Lyophilized powder containing 2-[(3-aminopropyl)amino]ethanethiol and its use for the preparation of thermogels

Abstract

A lyophilized powder for preparing a thermogel, comprising 1% to 35% of 2-[(3-aminopropyl)amino]ethanethiol or one of its pharmaceutically acceptable salts, 40% to 85% of one or more poloxamers, and 0.1% to 20% of one or more carbohydrate compounds.

Description

[Technical field]

[0001] The present invention relates to a lyophilized powder containing 2-[(3-aminopropyl)amino]ethanethiol and its use for preparing a thermogel. [Background technology]

[0002] Amifostine (S-{2-[(3-aminopropyl)amino]ethyl}dihydrogen phosphorothioate), also known as etiophos, is a phosphorylated prodrug that is converted to the free active 2-[(3-aminopropyl)amino]ethanethiol (amifostine thiol) under the action of alkaline phosphatase.

[0003] Amifostine is a cytoprotective adjunct used in cancer chemotherapy, including DNA-binding chemotherapy agents, and radiation therapy. To date, it is marketed under the trade name Ethyol® by Clinigen Group, Inc., as a sterile, lyophilized powder for IV infusion for the following indications: -Reduction of cumulative nephrotoxicity from repeated doses of cisplatin in patients with advanced ovarian cancer. - A reduction in the incidence of moderate to severe xerostomia in patients undergoing postoperative radiotherapy for head and neck cancer, where the radiation port includes most of the parotid gland.

[0004] Other possible uses of amifostine or amifostine thiol have been reported for many years. For example, Montana et al. tested the effect of topically applied amifostine to protect the intestinal mucosa in patients undergoing pelvic radiation therapy ("Topical Application of WR-2721 to Prevent Radiation-Induced Proctosigmoiditis", Cancer, 69(11), 2826-2830 (1992)). Similarly, Uzal et al. reported the protective effect of amifostine against radiation-induced proctitis when administered locally via the intrarectal route in high doses ("The Protective Effect of Amifostine on Radiation-Induced Proctitis: Systemic Versus Topical Application", Balkan Med J 29, 32-38 (2012)).

[0005] Clemenson et al. demonstrated that a thermogel containing the thiol metabolite of amifostine (CPh-1014) significantly reduced the severity of radiation-induced oral mucositis and dermatitis in an in vivo mouse model compared to a thermogel containing amifostine ("Preventing Radiation-Induced Injury by Topical Application of an Amifostine Metabolite-Loaded Thermogel", Int J Radiation Oncol Biol Phys, Vol. 104, No. 5, pp. 1141-1152 (2019)).

[0006] No. 6,239,119 discloses a method for treating or protecting mucosal tissues damaged by radiotherapy and / or chemotherapy treatment of cancer by topical application of amifostine and related compounds.The use of oral gel formulations for treating mucosal tissues in the oral cavity has been reported. Summary of the Invention [Problem to be solved by the invention]

[0007] The main problem encountered with formulations (including gels or thermogels) containing amifostine or its derivatives is their lack of stability, which leads to degradation of the active substance into various impurities, primarily symmetric disulfide impurities.

[0008] WO 2018 / 100008 discloses a method for the preparation of lyophilized 2-[(3-aminopropyl)amino]ethanethiol formulations that allow the preparation of thermogels, said lyophilized formulations being easy to reconstitute and stable during their storage. Although the method disclosed in that patent application significantly increases the stability of amifostine thiol during storage compared to previously known formulations by limiting the generation of disulfide impurities, such compositions must be stored at low temperatures (5° C. or lower) to prevent significant degradation of amifostine thiol into disulfides and other impurities.

[0009] To date, there remains a need for a lyophilized powder containing 2-[(3-aminopropyl)amino]ethanethiol that can be easily reconstituted to prepare a thermogel and is stable when stored at ambient conditions (i.e., temperature and humidity). [Means for solving the problem]

[0010] It has now surprisingly been found that a lyophilized powder containing 2-[(3-aminopropyl)amino]ethanethiol, a poloxamer and a carbohydrate compound can be easily reconstituted to prepare a thermogel and is stable for several months despite being stored at ambient conditions.

