral dosage form. In other words, the expression also means that the chemically stable, orally administrable solid pharmaceutical formulation of amorphous Letermovir or a pharmaceutically acceptable salt, solvate or hydrate thereof is characterized in that the absolute bioavailability (F) of the amorphous API Letermovir in the granulated formulation is >30%, preferably >40%, more preferably >50%, even more preferably >70%, even more preferably >80% and most preferably >90%.

[0274] The expression "immediate release or IR tablet formulation" in the context of the present invention generally refers to tablets and capsules that release the API Letermovir within a short period of time, generally less than 30 minutes. In particular, the expression refers to the characteristic that not less than 85% of the Letermovir drug amount is dissolved within 30 minutes using USP apparatus I at 100 rpm or using USP apparatus II at 50 rpm in a volume of 900 ml or less in each of the following media:

[0275] (1) Acidic media, such as USP simulated gastric fluid without enzymes;

[0276] (2) pH 4.5 buffer; and

[0277] (3) pH 6.8 buffer or USP simulated intestinal fluid without enzymes.

[0278] Otherwise, the Letermovir product is considered “slowly dissolving”.

[0279] Therefore, the term "delayed release or sustained release tablet formulation" in the context of the present invention refers to tablets and capsules that release the API Letermovir at a sustained and controlled release rate over a period of time. Typically, when tested by USP Apparatus I at 100 rpm or by USP Apparatus II as described above, delayed release tablets and capsules release their ingredients over a period of 8 hours, 12 hours, 16 hours and 24 hours.

[0280] An “IR product, IR tablet / capsule dosage form” is characterized as rapidly dissolving if not less than 85% of the labeled drug amount dissolves within 30 minutes in a volume of 900 ml or less using USP Apparatus I at 100 rpm or using USP Apparatus II at 50 rpm in each of the following media:

[0281] (1) Acidic media, such as USP simulated gastric fluid without enzymes;

[0282] (2) pH 4.5 buffer; and

[0283] (3) pH 6.8 buffer or USP simulated intestinal fluid without enzymes.

[0284] Otherwise, the drug product is considered to be slowly dissolving.

[0285] The term "pharmaceutical activity" of Letermovir means the antiviral activity against HCMV isolates of the corresponding individuals, with EC50±SD ranging from 0.0005 to 0.005±0.0001 to 0.001.

[0286] The term "chemically stable" in the context of the present invention means that the purity of API Letermovir in the provided solid pharmaceutical formulation is at least 97.0%, preferably higher than 97.0%, most preferably higher than 98.0%, and most preferably higher than 99.0%. Alternatively, "chemically stable" can also be characterized by: when the formulation is measured at a specific time point by an appropriate HPLC method, the maximum degradation amount of impurities degraded from the API under normal storage conditions (5°C-40°C, 40-80% relative humidity) is less than 3.0% mass fraction of the initial total mass of the API, and the HPLC method is, for example:

[0287] Gradient reversed-phase HPLC assay for determination of drug product identity and degradation products

[0288] Operating conditions:

[0289]

[0290] The term "physically stable" in the context of the present invention reflects that there is no detectable crystalline content / signal attributable to the API when analyzed by appropriate crystallographic methods and furthermore, that the particle size distribution and specific surface area do not change significantly.

[0291] With respect to the API Letermovir, the term “pure / purified” characterizes that the API is not contaminated by:

[0292] a) impurities resulting from degradation or by-products from reagents or synthetic process steps,

[0293] b) Residual solvents or water exceeding certain ranges (ie residual solvents according to current guidelines, and residual water according to the present invention < 2%).

[0294] Additionally, the term means that there is no residual MTBE content. Additionally, the term means that the mesityl oxide content does not exceed 800 ppm when measured by a gradient reverse phase HPLC assay for determining drug product identity and degradation products as follows:

[0295] Operating conditions:

[0296]

[0297]

[0298] In the context, the expression "pharmaceutically acceptable impurity content" for the isolated amorphous letermovir of the present invention means that the amorphous letermovir thus obtained is further characterized in that when determined by static headspace gas chromatography as detailed in the specific embodiment with number 12 above, the mesityl oxide content is ≤ 31 ppm, preferably ≤ 27 ppm, even more preferably ≤ 23 ppm, and most preferably ≤ 10 ppm.

[0299] and / or

[0300] When determined by gas chromatography with the following operating conditions, the 3-methoxyaniline content is < 20 ppm, preferably < 15 ppm, more preferably < 10 ppm, even more preferably < 5 ppm, and most preferably < 1.5 ppm:

[0301]

[0302]

[0303] and / or When determined by the corresponding methods outlined above, there is no residual MTBE content and / or there is < 2% residual water and / or there is less than 5000 ppm residual acetone and / or there is less than 410 ppm residual acetonitrile.

[0304] In the context of amorphous letermovir, the term "metastable state" represents a chemical state of a temporary energy well or a slightly stable intermediate stage of an energy system that may lose energy in discrete amounts.

[0305] In the context of amorphous letermovir, the term "chiral purity" means that when determined by the following chiral HPLC assay, the letermovir in one enantiomeric form of the R / S system is present at > 99%:

[0306] Chiral HPLC assay:

[0307]

[0308]

[0309] The expression "acceptable residual solvent limit" means that the amount of residual solvent is in accordance with ICH guidelines.

[0310] The term "residual solvents" in pharmaceutical context is defined herein as organic volatile chemicals used or generated in the manufacture of drug substances or excipients or in the preparation of drug products such as in the case of the present invention drug substances based on Letermovir.

[0311] Solvents are not completely removed by practical manufacturing techniques. Appropriate selection of solvents for the synthesis of drug substances based on toxicologically acceptable limits is critical for pharmaceutical galenic formulations. Since residual solvents do not have therapeutic benefit, all residual solvents should be removed to the extent that product specifications, good manufacturing practices or other quality-based requirements are met. Drug products should not contain residual solvent levels higher than those supported by safety data.

[0312] According to the present invention, the term "highest dosage strength" preferably means 240 mg to 480 mg Letermovir.

[0313] According to the present invention, the term "highest dosage strength" means 240 mg to 360 mg Letermovir.

[0314] The expression "long-term stable" in the context of the present invention means that the purity of Letermovir is >99% when stored at 25°C and 60% relative humidity for at least 24 months when measured by HPLC.

[0315] The expression "suitable physicochemical properties, physicochemical properties" in the context of amorphous Letermovir according to the invention denotes the following properties:

[0316] ● Electrostatic behavior, particle size distribution and specific surface area are appropriate for tableting

[0317] ● Limited hygroscopicity, enabling processing under production conditions without the need for controlled humidity equipment

[0318] ●Chemical stability under storage and processing conditions of 25°C and 60% relative humidity

[0319] • No uncontrolled crystallization tendency as determined by appropriate XRPD analysis.

[0320] In particular, the expression "appropriate physicochemical properties, physicochemical properties" includes that when the isolated Letermovir according to the present invention is subjected to a BET specific surface area analysis as outlined above, the isolated amorphous Letermovir has a specific surface area of ​​at least 1 m 2 / g; and / or when the isolated Letermovir according to the present invention is subjected to a particle size distribution analysis as outlined above, the median particle size distribution (D50 or d(0.5)) is not greater than 10 μm, preferably not greater than 9 μm.

[0321] The expression "suitable for solid oral dosage forms" in the context of the amorphous letermovir of the present invention means that the isolated amorphous letermovir has a median particle size distribution (PSD) of not more than 10 μm, preferably not more than 9 μm and / or a specific surface area of at least 1 m 2 / g, preferably at least 2 m 2 / g. Further, the expression means that the amorphous letermovir obtained by the isolation method of the present invention is characterized by a pharmaceutically acceptable impurity content, which means that the amorphous letermovir obtained is further characterized in that when the impurities are determined by the corresponding methods outlined above, the content of isopropylideneacetone is ≤ 31 ppm, preferably ≤ 27 ppm, even more preferably ≤ 23 ppm, most preferably ≤ 10 ppm; and / or the content of 3-methoxyaniline is < 20 ppm, preferably < 15 ppm, more preferably < 10 ppm, even more preferably < 5 ppm, most preferably < 1.5 ppm; and / or there is no residual MTBE content; and / or there is < 2% residual water; and / or there is less than 5000 ppm residual acetone; and / or there is less than 410 ppm residual acetonitrile.

