Dissolution Test

Abstract

The present invention relates to testing samples containing rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles, such as suspensions, and to measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in aqueous media. The present invention also relates to quality control testing of said samples and to releasing batches containing said samples for pharmaceutical use. The present invention also relates to media for use in dissolution testing.

Description

[Technical field]

[0001] The present invention relates to testing samples containing rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles, such as suspensions, and to measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in aqueous media. The present invention also relates to quality control testing of said samples and to releasing batches containing said samples for pharmaceutical use. The present invention also relates to media for use in dissolution testing. [Background technology]

[0002] The treatment of human immunodeficiency virus (HIV) infection, known to be the cause of acquired immunodeficiency syndrome (AIDS), remains a major medical challenge. Rilpivirine is an antiretroviral drug of the non-nucleoside reverse transcriptase inhibitor (NNRTI) class used to treat HIV infection. Rilpivirine is a second-generation NNRTI with greater efficacy and reduced side effect profile compared to older NNRTIs. Rilpivirine, its pharmacological activity, and some procedures for its preparation are described in WO 03 / 16306. Rilpivirine is approved for the treatment of HIV infection and is commercially available as a single tablet containing 25 mg of rilpivirine base equivalent per tablet for once-daily oral administration (EDURANT®), and as a single tablet regimen for once-daily oral administration (COMPLERA®, ODEFSEY®, JULUCA®).

[0003] WO 2007 / 147882 discloses intramuscular or subcutaneous injection of a therapeutically effective amount of rilpivirine in the form of microparticles or nanoparticles having a surface modifier adsorbed on its surface and a pharma- ceutically acceptable aqueous carrier in which the rilpivirine active ingredient is suspended. Rilpivirine extended release suspensions for injection, for administration in combination with cabotegravir extended release suspensions for injection, have been approved, e.g., in the United States and Canada as CABENUVA® and in Europe as REKAMBYS®. These are the first antiretroviral drugs to be provided in long-acting injectable formulations for administration at intervals of more than one day.

[0004] A problem faced in pharmaceutical development is the need to control the level of drug available in the systemic circulation to remain within its desired therapeutic range. Drug levels outside the therapeutic range can potentially lead to insufficient or lack of efficacy in the case of too low drug levels, or conversely, too high drug levels can potentially result in undesirable adverse events to the patient. Systemic drug levels are the result of absorption, distribution, metabolism, and excretion of the drug substance. The rate of absorption is affected by the release rate of the drug product. To aid in drug level control, dissolution testing is a standardized method for measuring drug release from a given dosage form. Dissolution testing should be robust and reproducible, with the ability to detect any significant changes in product performance, e.g., the ability to distinguish between different formulations, manufacturing process parameters, changes in stability, and / or batches. Dissolution testing methods are also used to guide formulation development and select formulations and batches for clinical trials. Thus, reliable dissolution testing is an important tool in several stages of pharmaceutical development. Dissolution testing is also a valuable tool in pharmaceutical production and quality control. The results obtained by dissolution testing can be employed to detect potential variations that may occur during manufacturing and to ensure batch-to-batch reproducibility or to release a batch for further manufacturing into an approved product.

[0005] The conditions used for dissolution testing, an in vitro technique, are typically selected to mimic as closely as possible the in vivo conditions in which the drug is released from its dosage form. This is one way in which the results of in vitro testing are considered to be biorelevant. Conditions include the temperature of the medium used for dissolution testing. Another variable in dissolution testing is the nature of the medium in which the drug substance is dissolved (e.g., its composition and pH). Several methods for dissolution testing of dosage forms are described in compendia such as the United States Pharmacopoeia and the European Pharmacopoeia. The US FDA also publishes methods for dissolution testing of FDA-approved drugs, specifying the conditions and media. Dissolution tests for dosage forms containing rilpivirine published by the FDA (e.g., https: / / www.accessdata.fda.gov / scripts / cder / dissolution / ) include the following (if no temperature is listed, it is generally understood that a physiological temperature is selected, e.g., 37°C for oral administration):

[0006] [Table 1]

[0007] Although dissolution tests were initially developed for immediate release oral solid dosage forms, their use has been extended to formulations with controlled and modified drug release profiles. However, designing a suitable dissolution test for a dosage form with sustained release intended for intramuscular or subcutaneous injection is difficult, especially due to the sustained release, and there is no established strategy to solve this problem. Summary of the Invention

[0008] Thus, there remains a need to develop a reliable dissolution test for sustained release dosage forms of rilpivirine, particularly for sustained release rilpivirine in the form of nanoparticles or microparticles for injection.

[0009] Thus, in a first aspect, the present invention provides a method of testing a sample of rilpivirine or a pharma- ceutically acceptable salt thereof, the sample comprising rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles, the method comprising: The sample is dissolved in an aqueous medium, Contains a surfactant, Dispersing in an aqueous medium maintained at a temperature of 2 to 15°C; measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in an aqueous medium.

[0010] In a second aspect, the present invention provides a method for quality control testing of a sample of rilpivirine or a pharma- ceutically acceptable salt thereof, the sample comprising rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles, the method comprising: subjecting a sample to the method of the first aspect; and determining whether the sample passed the quality control test based on the measured dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in the aqueous medium.

[0011] In a third aspect, the present invention provides a method of shipping a batch of rilpivirine or a pharma- ceutically acceptable salt thereof for pharmaceutical use, comprising the steps of: providing a batch of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles, optionally in a suspension; subjecting a sample taken from the batch to the quality control method of the second aspect; If the sample passes quality control testing, releasing the batch for pharmaceutical use.

[0012] In a fourth aspect, the present invention provides an aqueous medium for use in dissolution testing, the aqueous medium comprising: 4-8% w / v, or 5.5-6.5% w / v, or 5.94-6.06% w / v of a surfactant, particularly a non-ionic surfactant (e.g., polysorbate 20); containing a buffer (e.g., 0.05 M sodium phosphate buffer); An aqueous medium is provided having a pH of 6 to 8, 7 to 8, 7.2 to 7.8, or 7.3 to 7.5. [Brief description of the drawings]

[0013] The present invention will now be described, by way of example only, with reference to the accompanying drawings. [Figure 1] Dissolution studies with rilpivirine suspensions of various particle sizes. [Diagram 2] Dissolution studies with rilpivirine suspensions of various particle sizes. [Diagram 3] Dissolution studies with rilpivirine suspensions of various particle sizes. [Figure 4] Dissolution studies of rilpivirine suspensions at various temperatures. [Diagram 5] Dissolution studies of rilpivirine suspensions at various surfactant concentrations. [Figure 6] Equilibrium solubility of rilpivirine at various surfactant concentrations. [Figure 7] Dissolution studies of rilpivirine suspensions after various storage conditions.

[0014] These figures are further explained in the Examples section.

[0015] Disclosure of the Invention This application is described in several sections for ease of reading. However, this does not mean that each section should be read separately. On the contrary, unless otherwise specified, each section should be read with cross-reference to other sections, i.e., by interpreting the entire application as a whole. Unless explicitly stated, no artificial separation of embodiments is intended.

[0016] Thus, all of the embodiments described herein with respect to the first aspect of the invention apply equally to the second to fourth aspects herein, i.e. are disclosed in relation / combination with the second to fourth aspects as well. For example, the features of the aqueous medium described with respect to the first aspect apply to the second, third and fourth aspects. The features of the sample comprising rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles apply to the first, second and third aspects. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Dissolution Test The method of the first aspect of the invention is unique in that it measures the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof at a temperature significantly below physiological temperature. Physiological temperature is typically chosen for dissolution tests because in vitro tests may represent the behavior of the drug substance in vivo. Thus, a typical temperature for measuring the dissolution of oral dosage forms is 37°C. However, the inventors have surprisingly found that the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles can be measured at a lower temperature between 2 and 15°C, which improves the discriminatory power of the method and in particular makes it possible to discriminate between samples of different particle sizes. It is also found that lowering the temperature slows down the dissolution, thus making it possible with this method to assess the potential for a burst release of the drug substance from the dosage form. Given the discriminatory properties of the test, it can be considered to provide biorelevant results. Moreover, it has been found that this method allows the in vitro study of the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles intended for extended release over a practical time scale suitable for laboratory testing purposes. Due to these advantages, the present invention also provides in a second aspect an improved method for quality control testing of samples of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles. In a third aspect, the present invention provides an improved method for releasing batches of rilpivirine or a pharma- ceutically acceptable salt thereof for pharmaceutical use.

[0018] In one embodiment, the aqueous medium is maintained at a temperature of 3 to 10° C., or 4 to 6° C., preferably 4.5 to 5.5° C., especially 5° C. Using temperatures within a narrow range for each iteration of the dissolution method, for example within ±0.5° C. of the set temperature, can improve the robustness of the method.

[0019] Preferably, the sample or formulation to be tested is a suspension of microparticles or nanoparticles of rilpivirine or its pharma- ceutically acceptable salt in a pharma- ceutically acceptable carrier (e.g., a pharma-ceutically acceptable aqueous carrier). Suspensions are further described below. If the formulation or sample is a suspension, the suspension is preferably thoroughly resuspended and homogenized before the step of dispersing the sample in an aqueous medium. Homogenization may include mechanical homogenization, for example using a vortex mixer, may include manual homogenization, for example shaking by hand, and may include both mechanical and manual homogenization. To eliminate any potential dependence of the results on homogenization conditions, a homogenization protocol to be used for each iteration of dissolution testing may be established. For example, the homogenization protocol may require homogenizing the vial containing the sample for at least 15 seconds using a vortex mixer, followed by manually shaking the vial horizontally 30 times over approximately 25 cm within approximately 10 seconds.

[0020] The method is preferably not carried out under sink conditions. Sink conditions are defined as conditions in which the equilibrium solubility of rilpivirine or its pharma- ceutically acceptable salt in an aqueous medium is at least three times higher than the concentration that would be obtained if all the rilpivirine or its pharma- ceutically acceptable salt of the sample were dissolved in the aqueous medium. It will be understood that equilibrium solubility refers to the concentration of a substance in a solvent when the substance is in dynamic equilibrium between the solid state and the dissolved state in the solvent. Sink conditions are usually considered essential in dissolution test methods to allow the dissolution rate to be measured consistently; otherwise, when the concentration of the drug substance dissolved in the aqueous medium approaches the equilibrium solubility, the dissolution rate would decrease, affecting the reproducibility of the test results. Surprisingly, the inventors have found that the method of the present invention is not carried out under sink conditions, while still providing excellent reproducibility and discrimination ability, and the discrimination ability may be better when the method is not carried out under sink conditions than when it is carried out under sink conditions.

[0021] Preferably, the concentration that would be obtained if all of the rilpivirine or pharma- ceutically acceptable salt thereof of the sample were dissolved in the aqueous medium is equal to or less than the equilibrium solubility of the rilpivirine or pharma- ceutically acceptable salt thereof in the aqueous medium. In this manner, the dissolution of all of the rilpivirine or pharma- ceutically acceptable salt thereof of the sample can be measured, for example, using an infinity point as discussed further below.

[0022] In one embodiment, the concentration that would be obtained if all the rilpivirine or pharma- ceutically acceptable salts of the sample were dissolved in the aqueous medium is equal to or greater than the equilibrium solubility of rilpivirine or pharma- ceutically acceptable salts of the sample.In this way, not all the rilpivirine or pharma- ceutically acceptable salts of the sample are dissolved, and not all of the rilpivirine or pharma- ceutically acceptable salts of the sample can be measured, for example, at least 80% of the rilpivirine or pharma- ceutically acceptable salts of the sample are dissolved, or at least 85% of the rilpivirine or pharma- ceutically acceptable salts of the sample are dissolved, or at least 90% of the rilpivirine or pharma- ceutically acceptable salts of the sample are dissolved, or at least 95% of the rilpivirine or pharma- ceutically acceptable salts of the sample are dissolved.