[0011] The present invention relates to a freeze-dried powder for preparing a thermogel comprising: - 1% to 35% of 2-[(3-aminopropyl)amino]ethanethiol or one of its pharma- ceutically acceptable salts; - 40% to 85% of one or more poloxamers; and - Contains 0.1% to 20% of one or more carbohydrate compounds.

[0012] The lyophilized powder according to the invention can be stored at ambient temperature for several months without observing significant degradation of 2-[(3-aminopropyl)amino]ethanethiol to the disulfide impurity. Moreover, it can be easily reconstituted to obtain a thermogel that can be used by topical application to treat or protect mucosal or skin tissues damaged by anticancer therapy, in particular the treatment of cancer by radiation therapy and / or chemotherapy.

[0013] In the context of the present invention: - "freeze-dried powder" (or "lyophilised powder") refers to any powder containing less than 8% water, preferably less than 5% water, more preferably less than 2% water; - "2-[(3-aminopropyl)amino]ethanethiol" refers to the active cytoprotective thiol metabolite of amifostine, also known as "amifostine thiol" or "WR-1065"; - "Poloxamer" refers to non-ionic block copolymers of ethylene oxide (EO) and propylene oxide (PO) synthesized by sequential addition of first propylene oxide and then ethylene oxide to low molecular weight water-soluble propylene glycol (see G. Bonacucina et al., "Thermosensitive Self-Assembling Block Copolymers as Drug Delivery Systems", Polymers 2011, 3, 779-811). Poloxamers are commercialized under various names such as Pluronics®, Lutrol®, and Kolliphor®; - "Carbohydrate compounds" are C m (H2O) nCarbohydrate compounds are also known as "saccharides". Preferably, "carbohydrate compounds" refers to monosaccharides or disaccharides, i.e., sugars; - "thermogel" (or "thermosensitive thermogel") refers to any polymer solution that exhibits the property of transitioning between a liquid and a rigid gel during a temperature transition. Preferably, "thermogel" refers to a hydrogel that is liquid at room temperature, gels at body temperature, and is capable of adhering to mucous membranes and skin due to its gelled state; - "Pharmaceutically acceptable salt" of an active ingredient refers to any salt of said active ingredient with an inorganic or organic acid, which is effected by the action of such an acid in an organic or aqueous solvent, such as an alcohol, a ketone, an ether or a chlorinated solvent, and which is acceptable from a pharmaceutical point of view. - Unless otherwise stated, all percentages are by weight.

[0014] The present invention relates to a lyophilized powder for preparing a thermogel comprising 2-[(3-aminopropyl)amino]ethanethiol, a poloxamer and a carbohydrate compound. Preferably, the present invention relates to a lyophilized powder for preparing a thermogel as defined above, having the following individual or combined characteristics: - the lyophilized powder contains 5% to 30% 2-[(3-aminopropyl)amino]ethanethiol; more preferably 10% to 20% 2-[(3-aminopropyl)amino]ethanethiol; - the lyophilized powder contains 45% to 80% poloxamer; more preferably 60% to 75% poloxamer; - the lyophilized powder contains one or more poloxamers selected as poloxamer 407 or poloxamer 188. More preferably, the lyophilized powder contains a mixture of poloxamer 407 and poloxamer 188. Even more preferably, the lyophilized powder contains a mixture of poloxamer 407 and poloxamer 188, wherein the weight ratio of poloxamer 407:poloxamer 188 is between 1.5 and 6. the lyophilized powder comprises between 0.5% and 15% carbohydrate compounds, more preferably between 1% and 10% carbohydrate compounds; and / or - the lyophilized powder contains one or more carbohydrate compounds selected from sugars. More preferably, the lyophilized powder contains one or more carbohydrate compounds selected from mannitol, lactose, sucrose, trehalose, sorbitol, glucose and raffinose. Even more preferably, the lyophilized powder contains one or more carbohydrate compounds selected from sorbitol and mannitol.

[0015] The lyophilized powder according to the invention may also contain further ingredients, such as flavorings or high-density sweeteners. Accordingly, the present invention also further relates to a lyophilized powder for preparing a thermogel as defined above, containing one or more of the following ingredients: flavourings such as apple, banana, cherry, coconut lemon, menthol, orange, raspberry, strawberry, tutti frutti or vanilla; and / or - High intensity sweeteners such as saccharin, aspartame, acesulfame potassium, sucralose or neotame.