[0322] In addition, the expression "suitable for solid oral dosage forms" also means that the amorphous letermovir obtained by the isolation method of the present invention exhibits sufficient dissolution characteristics, which means that when dissolution is tested using European Pharmacopoeia method 2.9.3, apparatus 2, at a paddle speed of 50 rpm at 37.0 °C ± 0.5 °C in 1000 ml of 0.1 N HCl / 0.2% sodium lauryl sulfate medium and measured by reverse-phase HPLC at time points 15, 30 and 45 minutes as follows, the dissolution of amorphous letermovir is > 50% within 30 minutes, preferably > 60% within 30 minutes, more preferably > 70% within 30 minutes, even more preferably > 75% within 30 minutes, even more preferably > 80% within 30 minutes, even more preferably > 85% within 30 minutes, and most preferably the dissolution of amorphous letermovir is > 90% within 30 minutes:

[0323]

[0324] In the above circumstances, the expression "suitable for use as a medicament for oral administration" with respect to the above-characterized amorphous letermovir obtainable according to the present invention means that the letermovir as an API can be readily formulated directly into the galenic preparations of the present invention and administered directly in solid oral dosage forms for use in the treatment of viral diseases, in particular human cytomegalovirus (hereinafter referred to as HCMV) infections.

[0325] The term "pharmaceutical grade" in the context of the present invention refers to the purity and stability of amorphous Letermovir required by the de facto international standards according to ICH, FDA and EMEA.

[0326] The term "ICH guideline" within the context of the present invention means International Conference on Harmonization of impurities: Guideline for residual solvents Q3C (R5). The purpose of this guideline is to recommend acceptable amounts of residual solvents in pharmaceuticals for the safety of patients. The guideline recommends the use of less toxic solvents and describes levels of some residual solvents that are considered toxicologically acceptable. The guideline applies to all dosage forms and routes of administration. In certain circumstances, such as short-term (30 days or less) or topical applications, higher levels of residual solvents may be acceptable.

[0327] "Direct compression" is a term used to define the process of compressing a powder blend of drug substance and excipients directly on a tablet press. Apart from the mixing process, there is no mechanical treatment of the powder. The most obvious advantage of direct compression is its simplicity and subsequent economy.

[0328] According to the present invention, "drying" or "drying step" may be performed by drying using a cone dryer, a drum dryer or any other suitable technique known to a person skilled in the art.

[0329] The expression "particle size" of the particle to be determined means according to the invention the diameter of an equivalent particle which is considered to be spherical and has the same light scattering pattern as the particle to be determined. According to the invention, the particle size is determined by laser diffractometer. In particular, for the determination of the particle size, a Mastersizer 2000 from Malvern Instruments is used according to the invention.

[0330] According to the present invention, the "D50 value" or "d(0.5) value" of a particle size distribution describes the particle size at which 50% by volume of the particles have a particle size smaller than the particle size corresponding to the D50 value (d(0.5)). This also means that 50% by volume of the particles have a particle size larger than the D50 value (d(0.5)). Thus, the D90 value (d(0.9)) of a particle size distribution is defined as the particle size at which 90% by volume of the particles have a particle size smaller than the particle size corresponding to the D90 value (d(0.9)). Similarly, the D10 value (d(0.1)) of a particle size distribution is defined as the particle size at which 10% by volume of the particles have a particle size smaller than the particle size corresponding to the D10 value (d(0.1)).

[0331] According to the present invention, the "excipients" used in solid pharmaceutical preparations do have the functions as summarized in Table 1 below:

[0332] Table 1: Excipients / Function

[0333] excipient Function Microcrystalline Cellulose Fillers / Binders Colloidal Anhydrous Silica Glidants Polyvinylpyrrolidone Polymer / Binder Croscarmellose Sodium Disintegrants Magnesium Stearate Lubricants Polyethylene glycol Plasticizers Hydroxypropyl methylcellulose Film former Titanium Dioxide Color Pigments Iron oxide yellow Color Pigments Purified water Processing agent

[0334] abbreviation

[0335] Throughout this specification, the following abbreviations are used:

[0336] "API" stands for active pharmaceutical ingredient.

[0337] "MTBE" stands for methyl tert-butyl ether, also known as methyl tert-butyl ether, which has the molecular formula (CH 3 ) 3 COCH 3 MTBE is a volatile, flammable, and colorless liquid that is not easily soluble in water.

[0338] "DMF" means dimethylformamide.

[0339] "DMSO" means dimethyl sulfoxide.

[0340] "NMP" means N-methyl-2-pyrrolidone.

[0341] "MEK" stands for methyl ethyl ketone.

[0342] "THF" means tetrahydrofuran.

[0343] "XRPD" means X-ray powder diffraction.

[0344] "CMV" means cytomegalovirus.

[0345] "Ph.Eur." stands for European Pharmacopoeia, which is a pharmacopoeia that lists a wide range of active substances and excipients used in Europe to prepare medicinal products. This monograph gives quality standards for all major drugs used in Europe. All medicines sold in the 36 member states of the European Pharmacopoeia must meet these quality standards so that consumers have assurance of the products they get from pharmacies and other legitimate suppliers.

[0346] "Ph. Eur. Method 2.9.3" refers to the dissolution test for solid dosage forms. This test is used to determine the dissolution rate of the active ingredient of solid dosage forms (e.g., tablets, capsules, and suppositories).

[0347] "Ph. European Method 2.5.12" means the semi-micro determination of water according to P. European 5.0 01 / 2005:20512. This test is used to determine the water content of the API Letermovir in the amorphous state.

[0348] "IPC" stands for In-Process Control.

[0349] “SCDT” means (2S,3S)-2,3-bis[(4-methylbenzoyl)oxy]succinic acid-methyl{(4S)-8-fluoro-2-[4-(3-methoxyphenyl)piperazin-1-yl]-3-[2-methoxy-5-(trifluoromethyl)phenyl]-3,4-dihydroquinazolin-4-yl}acetate (1:1).

[0350] "PSD" stands for particle size distribution.

[0351] "SSA" stands for specific surface area.

[0352] "BET" stands for the Brunauer-Emmett-Teller method for specific surface area analysis.

[0353] Example

[0354] 1) Amorphous Letermovir preparation containing L-arginine

[0355] Initial formulation development studies were conducted on an amorphous oral dosage form of Letermovir containing L-arginine. The purpose of L-arginine in the amorphous Letermovir formulation was to improve the dissolution properties of the drug substance and therefore improve bioavailability.

[0356] Several test batches were prepared using the L-arginine granulation formulation as shown in Table 2.

[0357] Table 2: Formulations containing L-arginine for dissolution testing

[0358]

[0359] First, a dissolution study was performed to investigate suitable preparation methods and formulations for Letermovir granulation solutions. In the next trial, a process setting for high shear granulation was explored. Because this resulted in tablet batches with long disintegration times and slow release profiles, the study was switched to fluidized bed granulation. It became apparent that, surprisingly and unexpectedly, this did not result in an improvement in the dissolution characteristics of the formulation.

[0360] 1a) Results

[0361] Due to the poor wettability of the drug substance, the dissolution behavior of Letermovir in trials 1 to 3 with L-arginine was not ideal. Letermovir floated on the surface of the solution. In addition, the solution foamed to a lesser extent and turned slightly yellow.

[0362] The dissolution times of these three tests in pH 1.0+0.2% SDS are:

[0363] -1) 22 minutes

[0364] -2) 37 minutes

[0365] -3)>2 hours (complete dissolution after 2 days).