[0023] Whether a system, for example a particular sample in combination with a particular aqueous medium, is in a sink condition can be controlled by varying parameters that affect the equilibrium concentration, for example, the temperature, pH, and / or surfactant concentration of the aqueous medium.

[0024] Whether a system, e.g., a particular sample in combination with a particular aqueous medium, is in a sink condition can be controlled by varying the concentration that would be obtained if all the rilpivirine or pharma- ceutically acceptable salt thereof of the sample were dissolved in the medium, e.g., by varying the amount of rilpivirine or pharma- ceutically acceptable salt thereof in the sample, and / or by varying the volume of the medium, and / or by varying the volume or weight of the sample. The sample may contain 10-30 mg, or 16-20 mg, or 17.1-18.9 mg of rilpivirine or pharma- ceutically acceptable salt thereof. The volume of the aqueous medium may be 500-1500 mL, or 700-1,100 mL, or about 900 mL. When all of the rilpivirine or pharma- ceutically acceptable salt thereof in the sample is dissolved in the aqueous medium, the concentration of the rilpivirine or pharma- ceutically acceptable salt thereof in the aqueous medium may be about 0.015-0.025 mg / mL, or about 0.019-0.021, or about 0.020 mg / mL. These concentrations preferably represent non-sink conditions.

[0025] The aqueous medium contains a surfactant that aids in dissolving the rilpivirine or a pharma- ceutically acceptable salt thereof in the aqueous medium. The surfactant should be selected so that it does not crystallize at the low temperatures used in the process. The surfactant may be a non-ionic surfactant, such as a polysorbate (available as Tween™ surfactants); a poly(alkylene-oxide) block copolymer, such as poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (available as Pluronic™ surfactants), poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide)-poly(propylene oxide) (available as Pluronic R™ surfactants), poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide), poly(butylene oxide)-poly(ethylene oxide), and tetrafunctional poly(alkylene-oxide) block copolymers (available as Tetronic™ surfactants); an oligomeric alkyl-ethylene oxide (available as Brij™ or Tergitol™ surfactants); an alkyl-phenol-polyethylene (available as Triton™ surfactants); and mixtures thereof. In one embodiment, the surfactant may be a non-ionic surfactant, such as a polysorbate (available as Tween™ surfactants); an oligomeric alkyl-ethylene oxide (available as Brij™ or Tergitol™ surfactants). Preferably, the surfactant is polysorbate 20.

[0026] In one embodiment, the surfactant is a sorbitan ester, such as sorbitan oleate (available as Span™ surfactants).

[0027] The surfactant concentration can be controlled to further improve the discrimination characteristics of the dissolution method. For example, the surfactant concentration can be controlled to affect the dissolution profile and therefore the performance of the method. A preferred implementation method is capable of detecting a potential burst release (initial release of reference (first time point to measure dissolution is preferably measured between 1 and 5 minutes after the start of the experiment, e.g., 1, 2, 3, 4, or 5 minutes) is preferably less than 10% dissolution, or less than 20% dissolution, or less than 25% dissolution, or less than 30% dissolution), characterizing the release profile (time point sufficient for 20% to 65% dissolution), and detecting a final release of more than 50%, or 60%, or 70%, or 80%, or 90%, preferably 100% dissolution. The performance of each method can be defined by calculating the difference between the lowest and highest dissolution % in the dissolution profile, i.e., delta dissolution %. For example, the delta dissolution % of a 6% polysorbate 20 method is approximately 80%. The higher the dissolution %, the greater the ability of the method to distinguish between different particle sizes of rilpivirine. In one embodiment, the delta dissolution % is at least 40%, at least 50%, at least 60%, at least 70%, at least 80%. Similarly, the surfactant concentration may be controlled to optimize the method by increasing the delta dissolution %. Thus, the surfactant, e.g., polysorbate 20, may be present in the aqueous medium at a concentration of 2-8% w / v, or 4-8% w / v, or 5.5-6.5% w / v, or 5.94-6.06% w / v, or 5% w / v, or 5.5% w / v, or 6% w / v. The robustness of the method may be improved by using a narrow range of concentrations, e.g., ±1% of the set concentration, for each iteration of the dissolution method.

[0028] The aqueous medium may contain a buffer. It has been found that various buffers can be used while maintaining the distinguishing characteristics of the method. Suitable buffers include phosphate buffer, citrate buffer, citrate-phosphate buffer (e.g., McIlvaine buffer), tris(hydroxymethyl)aminomethane buffer, borate buffer, phthalate buffer, acetate buffer, and mixtures thereof. A preferred buffer is 0.05M sodium phosphate buffer.

[0029] In one embodiment, the aqueous medium contains a pH adjuster, such as sodium hydroxide.

[0030] One of the factors that can be controlled to affect the solubility of rilpivirine is the pH of the aqueous medium. The aqueous medium can have a pH of 6-8, 7-8, 7.2-7.8, or 7.3-7.5. Using a pH within a narrow range for each iteration of the dissolution method, for example, a set pH of ±0.1, can improve the robustness of the method. The selection of a pH within the recited range for measuring the dissolution of rilpivirine is unique. For example, each of the dissolution tests published by the US FDA for dosage forms containing rilpivirine involves an aqueous medium of pH 2.0.

[0031] When multiple samples are tested, preferably the method comprises a first repetition of the dissolution test on a first sample and a second repetition of the dissolution test on a second sample, wherein the concentration of the surfactant in the aqueous medium in the second repetition is maintained within ±1% of the concentration of the surfactant in the aqueous medium in the first repetition, the temperature of the aqueous medium in the second repetition is maintained within ±0.5° C. of the temperature of the aqueous medium in the first repetition, and the pH of the aqueous medium in the second repetition is maintained within ±0.1 of the pH of the aqueous medium in the first repetition. In this way, the results of the first and second repetitions can be directly compared.

[0032] Most preferably, the aqueous medium contains 5.94-6.06% w / v polysorbate 20, contains 0.05M sodium phosphate buffer, has a pH of 7.3-7.5, and is maintained at a temperature of 4.5-5.5°C.

[0033] The dissolution method may be carried out in any suitable apparatus, such as standard dissolution equipment described in pharmacopoeias, e.g. USP42-NF37 2019. Dispersing a sample of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles in an aqueous medium typically involves stirring. For example, a paddle apparatus, in particular a USP type 2 apparatus, can be used. The rotation speed of the apparatus is typically 10-100 rpm, or 25-75 rpm, or about 50 rpm.

[0034] In vitro, drug dissolution is generally monitored for a period of time similar to that required for in vivo drug release. This would therefore mean monitoring dissolution over weeks or months for a sample of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles intended for administration by intramuscular or subcutaneous injection for long-term treatment of HIV infection or for long-term prevention of HIV infection, for example a sample of a sustained release injectable rilpivirine suspension. Long-term treatment of HIV infection or long-term prevention of HIV infection in a subject at risk of HIV infection can be understood as treatment of HIV infection or prevention of HIV infection in a subject at risk of HIV infection, where rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles, optionally in suspension, is administered subcutaneously or intramuscularly intermittently at time intervals ranging from 1 week to 2 years, or from 2 weeks to 1 year, or from 1 month to 6 months, or about 1 month, or about 2 months, or about 3 months, or about 4 months, or about 5 months, or about 6 months. However, this may be impractical for quality control and development purposes. Thus, measurements of dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in aqueous media may be performed over 24 hours, or 4-8 hours, or 5-7 hours, or about 6 hours. The inventors have found that the in vitro method provides results that are biorelevant by its discriminating properties, despite the significant difference between the in vitro monitoring period (on the order of hours) and the in vivo drug release period (on the order of weeks or months).

[0035] The dissolution test may be operated such that at least 80% or at least 85% of the rilpivirine or pharma- ceutically acceptable salt thereof of the sample is dissolved in the aqueous medium after about 6 hours. In this way, dissolution of a sufficient amount of the sample to provide robust results is determined over a practical time scale.

[0036] The dissolution test is carried out to determine the following characteristics (a) to (l): (a) about 14% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved after about 5 minutes; (b) about 25% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved after about 10 minutes; (c) about 34% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved after about 15 minutes; (d) about 52% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved after about 30 minutes; (e) about 62% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved after about 45 minutes; (f) about 69% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved after about 60 minutes; (g) about 77% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved after about 90 minutes; (h) about 82% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved after about 120 minutes; (i) about 88% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved after about 180 minutes; (j) about 91% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved after about 240 minutes; (k) about 94% of the rilpivirine or pharma- ceutically acceptable salt thereof is dissolved after about 360 minutes.

[0037] For example, features (a), (d), and (j) may be present, or (a), (c), (e), and (i) may be present, or all of (a) through (k) may be present.

[0038] The dissolution test is carried out to determine the characteristics (i) to (vi): (i) ≦30% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved in 5 minutes; (ii) 10 to 40% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved within 10 minutes; (iii) 39 to 59% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved within 30 minutes; (iv) 45 to 75% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved in 45 minutes; (v) 64 to 84% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved in 90 minutes; (vi) at 360 minutes, ≧80% of the rilpivirine or pharma- ceutically acceptable salt thereof is dissolved.

[0039] For example, features (ii), (iv), and (vi) may be present, or preferably features (i), (iii), (v), and (vi) may be present.

[0040] The dissolution test may include measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in an aqueous medium at an infinity point where at least about 80%, at least about 85%, at least about 90%, at least about 95%, or preferably about 100% (i.e., nearly all) of the rilpivirine or a pharma- ceutically acceptable salt thereof of a sample is dissolved in the aqueous medium. The infinity point may be achieved by raising the temperature of the aqueous medium from an initial temperature (e.g., 2-15, 3-10, 4-6, or 4.5-5.5° C.) to room temperature (e.g., about 22° C.) or above, such as about 37° C., and optionally maintaining the aqueous medium at the elevated temperature for about 1 hour. For example, in one embodiment, the dissolution test may involve measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in an aqueous medium at 2-15° C. as a function of time, optionally over a period of 3-8 hours, or 4-8 hours, or 5-7 hours, or about 6 hours, with the subsequent steps of raising the temperature of the aqueous medium to above room temperature (e.g., about 22° C.), such as about 37° C., and maintaining the aqueous medium at the elevated temperature for about 1 hour, and measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in the aqueous medium. For example, in one embodiment, a dissolution test may involve measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in an aqueous medium at 2-15° C. until at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 85%, or at least about 90%, or at least about 95% of the rilpivirine or pharma- ceutically acceptable salt thereof in a sample is dissolved, with the subsequent steps of raising the temperature of the aqueous medium to above room temperature (e.g., about 22° C.), such as about 37° C., maintaining the aqueous medium at the elevated temperature for about 1 hour, and measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in the aqueous medium.For example, in one embodiment, a dissolution test may involve measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in an aqueous medium at 2-15° C. until about 40%, about 50%, about 60%, about 70%, about 80%, about 85%, or about 90%, or about 95% of a sample of rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved, with the subsequent steps of raising the temperature of the aqueous medium to above room temperature (e.g., about 22° C.), such as about 37° C., and maintaining the aqueous medium at the elevated temperature for about 1 hour, and measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in the aqueous medium. For example, in one embodiment, the dissolution test may include measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in an aqueous medium as a function of time, over a period of 3-8 hours, or 4-8 hours, or 5-7 hours, or about 6 hours, and until at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 85%, or at least about 90%, or at least about 95% of the rilpivirine or a pharma- ceutically acceptable salt thereof of the sample has dissolved at 2-15° C., with the subsequent steps of raising the temperature of the aqueous medium to above room temperature (e.g., about 22° C.), such as about 37° C., and maintaining the aqueous medium at the elevated temperature for about 1 hour, and measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in the aqueous medium. For example, in one embodiment, the dissolution test may include measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in an aqueous medium as a function of time, over a period of 3-8 hours, or 4-8 hours, or 5-7 hours, or about 6 hours, and until about 40%, about 50%, about 60%, about 70%, about 80%, about 85%, or about 90%, or about 95% of the rilpivirine or a pharma- ceutically acceptable salt thereof of the sample is dissolved at 2-15° C., with the subsequent steps of raising the temperature of the aqueous medium to above room temperature (e.g., about 22° C.), such as about 37° C., and maintaining the aqueous medium at the elevated temperature for about 1 hour, and measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in the aqueous medium.For example, in one embodiment, the dissolution test may include measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in an aqueous medium as a function of time, over a period of 3-8 hours, or 4-8 hours, or 5-7 hours, or about 6 hours, and until at least about 80%, at least about 85%, or at least about 90%, or at least about 95% of the rilpivirine or a pharma-ceutically acceptable salt thereof of the sample is dissolved at 2-15° C., with the subsequent steps of raising the temperature of the aqueous medium to above room temperature (e.g., about 22° C.), such as about 37° C., and maintaining the aqueous medium at the elevated temperature for about 1 hour, and measuring the dissolution of rilpivirine or a pharma-ceutically acceptable salt thereof in the aqueous medium. For example, in one embodiment, the dissolution test may include measuring the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in an aqueous medium as a function of time, over a period of 3-8 hours, or 4-8 hours, or 5-7 hours, or about 6 hours, and until about 80%, about 85%, or about 90%, or about 95% of the rilpivirine or a pharma-ceutically acceptable salt thereof of the sample is dissolved at 2-15° C., with the subsequent steps of raising the temperature of the aqueous medium to above room temperature (e.g., about 22° C.), such as about 37° C., and maintaining the aqueous medium at the elevated temperature for about 1 hour, and measuring the dissolution of rilpivirine or a pharma-ceutically acceptable salt thereof in the aqueous medium.