[0016] The lyophilized powder according to the invention can be prepared according to any process known to those skilled in the art. In particular, the present invention also relates to a method for preparing the lyophilized powder defined above, said method comprising the following steps: - Hydrolysis of amifostine to amifostine thiol under acidic conditions. - Solutions containing excipients are prepared according to the following method: First, all excipients contained in the formulation, except for the poloxamer, are dissolved and mixed; The temperature is cooled before slowly adding in order to obtain a homogenous excipient solution. - Mixing the obtained amifostine thiol solution with the obtained excipient solution. The resulting solution is freeze-dried. - Nitrogen inerted before sealing.

[0017] As mentioned above, the lyophilized powder according to the invention can be used to prepare a thermogel useful for treating or protecting, by topical application, mucosal or skin tissues damaged by anti-cancer therapy, in particular by the treatment of cancer by radiotherapy and / or chemotherapy. The present invention also relates to a method for the preparation of a thermogel comprising reconstitution of the lyophilized powder as defined above with an aqueous solution. The aqueous solutions used to prepare thermogels may be made up of only water or may contain one or more ingredients such as poloxamers, penetration enhancers, taste masking agents such as flavors or sweeteners, mucoadhesives, co-solvents, humectants or colorants. The aqueous solution may be added at a ratio of 1-5 lyophilized powder:aqueous solution (w / w).

[0018] The thermogels prepared according to the above method are novel. The present invention also relates to the thermogels obtained by the process as described above.

[0019] The thermogel according to the invention can be used by topical application to treat or protect mucosal or skin tissues damaged by anti-cancer therapy, in particular the treatment of cancer by radiotherapy and / or chemotherapy.The invention also relates to a thermogel as defined above for treating or protecting mucosal or skin tissues damaged by anti-cancer therapy, in particular the treatment of cancer by radiotherapy and / or chemotherapy. Damage from cancer radiation therapy includes oral mucositis (in head and neck cancer radiation), cervical epitheliitis (in head and neck cancer radiation), esophagitis (in lung radiation), skin erythema (in breast radiation), enteritis (in abdominal radiation), vaginitis and vaginal dryness (in pelvic radiation), proctitis (in pelvic radiation), and alopecia (in brain radiation). Preferably, the present invention relates to a thermogel as described above for treating radiation-induced oral mucositis or skin erythema.

[0020] Finally, the present invention also relates to a method for treating or protecting mucosal or skin tissue damaged by anti-cancer therapy, in particular by the treatment of cancer by radiotherapy and / or chemotherapy, comprising the topical application of a thermogel as defined above.Preferably, the present invention relates to a method for treating radiation-induced oral mucositis or skin erythema by the topical application of a thermogel as defined above. The present invention will now be illustrated, but not limited, by the following examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] [Example] Example 1 - Lyophilized composition 1.1- Method for preparing the lyophilized composition A solution of 500 mg / ml amifostine is prepared in 4M hydrochloric acid and heated in a 60° C. water bath for 1 hour to obtain an amifostine thiol solution.

[0022] The excipient-containing solution is prepared by the following method: - firstly, all the excipients presented in the formulation, except for the poloxamer, are dissolved and mixed in a bottle containing water under magnetic stirring; - Cool the temperature of the resulting solution by placing the bottle in ice and keeping it chilled for the next step; - Under magnetic stirring, gradually add the poloxamer (Kolliphor®) until completely solubilized.

[0023] The resulting amifostine thiol solution and excipient solution are mixed in the required ratio to obtain a solution of the desired composition and concentration.

[0024] The solution is then distributed in 20 ml vials and freeze-dried using the program reported in Table 1 below.

[0025] [Table 1] The resulting lyophilized powder is then manually inactivated under nitrogen for 30 seconds before being sealed using rubber stoppers and aluminum crimps.

[0026] 1.2-Lyophilized powders 1 and 2 The compositions of lyophilized powders 1 and 2 (LP1 and LP2) reported in Table 2 below were prepared according to the process disclosed above (Example 1.1).

[0027] [Table 2] The resulting white lyophilized powders LP1 and LP2 are good appearance and well formed cakes.

[0028] Example 2 - Preparation of Thermogel To reconstitute the lyophilized powders LP1 and LP2 into a thermogel, 5 ml of water is introduced into the sealed vial through the stopper using a needle and syringe.