[0366] The viscosity of the solution of test 1 to 3 increases after complete dissolution. In test 4 and 5, there is no wettability problem during the dissolution of Letermovir in L-arginine / hydroxypropyl methylcellulose solution. Because the viscosity of the solution is higher, Letermovir is mixed into the solution and does not float on the surface. Due to the bubbling and air entrapment in the solution, the dissolution duration of the drug substance in these tests can not be assessed. When the solution kept standing for 12 hours, it was observed that a clear solution (slightly yellow) was obtained.

[0367] 1b) Conclusion

[0368] The first three dissolution tests confirmed that Letermovir has poor wettability in water. In addition, the dissolution time of Letermovir in water depends on the amount of L-arginine and (as expected) its concentration in water.

[0369] By increasing the aqueous viscosity with hypromellose, the wettability problem of Letermovir was solved. The drug substance does not float on the surface of the solution and mixes into the solution immediately. However, due to foaming and air entrapment in the resulting solution, the dissolution time of amorphous Letermovir could not be evaluated.

[0370] Further experiments showed that the concentration of amorphous Letermovir in solution could be increased from 16% (120 mg / dose Letermovir in 750 mg / dose water) to 24% (120 mg / dose Letermovir in 500 mg / dose water). In addition, the amount of L-arginine and hypromellose / hydroxypropylcellulose in the formulation could be reduced. No significant difference in the solubility behavior of Letermovir was observed in the hypromellose and hydroxypropylcellulose solutions. Both solutions were used in subsequent granulation experiments.

[0371] The granulation process was problematic. Because the amount of granulation liquid was relatively high to dissolve all Letermovir, granulation was divided into three steps to avoid the risk of overwetting the substrate. Due to repeated granulation and drying, the hardness of the obtained granules after drying was very high, which prevented grinding of the granules. Manual compression of the obtained tablets gave tablets of appropriate hardness. However, the tablets did not disintegrate within 30 minutes and the dissolution of the tablets in pH 1.0 + 0.2% SDS was too slow.

[0372] In order to reduce the amount of granulation solution required, ethanol and acetone were used as co-solvents for the granulation fluid. However, the use of acetone did not confer significant processing advantages over water. Attempts to eliminate multiple drying and granulation steps by increasing the amount of colloidal anhydrous silica in the formulation were also unsuccessful.

[0373] Fluidized bed granulation method is used to eliminate multiple granulation and drying steps required for high shear granulation of Letermovir. The realization of granulation does not have great problems and is completely under control. The obtained test batches contain different amounts of disintegrants, but all three batches reveal disintegration times (in water) within the range of 12 to 15 minutes. These disintegration times are shorter than the disintegration times of the test batches prepared with high shear granulation, and dissolution is slower when compared with the high shear granulation test batches.

[0374] 1c) Summary of the L-arginine formulation of amorphous Letermovir

[0375] Laboratory scale development of L-arginine-containing Letermovir formulations did not produce methods and products with the desired properties. Dissolution of the prepared test batches was too slow for an immediate release drug product. Subsequent attempts to improve dissolution by using high shear granulation and processing by fluidized bed granulation were unsuccessful. L-arginine does not appear to have a positive effect on the dissolution characteristics of Letermovir. Therefore, it is not expected that incorporating L-arginine into a solid dosage form would have a positive effect on the bioavailability of Letermovir.

[0376] 2) Letermovir solubility

[0377] The present inventors performed solubility studies of amorphous Letermovir to investigate its biopharmaceutical status by standardized measures. The present inventors were directed to the established guidelines of the Biopharmaceutics Classification System (BCS).

[0378] The BCS system broadly allows prediction of rate-limiting steps in the intestinal absorption process after oral administration (see Arik Dahan et al., Prediction of Solubility and Permeability Class Membership: Provisional BCS Classification of the World's Top Oral Drugs. The AAPS Journal, Vol. 11, No. 4, December 2009, DOI: 10.1208 / s12248-009-9144-x).

[0379] The solubility classification limits according to the BCS are based on the highest dosage strength of the IR product. The equilibrium solubility of amorphous Letermovir under physiological pH conditions was determined by using the BCS method. The pH solubility curve of amorphous Letermovir was determined in an aqueous medium with a pH range of 1-7.5 at 37±1°C. A sufficient number of pH conditions were evaluated to accurately define the pH solubility curve of amorphous Letermovir. The number of pH conditions used for solubility determination is based on the ionization characteristics of Letermovir. A minimum of three replicates of solubility determination were performed under each pH condition.

[0380] In detail:

[0381] The maximum dose of Letermovir is illustratively 240mg. When dissolved in 250ml, this is equivalent to a concentration of 0.96mg / ml. According to FDA-industry guidelines, for the exemption of in vivo bioavailability and bioequivalence studies of the immediate release solid oral dosage based on the biopharmaceutics classification system (Guidance for Industry, Waiver of In Vivo Bioavailability and Bioequivalence Studies for Immediate-Release Solid Oral Dosages Based on a Biopharmaceutics Classification System), the solubility of Letermovir is measured in a standard buffer solution at 37°C ± 1°C after stirring for 24 hours.

[0382] Table 3: Letermovir solubility in the pH range 1 to 7.5

[0383]

[0384]

[0385] The Letermovir solubility data are reported in Table 3, which demonstrates that Letermovir cannot be considered a highly soluble drug substance. As shown in Table 3, the solubility of Letermovir varies from 0.4 mg / ml to >1 mg / ml in the pH range of 1 to 7.5. This data reflects the challenges encountered in providing an amorphous API Letermovir in an orally administrable IR tablet formulation.

[0386] 3) Isolation of amorphous Letermovir

[0387] For later tableting of orally administrable amorphous Letermovir formulations, the API must first be isolated from an organic solution in solid amorphous form. In addition, the API must be dried without any impairment of its physical and chemical properties, resulting in a residual solvent content required by current ICH guidelines.

[0388] 3a) Separation by drum drying

[0389] A vacuum drum dryer (GMF Gouda, VT2 / 4.75 model) was used to obtain pharmaceutical grade amorphous Letermovir. The drum dryer had the following specifications:

[0390]

[0391] In detail:

[0392] Acetone containing 30% Letermovir was injected at about 1.2 kg / h via an adjustable slit (best performance at 0.15 mm). From 9.8 kg of initial acetone solution, 2.35 kg of solid amorphous Letermovir was obtained. The residual acetone content was 1.7% to 3%; however, after a subsequent drying step in, for example, a vacuum dryer or a conical dryer, the remaining acetone could be reduced to <0.5%.

[0393] The specific surface area of ​​this product is <1m 2 / g and sufficient tablet quality can only be obtained by applying a wet granulation method.

[0394] In the following exemplary formulations of the invention, amorphous Letermovir isolated by roller drying and further processed by wet granulation showed sufficient dissolution according to the invention, ie >50% dissolution within 30 minutes.

[0395] Table 4: Exemplary formulations of drum-dried amorphous Letermovir

[0396] Material - Particles (Wet) mg / dose Letermovir (tumble dried) 30.00 Microcrystalline Cellulose 28.00 Colloidal Anhydrous Silica 0.500 Povidone 25 2.500 Purified water 25.00 Total particulate matter 61.00 Materials - Final Blend mg / dose Wet Particles 61.00 Microcrystalline Cellulose 8.50 Colloidal Anhydrous Silica 1.00 Magnesium Stearate 0.75 Final blend total 75.00

[0397] 3b) Separation by precipitation

[0398] A mixture of (2S,3S)-2,3-bis[(4-methylbenzoyl)oxy]succinic acid-{(4S)-8-fluoro-2-[4-(3-methoxyphenyl)piperazine-1-yl]-3-[2-methoxy-5-(trifluoromethyl)phenyl]-3,4-dihydroquinazolin-4-yl}acetic acid methyl ester (1:1 salt) (30.8 kg), sodium bicarbonate (16.4 kg) and water (315 L) was stirred with MTBE (160 L). The phases were separated and the organic phase was treated with 35 L of 7% sodium bicarbonate solution. The phases were separated again and the organic phase was treated with 125 L of 4% sodium hydroxide solution. The mixture was heated under reflux conditions. The solvent was distilled to dryness. The residual contents of the reactor were stirred at 55-60° C. for another 5 hours. MTBE (160 L) and water (65 L) were added to the mixture while stirring at 22° C. Separate the obtained phases again and extract the organic phase with the aid of 6% sodium chloride aqueous solution (30L). The aqueous phase is recombined and stirred with water (25L) and MTBE (160L). The pH is adjusted to 6.5 with the aid of 1N hydrochloric acid. The organic phase is separated, the solvent is gently distilled to dry and the residue is dissolved in acetone (about 75L). The solvent is replaced with acetone with the aid of 6 distillation steps of 130L each time. The product is subsequently precipitated by adding residual solvent (about 60L) under stirring conditions (61rpm) in excess water (492L) at room temperature. After centrifugation, the separated product is dried at 40 to 80°C in a vacuum dryer equipped with a spiral crushing roller. By this procedure, (S)-{8-fluoro-2-[4-(3-methoxyphenyl)piperazin-1-yl]-3-(2-methoxy-5-trifluoromethylphenyl)-3,4-dihydroquinazolin-4-yl}acetic acid was obtained as an amorphous compound in a yield of 16.5 kg, corresponding to 96.4% of theory.