[0041] Measurement of the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in an aqueous medium can be easily accomplished by removing an aliquot from the medium, optionally filtering the aliquot, and measuring the amount of rilpivirine or a pharma- ceutically acceptable salt thereof dissolved in the aliquot. Filtration removes undissolved rilpivirine particles. Filters, such as syringe filters with a pore size of 0.1 μm, such as regenerated cellulose or polyvinylidene difluoride (PVDF) membranes, have been found to be suitable. If the aliquot is filtered, typically a new filter is used for each aliquot to avoid possible contamination. Alternatively, the aliquot can be centrifuged, cooled, and / or diluted before measuring the amount of rilpivirine or a pharma- ceutically acceptable salt thereof dissolved in the aliquot. If more than one aliquot is taken from a container, the % dissolution should be corrected to reflect the removal of rilpivirine or a pharma- ceutically acceptable salt thereof and the volume of the dissolution medium.

[0042] The amount of rilpivirine or a pharma- ceutically acceptable salt thereof present in an aliquot can be determined by standard techniques, such as high performance liquid chromatography (HPLC), in particular gradient ultra-high performance liquid chromatography (UHPLC) with UV detection.

[0043] Measurement of the dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in aqueous media can also be accomplished without removing aliquots using in-line spectroscopic techniques, such as in-line UV spectroscopy.

[0044] In a fourth aspect, the present invention provides an aqueous medium for use in dissolution testing, the medium comprising 4-8% w / v, or 5.5-6.5% w / v, or 5.94-6.06% w / v of a surfactant, such as a non-ionic surfactant (e.g., polysorbate 20), a buffer (e.g., 0.05 M sodium phosphate buffer), and having a pH of 6-8, 7-8, 7.2-7.8, or 7.3-7.5. This represents a particularly effective aqueous medium for use in the dissolution testing method of the first aspect. Preferably, the aqueous medium comprises 5.94-6.06% w / v of polysorbate 20, a buffer (e.g., 0.05 M sodium phosphate buffer), and has a pH of 7.3-7.5. The aqueous medium may be maintained at a temperature of 2-15, 3-10, 4-6, or preferably 4.5-5.5°C. The aqueous medium can contain dissolved rilpivirine or a pharma- ceutically acceptable salt thereof, for example, present from a dissolution test.

[0045] quality control In a second embodiment, the results of the dissolution test are used for quality control testing of samples of rilpivirine or a pharma- ceutically acceptable salt thereof. For example, as shown in the examples, the test of the first embodiment discriminates between different particle size distributions. Thus, in the second embodiment, the measured dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in an aqueous medium preferably indicates that a sample comprising rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles has a specified particle size distribution, e.g., a specified D v 50 or specified D v 90 or specified D v 10 or designated D v 10. D v 50, and D v90 is met. Determining whether a specified particle size distribution has been achieved is an important step in the manufacture of certain formulations of rilpivirine or a pharma- ceutically acceptable salt thereof for pharmaceutical use. Furthermore, upon storage of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles, some aggregation may occur, altering the particle size distribution. Thus, the measured dissolution of rilpivirine in a medium can be used to determine whether rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles stored for a period of time has retained its particle size distribution.

[0046] Determining whether the sample has passed the quality control test can be accomplished by comparing the measured dissolution of rilpivirine or a pharma- ceutically acceptable salt thereof in an aqueous medium to one or more reference values ​​of dissolution of a reference sample of rilpivirine or a pharma- ceutically acceptable salt thereof in microparticle or nanoparticle form, and determining whether the sample has passed the quality control test based on the comparison. For example, determining can include comparing the measured dissolution to one or more reference values ​​at a single time point, or at least two time points, or preferably at least three time points.

[0047] The determining may include comparing the measured lysis to one or more reference values, wherein the measured lysis is greater than or equal to reference values ​​(i)-(vi): (i) ≦30% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved in 5 minutes; (ii) 10 to 40% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved within 10 minutes; (iii) 39 to 59% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved within 30 minutes; (iv) 45 to 75% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved in 45 minutes; (v) 64 to 84% of the rilpivirine or a pharma- ceutically acceptable salt thereof is dissolved in 90 minutes; (vi) ≧80% of the rilpivirine or pharma- ceutically acceptable salt thereof is dissolved in 360 minutes.

[0048] For example, a sample can be determined to pass the quality control test if the measured dissolution meets values ​​(ii), (iv), and (vi), or preferably meets values ​​(i), (iii), (v), and (vi).

[0049] The characteristics of the reference sample, such as particle size distribution, may be independently verified by another technique, such as laser diffraction. Preferably, the reference value is for the dissolution of the reference sample in the same medium in which the sample was dispersed, and most preferably, the dissolution of the reference sample and the sample were tested using the same method, as this allows for a direct comparison. In the same method, the concentration of the surfactant in the aqueous medium when the sample is tested is maintained within ±1% of the concentration of the surfactant in the aqueous medium when the reference sample is tested, the temperature of the aqueous medium when the sample is tested is maintained within ±0.5°C of the temperature of the aqueous medium when the reference sample is tested, and the pH of the aqueous medium when the sample is tested is maintained within ±0.1 of the pH of the aqueous medium when the reference sample is tested.

[0050] However, in one aspect, a reference value can be obtained from the dissolution in different media, provided that a relationship between the dissolution in the different media is established such that the dissolution in the different media can be correlated with the dissolution of the sample in the selected medium.

[0051] Shipping of batches for pharmaceutical use In a third aspect, the quality control method is used to determine whether a batch of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles can be shipped for pharmaceutical use. For example, the batch can be shipped for sale, supply, or export. Shipping the batch can include providing the batch with documentation that certifies that the batch is suitable for pharmaceutical use. The batch can be of an approved pharmaceutical product (e.g., a product approved by the US Food and Drug Administration (FDA), the European Medicines Agency (EMA), and / or the UK Medicines & Healthcare products Regulatory Agency (MHRA)). For example, the batch can be of an NDA drug product, an ANDA drug product, a supplemental new drug application drug product, or a section 505(b)(2) drug product.

[0052] The pharmaceutical use preferably comprises the treatment of HIV infection or the prevention of HIV infection in a subject at risk of being infected with HIV, most preferably the long-term treatment of HIV infection or the long-term prevention of HIV infection in a subject at risk of being infected with HIV, in particular the treatment of HIV infection or the prevention of HIV infection in a subject at risk of being infected with HIV, wherein rilpivirine or a pharma- ceutically acceptable salt thereof, in the form of microparticles or nanoparticles, optionally in a suspension, is administered subcutaneously or intramuscularly intermittently at time intervals ranging from 1 week to 2 years, or from 2 weeks to 1 year, or from 1 month to 6 months, or about 1 month, or about 2 months, or about 3 months, or about 4 months, or about 5 months, or about 6 months.

[0053] The method may be performed as part of a process for producing rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles for pharmaceutical use. Thus, providing the batch may include producing the batch. The method may be performed as a means for checking the quality of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles obtained from a source. Thus, providing the batch may include obtaining the batch from a source. The method may be performed as a means for checking whether a stored batch of pharmaceutical product is in a suitable state for use. Thus, the batch may be stored for a period of time before the sample is taken; for example, at least 1 month, 3 months, or 6 months.

[0054] It will be understood that a batch refers to a larger amount of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles, and a smaller amount of a sample taken from a batch is considered to be representative of the batch. For example, a batch may include at least 100 g, at least 1 kg, or at least 10 kg of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles, optionally in suspension.

[0055] Providing the batch includes a continuous manufacturing process of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles, where quality control methods may be performed on a sample taken from the product of the continuous manufacturing process, and if the sample passes quality control tests, the batch of the manufacturing process occurring concurrently with the sample is released for pharmaceutical use. Samples may be taken from the product of the continuous manufacturing process at set periods to verify whether the process is operating as intended, e.g., that the intended particle size distribution is being obtained.

[0056] Rilpivirine Rilpivirine (4-[[4-[[4-[(1E)-2-cyanoethenyl]-2,6-dimethylphenyl]amino]-2-pyrimidinyl]amino]benzonitrile, TMC278, has the following structural formula:

[0057] [ka]

[0058] "Rilpivirine" means rilpivirine having the structural formula above, ie, the free base form.

[0059] The rilpivirine or a pharma- ceutically acceptable salt thereof is in the form of microparticles or nanoparticles, e.g., microparticles or nanoparticles of rilpivirine or a pharma- ceutically acceptable salt thereof in suspension, in particular microparticles or nanoparticles of rilpivirine or a pharma- ceutically acceptable salt thereof suspended in a pharma- ceutically acceptable carrier, such as a pharma- ceutical acceptable aqueous carrier.

[0060] A pharmaceutically acceptable salt of rilpivirine means that the counter ion is pharmaceutically acceptable. A pharmaceutically acceptable salt is meant to include the therapeutically active non-toxic acid addition salt forms that rilpivirine can form. These salt forms can be conveniently obtained by treating rilpivirine with a suitable acid, such as an inorganic acid (e.g., hydrohalic acid (e.g., hydrochloric acid, hydrobromic acid, etc.)), sulfuric acid, nitric acid, phosphoric acid, etc.), or an organic acid, such as acetic acid, propanoic acid, hydroxyacetic acid, 2-hydroxypropanoic acid, 2-oxopropanoic acid, oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, malic acid, tartaric acid, 2-hydroxy-1,2,3-propanetricarboxylic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, 4-methylbenzenesulfonic acid, cyclohexanesulfamic acid, 2-hydroxybenzoic acid, 4-amino-2-hydroxybenzoic acid, etc.

[0061] Preferably, the rilpivirine or a pharma- ceutically acceptable salt thereof used in the present invention is rilpivirine.

[0062] Those skilled in the art will understand that the size of the microparticles or nanoparticles should be below a maximum size above which administration by subcutaneous or intramuscular injection is impaired or even no longer possible, depending on the limitations imposed, for example, by the diameter of the needle, or by the body's adverse reactions to larger particles, or both.