[0029] After waiting 1 minute for the water to penetrate into the cake, the vial is gently shaken by hand for 2 minutes to obtain a clear thermogel.

[0030] Example 3 - Stability of lyophilized powders 3.1- Reference A lyophilized powder free of carbohydrate compounds and prepared according to the method disclosed in Example 1.1 is used as a reference (i.e., Ref.) for this evaluation. The composition of said reference lyophilized powder is reported in Table 3 below.

[0031] [Table 3] 3.2-Experimental Procedure Vials of LP1, LP2 and Ref. were stored in a stability chamber under the following conditions: - 5°C / ambient RH (i.e., relative humidity), - 25℃ / 60%RH, and - 40℃ / 75%RH.

[0032] The stability of LP1, LP2 and Ref. under these conditions was evaluated after 1, 3 and 6 months of storage.

[0033] Stability studies were performed according to the ICH guideline "Q1A(R2) Stability Studies of New Drug Substances and New Drug Products." The following parameters were evaluated: - visual appearance of the cake; - Visual appearance of the solution, - pH measured by a pH meter, - Purity and impurities by HPLC.

[0034] 3.3-Results The results obtained for LP1, LP2 and Ref. are reported in Tables 4 to 6 below.

[0035] [Table 4]

[0036] [Table 5]

[0037] [Table 6] 3.4-Conclusion The reference formulation Ref. (containing no carbohydrate) is unstable when stored at accelerated conditions of 40°C / 75% RH. The major degradation impurity disulfide (RRT1.25) notably increased (>2.6%) after 6 months storage at 40°C / 75% RH. Conversely, the stability of LP1 and LP2 is excellent even after storage for 6 months at accelerated conditions (40°C / 75% RH). Purity determination by HPLC showed low levels of the major impurities, amifostine and its disulfide.

[0038] Furthermore, the addition of carbohydrate compounds, especially mannitol (see LP2) in the lyophilized composition, may be beneficial for reconstitution: reconstitution of products containing mannitol is rapid and no significant changes are observed after 6 months of storage, even at 40°C / 75% RH.

Claims

1. A lyophilized powder for preparing a thermogel, comprising: 1% to 35% of 2-[(3-aminopropyl)amino]ethanethiol or one of its pharma- ceutically acceptable salts; 40% to 85% of one or more poloxamers, and containing 0.1% to 20% of one or more carbohydrate compounds; The lyophilized powder, characterized in that the carbohydrate compound is selected from sorbitol or mannitol.

2. The lyophilized powder according to claim 1, characterized in that it contains 5% to 30% 2-[(3-aminopropyl)amino]ethanethiol.

3. The lyophilized powder according to claim 1 or 2, characterized in that it contains 45% to 80% poloxamer.

4. The lyophilized powder according to claim 3, characterized in that it contains 60% to 75% poloxamer.

5. The lyophilized powder according to any one of claims 1 to 4, characterized in that the poloxamer is selected from poloxamer 407 or poloxamer 188.

6. Lyophilized powder according to any one of claims 1 to 5, characterized in that it contains a mixture of poloxamer 407 and poloxamer 188.

7. The lyophilized powder according to any one of claims 1 to 6, characterized in that it contains 0.5% to 15% carbohydrate compounds.

8. The lyophilized powder according to claim 7, characterized in that it contains 1% to 10% carbohydrate compounds.

9. The lyophilized powder according to any one of claims 1 to 8, further comprising one or more of the following ingredients: flavourings such as apple, banana, cherry, coconut, lemon, menthol, orange, raspberry, strawberry, coconut, tutti frutti or vanilla; and / or High intensity sweeteners such as saccharin, aspartame, acesulfame potassium, sucralose or neotam.

10. A method for producing a freeze-dried powder according to any one of claims 1 to 9, Hydrolysis of amifostine to amifostine thiol under acidic conditions; Preparation of excipient-containing solutions by the following method: First, dissolve and mix all excipients present in the formulation, except for the poloxamer, Cooling the temperature before slowly adding the poloxamer to obtain a homogenous excipient solution. mixing the obtained amifostine thiol solution with the obtained excipient solution; freeze-drying the resulting solution, Inerted with nitrogen before sealing, A method for producing a freeze-dried powder comprising the steps of:

11. A method for preparing a thermogel comprising reconstituting the lyophilized powder according to any one of claims 1 to 9 with an aqueous solution.

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