[0399] 1 H NMR (300MHz, d 6 -DMSO):δ=7,53(d, 2 J=8,4,1H),7,41(brs,1H),7,22(d, 2 J=8,5,1H),7,09-7,01(m,2H),6,86(m,2H),6,45(dd, 2 J=8,2, 3 J=1,8,1H),6,39-6,34(m,2H),4,87(t, 2J=7,3,1H),3,79(brs,3H),3,68(s,3H),3,50-3,38(m,4H),2,96-2,75(m,5H),2,45-2,40(m,1H)ppm; MS(API-ES-neg.):m / z=571[(MH),100%];

[0400] The selection of appropriate distillation conditions before the actual separation can minimize the potential residual MTBE and mesityl oxide content. In order to prevent acetone from condensing itself into mesityl oxide, the temperature during the solvent exchange should be kept as low as possible by applying a vacuum (200 mbar) to the distillation step.

[0401] In particular, complete drying of acetone-wet Letermovir in vacuum resulted in values ​​<0.5% according to pharmaceutical grade (ICH guidelines) and a residual water content <2%. API Letermovir remained in amorphous form, which exhibited 1.2-2 m 2 / g specific surface area.

[0402] Those properties allow direct use in tablet formulation using dry granulation by roller compaction.

[0403] 3c) Effect of organic solvents on the precipitation of Letermovir

[0404] The effect of organic solvents on the precipitation of Letermovir was studied.

[0405] All results described in this article are based on relevant laboratory experiments.

[0406] The solvent exchange and precipitation procedures were simulated using the readily available amorphous API Letermovir and five different investigation solvents.

[0407] The specific choice of organic solvent used for this study was based on the following requirements:

[0408] A specific choice of structurally unrelated solvents was applied to provide a broader picture. The solvents had to be water miscible to easily match the precipitation process. Only process-relevant solvents were investigated, i.e., those that exhibited acceptable toxicity, high volatility, and low cost. Thus, this study excluded high boiling point solvents such as DMF, DMSO, NMP, etc. or highly toxic solvents such as glyme (1,2-dimethoxyethane).

[0409] The corresponding solvents to be investigated were methanol, ethanol, tetrahydrofuran (THF), methyl ethyl ketone (MEK; 2-butanone) and acetonitrile (ACN).

[0410] The Letermovir sample (dosage strength 5g) was dissolved in MTBE (26.5ml). Each solvent was distilled at 1atm at 60°C. Solvent (13.5ml) was added and distilled at a maximum temperature of 40°C under reduced pressure (200 mbar). Then the solvent (21.5ml) was supplemented and the distillation was repeated. The steps were performed five times, and then 10ml of solvent was added. At ambient temperature, the solution was added to water (160ml, reverse osmosis quality) under stirring within 30 minutes, and the product precipitated thereafter. The suspension was stirred for another hour, the solid was separated by filtration, washed twice with water (5ml each, reverse osmosis quality), and dried in a vacuum oven at 45°C for 24 hours.

[0411] After this period a first intermediate sample was taken and drying continued for a further 63 hours to investigate long term effects. The material was then probed a second time.

[0412] For analysis, HPLC purity and residual solvent content (RCS) were determined by gradient reverse phase HPLC-purity and static headspace gas chromatography as follows.

[0413] Gradient reverse phase HPLC-Purity:

[0414]

[0415]

[0416] Static Headspace Gas Chromatography:

[0417]

[0418]

[0419] 3c) Results

[0420] After this separation process, all solvents except MEK (see below) were subjected to essentially similar precipitation, filtration, and washing.

[0421] In all cases, there were no significant differences in the starting materials with respect to chiral purity. Therefore, this study focused on purity and residual solvent characteristics. The physical test results are summarized in Table 5 below.

[0422] Table 5: Physical testing of precipitated Letermovir in terms of HPLC purity and residual solvent content (RCS)

[0423]

[0424]

[0425] 1)The first value in the cell represents the Letermovir purity in HPLC; impurities characterized by percentages greater than or equal to 0.10% are listed below the Letermovir value.

[0426] 2) Amount of residual solvent content (RSC) in ppm. Limits according to ICH guidelines in ppm: methanol: 3,000; ethanol: 5,000; THF: 720; MEK: 5,000; ACN: 410; acetone: 5,000.

[0427] 3) The yield of this production batch was ignored because the process started with (2S,3S)-2,3-bis[(4-methylbenzoyl)oxy]succinic acid-methyl{(4S)-8-fluoro-2-[4-(3-methoxyphenyl)piperazin-1-yl]-3-[2-methoxy-5-(trifluoromethyl)phenyl]-3,4-dihydroquinazolin-4-yl}acetate (1:1) (SCDT).

[0428] In more detail:

[0429] 3d) Methanol as organic solvent

[0430] In principle, methanol could be used for the precipitation step, but from independent experiments it is evident that re-esterification can occur under stressed conditions (elevated temperature) using lower alcohols such as methanol or ethanol.

[0431] 3e) Ethanol as organic solvent

[0432] Ethanol does produce byproducts which surprisingly decrease during drying, but not completely. Since the nature of this byproduct is unknown, the reasons for this supposed "reversibility" are not discussed herein.

[0433] As for methanol, the presence of ethanol in the final product was negligible, only 7 and 3 ppm, respectively, after long-term drying.

[0434] 3f) THF as organic solvent

[0435] THF did also produce about 0.35% of an unknown impurity which proved to be stable under dry conditions.

[0436] Most importantly, residual THF proved very difficult to remove: the amount exceeded the 720 ppm limit by at least 30 times, leaving a residual amount of greater than 20,000 ppm.

[0437] 3g) MEK as organic solvent

[0438] On the other hand, MEK did provide very acceptable HPLC purity, but was also found to be unsuitable for the method: the precipitate was sticky, which could make filtration difficult on a technical scale. With respect to residual solvent analysis, MEK was essentially as unusable as THF: residual solvent levels significantly greater than 10,000 ppm (after extensive drying) exceeded the 5,000 ppm limit by at least a factor of two. THF, this solvent was considered unsuitable.

[0439] 3h) Acetonitrile as organic solvent

[0440] Acetonitrile did not cause any problems. Although its toxicity and therefore the strict limit (410 ppm) could cause questions regarding residual solvents, the amount determined after one day of drying was already well below 410 ppm and only slipped past the quantification limit of 5 ppm after a further 63 hours (amount: 4 ppm).

[0441] All these data favour acetonitrile, but from independent experiments it is evident that some racemization can be observed in this solvent under the influence of base and elevated temperature.

[0442] 3i) Acetone as organic solvent

[0443] However, as a surprising discovery, water-soluble acetone provided the best results in terms of the isolation characteristics of Letermovir. Acetone did not affect the quality of Letermovir at all and could be removed by drying (well below the 0.5% threshold according to ICH guidelines), resulting in a product that can be used directly for oral and intravenous formulations (water for injection is used for the precipitation step to provide API Letermovir for intravenous formulations).