[0063] In one embodiment, the rilpivirine or a pharma- ceutically acceptable salt thereof is in the form of nanoparticles.

[0064] In one embodiment, the rilpivirine or a pharma- ceutically acceptable salt thereof is in the form of microparticles.

[0065] In one embodiment, the microparticles or nanoparticles described herein have a D of less than about 20 μm, or less than about 10 μm, or less than about 2 μm. v 50 particle diameter.

[0066] Two embodiments having preferred particle sizes for rilpivirine or a pharma- ceutically acceptable salt thereof are contemplated herein.

[0067] In a first preferred particle size embodiment of rilpivirine or a pharma- ceutically acceptable salt thereof, the particles have a D v In this embodiment, the particles have a D of about 100 nm to about 2 μm. v In this embodiment, the particles may have a D of 200 nm to about 2 μm. v In this embodiment, the particles may have a D of 300 nm to about 2 μm. v In this embodiment, the particles may have a D of 400 nm to about 2 μm. v In this embodiment, the particles may have a D of 500 nm to about 2 μm. v 90. Preferably, in this embodiment, the particles have a D of 500 nm to about 1,600 nm. v D of 90 or 500 nm to about 1,000 nm v It has 90.

[0068] The term “D v "D 90" as used herein refers to the diameter below which 90% by volume of the particle population is found. v "D 50" as used herein refers to the diameter below which 50% by volume of the particle population is found. v "10" as used herein refers to the diameter below which 10% by volume of the particle population is found.

[0069] In a first preferred particle size embodiment of rilpivirine or a pharma- ceutically acceptable salt thereof, the particles have a D v 50. In this embodiment, the particles may have a D of about 10 nm to about 1,000 nm. v 50. In this embodiment, the particles may have a D of about 50 nm to about 700 nm. v 50. In this embodiment, the particles may have a D of about 100 nm to about 600 nm. v 50. In this embodiment, the particles may have a D of about 150 nm to about 500 nm. v 50. Preferably, in this embodiment, the particles have a D of about 200 nm to about 500 nm. v Has 50.

[0070] In a first preferred particle size embodiment of rilpivirine or a pharma- ceutically acceptable salt thereof, the particles have a D v In this embodiment, the particles may have a D of about 10 nm to about 500 nm. v In this embodiment, the particles may have a D of about 25 nm to about 400 nm. v In this embodiment, the particles may have a D of about 50 nm to about 300 nm. v In this embodiment, the particles may have a D of about 50 nm to about 200 nm. v 10. Preferably, in this embodiment, the particles have a D of about 75 nm to about 200 nm. v Has 10.

[0071] Preferably, in this embodiment, the particles of rilpivirine or a pharma- ceutically acceptable salt thereof have a D v 90, D of about 200 nm to about 500 nm v 50, and D of about 75 nm to about 200 nm v Has 10.

[0072] Alternatively, the particles of rilpivirine or a pharma- ceutically acceptable salt thereof have a D v 90, D of about 200 nm to about 500 nm v 50, and D of about 75 nm to about 200 nm v Has 10.

[0073] In a second preferred particle size embodiment of rilpivirine or a pharma- ceutically acceptable salt thereof, the particles have a D v In this embodiment, the particles may have a D of about 2 μm to about 9 μm. v In this embodiment, the particles may have a D of about 3 μm to about 8 μm. v In this embodiment, the particles may have a D of about 3 μm to about 7 μm. v 90. Preferably, in this embodiment, the particles have a D of about 4 μm to about 6 μm. v It has 90.

[0074] In a second preferred particle size embodiment of rilpivirine or a pharma- ceutically acceptable salt thereof, the particles have a D v In this embodiment, the particles have a D of less than about 2.5 μm. v In this embodiment, the particles may have a D of about 1 μm to about 2.5 μm. v In this embodiment, the particles may have a D of about 1.2 μm to about 2.2 μm. v 50. Preferably, in this embodiment, the particles have a D of about 1.5 μm to about 2 μm. v Has 50.

[0075] In a second preferred particle size embodiment of rilpivirine or a pharma- ceutically acceptable salt thereof, the particles have a Dv In this embodiment, the particles may have a D of about 10 nm to about 1000 nm. v In this embodiment, the particles may have a D of about 100 nm to about 700 nm. v In this embodiment, the particles may have a D of about 200 nm to about 600 nm. v 10. Preferably, in this embodiment, the particles have a D of about 300 nm to about 500 nm. v Has 10.

[0076] Preferably, in this embodiment, the particles of rilpivirine or a pharma- ceutically acceptable salt thereof have a D v 90, D of about 1.5 μm to about 2 μm v 50, and D of about 300 nm to about 500 nm v Has 10.

[0077] As used herein, D v 10. D v 50, and D v 90 is determined by conventional laser diffraction techniques, for example according to ISO 13320:2009.

[0078] Laser diffraction relies on the principle that particles scatter light at angles that vary with the size of the particle, and a collection of particles produces a pattern of scattered light defined by intensity and angle that can be correlated to particle size distribution. Many laser diffraction instruments are commercially available for fast and reliable measurement of particle size distribution. For example, particle size distribution can be measured by a conventional Malvern Mastersizer™ 3000 particle size analyzer manufactured by Malvern Instruments. The Malvern Mastersizer™ 3000 particle size analyzer works by projecting a helium-neon gas laser beam through a transparent cell that contains particles of interest suspended in an aqueous solution. The light that strikes the particles is scattered at angles that are inversely proportional to the particle size, a photodetector array measures the light intensity at several predefined angles, and the measured intensities at different angles are processed by a computer using standard theoretical principles to determine the particle size distribution. Laser diffraction values ​​can be obtained using a wet dispersion of particles in distilled water.

[0079] D v 10. D v 50, and D v Other methods commonly used in the art for measuring 90 include disk centrifugation, scanning electron microscope (SEM), sedimentation field flow fractionation, and photon correlation spectroscopy.

[0080] It was found that samples with larger particle sizes have a slower dissolution rate of rilpivirine or a pharma- ceutically acceptable salt thereof in aqueous media than samples with smaller particle sizes (see FIG. 3). Increasing the temperature of the aqueous medium increases the dissolution rate (see FIG. 4). Thus, the temperature at which the aqueous medium is maintained can be further optimized based on the expected particle size distribution of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles. The aqueous medium can be maintained at a higher temperature when testing samples with larger particle sizes in order to provide results within a reasonable time scale (e.g., more than 85% of the drug substance dissolves after 6 hours). When testing samples with smaller particle sizes, the aqueous medium can be maintained at a lower temperature because the lower temperature improves the discriminatory properties of the test while still providing results within a reasonable time scale. For example, when testing samples according to the first preferred embodiment of the particle size of rilpivirine or a pharma- ceutically acceptable salt thereof, the aqueous medium can be maintained at a temperature of 3-10° C., or 4-6° C., or 4.5-5.5° C. When testing samples according to the second preferred embodiment of the particle size of rilpivirine or a pharma- ceutically acceptable salt thereof, the aqueous medium can be maintained at a temperature of 7-15° C. or 10-15° C.

[0081] In one embodiment, the microparticles or nanoparticles of rilpivirine or a pharma- ceutically acceptable salt thereof have one or more surface modifiers adsorbed to their surface.

[0082] The surface modifier may be selected from known organic and inorganic pharmaceutical excipients, including various polymers, low molecular weight oligomers, natural products, and surfactants. Specific surface modifiers that may be used in the present invention may include non-ionic surfactants and anionic surfactants. Representative examples of surface modifiers include gelatin, casein, lecithin, salts or acid forms of negatively charged phospholipids (phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, phosphoric acid, and salts thereof, such as alkali metal salts, e.g., their sodium salts, e.g., sodium egg phosphatidylglycerol, such as the product available under the trade name Lipoid™ EPG), gum acacia, stearic acid, benzalkonium chloride, polyoxyethylene alkyl ethers, e.g., macrogol ethers, such as Cetomacrogol 1000, polyoxyethylene castor oil derivatives; polyoxyethylene stearate, colloidal silicon dioxide, sodium dodecyl sulfate, sodium carboxymethylcellulose, bile salts, such as sodium taurocholate, sodium desoxytaurocholate, sodium desoxycholate; methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, magnesium aluminosilicate, polyvinyl alcohol (polyvinyl alcohol), ... alcohol, PVA), poloxamers such as Pluronic™ F68, F108 and F127, which are block copolymers of ethylene oxide and propylene oxide; tyloxapol; vitamin E-TGPS (α-tocopheryl polyethylene glycol succinate, especially α-tocopheryl polyethylene glycol 1000 succinate); poloxamines such as Tetronic™ 908 (T908), which is a tetrafunctional block copolymer derived from the sequential addition of ethylene oxide and propylene oxide to ethylenediamine; dextran; lecithin; dioctyl esters of sodium sulfosuccinate, such as the product sold under the trade name Aerosol OT™ (AOT); sodium lauryl sulfate (Duponol™ P); alkylaryl polyether sulfonates sold under the trade name Triton™ X-200;Polyoxyethylene sorbitan fatty acid esters (Tweens™ 20, 40, 60 and 80); sorbitan esters of fatty acids (Span™ 20, 40, 60 and 80 or Arlacel™ 20, 40, 60 and 80); polyethylene glycols (such as those sold under the trade names Carbowax™ 3550 and 934); mixtures of sucrose stearate and sucrose distearate (e.g., products sold under the trade names Crodesta™ F110 or Crodesta™ SL-40); hexyldecyl trimethyl ammonium chloride (CTAC); polyvinylpyrrolidone (PVP), and the like. If necessary, two or more surface modifiers may be used in combination.;

[0083] In one embodiment, the surface modifier is selected from poloxamers, α-tocopheryl polyethylene glycol succinate, polyoxyethylene sorbitan fatty acid esters, and salts of negatively charged phospholipids or their acid forms. In a preferred embodiment, the surface modifier is selected from polyoxyethylene sorbitan fatty acid esters such as Pluronic™ F108, Vitamin E TGPS (α-tocopheryl polyethylene glycol succinate, particularly α-tocopheryl polyethylene glycol 1000 succinate), Tween™ 80, and phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, phosphoric acid, and salts thereof such as alkali metal salts, for example, their sodium salts, for example, egg phosphatidylglycerol sodium, such as the product available under the trade name Lipoid™ EPG.

[0084] In a preferred embodiment, the surface modifier is a poloxamer, in particular Pluronic™ F108. Pluronic™ F108 corresponds to poloxamer 338 and has the formula HO-[CH2CH2O] x -[CH(CH3)CH2O] y -[CH2CH2O]z -H, where the average values ​​of x, y, and z are 128, 54, and 128, respectively. Other trade names for poloxamer 338 are Hodag Nonionic™ 1108-F and Synperonic™ PE / F 108. In one embodiment, the surface modifier comprises a combination of a polyoxyethylene sorbitan fatty acid ester and a phosphatidylglycerol salt, particularly sodium egg phosphatidylglycerol.

[0085] In one embodiment, the relative amount (w / w) of rilpivirine or a pharma- ceutically acceptable salt thereof to the surface modifier in a sample or batch is from about 1:2 to about 20:1, particularly from about 1:1 to about 10:1, for example from about 4:1 to about 6:1, preferably about 6:1.

[0086] In one embodiment, the microparticles or nanoparticles of the invention comprise rilpivirine or a pharma- ceutically acceptable salt thereof, as defined herein, and one or more surface modifiers, as defined herein, wherein the amount of rilpivirine or a pharma- ceutically acceptable salt thereof is at least about 50% by weight of the microparticle or nanoparticle, at least about 80% by weight of the microparticle or nanoparticle, at least about 85% by weight of the microparticle or nanoparticle, at least about 90% by weight of the microparticle or nanoparticle, at least about 95% by weight of the microparticle or nanoparticle, or at least about 99% by weight of the microparticle or nanoparticle, particularly in the range of 80% to 90% by weight of the microparticle or nanoparticle, or in the range of 85% to 90% by weight of the microparticle or nanoparticle.