[0444] With regard to the results described above, using acetone offers several advantages:

[0445] ●Highly volatile and therefore reasonably easy to remove;

[0446] ● Low toxicity, so the presence of acceptable levels of residual solvents;

[0447] ● Non-responsiveness to API Letermovir and therefore,

[0448] ●Almost no by-products.

[0449] 3j) Summary and conclusion

[0450] Under laboratory conditions, among the tested solvents, ethanol, THF and MEK proved to be unsuitable for quality or process reasons. Although methanol and acetonitrile gave positive results in terms of HPLC purity, they are not recommended: potential side reactions are re-esterification and racemization, respectively.

[0451] Although acetonitrile would be a good alternative, acetone is still preferred as organic solvent for precipitation of the API Letermovir according to the present invention from toxicological and economical aspects.

[0452] 4) Galenic formulation / tabletting method

[0453] The present inventors have found that the following galenic form and processing method are suitable for formulating amorphous Letermovir in an immediate release formulation.

[0454] The excipients used and their functions are described in Table 6:

[0455] Table 6: Excipients / functions used in galenic formulations

[0456] excipient Function Microcrystalline Cellulose Fillers / Binders Colloidal Anhydrous Silica Glidants Povidone 25 Polymer / Binder Croscarmellose Sodium Disintegrants Magnesium Stearate Lubricants Ethanol Processing agent acetone Processing agent Purified water Processing agent

[0457] To demonstrate an immediate release formulation, dissolution testing was performed using Ph. Eur. 2.9.3, Apparatus 2, at a paddle speed of 50 rpm. The proposed dissolution method is summarized below. A reverse phase HPLC method was used to analyze the samples.

[0458]

[0459] Assays and related substances

[0460] A gradient reverse phase HPLC assay was used to determine drug product identity, assay, and degradation products.

[0461]

[0462]

[0463] 4a) Wet granulation of drum dried and precipitated amorphous Letermovir

[0464] High shear wet granulation with purified water as processing agent resulted in the formation of good granules, where the material was well bound, softened and bulky. High shear wet granulation was performed with drum dried and precipitated API when water was used as processing agent. The quantitative formulations of high shear wet granulation of drum dried and precipitated amorphous Letermovir are reported in Table 7.

[0465] Table 7: Formulations of high shear wet granulation of drum dried and precipitated Letermovir

[0466] Material - Particles (Wet) mg / dose Letermovir (drum dried or precipitated) 30.00 Microcrystalline Cellulose 28.00 Colloidal Anhydrous Silica 0.50 Povidone 25 2.50 Purified water 25.00 Total particulate matter 61.00 Materials - Final Blend mg / dose Wet Particles 61.00 Microcrystalline Cellulose 10.00 Croscarmellose Sodium 2.25 Colloidal Anhydrous Silica 1.00 Magnesium Stearate 0.75 Final blend total 75.00

[0467] The particles of Letermovir (40311P18) mixed with precipitation seem to be more solid than the particles of Letermovir (40311P17) mixed with drum drying. The particles of Letermovir mixed with drum drying seem to flow more freely than the particles of Letermovir mixed with precipitation. This obvious difference in powder flow leads to the higher variation observed in the measured compression force during tablet manufacturing when the particles of Letermovir containing precipitation are compressed. This compression force variability difference leads to tablets containing drum-dried Letermovir particles showing more uniform tablet weight and thickness (reported in Table 8 and Table 9).

[0468] Table 8: IPC results for drum dried Letermovir (40311P17) versus precipitated Letermovir (40311P18)

[0469]

[0470] Tablets containing drum-dried Letermovir (40311P17) showed faster dissolution (reported in Table 9).

[0471] Table 9: Dissolution results of drum-dried Letermovir (40311P17) versus precipitated Letermovir (40311P18)

[0472]

[0473] * Comments: Single values ​​68%, 87%, 88%, 88%, 79%, 82%

[0474] Conclusion of 4a)

[0475] Granulation of the two separate Letermovir types can be performed using purified water / povidone solution as a processing agent. Tablets made from drum-dried Letermovir granules are more uniform in thickness and weight than tablets made from precipitated Letermovir granules processed by high shear wet granulation. In addition, dissolution of tablets containing drum-dried Letermovir showed faster dissolution of up to 30 minutes compared to tablets containing precipitated Letermovir.

[0476] 4b) Drum-dried Letermovir

[0477] In addition, the inventors tested only drum-dried Letermovir. The amount of disintegrant croscarmellose sodium was increased from 3% to 5% to promote disintegration of the tablets and reduce dissolution variability. The amount of microcrystalline cellulose was reduced accordingly to maintain tablet weight. The quantitative formulations are reported in Table 10.

[0478] Table 10: Exemplary formulations of drum-dried Letermovir with increased croscarmellose sodium

[0479] Material - Particles (Wet) mg / dose Letermovir (tumble dried) 30.00 Microcrystalline Cellulose 28.00 Colloidal Anhydrous Silica 0.50 Povidone 25 2.50 Purified water 25.00 Total particulate matter 61.00 Materials - Final Blend mg / dose Wet Particles 61.00 Microcrystalline Cellulose 8.50 Croscarmellose Sodium 3.75 Colloidal Anhydrous Silica 1.00 Magnesium Stearate 0.75 Final blend total 75.00

[0480] Results of 4b):

[0481] Granulation and tableting were performed without problems and the IPC (Process Control) data are reported in Tables 11 and 12.

[0482] Table 11: IPC data for Letermovir drum dried as wet granulation in formulations with increased croscarmellose sodium

[0483]

[0484] Table 12: Dissolution data of Letermovir as a wet granulation drum dried in formulations with increased croscarmellose sodium

[0485]

[0486] in conclusion:

[0487] All IPC results and dissolution results were according to the specifications as shown in Table 21. A standard deviation of about 1.3% after 30 minutes, 45 minutes and 60 minutes is pharmaceutically acceptable.

[0488] 5) Dry granulation of drum dried and precipitated amorphous Letermovir

[0489] In parallel with the wet granulation trials, dry granulation trials were also performed using a Kilian rotary tablet press to compress the isolated Letermovir into compacts, which were then milled using a conical grinder using the formulation reported in Table 13.

[0490] Table 13: Exemplary formulations of dry granulated Letermovir

[0491] Material - Particles (Dry) mg / dose Letermovir (tumble dried) 30.00 Microcrystalline Cellulose 18.00 Colloidal Anhydrous Silica 0.50 Povidone 25 2.50 Magnesium Stearate 0.30 Total particulate matter 51.30 Materials - Final Blend mg / dose Dry Particles 51.30 Microcrystalline Cellulose 20.00 Croscarmellose Sodium 2.25 Colloidal Anhydrous Silica 1.00 Magnesium Stearate 0.45 Final blend total 75.00

[0492] 5) Results:

[0493] Dry granulation, crushing of dry granules and preparation of final blends can be carried out on a small scale. All IPC results are according to the specifications and are reported in Table 14:

[0494] Table 14: IPC data for exemplary dry granulation of Letermovir

[0495] Physical parameters Nominal value Actual value Average mass [mg] 75±3％(73-77) 75 Minimum mass [mg], 68 69 Maximum mass [mg] 82 83 Diameter [mm] 5.4-5.6 5.5 Height [mm] Determination 3.0-3.1 Hardness [N] Determination 92 Brittleness [%] ≤1.0 0.2 <![CDATA[Disintegration in H 2 O [minutes]]]> ≤30 9'40-17'20

[0496] However, as reported in Table 15, the dissolution data at 30 minutes was less than 80%:

[0497] Table 15: Dissolution data of exemplary dry granulation of Letermovir

[0498]

[0499] in conclusion:

[0500] For this formulation, manufacturing using dry granulation can be performed on a small scale. The dissolution results are below the target specification. In addition, the standard deviation at the 15 minute time point is very high, which indicates that the dissolution rate may be limited by the initial disintegration of the tablet. In order to promote the disintegration of the tablet, the amount of croscarmellose sodium was also increased from 3% to 5% and the amount of microcrystalline cellulose was correspondingly reduced to maintain the tablet weight. The increase in the amount of disintegrant croscarmellose sodium also resulted in faster dissolution of the core as already shown above for wet granulation. The results are in accordance with the specification. When the disintegrant is incorporated into the dry granules, the dissolution is further improved.