[0087] The sample or batch of rilpivirine or its pharma- ceutically acceptable salt in the form of microparticles or nanoparticles is preferably in the form of a suspension comprising a pharma- ceutically acceptable aqueous carrier in which the microparticles or nanoparticles are suspended. The pharma- ceutically acceptable aqueous carrier comprises sterile water (e.g., water for injection), optionally mixed with other pharma- ceutical acceptable components. The latter comprises any component for use in an injectable formulation. These components may be selected from one or more of the following components: suspending agents, buffering agents, pH adjusting agents, preservatives, tonicity agents, surface modifiers, chelating agents, etc. In one embodiment, the component is selected from one or more of the following: suspending agents, buffering agents, pH adjusting agents, and optionally preservatives and tonicity agents. A particular component may function as two or more of these agents simultaneously, for example acting as a preservative and a buffering agent, or acting as a buffering agent and a tonicity agent. In one embodiment, the component is selected from one or more of a buffering agent, a pH adjusting agent, a tonicity agent, a chelating agent, and a surface modifier. In one embodiment, the component is selected from one or more of a buffering agent, a pH adjusting agent, a tonicity agent, and a chelating agent.

[0088] In one embodiment, the suspension is formulated for administration by subcutaneous or intramuscular injection. In one embodiment, the suspension is formulated for administration by subcutaneous injection. In one embodiment, the suspension is formulated for administration by intramuscular injection.

[0089] In one embodiment, the suspension further comprises a buffering agent and / or a pH adjusting agent. Suitable buffering agents and pH adjusting agents should be used in an amount sufficient to bring the suspension to a pH range of 6 to 8.5, preferably 7 to 7.5. Particular buffering agents are salts of weak acids. The buffering agent and pH adjusting agent that can be added can be selected from tartaric acid, maleic acid, glycine, sodium lactate / lactic acid, ascorbic acid, sodium citrate / citric acid, sodium acetate / acetic acid, sodium bicarbonate / carbonic acid, sodium succinate / succinic acid, sodium benzoate / benzoic acid, sodium phosphate, tris(hydroxymethyl)aminomethane, sodium bicarbonate / sodium carbonate, ammonium hydroxide, benzenesulfonic acid, sodium benzoate / acid, diethanolamine, glucono delta lactone, hydrochloric acid, hydrogen bromide, lysine, methanesulfonic acid, monoethanolamine, sodium hydroxide, tromethamine, gluconic acid, glyceric acid, glutaric acid, glutamic acid, ethylene diamine tetraacetic acid (EDTA), triethanolamine, and mixtures thereof. In one embodiment, the buffering agent is a sodium phosphate buffer, such as sodium dihydrogen phosphate monohydrate. In one embodiment, the pH adjusting agent is sodium hydroxide.

[0090] In one embodiment, the suspension further comprises a preservative. The preservative is an antimicrobial and antioxidant that can be selected from the group consisting of benzoic acid, benzyl alcohol, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), chlorobutol, gallates, hydroxybenzoates, EDTA, phenol, chlorocresol, metacresol, benzethonium chloride, myristyl-gamma-picolinium chloride, phenylacetate nitrate, and thimerosal. Radical scavengers include BHA, BHT, vitamin E, and ascorbyl palmitate, and mixtures thereof. Oxygen scavengers include sodium ascorbate, sodium sulfite, L-cysteine, acetylcysteine, methionine, thioglycerol, acetone sodium bisulfite, isoascorbic acid, and hydroxypropyl cyclodextrin. Chelating agents include sodium citrate, sodium EDTA, citric acid, and malic acid. In one embodiment, the chelating agent is citric acid, for example, citric acid monohydrate.

[0091] In one embodiment, the suspension further comprises an isotonicity agent. An isotonizing agent or isotonifier may be present to ensure the isotonicity of the pharmaceutical composition of the invention, and includes sugars such as glucose, dextrose, sucrose, fructose, trehalose, lactose; polyhydric sugar alcohols, preferably trihydric or higher sugar alcohols, such as glycerin, erythritol, arabitol, xylitol, sorbitol, and mannitol. Alternatively, sodium chloride, sodium sulfate, or other suitable inorganic salts may be used to make the solution isotonic. These isotonicity agents may be used alone or in combination. The suspension advantageously comprises 0-10% (w / v), in particular 0-6% (w / v), of the isotonicity agent. Non-ionic isotonicity agents, such as glucose, mannitol, are of interest, since electrolytes may affect colloidal stability.

[0092] In one embodiment, the batch contains multiple doses of rilpivirine or a pharma- ceutically acceptable salt thereof, optionally formulated to be suitable for administration by intramuscular or subcutaneous injection, for the long-term treatment of HIV infection in HIV-infected subjects or for the long-term prevention of HIV infection in subjects at risk of HIV infection.

[0093] In one embodiment, the batch contains multiple doses, each of which contains up to about 150 mL of the suspension described herein, i.e., the volume of the suspension containing rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles, may have a volume of up to 150 mL. In one embodiment, each dose contains from about 2 mL to about 100 mL of the suspension. In another embodiment, each dose contains from about 3 mL to about 75 mL of the suspension. In another embodiment, each dose contains from about 4 mL to about 50 mL of the suspension. In another embodiment, each dose contains from about 5 mL to about 25 mL of the suspension. In another embodiment, each dose contains from about 6 mL to about 20 mL of the suspension. In another embodiment, each dose contains from about 6 mL to about 18 mL of the suspension. In another embodiment, each dose contains from about 6 mL to about 15 mL of the suspension. In another embodiment, each dose contains from about 6 mL to about 12 mL of the suspension. In another embodiment, each dose contains from about 9 mL to about 18 mL of the suspension. In another embodiment, each dose contains about 9 mL to about 15 mL of the suspension. In another embodiment, each dose contains about 9 mL to about 12 mL of the suspension. In another embodiment, each dose contains about 6 mL of the suspension. In another embodiment, each dose contains about 9 mL of the suspension. In another embodiment, each dose contains about 12 mL of the suspension. In another embodiment, each dose contains about 15 mL of the suspension. In another embodiment, each dose contains about 18 mL of the suspension. In one embodiment, the rilpivirine suspension contains 300 mg of rilpivirine or a pharma- ceutically acceptable salt thereof / mL. In one embodiment, the rilpivirine suspension contains 300 mg of rilpivirine or a pharma- ceutically acceptable salt thereof / mL and the dose is 2 mL. In one embodiment, the rilpivirine suspension contains 300 mg of rilpivirine or a pharma- ceutically acceptable salt thereof / mL and the dose is 3 mL.

[0094] In one embodiment, when the rilpivirine or pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles is for the treatment of HIV infection, the batch contains multiple doses formulated such that the dose administered can be calculated based on about 300 mg to about 1200 mg / month, or about 450 mg to about 1200 mg / month, or about 450 mg to about 900 mg / month, or about 600 mg to about 900 mg / month, or about 450 mg to about 750 mg / month, or 450 mg / month, or 600 mg / month, or 750 mg / month, or 900 mg / month. Doses for other dosing regimens can be easily calculated by multiplying the monthly dose by the number of months between each administration. For example, for a dose of 450 mg / month and a time interval of 6 months between each administration, the dose administered in each administration is 2700 mg. The "mg" indicated corresponds to mg of rilpivirine (i.e., rilpivirine in its free base form). Thus, by way of example, 1 mg of rilpivirine (ie, rilpivirine in its free base form) is equivalent to 1.1 mg of rilpivirine hydrochloride.

[0095] In one embodiment, for the treatment of HIV infection, the batch contains multiple doses formulated such that the dose administered can be calculated based on about 300 mg to about 1200 mg / 4 weeks (28 days), or about 450 mg to about 1200 mg / 4 weeks (28 days), or about 450 mg to about 900 mg / 4 weeks (28 days), or about 600 mg to about 900 mg / 4 weeks (28 days), or about 450 mg to about 750 mg / 4 weeks (28 days) or 450 mg / 4 weeks (28 days), or 600 mg / 4 weeks (28 days), or 750 mg / 4 weeks (28 days) or 900 mg / 4 weeks (28 days). Doses for other dosing regimens can be readily calculated by multiplying the weekly or daily dose by the number of weeks between each administration. For example, in the case of a dose of 450 mg / 4 weeks (28 days) and the time interval between each administration is 24 weeks, the dose administered in each administration is 2700 mg. Alternatively, for example, in the case of a dose of 750 mg / 4 weeks (28 days) and the time interval between each administration is 24 weeks, the dose administered in each administration is 4500 mg. The "mg" shown corresponds to mg of rilpivirine. Thus, for example, 1 mg of rilpivirine corresponds to 1.1 mg of rilpivirine hydrochloride.

[0096] In one embodiment, for the treatment of HIV infection, the batch contains at least about 600 mg of rilpivirine or a pharma- ceutically acceptable salt thereof, for example, about 900 mg to about 28,800 mg (e.g., about 900 mg to about 14,400 mg, or about 900 mg to about 7,200 mg, or about 900 mg to about 3,600 mg), preferably about 1,200 mg to about 14,400 mg, preferably about 1,350 mg to about 13,200 mg, and preferably about 1,500 mg to about 2,500 mg. contains multiple doses formulated to contain about 1500 mg to about 12000 mg (e.g., about 3000 mg to about 12000 mg), preferably about 1800 mg to about 10800 mg (e.g., about 2700 mg to about 10800 mg, or about 1800 mg to about 3600 mg), and most preferably about 1800 mg to about 7200 mg or about 2700 mg to about 4500 mg of rilpivirine or a pharma- ceutically acceptable salt thereof.

[0097] Therefore, the amount of rilpivirine or a pharma- ceutically acceptable salt thereof in a dose in a batch may be at least about 600 mg, for example, about 900 mg to about 28,800 mg (e.g., about 900 mg to about 14,400 mg, or about 900 mg to about 7,200 mg, or about 900 mg to about 3,600 mg), preferably about 1,200 mg to about 14,400 mg, preferably about 1,350 mg to about 13,200 mg, preferably about 1,500 mg to about 12,000 mg (e.g., about 3,000 mg to about 12,000 mg), preferably about 1,800 mg to about 10,800 mg (e.g., about 2,700 mg to about 10,800 mg, or about 1,800 mg to about 3,600 mg), and most preferably about 1,800 mg to about 7,200 mg or about 2,700 mg to about 4,500 mg. The "mg" indicated corresponds to mg of rilpivirine. Thus, by way of example, 1 mg of rilpivirine corresponds to 1.1 mg of rilpivirine hydrochloride. In one embodiment, the amount of rilpivirine or a pharma- ceutically acceptable salt thereof in a dose is 600 mg. In one embodiment, the amount of rilpivirine or a pharma- ceutically acceptable salt thereof in a dose is 900 mg.

[0098] In the case of prevention of HIV infection, each administration of rilpivirine or a pharma- ceutically acceptable salt thereof may contain the same dose as for therapeutic applications as described above.

[0099] In one embodiment, the doses in the batch are formulated such that, in use, preferably for the treatment of HIV infection, particularly HIV-1 infection, the plasma concentration of rilpivirine in the subject is maintained at a level of more than about 12 ng / ml, preferably in the range of about 12 ng / ml to about 100 ng / ml, more preferably about 12 ng / ml to about 50 ng / ml, for at least one month, or two months, or three months, or at least six months, or at least nine months, or at least one year, or at least two years after each dose. In one embodiment, the doses in the batch are formulated such that, in use, the plasma concentration of rilpivirine in the subject is maintained at a level of 12 ng / ml to 100 ng / ml for one month. In one embodiment, the doses in the batch are formulated such that, in use, the plasma concentration of rilpivirine in the subject is maintained at a level of 12 ng / ml to 100 ng / ml for two months. In one embodiment, the doses in a batch are formulated such that, upon use, the plasma concentration of rilpivirine in a subject is maintained at a level between 12 ng / ml and 100 ng / ml for at least 6 months.