[0501] 6) Dry granulation - drum dried API vs. precipitated API

[0502] A trial was conducted to evaluate whether dry granulation could be performed with both drum-dried and precipitated Letermovir. The quantitative formulations are reported in Table 16.

[0503] Table 16: Dry granulation formulations of drum dried and precipitated Letermovir

[0504] Material - Particles (Dry) mg / dose Letermovir (drum dried; precipitated) 30.00 Microcrystalline Cellulose 16.50 Colloidal Anhydrous Silica 0.50 Povidone 25 2.50 Croscarmellose Sodium 1.50 Magnesium Stearate 0.30 Total particulate matter 51.30 Materials - Final Blend mg / dose Dry Particles 51.30 Microcrystalline Cellulose 20.00 Croscarmellose Sodium 2.25 Colloidal Anhydrous Silica 1.00 Magnesium Stearate 0.45 Final blend total 75.00

[0505] Dry granulation, crushing of dry granules and preparation of final blends were performed without problems using drum-dried Letermovir (40311P15) and precipitated Letermovir (40311P16). The granules mixed with precipitated Letermovir seemed to flow more freely than the granules mixed with drum-dried Letermovir. This powder flow difference is reflected in the higher variation in compression force observed during tablet manufacturing when compressing the granules containing precipitated Letermovir. This results in tablets containing precipitated Letermovir granules showing more uniform tablet weight and thickness. For details, see the corresponding IPC data in Table 17.

[0506] Table 17: IPC data for dry granulated formulations of drum-dried Letermovir (40311P15) and precipitated Letermovir (40311P16)

[0507]

[0508] The corresponding dissolution results are shown in Table 18.

[0509] Table 18: Dissolution results; dry granulation formulations of roller-dried Letermovir (40311P15) and precipitated Letermovir (40311P16)

[0510]

[0511] Conclusion

[0512] Initial development trials were started by studying processing using wet granulation and dry granulation. Initial attempts at high shear wet granulation using organic solvents were unsuccessful. However, by using water as a processing agent, granulation was improved.

[0513] Manufacturing by using dry granulation is preferred over wet granulation because the dry granulation process is not limited by batch size and is expected to be easier to scale up reproducibly. The dissolution rate can be increased by promoting tablet disintegration by increasing the amount of disintegrant in the formulation. The highest effect is shown by adding intragranular disintegrants.

[0514] Experiments were performed using two types of amorphous Letermovir manufactured using two different methods, namely drum-dried Letermovir and precipitated Letermovir.

[0515] During several trials, it was found that drum dried API was more suitable for wet granulation technique and precipitated API was more suitable for dry granulation technique. Using both techniques, 30 mg tablets with acceptable physical parameters and adequate dissolution as per specifications were manufactured.

[0516] Additionally, one trial utilizing dry granulation technology was successfully manufactured with the highest dosage strength in the homogenous series. Physical data and dissolution were acceptable for all dosage strengths.

[0517] 7) Exemplary formulations of four dosage strengths for precipitated API according to the present invention

[0518] Table 19: Exemplary formulations of Letermovir at dosage strengths of 30 mg, 60 mg, 120 mg and 240 mg

[0519]

[0520] 8) Roller compactor for dry granulation of precipitated Letermovir

[0521] Subsequently, the dry granulation process was transferred to a roller compactor. Roller compaction is a more easily scaled-up dry granulation method than the mill compaction of the compacts used for the initial feasibility batch. Compared to dry granulation using a tablet press (pressed tablets) and grinding, the dry granulation was also performed using the Gerteis A roller compactor was used to improve powder flow. The formulation was further optimized by using a coarser grade of microcrystalline cellulose. The "initial" and "optimized" formulations are shown in Table 20 below.

[0522] Table 20: Optimized formulation of Letermovir as precipitate for dry granulation for roller compaction

[0523]

[0524] 8) Results:

[0525] The dry granulation process was subsequently scaled up to a 12 kg batch size without negatively affecting the compression properties. Content uniformity of samples taken at the beginning, middle and end of the tableting process for representative samples of 60 mg dosage strength tablets and 240 mg dosage strength tablets demonstrated homogeneity of Letermovir within the tablet blend. Dissolution results were acceptable for all tablet strengths.

[0526] 9) Proposed shelf life specifications for amorphous Letermovir in tablet formulations

[0527] Table 21 Specifications and test methods for the proposed Letermovir tablets

[0528]

[0529] NMT=no more than

[0530] 10) Long-term stability

[0531] Long-term stability studies were conducted using tests for color, dissolution, degradation products and assays at regular time intervals to confirm the stability of the amorphous Letermovir precipitate tablets.

[0532] The analytical methods used in these studies are reported in Table 21. In addition, disintegration, water content, and hardness / breaking load were performed as informative tests.

[0533] Samples of one batch of Letermovir precipitate tablets of each dosage strength packaged in 45 ml HDPE bottles with child-resistant caps were stored at 25°C / 60% relative humidity and 40°C / 75% relative humidity. Stability data after 36 months of storage are reported.

[0534] Additional forced degradation studies were performed. One batch of Letermovir of each dosage strength was stored at 60°C for 3 months. To assess hydrolytic stability, one batch of the 20 mg dosage strength was stored open at 40°C / 75% relative humidity for 3 months.

[0535] Conclusion of stability study

[0536] All test parameters (i.e., appearance, dissolution, degradation products, and assays) met shelf life specifications throughout the study duration (36 months). Letermovir was stable under long-term storage conditions (25°C / 60% relative humidity) and under accelerated storage conditions (40°C / 75% relative humidity); no significant changes were observed. Only a slight increase in degradation products (maximum 0.2%) was detected. The largest single degradation product remained below 0.5%. Representative stability data are reported in the tables of Figure 8: a); b); c).

[0537] Because the available data after the 36-month stability study (real-time data at 25°C / 60% RH) fully complied with the shelf-life specifications, and considering that there was no significant increase in degradation products, no signs of crystallization or any other negative changes in quality during storage, a shelf life of 36 months was assigned for both tested dosage strengths.

[0538] 11) Absolute bioavailability of Letermovir in amorphous state

[0539] Pharmacokinetic Targets in Clinical Trial Cohort 1:

[0540] The absolute bioavailability after oral administration of 30 mg of Letermovir in the amorphous state was evaluated relative to 30 minutes of intravenous administration of 30 mg of Letermovir in 150 ml of saline solution 0.9%.

[0541] design

[0542] Cohort 1 was conducted in 12 healthy female subjects in an open label, randomized (for treatment sequence), single center crossover design (2 periods). Subjects received a single intravenous dose of 30 mg of Letermovir via a 30-minute infusion in one period ("reference") and a single oral dose of 30 mg of Letermovir in an amorphous state in another period ("test"). In both periods, subjects were in-house from Day -1 to Day 4 (72 hours after dosing on Day 1). The washout period between the two periods (i.e., dosing) was at least one week. The 30 mg dose in Cohort 1 (see Table 1) was evaluated. Figure 7a and Figure 7b ).

[0543] method

[0544] Plasma concentrations of Letermovir were determined using a lower limit of quantitation (LLOQ) of 1.00 ng / mL. The pharmacokinetic parameter AUC for cohort 1 was calculated in WinNonlin using the actual sampling time 0-∞ , C max ,F,AUC 0-最后 ,t max ,λz,t 1 / 2z, CL / F, CL, Vd / F, Vd, MRT, AUC 0-∞ / D, C max / D、AUC 0-最后 / D. Descriptive statistics were calculated for plasma concentrations and derived pharmacokinetic parameters. Statistics included sample size (n), mean, standard deviation (SD), percent coefficient of variation (%CV), geometric mean, median, minimum, and maximum. In cohort 1, a linear mixed effects model was used to compare the log-transformed AUC of oral Letermovir in amorphous state (test) and intravenous Letermovir (reference). 0-最后 and AUC 0-∞ The absolute bioavailability of Letermovir was statistically explored using the values ​​of the paired observations. Only paired observations were included in the statistical analysis.