[0100] In one embodiment, the batch contains multiple doses formulated for administration intermittently at time intervals ranging from 1 week to 2 years, or from 2 weeks to 1 year, or from 1 month to 6 months, or about 1 month, or about 2 months, or about 3 months, or about 4 months, or about 5 months, or about 6 months, preferably by subcutaneous or intramuscular injection.

[0101] In certain embodiments, a sample or batch of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles is formulated as a suspension containing one or more, optionally all, of the following components: Rilpivirine or a pharma- ceutically acceptable salt thereof, in particular rilpivirine; Surface modifiers as defined herein, in particular poloxamer 338, Tonicity agents, especially glucose monohydrate, buffering agents, especially sodium dihydrogen phosphate; Chelating agents, especially citric acid monohydrate, pH adjusters, especially sodium hydroxide, and Water, especially water for injections.

[0102] In another particular embodiment, a sample or batch of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles is formulated as a suspension comprising one or more, optionally all, of the following components: Rilpivirine or a pharma- ceutically acceptable salt thereof, in particular rilpivirine; Poloxamer 338, glucose monohydrate, Sodium dihydrogen phosphate, Citric acid monohydrate, Sodium hydroxide, and Water, especially water for injections.

[0103] In one embodiment, a sample or batch of rilpivirine or a pharma- ceutically acceptable salt thereof in the form of microparticles or nanoparticles is formulated as an aqueous suspension comprising, by weight, the following, based on the total volume of the suspension: (a) 3% to 50% (w / v), or 10% to 40% (w / v), or 10% to 30% (w / v) of rilpivirine or a pharma- ceutically acceptable salt thereof, in particular rilpivirine; (b) 0.5% to 10% (w / v), or 0.5% to 5% (w / v), or 0.5% to 2% (w / v) of a surface modifier, in particular poloxamer 338; (c) one or more buffers, in particular sodium dihydrogen phosphate, at 0% to 10% (w / v), or 0% to 5% (w / v), or 0% to 2% (w / v), or 0% to 1% (w / v); (d) 0% to 10% (w / v), or 0% to 6% (w / v), or 0% to 5% (w / v), or 0% to 3% (w / v), or 0% to 2% (w / v) of an isotonicity agent, in particular glucose monohydrate; (e) 0% to 2% (w / v), or 0% to 1% (w / v), or 0% to 0.5% (w / v), or 0% to 0.1% (w / v) of a pH adjuster, in particular sodium hydroxide; (f) 0% to 2% (w / v), or 0% to 1% (w / v), or 0% to 0.5% (w / v), or 0% to 0.1% (w / v) of a chelating agent, in particular citric acid monohydrate; (g) 0% to 2% (w / v) of a preservative, and (h) Water for injection, qs to 100%.

[0104] In one embodiment, the aqueous suspension may include, on a weight basis and based on the total volume of the suspension, the following: (a) 3% to 50% (w / v), or 10% to 40% (w / v), or 10% to 30% (w / v) of rilpivirine or a pharma- ceutically acceptable salt thereof, in particular rilpivirine; (b) 0.5% to 10% (w / v), or 0.5% to 5% (w / v), or 0.5% to 2% (w / v) of a surface modifier, in particular poloxamer 338; (c) one or more buffers, in particular sodium dihydrogen phosphate, at 0% to 10% (w / v), or 0% to 5% (w / v), or 0% to 2% (w / v), or 0% to 1% (w / v); (d) 0% to 10% (w / v), or 0% to 6% (w / v), or 0% to 5% (w / v), or 0% to 3% (w / v), or 0% to 2% (w / v) of an isotonicity agent, in particular glucose monohydrate; (e) 0% to 2% (w / v), or 0% to 1% (w / v), or 0% to 0.5% (w / v), or 0% to 0.1% (w / v) of a pH adjuster, in particular sodium hydroxide; (f) 0% to 2% (w / v), or 0% to 1% (w / v), or 0% to 0.5% (w / v), or 0% to 0.1% (w / v) of a chelating agent, in particular citric acid monohydrate, and (g) Water for injection, qs to 100%.

[0105] In certain embodiments, a sample or batch of rilpivirine or a pharma- ceutically acceptable salt thereof is formulated as a microparticle or nanoparticle suspension, the suspension comprising the following components in the following amounts: (a) rilpivirine (300 mg), (b) poloxamer 338 (50 mg), and (c) Water for injection (up to 1 mL).

[0106] Alternatively, these components can be used in various amounts, but the weight ratio between the components and the total volume (made up by water for injection) scaled by the same values ​​is the same.

[0107] In certain embodiments, a sample or batch of rilpivirine or a pharma- ceutically acceptable salt thereof is formulated (and administered) as a microparticle or nanoparticle suspension, the suspension comprising the following components in the following amounts: Rilpivirine (300 mg), b. Poloxamer 338 (50 mg), c. glucose monohydrate (19.25 mg), d. Sodium dihydrogen phosphate (2.00 mg), e. citric acid monohydrate (1.00 mg), f. Sodium hydroxide (0.866 mg), and g. Water for injection (up to 1 mL).

[0108] Alternatively, these components can be used in various amounts, but the weight ratio between the components and the total volume (made up by water for injection) scaled by the same values ​​is the same.

[0109] In one embodiment, the suspension of rilpivirine or a pharma- ceutically acceptable salt thereof described herein is suitable for administration by a manual injection process.

[0110] As used herein, the term "treatment of HIV infection" relates to the treatment of subjects infected with HIV, particularly HIV-1. The term "treatment of HIV infection" also relates to the treatment of diseases associated with HIV infection (e.g., AIDS) or other conditions associated with HIV infection (including thrombocytopenia, Kaposi's sarcoma, and infection of the central nervous system characterized by progressive demyelination resulting in dementia and symptoms (e.g., progressive anaarthria, ataxia, and disorientation)), as well as further conditions with which HIV infection is also associated (e.g., peripheral neuropathy, progressive generalized lymphadenopathy (PGL), and AIDS-related complex (ARC)).

[0111] As used herein, the term "prevention of HIV infection" refers to preventing or avoiding a subject (not infected with HIV) from becoming infected with HIV, in particular HIV-1. The source of infection can be various HIV-containing materials, in particular HIV-containing body fluids, such as blood or semen, or another subject infected with HIV. Prevention of HIV infection refers to preventing the transmission of the virus from HIV-containing materials or HIV-infected individuals to uninfected individuals, or to preventing the virus from entering the body of an uninfected individual. Transmission of the HIV virus can be by any of the known causes of HIV transfer, such as by sexual transmission or by contact with the blood of an infected subject (e.g., medical staff providing care to an infected subject). Transfer of HIV can also occur by contact with HIV-infected blood, for example when handling blood samples or using blood transfusions. It can also be by contact with infected cells, for example when performing laboratory experiments with HIV-infected cells.

[0112] The term "treatment of HIV infection" refers to a treatment in which the HIV viral load (expressed as the number of copies of viral RNA in a specific volume of serum) is reduced. The more effective the treatment, the lower the viral load. Preferably, the viral load should be reduced to the lowest possible level, for example below about 200 copies / mL, in particular below about 100 copies / mL, more in particular below 50 copies / mL, and if possible below the detection limit of the virus. A reduction in viral load of one, two or even three orders of magnitude (for example, from about 10 to about 10 2 , or more, for example, about 10 3 A decrease in the CD4 count (of the order of magnitude of a decrease in the CD4 count) is an indication of the effectiveness of the treatment. Another parameter for measuring the effectiveness of HIV treatment is the CD4 count, which ranges from 500 to 1500 cells per μL in healthy adults. A decrease in the CD4 count is an indication of HIV infection, and when it falls below about 200 cells / μL, AIDS may develop. An increase in the CD4 count (e.g., about 50, 100, 200, or more cells per μL) is also an indication of the effectiveness of anti-HIV treatment. In particular, the CD4 count should increase to a level of more than about 200 cells per μL, or to a level of more than about 350 cells per μL. The viral load or the CD4 count, or both, can be used to diagnose the extent of HIV infection. Another parameter for measuring the effectiveness of HIV treatment is keeping an HIV-infected subject virologically suppressed (HIV-1 RNA<50 copies / mL) when undergoing treatment according to the invention.

[0113] The term "treatment of HIV infection" and similar terms refer to that treatment that reduces viral load, increases CD4 count, or both, or keeps HIV-infected subjects in a virologically suppressed state, as described above. The term "prevention of HIV infection" and similar terms refer to a situation in which there is a reduction in the relative number of newly infected subjects in a population that is in contact with a source of HIV infection (e.g., a material containing HIV) or an HIV-infected subject. Effective prevention can be measured, for example, by measuring in a mixed population of HIV-infected and uninfected individuals, when there is a reduction in the relative number of newly infected individuals when comparing uninfected individuals treated with the pharmaceutical composition of the present invention to uninfected individuals that are not treated. This reduction can be measured by statistical analysis of the number of infected and uninfected individuals in a given population over time.

[0114] general definition The term "comprising" encompasses "including" as well as "consisting," e.g., a composition "comprising" X may consist only of X, or may include something additional, e.g., X+Y. As used herein, the term "comprising" also encompasses "consisting essentially of," e.g., a composition "comprising" X may consist of X and any other components that do not substantially affect the essential characteristics of the composition.

[0115] The term "about" in reference to a numerical value Y is optional and means, for example, Y±10%.

[0116] When a time interval is expressed as a specified number of months, the time interval extends from a given numbered day in a given month to the same numbered day in the month that falls the specified number of months later. If the same numbered day does not exist in the month that falls the specified number of months later, the time interval extends the same number of days into the next month, if the same numbered day does exist in the month that falls the specified number of months later.

[0117] When a time interval is expressed as a number of years, the time interval lasts from a given date in a given year to the same date in the year that falls the specified number of years later. If the same date does not exist in the year that falls the specified number of years later, the time interval lasts for the same number of days if the same numbered day exists in the month that falls the specified number of months later. In other words, if a time interval starts on February 29th of a given year but ends in a year that does not have February 29th, the period ends on March 1st of that year. The term "about" in connection with such a definition means that the time interval may end on a date that is ±10% of the time interval.

[0118] In one embodiment, the time interval may begin up to 7 days before or after the start of the time interval and end up to 7 days before or after the end of the time interval.

[0119] All publications cited herein are incorporated by reference in their entirety.

[0120] The present invention will now be described with reference to the following examples. For the avoidance of doubt, these examples are not intended to limit the scope of the present invention. Modifications may be made within the scope and spirit of the present invention. EXAMPLES

[0121] Example 1 - Differentiating different particle sizes The ability of the dissolution test to distinguish between different particle sizes of rilpivirine was investigated. Suspensions of 300 mg / mL rilpivirine with the following excipients were prepared: Poloxamer 338 (50mg / ml) Glucose monohydrate (19.25mg / ml) Sodium dihydrogen phosphate monohydrate (2.00 mg / ml) Citric acid monohydrate (1.00mg / ml) Sodium hydroxide (0.866mg / ml) ·Water for injection (appropriate amount 1mL)

[0122] The particle size distribution of rilpivirine was varied by controlling the milling parameters used in preparing the suspension and determined using laser diffraction.

[0123] [Table 2]

[0124] Dissolution of the suspension was tested using a paddle apparatus (USP type 2, Ph.Eur, JP) at a rotation speed of 50 rpm in 900 mL of 6.0% w / v polysorbate 20 in 0.05 M sodium phosphate buffer pH 7.4 at 5° C. The sample amount corresponds to 18 mg of rilpivirine.

[0125] After 360 min, the temperature was increased to 37° C. and maintained for 60 min to simulate an infinity time point. The sample taken after the infinity temperature time point is labeled 420 min.

[0126] The amount of dissolved drug substance was determined by a gradient ultra-performance liquid chromatography (UHPLC) method with UV detection at 280 nm.

[0127] The results are shown in Figure 1. This dissolution method was found to discriminate the size distribution of drug substance particles that determines the behavior of the drug substance in vivo. Surprisingly, the method discriminates even for samples with small particle sizes, e.g., D v The suspension (h) having 50=184 nm was D- v50=174 nm. The dissolution method therefore provides a convenient method for the quality control of batches of rilpivirine or a pharma- ceutically acceptable salt thereof in microparticle or nanoparticle form.

[0128] Example 2 - Differentiating different particle sizes This example compares the dissolution profiles of three rilpivirine suspensions, each with a different particle size.

[0129] Suspension 1 A 300 mg / mL suspension of rilpivirine (D v A 3.380 mL fill of 1000 μl ... Poloxamer 338 (50mg / ml) Glucose monohydrate (19.25mg / ml) Sodium dihydrogen phosphate monohydrate (2.00 mg / ml) Citric acid monohydrate (1.00mg / ml) Sodium hydroxide (0.866mg / ml) ·Water for injection (appropriate amount 3mL)

[0130] The suspension was prepared as follows: The buffer solution was prepared by dissolving citric acid monohydrate, sodium dihydrogen phosphate monohydrate, sodium hydroxide, and glucose monohydrate in water for injection in a stainless steel container. Poloxamer 338 was added to the buffer solution and mixed until dissolved. The first fraction of the poloxamer 338 buffer solution was passed sequentially through a prefilter and two sterile filters connected in series into a sterile stainless steel container. The sterile drug substance (micronized and irradiated) was aseptically dispersed in the sterile solution via a charging isolator. The remaining fraction of the poloxamer 338 buffer solution was passed sequentially through a prefilter and two sterile filters connected in series into a grinding container to create a suspension concentrate. During and after the addition of the drug substance, the suspension concentrate was mixed to wet and disperse the drug substance.

[0131] Grinding of suspension concentrates The suspension concentrate in the grinding vessel was aseptically milled by circulating it through a sterile stainless steel grinding chamber using sterile zirconia beads as the grinding media. During the grinding process, the suspension was circulated between the grinding chamber and the grinding vessel by a peristaltic pump until the target particle size was achieved.

[0132] Dilution of suspension concentrate to final concentration The suspension concentrate in the holding vessel was diluted with water for injection, which was sterile filtered through a prefilter and two in-line sterile filters, through a grinding chamber and a 70 μm stainless steel filter into the vessel. After the final dilution, the headspace of the vessel was blanketed with nitrogen and the suspension was mixed until homogenous.

[0133] Final suspension holding and filling With mixing, the suspension was aseptically transferred from the holding vessel to a time / pressure (t / p) dosing vessel from which it was filled into vials, which were flushed with nitrogen, stoppered, and capped with aluminum seals having flip-off buttons.

[0134] Suspensions 2 and 3 Two further suspensions with the same composition but different particle sizes were prepared by blending and milling as described below (Suspensions 2 and 3). 1.586.62 g of water for injection was added to a 2 L glass beaker containing a magnetic stir bar. 2. The correct amounts of citric acid monohydrate, sodium dihydrogen phosphate monohydrate, sodium hydroxide were added and stirred until dissolved. 3. The correct amount of Poloxamer 338 and glucose monohydrate were added and stirred until dissolved. 4. Filter the diluent through a 0.22 μm filter and rinse the beaker with the remaining 100 mL of Water for Injection and filter. 5. Rilpivirine nanoparticles were added and stirred until a homogenous suspension was obtained. 6. 500 mL of the suspension was transferred to a sterile beaker and placed in a double-walled cooled glass beaker with a magnetic stir bar. 7. Start milling in the Netzsch Labstar and mill until the target particle size distribution is reached. For suspension 2, the milling time was approximately 180 minutes. For suspension 3, the milling time was approximately 35 minutes. 8. The particle size distribution was measured during grinding. 9. Each suspension was diluted to 300 mg / mL.

[0135] Particle size distribution measurement Volumetric particle size distribution of the rilpivirine suspension was determined by wet dispersion laser diffraction using a Malvern Mastersizer3000 laser diffraction (Malvern Instruments) and a HydroMV wet dispersion module.

[0136] The particle sizes of the three rilpivirine suspensions were as defined in Table 2.

[0137] [Table 3]

[0138] In vitro dissolution assay Dissolution of the three rilpivirine suspensions in water was performed using a paddle apparatus (USP type 2, Ph.Eur., JP.) at 50 rpm in 900 mL of 6.0% (w / v) polysorbate 20 in 0.05 M sodium phosphate buffer (pH 7.4) at 5.0 ± 0.5 °C. 64.98 mg (= 0.06 mL × 1.083 g / mL (theoretical density of the suspension)) ± 5% homogeneous suspension of rilpivirine (corresponding to 18 ± 0.9 mg of rilpivirine) was added.

[0139] Measurement of the amount of rilpivirine present in the dissolution samples was based on a gradient ultra-performance liquid chromatography (UHPLC) method with UV detection at 280 nm. The results are shown in Figure 2 and demonstrate the ability of the dissolution test to distinguish between suspensions 1, 2, and 3. The dissolution test shows that rilpivirine in the form of microparticles or nanoparticles with larger particle sizes shown in Table 2 surprisingly reduced, i.e. flattened, the dissolution profile of rilpivirine.

[0140] Example 3 - Differentiating different particle sizes This example compares the dissolution profiles of five rilpivirine suspensions, each with a different particle size.

[0141] Preparation of Rilpivirine Suspensions and Measurement of Particle Size Five suspensions of rilpivirine were prepared according to methods corresponding to those described for suspensions 2 and 3 in Example 2. The volumetric particle size distribution of the rilpivirine microparticles or nanoparticles in the suspensions was determined according to methods corresponding to those defined in Example 2.

[0142] [Table 4]

[0143] In vitro dissolution assay Dissolution of the five rilpivirine suspensions in water was performed according to the method defined in Example 2. The results are shown in Figure 3, which demonstrates that the dissolution test is able to distinguish between different particle sizes of rilpivirine. As the particle size of rilpivirine in the form of microparticles or nanoparticles increases, the dissolution profile of rilpivirine decreases, i.e., flattens out.

[0144] Example 4 - Melting Temperature D of about 200 nm v Dissolution of a suspension of nanoparticulate rilpivirine having a molecular weight of 50 was tested using the method of Example 1, but with dissolution media at different temperatures (37° C., 25° C., 15° C., and 5° C.). The dissolution profiles are shown in FIG.

[0145] The use of a dissolution medium temperature below the physiological temperature of 37°C was found to be essential for the ability of the dissolution test to distinguish between different particle sizes of rilpivirine. At 37°C, rilpivirine is completely dissolved in about 10 minutes. However, the use of lower temperatures delayed the release of rilpivirine to such an extent that the discriminatory power of the method was significantly increased. At 5°C, the drug substance is less than 30% dissolved in 5 minutes, thereby allowing the detection of a potential initial increase (burst) release. More than 85% of the drug substance is dissolved after 6 hours, thereby providing a dissolution profile that is sufficiently variable to allow the discrimination of different particle sizes of rilpivirine or its pharma- ceutically acceptable salts in the form of microparticles or nanoparticles over a practically convenient time scale.

[0146] Example 5 - Surfactant concentration D at 218 nm v Dissolution of suspensions of nanoparticulate rilpivirine with 50 was tested using the method of Example 1, but with different concentrations of surfactant (1-6% w / v polysorbate 20). The dissolution profiles are shown in Figure 5.

[0147] The use of higher concentrations of polysorbate 20 resulted in a more optimized dissolution profile. For example, when 6% polysorbate 20 was added, the initial release of rilpivirine was still far below 20% dissolution, but could reach more than 85% dissolution after 360 minutes. As a result, this allows a single method to better detect potential burst release, characterize the release profile, and detect a final release of more than 50%, or 60%, or 70%, or 80%, or 90%, preferably 100% dissolution. The performance of each method can also be defined by calculating the difference between the lowest and highest dissolution % in the dissolution profile, i.e., delta dissolution %. The delta dissolution % of the 6% polysorbate 20 method is approximately 80%. The higher the dissolution % is, the higher the ability of the method to distinguish between different particle sizes of rilpivirine. Similarly, the surfactant concentration can be controlled to optimize the method by increasing the delta dissolution %.

[0148] Example 6: Sink conditions The equilibrium solubility of rilpivirine in 0.05 M phosphate buffer at pH 7.4 as a function of polysorbate 20 concentration was determined at 5° C. and is presented in FIG. 6. Reference lines indicate the concentration equivalent to a single dose of 18 mg rilpivirine dissolved in medium (0.002 g / 100 mL, lower horizontal line) and sink conditions (defined as ≧3×single dose, i.e. ≧0.006 g / 100 mL, upper horizontal line). Although not sink conditions, dissolution tests have been found to distinguish between different particle sizes of rilpivirine, as shown by the examples herein.

[0149] Example 7 - Identification of storage conditions D at 192 nm stored under different conditions vThe dissolution of a suspension of nanoparticulate rilpivirine having a pH of 50 was tested using the method of Example 1. Storage conditions were 5° C. for 6 months and 6 months under accelerated stress conditions of 25° C. / 40% RH, 30° C. / 35% RH, and 40° C. / 25% RH. The dissolution profiles are shown in FIG. 7. As samples stored at the different conditions tested could be differentiated, it can be concluded that the dissolution method is capable of detecting changes to drug products after exposure to stressful temperature and humidity conditions.

Claims

1. 1. A method of testing a sample of rilpivirine or a pharmaceutically acceptable salt thereof, wherein the sample comprises rilpivirine or a pharmaceutically acceptable salt thereof in the form of microparticles or nanoparticles, the method comprising: Dispersing the sample in an aqueous medium, the aqueous medium containing a surfactant, and maintained at a temperature of 2 to 15°C; measuring the dissolution of said rilpivirine or a pharmaceutically acceptable salt thereof in said aqueous medium.

2. 10. The method of claim 1, wherein the aqueous medium is maintained at a temperature of from 3 to 10°C, or from 4 to 6°C, or from 4.5 to 5.5°C.

3. 10. The method of claim 1, wherein the aqueous medium has a pH of 6 to 8, 7 to 8, 7.2 to 7.8, or 7.3 to 7.

5.

4. 10. The method of claim 1, wherein the surfactant is a non-ionic surfactant, and optionally, the surfactant is polysorbate 20.

5. 2. The method of claim 1, wherein the surfactant is present in the aqueous medium at a concentration of 4 to 8% w / v, or 5.5 to 6.5% w / v, or 5.94 to 6.06% w / v.

6. 2. The method of claim 1, wherein the method is not performed under sink conditions, which are defined as conditions in which the equilibrium solubility of rilpivirine or a pharmaceutically acceptable salt thereof in the aqueous medium is at least three times higher than the concentration that would be obtained if all of the rilpivirine or a pharmaceutically acceptable salt thereof in the sample were dissolved in the aqueous medium.

7. 7. The method of claim 1, wherein the equilibrium solubility of rilpivirine or a pharmaceutically acceptable salt thereof in the aqueous medium is at least as high as the concentration that would be obtained if all of the rilpivirine or a pharmaceutically acceptable salt thereof in the sample were dissolved in the aqueous medium.