[0545] Pharmacokinetic results:

[0546] See also Figure 7a and Figure 7b .

[0547] in conclusion:

[0548] Following a single 30 mg oral and intravenous (30-minute infusion) dose of Letermovir, the 0-最后 According to the statistical analysis, the absolute bioavailability of Letermovir was 76%.

[0549] 12) BET specific surface area analysis

[0550] BET specific surface area analysis was performed on different batches of precipitated amorphous Letermovir. BET specific surface area analysis was performed on a batch of Letermovir (referred to as BXR3GBL) manufactured according to Example 11 of WO 2006 / 133822. The results of the analysis are shown in Table 22 below:

[0551] Table 22BET specific surface area analysis

[0552]

[0553] It can be seen from Table 22 that the batch of BXR3GBL prepared according to the prior art WO 2006 / 133822 has an average BET value of 0.64 m 2 / g SSA, while the precipitated amorphous Letermovir of the present invention has an average BET value ranging from 1.03 m 2 / g (test number 40483515) to 2.25m 2 / g (test number 40479198) of SSA.

[0554] A specific BET method is characterized by the following parameters:

[0555] Principle: Nitrogen adsorption at 77K; according to the method of Brunauer, Emmett and Teller (BET)

[0556] Method: According to USP <846> Volumetric determination method (Method II)

[0557] Instrument: Tristar 3000 / VacPrep 061 (Micromeritics)

[0558] Sample mass: about 1.5-2.5g

[0559] Sample preparation: Degassing at 40°C under vacuum (final vacuum < 2.7 Pa) for 2 hours Pressure range p / p0: 0.05-0.15 (3 data points).

[0560] 13) Laser diffraction particle size distribution analysis (Mastersizer 2000)

[0561] Laser diffraction particle size distribution analysis was performed on two batches of precipitated amorphous Letermovir of the present invention and one batch of amorphous Letermovir manufactured according to Example 11 of WO 2006 / 133822 (referred to as BXR3GBL) using the laser diffraction technique of Mastersizer 2000 (Malvern Instruments). The results of the analysis are presented in three particle size distribution diagrams in Figure 9 (ac) and the numerical portion of the results is shown in Table 23 below:

[0562] Table 23 Laser diffraction particle size distribution analysis (Mastersizer 2000) and another BET specific surface area measurement

[0563]

[0564] As can be seen from Table 23, the prior art batch of BXR3GBL prepared by the method according to Example 11 of WO 2006 / 133822 exhibits a significantly higher median particle size than the precipitated amorphous Letermovir of the present invention. This indicates that the particle size distribution of BXR3GBL is significantly higher than the particle size distribution of the precipitated amorphous Letermovir according to the present invention.

[0565] A specific PSD analysis method is characterized by the following parameters:

[0566] Apparatus: Mastersizer 2000 with dry dispersion

[0567] Procedure: Fraunhofer; weighing amount: 0.3-0.4g

[0568] Measuring time: 20 seconds

[0569] Background time: 6 seconds

[0570] Shading limit: 0.5% to 6%

[0571] Sample tray: micro volume; small sieve with balls

[0572] Feed rate: 45-55%

[0573] Dispersion pressure: 2.5 bar

[0574] Four independent analyses were performed and the results were averaged.

[0575] 14) Purity determination by gas chromatography

[0576] The purity of four batches of precipitated amorphous Letermovir and one batch of amorphous Letermovir manufactured according to Example 11 of WO 2006 / 133822 (referred to as BXR3GBL) were determined by gas chromatography. The results of the analysis are shown in Table 24 below:

[0577] Table 24 Purity determination by gas chromatography

[0578]

[0579] As can be gathered from Table 24, the prior art batch of BXR3GBL prepared according to Example 11 of WO 2006 / 133822 shows a significantly increased content of toxic impurities compared to the precipitated amorphous Letermovir obtained by the process of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0580] Figure 1 : Precipitation experiments. Entries 1-3: Removal of MTBE by distillation with methanol, ethanol and acetonitrile; precipitation of Letermovir by addition of water. Entries 4: Removal of MTBE by distillation with acetone; precipitation of Letermovir by addition to water. Entries 5-6: Reverse precipitation: addition of water to acetone and acetonitrile solutions, respectively. Entries 7-11: Drum dryer simulation of drum drying of Letermovir using methanol, ethanol, acetonitrile, DCM and MTBE as volatile solvents. 1) The indicated yield was reduced by loss of material to the glass walls.

[0581] Figure 2 : Shows from Figure 1XRPD diffraction pattern of entry 11 of . A sample of entry 11 was isolated by drum dryer simulation of drum dried Letermovir using MTBE as volatile solvent. This pattern is typical for an amorphous solid such as Letermovir. All other diffraction patterns (entries 1 to 10) are essentially the same relative to the diffraction pattern of entry 11. Obviously, all separation techniques produce amorphous material (see also Figure 1 'Morphology by XRPD' in the 'Speciation by XRPD' column).

[0582] Figure 3 : HPLC chromatogram of separated Letermovir.

[0583] Figure 4 : Raman spectrum of amorphous Letermovir. According to the European Pharmacopoeia VI, Raman spectrum measurements were performed using a Bruker RFS100 / S Raman spectrometer as follows: excitation laser power 400 mW, resolution 2 cm -1 , scan number = 128, acquisition range 3300-0cm -1 , 5.0 mm aperture, 96-well glass vials, and spectral processing for linear baseline correction and normalization. Figure 4 A comparison of solid Letermovir (1) and dissolved Letermovir (2) compared to DMSO (3) is shown. Figure 2 Consistent with the XRPD results, Raman spectroscopy also confirmed that solid Letermovir was amorphous.

[0584] Figure 5 : Solubility of amorphous Letermovir in water.

[0585] Figure 6 : pH solubility curve of Letermovir.

[0586] Figure 7a and Figure 7b : Pharmacokinetic results. The absolute bioavailability of Letermovir at a subtherapeutic dose of 30 mg was tested.

[0587] Figure 8: a) Testing the stability characteristics of tablets of 240 mg Letermovir; b) Testing the stability characteristics of tablets of 60 mg Letermovir; c) Testing the stability characteristics of tablets of 120 mg Letermovir.

[0588] Figure 9: a) The particle size distribution diagram of a batch of precipitated Letermovir (1300750) according to the present invention shows different parts with time differences of about 2 to 3 minutes; b) The particle size distribution diagram of another batch of precipitated Letermovir (1300735) according to the present invention shows different parts with time differences of less than 2 minutes; c) The particle size distribution diagram of a batch of Letermovir (called BXR3GBL) manufactured according to Example 11 of WO 2006 / 133822 A1 shows different parts with time differences of about 2 minutes.

[0589] Fig.10 : Stability data of precipitated amorphous Letermovir of batch 10101001 of the present invention at 25°C / 60% relative humidity (long-term conditions).

[0590] Fig.11 : Stability data of precipitated amorphous Letermovir of batch 09041001 of the present invention at 25°C / 60% relative humidity for 48 months.

[0591] Fig.12 : Reaction scheme of the preferred synthetic route of Letermovir. Step 4) - The asterisk on the lower left before the solvent switch indicates the step of starting separation according to the present invention. Herein, the most preferred separation method exemplifies the solvent switch to acetone (4), followed by spray precipitation into water (5). Then centrifugal separation.

Claims

1. Letermovir represented by the following formula (I), It is in an amorphous state and is suitable for use in solid oral dosage forms, wherein the Letermovir is characterized by i) When BET surface area analysis is performed, the specific surface area is at least 1 m 2 / g and / or ii) When a particle size distribution analysis is performed, the median value of the particle size distribution does not exceed 10 μm.