8. 7. The method of claim 1, wherein the concentration of rilpivirine or a pharmaceutically acceptable salt thereof in the sample is about 0.015 to 0.025 mg / mL, or about 0.019 to 0.021 mg / mL, or about 0.020 mg / mL, when all of the rilpivirine or a pharmaceutically acceptable salt thereof in the sample is dissolved in the aqueous medium.

9. The method of any one of claims 1 to 6, wherein the sample contains 10 to 30 mg, or 16 to 20 mg, or 17.1 to 18.9 mg of rilpivirine or a pharmaceutically acceptable salt thereof.

10. 7. The method of any one of claims 1 to 6, wherein the volume of the aqueous medium is 500 to 1500 mL, or 700 to 1,100 mL, or about 900 mL.

11. 7. The method of any one of claims 1 to 6, wherein the aqueous medium comprises a buffer, optionally wherein the buffer is 0.05 M sodium phosphate buffer.

12. The aqueous medium is containing 5.94 to 6.06% w / v polysorbate 20, containing 0.05M sodium phosphate buffer, having a pH of 7.3 to 7.5; 10. The method of claim 1, wherein the temperature is maintained at 4.5 to 5.5°C.

13. 13. The method of claim 12, wherein the sample contains 17.1 to 18.9 mg of rilpivirine or a pharmaceutically acceptable salt thereof and the volume of the aqueous medium is about 900 mL.

14. 13. The method of any one of claims 1 to 6, comprising performing a first iteration of the method on a first sample and performing a second iteration of the method on a second sample, wherein the concentration of the surfactant in the aqueous medium in the second iteration is maintained within ±1% of the concentration of the surfactant in the aqueous medium in the first iteration, the temperature of the aqueous medium in the second iteration is maintained within ±0.5°C of the temperature of the aqueous medium in the first iteration, and the pH of the aqueous medium in the second iteration is maintained within ±0.1 of the pH of the aqueous medium in the first iteration.

15. 10. The method of claim 1, wherein dispersing the sample in the aqueous medium optionally comprises agitation using a paddle device.

16. 10. The method of claim 1, wherein dispersing the sample in the aqueous medium is accomplished using a USP apparatus, optionally a USP Type 2 apparatus.

17. 17. The method of claim 15 or 16, wherein the rotation speed of the device is between 10 and 100 rpm, or between 25 and 75 rpm, or about 50 rpm.

18. 10. The method of claim 1, wherein measuring the dissolution of the rilpivirine or pharmaceutically acceptable salt thereof in the aqueous medium is performed as a function of time, optionally over a period of 4 to 8 hours, or 5 to 7 hours, or about 6 hours.

19. 19. The method of claim 18, wherein at least 85% of the rilpivirine or pharmaceutically acceptable salt thereof in the sample is dissolved after about 6 hours.

20. The method comprises features (i) to (vi): (i) ≦30% of the rilpivirine or pharmaceutically acceptable salt thereof dissolves in 5 minutes; (ii) 10 to 40% of the rilpivirine or pharmaceutically acceptable salt thereof dissolves in 10 minutes; (iii) 39 to 59% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved in 30 minutes. (iv) 45 to 75% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved in 45 minutes. (v) 64 to 84% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved in 90 minutes. (vi) ≥ 80% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved in 360 minutes.

21. 21. The method of claim 20, wherein features (ii), (iv), and (vi) are present, or features (i), (iii), (v), and (vi) are present.

22. The method further comprises features (a) to (k): (a) about 14% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved after about 5 minutes; (b) about 25% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved after about 10 minutes; (c) about 34% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved after about 15 minutes. (d) about 52% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved after about 30 minutes. (e) about 62% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved after about 45 minutes. (f) about 69% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved after about 60 minutes. (g) about 77% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved after about 90 minutes. (h) about 82% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved after about 120 minutes. (i) about 88% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved after about 180 minutes; (j) about 91% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved after about 240 minutes. (k) about 94% of the rilpivirine or pharmaceutically acceptable salt thereof is dissolved after about 360 minutes.

23. 23. The method of claim 22, wherein features (a), (d), and (j) are present, or features (a), (c), (e), and (i) are present.

24. 13. The method of any one of claims 1 to 6 or 12, comprising measuring the dissolution of the rilpivirine or pharmaceutically acceptable salt thereof in the aqueous medium at an infinity point at which substantially all of the rilpivirine or pharmaceutically acceptable salt thereof in the sample has dissolved.

25. 25. The method of claim 24, wherein the infinity point is reached by raising the temperature of the aqueous medium from 2-15°C to above room temperature, optionally to about 37°C, and optionally maintaining the aqueous medium at the elevated temperature for about 1 hour.

26. 13. The method of any one of claims 1 to 6 or 12, wherein measuring the dissolution of the rilpivirine or pharmaceutically acceptable salt thereof in the aqueous medium comprises removing an aliquot from the aqueous medium, optionally filtering the aliquot, and measuring the amount of rilpivirine or pharmaceutically acceptable salt thereof dissolved in the aliquot.

27. 27. The method of claim 26, wherein the aliquot is filtered before measuring the amount of rilpivirine or a pharmaceutically acceptable salt thereof dissolved in the aliquot, and the filtration is accomplished using a filter (e.g., a regenerated cellulose or PVDF membrane) having a pore size of 0.1 μm.

28. 13. The method of any one of claims 1 to 6 or 12, wherein measuring the dissolution of the rilpivirine or pharmaceutically acceptable salt thereof in the aqueous medium is achieved using HPLC, optionally using a gradient ultra-high performance liquid chromatography (UHPLC) method with UV detection.

29. The microparticles or nanoparticles have a D of less than 20 μm, or less than 10 μm, or less than 2 μm. ｖ 13. The method of any one of claims 1 to 6 or 12, wherein the granules have a particle diameter of 50.

30. The microparticles or nanoparticles have a D of about 500 nm to about 1,600 nm ｖ 90 particle diameter, D of about 200 nm to about 500 nm ｖ 50 particle diameter, and D of about 75 nm to about 200 nm ｖ 13. The method of any one of claims 1 to 6 or 12, wherein the particles have a diameter of 10.

31. The microparticles or nanoparticles have a D of about 4 μm to about 6 μm. ｖ 90 particle diameter, D of about 1.5 μm to about 2 μm ｖ 50 particle diameter, and D of about 300 nm to about 500 nm ｖ 13. The method of any one of claims 1 to 6 or 12, wherein the particles have a diameter of 10.

32. 13. The method of any one of claims 1 to 6 or 12, wherein the rilpivirine or pharmaceutically acceptable salt thereof in the form of microparticles or nanoparticles has a surface modifier adsorbed to its surface, and optionally the surface modifier is a poloxamer (e.g., poloxamer 338).

33. The method according to any one of claims 1 to 6 or 12, wherein the rilpivirine or a pharmaceutically acceptable salt thereof is rilpivirine.

34. 13. The method of any one of claims 1 to 6 or 12, wherein the sample is a suspension of microparticles or nanoparticles of rilpivirine or a pharmaceutically acceptable salt thereof in a pharmaceutically acceptable carrier (e.g., a pharmaceutically acceptable aqueous carrier).

35. 35. The method of claim 34, wherein the suspension comprises about 300 mg / mL of rilpivirine or a pharmaceutically acceptable salt thereof.

36. 35. The method of claim 34, wherein the suspension is homogenized prior to the step of dispersing the sample in the aqueous medium.

37. The suspension comprises rilpivirine or a pharmaceutically acceptable salt thereof, in particular rilpivirine, and the following components: surface modifiers, particularly poloxamer 338; tonicity agents, especially glucose monohydrate; buffering agents, especially sodium dihydrogen phosphate; chelating agents, especially citric acid monohydrate, pH adjusters, especially sodium hydroxide, and and one or more, optionally all, of the following: water, in particular water for injection.

38. 13. The method of any one of claims 1 to 6 or 12, wherein the sample is suitable for administration by intramuscular or subcutaneous injection, optionally for long-term treatment of HIV infection in a subject infected with HIV, or for long-term prevention of HIV infection in a subject at risk of becoming infected with HIV.

39. 39. The method of claim 38, wherein the long-term treatment of HIV infection in an HIV-infected subject or the long-term prevention of HIV infection in a subject at risk of HIV infection comprises administering rilpivirine or a pharmaceutically acceptable salt thereof in the form of microparticles or nanoparticles subcutaneously or intramuscularly intermittently at time intervals ranging from about 1 month, or about 2 months, or about 3 months, or about 4 months, or about 5 months, or about 6 months.

40. 1. A method for quality control testing a sample of rilpivirine or a pharmaceutically acceptable salt thereof, wherein the sample comprises rilpivirine or a pharmaceutically acceptable salt thereof in the form of microparticles or nanoparticles, the method comprising: subjecting the sample to a method according to any one of claims 1 to 6 or 12; and determining whether the sample passed the quality control test based on the measured dissolution of the rilpivirine or pharmaceutically acceptable salt thereof in the aqueous medium.

41. 41. The method of claim 40, comprising comparing the measured dissolution of the rilpivirine or pharmaceutically acceptable salt thereof in the aqueous medium with one or more reference values ​​of dissolution of a reference sample of rilpivirine or a pharmaceutically acceptable salt thereof in microparticle or nanoparticle form, and determining whether the sample passed the quality control test based on the comparison.

42. 42. The method of claim 41 , wherein the one or more reference values ​​are for the dissolution of the reference sample in the same aqueous medium as the aqueous medium in which the sample is dispersed, and optionally the dissolution of the reference sample and the dissolution of the sample are tested using the same method.

43. 1. A method of shipping a batch of rilpivirine or a pharmaceutically acceptable salt thereof for pharmaceutical use, comprising: providing a batch of rilpivirine or a pharmaceutically acceptable salt thereof in the form of microparticles or nanoparticles, optionally in a suspension; subjecting a sample taken from said batch to the quality control method of claim 40; and if said sample passes said quality control test, releasing said batch for pharmaceutical use.

44. 44. The method of claim 43, wherein providing a batch of rilpivirine or a pharmaceutically acceptable salt thereof in the form of microparticles or nanoparticles comprises manufacturing the batch.

45. 44. The method of claim 43, wherein the batch contains multiple doses of rilpivirine or a pharmaceutically acceptable salt thereof formulated to be suitable for administration by intramuscular or subcutaneous injection, optionally for the long-term treatment of HIV infection in HIV-infected subjects or for the long-term prevention of HIV infection in subjects at risk of HIV infection.

46. 46. ​​The method of claim 45, wherein the long-term treatment of HIV infection in an HIV-infected subject or the long-term prevention of HIV infection in a subject at risk of HIV infection comprises administering rilpivirine or a pharmaceutically acceptable salt thereof in the form of microparticles or nanoparticles subcutaneously or intramuscularly intermittently at time intervals ranging from about 1 month, or about 2 months, or about 3 months, or about 4 months, or about 5 months, or about 6 months.

47. 44. The method of claim 43, wherein the batch is of an approved pharmaceutical product (e.g., a product approved by the FDA, EMA, and / or MHRA).

48. An aqueous medium for use in dissolution testing, the aqueous medium comprising: 4-8% w / v, or 5.5-6.5% w / v, or 5.94-6.06% w / v of a surfactant, optionally a non-ionic surfactant (e.g., polysorbate 20); containing a buffer (e.g., 0.05 M sodium phosphate buffer); The aqueous medium has a pH of 6 to 8, 7 to 8, 7.2 to 7.8, or 7.3 to 7.

5.

49. 49. The aqueous medium of claim 48, maintained at a temperature of from 2 to 15, from 3 to 10, from 4 to 6, or from 4.5 to 5.5°C.

50. 50. The aqueous medium of claim 48 or 49, comprising dissolved rilpivirine or a pharmaceutically acceptable salt thereof.

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