2. Letermovir according to claim 1, wherein the amorphous state is characterized by no detectable crystalline content / signal within a detection limit of 2% when the Letermovir is determined by any of the three standard XRPD methods i), ii) or iii); wherein in i), a Letermovir powder sample was prepared on a rotating sample holder having an effective surface area of ​​1.9 mm (diameter); a powder diffraction pattern was recorded using a Bruker D8 Advance powder diffractometer equipped with a LynxEye PSD detector and a Niβ filter and using CuKα radiation operated at 40 kV and 30 mA; and the measurement was performed using a step size of 0.06° and a step time of 0.5 seconds; wherein in ii), a Siemens powder diffractometer D5000 equipped with a secondary graphite monochromator and using CuKα radiation operated at 40 kV and 30 mA was used; the effective surface area was equal to 6×10 mm; and the measurement was performed using a step size of 0.02° and a step time of 2 seconds; In iii), a Seifert X-ray tube DX-Cu8*0,4-S equipped with a Germanium (111) monochromator 616.2 and an imaging plate Guinier camera G670 from Huber and with CuKα radiation operated at 40 kV and 30 mA was used with a scanning range of 0°<2Θ<100° and a step width of Δ(2Θ)=0.005°.

3. Letermovir according to claim 1 or 2, wherein the Letermovir in the amorphous state is a zwitterion with a pI of 5.

55.

4. Letermovir according to any one of the preceding claims, which can be obtained by the following method: a) providing an organic solution of Letermovir, and any one of the following: b1) isolating the Letermovir by drum drying the organic solution in a volatile organic solvent, in particular acetone, at a temperature of 30°C to 60°C, in particular 40°C to 50°C, and subsequently drying the resulting amorphous Letermovir, or b2) Isolating amorphous Letermovir by precipitating it from a water-miscible solvent, in particular acetone or acetonitrile, into excess water as anti-solvent and subsequently filtering or centrifuging the resulting Letermovir.

5. Letermovir according to claim 4, wherein the method according to step b2) has a final drying step.

6. Letermovir according to claim 4 or 5, wherein the Letermovir obtained in step b1) or b2) is processed by wet granulation.

7. Letermovir according to claim 4 or 5, wherein the Letermovir obtained in step b1) or b2) is processed by dry granulation.

8. Letermovir according to any one of claims 4 to 7, wherein the Letermovir in an amorphous state is not isolated by spray drying or evaporation of a solution of Letermovir in an organic solvent.

9. Letermovir according to any one of claims 4 to 8, wherein in step b2), the Letermovir in the amorphous state is not isolated by precipitation using alcohol, in particular methanol or ethanol, or using THF or MEK.

10. A method for obtaining Letermovir according to any one of claims 1 to 3, wherein The following steps are involved: a) providing an organic solution of Letermovir, and any one of the following: b1) isolating the Letermovir by drum drying the organic solution in a volatile organic solvent, in particular acetone, at a temperature of 30°C to 60°C, in particular 40°C to 50°C, and subsequently drying the resulting amorphous Letermovir, or b2) Isolating amorphous Letermovir by precipitating it from a water-miscible solvent, in particular acetone or acetonitrile, into excess water as anti-solvent and subsequently filtering or centrifuging the resulting Letermovir.

11. The method according to claim 10, further comprising a final drying step after step b2).

12. The method according to claim 10 or 11, further comprising the step of processing the Letermovir obtained in step b1) or b2) by wet granulation.

13. The method according to claim 10 or 11, further comprising the step of processing the Letermovir obtained in step b1) or b2) by dry granulation.

14. The process according to any one of claims 10 to 13, wherein the precipitation in step b2) is not carried out using alcohol or using THF or MEK.

15. A solid pharmaceutical formulation comprising Letermovir in an amorphous state, wherein the solid pharmaceutical formulation is orally administrable.

16. The solid pharmaceutical formulation according to claim 15, comprising Letermovir in an amorphous state according to any one of claims 1 to 9.

17. The solid pharmaceutical preparation according to claim 15 or 16, further comprising povidone, croscarmellose sodium, microcrystalline cellulose, colloidal anhydrous silicon dioxide and magnesium stearate.

18. The solid pharmaceutical formulation according to claim 17, wherein the amorphous Letermovir is contained in an amount of 30.0% to 50.0% w / w, the povidone is contained in an amount of 2.0% to 10.0% w / w, the croscarmellose sodium is contained in an amount of 2.0% to 10.0% w / w, the microcrystalline cellulose is contained in an amount of 20.0% to 70.0% w / w, the colloidal anhydrous silicon dioxide is contained in an amount of 0.5% to 5.0% w / w, and the magnesium stearate is contained in an amount of 0.1% to 5.0% w / w.

19. The solid pharmaceutical formulation according to claims 15 to 18, which is effective to achieve an absolute bioavailability of 70% ± 30% of Letermovir when orally administered in said formulation comprising at least 5 mg of Letermovir in an amorphous state.

20. A solid pharmaceutical formulation according to any one of claims 15 to 18, wherein Letermovir in the amorphous state exhibits a dissolution of >50% within 30 minutes, preferably a dissolution of >60% within 30 minutes, more preferably a dissolution of >70% within 30 minutes, even more preferably a dissolution of >80% within 30 minutes, most preferably a dissolution of >90% within 30 minutes when tested using Ph. Eur. method 2.9.3, apparatus 2, at a paddle speed of 50 rpm at 37.0°C ± 0.5°C in 1000 ml 0.1 N HCl / 0.2% sodium lauryl sulfate medium and the dissolution of Letermovir in the amorphous state is measured by reverse phase HPLC at time point 30 minutes as follows: HPLC operating conditions: Column: Waters Symmetry Nucleosil 100C18, 40mm×4.0mm, 10μm Detection wavelength: 256nm Approximate running time: 4 minutes Approximate retention time: 1.3 minutes Column temperature: 40°C Injection volume: 20 μL Flow rate: 1.5ml / min Mobile phase: buffer pH 4.0 / acetonitrile; 55 / 45 v / v.

21. The solid pharmaceutical formulation according to any one of claims 15 to 20, wherein the solid pharmaceutical formulation is an immediate release formulation, Features Not less than 85% of the amount of Letermovir in the amorphous state is dissolved within 30 minutes in a volume of 900 ml or less using USP Apparatus I at 100 rpm or using USP Apparatus II at 50 rpm in each of the following media: (1) Acidic media, such as USP simulated gastric fluid without enzymes; (2) pH 4.5 buffer; and (3) pH 6.8 buffer or USP simulated intestinal fluid without enzymes.

22. A solid pharmaceutical formulation according to any one of claims 15 to 21, wherein the Letermovir in an amorphous state exhibits a chemical stability of at least 36 months during storage at room temperature 25°C and 60% relative humidity when determined by gradient reverse phase HPLC as follows: HPLC operating conditions: Column: Intertsil ODS III 5μm or equivalent Solvent: acetonitrile / 0.1N HCl; 3+7 (v / v) Eluent A: water, pH 2.40; B: acetonitrile Detection wavelength: 235nm Column temperature: 40°C Injection volume: 15 μL Flow rate: 1.0ml / min Running time: 30 minutes.

23. The solid pharmaceutical formulation according to any one of claims 15 to 22, for use in a method for the prevention or treatment of a disease associated with the herpes virus group, preferably associated with cytomegalovirus (CMV), even more preferably associated with human cytomegalovirus (HCMV).

24. The solid pharmaceutical formulation according to claim 23, for use in a method for preventing or treating a disease selected from the group consisting of: HCMV infection in a subject, in particular HCMV infection in a subject suffering from AIDS, HCMV pneumonia, HCMV encephalitis, and gastrointestinal and systemic HCMV infection, HCMV infection in newborns and children, acute HCMV infection in pregnant women, HCMV infection in immunosuppressed cancer patients, HCMV infection in HCMV-positive cancer patients who need to treat HCMV-mediated tumor progression.

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