Voriconazole inclusion complexes

Abstract

Described are voriconazole formulations including 2-hydroxypropyl-β-cyclodextrins and the preparation thereof.

Claims

1. A method of stabilizing a lyophilized solid voriconazole formulation, comprising dissolving a substituted β-cyclodextrin characterized by a molar substitution of the β-cyclodextrin by hydroxypropyl groups of more than 0.8 and voriconazole in an aqueous vehicle including no organic solvents to form a dissolved composition, wherein the dissolved composition has pH of 4-7, and lyophilizing the dissolved composition comprising the voriconazole and the substituted β-cyclodextrin characterized by a molar substitution of the β-cyclodextrin by hydroxypropyl groups of more than 0.8 to provide a stabilized lyophilized solid voriconazole formulation, provided that the stabilized lyophilized solid pharmaceutical formulation does not comprise lactose.

2. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 1, wherein the substituent on the β-cyclodextrin is a 2-hydroxypropyl group.

3. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 2, wherein the molar substitution of the 2-hydroxypropyl β-cyclodextrin is 0.8-1.1.

4. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 3, wherein the molar substitution of the 2-hydroxypropyl β-cyclodextrin is 0.8-1.0.

5. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 4, wherein the molar substitution of the 2-hydroxypropyl β-cyclodextrin is 0.9.

6. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 4, wherein the molar substitution of the 2-hydroxypropyl β-cyclodextrin is 0.9.

7. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 1, wherein the dissolved composition further comprises a pH adjusting agent.

8. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 1, wherein the dissolved composition further comprises an acidification agent.

9. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 7, wherein the dissolved composition further comprises one or more organic carboxylic acids.

10. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 1, wherein the dissolved composition further comprises citric, acetic, tartaric and/or succinic acids.

11. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 1, wherein the lyophilized composition comprises 4-10% w/w voriconazole in a solid state.

12. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 11, wherein the lyophilized composition comprises 6% w/w voriconazole in a solid state.

13. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 1, wherein lyophilized the composition comprises about 90-96% w/w β-cyclodextrin in a solid state.

14. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 13, wherein the lyophilized composition comprises about 94% w/w β-cyclodextrin in the solid state.

15. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 2, wherein the lyophilized composition comprises voriconazole and 2-hydroxypropyl-β-cyclodextrin in a molar ratio of up to 1:5.

16. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 2, wherein the said lyophilized composition comprises voriconazole and 2-hydroxypropyl-β-cyclodextrin in a molar ratio of 1:3.6.

17. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 2, wherein the said lyophilized composition comprises voriconazole and 2-hydroxypropyl-β-cyclodextrin in a weight ratio of 1:22 to 1:10.

18. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 17, wherein the lyophilized composition comprises voriconazole and 2-hydroxypropyl-β-cyclodextrin in a weight ratio of 1:18 to 1:14.

19. The method of stabilizing a lyophilized solid voriconazole formulation according to claim 18, wherein the lyophilized composition comprises voriconazole and 2-hydroxypropyl-β-cyclodextrin in a weight ratio of 1:16.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) Voriconazole is only sparingly soluble in water. Without being bound by theory, it is believed that 2-hydroxypropyl-substituted β-cyclodextrin can form inclusion complex with voriconazole and thus increase its aqueous solubility. Further, such voriconazole complexes are more stable in aqueous media than voriconazole itself.

(2) Furthermore, data from the literature imply that voriconazole is unstable in alkaline media, where it degrades quickly especially when it is exposed to elevated temperatures. Available data also imply that pH of the media can have an impact on the stability of voriconazole formulations.

(3) Cyclodextrins are a group of structurally related natural products formed by bacterial digestion of cellulose. These cyclic oligosaccharides consist of (α-1,4)-linked α-D-glucopyranose units and contain a somewhat lipophilic central cavity and a hydrophilic outer surface. Due to the chair conformation of the glucopyranose units, the cyclodextrins are shaped like a truncated cone rather than perfect cylinders. The hydroxyl functions are orientated to the cone exterior with the primary hydroxyl groups of the sugar residues at the narrow edge of the cone and the secondary hydroxyl groups at the wider edge. The central cavity is lined by the skeletal carbons and ethereal oxygens of the glucose residues, which gives it a lipophilic character. The polarity of the cavity has been estimated to be similar to that of an aqueous ethanolic solution. The natural α-, β- and γ-cyclodextrin consist of six, seven, and eight glucopyranose units, respectively. Cyclodextrin derivatives of pharmaceutical interest include the hydroxypropyl derivatives of β- and γ-cyclodextrin, the randomly methylated β-cyclodextrin, sulfobutylether β-cyclodextrin, and the so-called branched cyclodextrins such as glucosyl-β-cyclodextrin.

(4) In aqueous solutions cyclodextrins are able to form inclusion complexes with many drugs by taking up a drug molecule or more frequently some lipophilic moiety of the molecule, into the central cavity. No covalent bonds are formed or broken during the complex formation and drug molecules in the complex are in rapid equilibrium with free molecules in the solution. The driving forces for the complex formation include release of enthalpy-rich water molecules from the cavity, electrostatic interactions, van der Waals interactions, hydrophobic interactions, hydrogen bonding, and release of conformational strain and charge-transfer interactions.

(5) In the pharmaceutical industry cyclodextrins have mainly been used as complexing agents to increase aqueous solubility of poorly soluble drugs, and to increase their bioavailability and stability.

(6) Although the natural CDs and their complexes are hydrophilic, their aqueous solubility can be rather limited, especially in the case of βCD. This is thought to be due to relatively strong binding of the CD molecules in the crystal state (i.e. relatively high crystal lattice energy). Random substitution of hydroxyl groups, even by hydrophobic moieties such as methoxy functions, will result in dramatic improvements in their solubility. Moreover, some derivatives, such as 2-hydroxypropyl (HPβCD and HPγCD) and sulfobutylether (SBEβCD), possess improved toxicological profiles in comparison to their parent CDs.

(7) The Degree of Substitution of cyclodextrin (DS) is defined as the average number of substituted hydroxyl groups per glucopyranose unit of CD ring. Since the number of reactive hydroxyls per mole of glucopyranose unit is 3, the maximum numbers of substituents possible for α-, β-, and γ-CDs are 18, 21, and 24, respectively.

(8) Another term used to describe cyclodextrin substitution is molar substitution (MS). This term, as used in this specification, describes the average number of moles of the substituting agent, e.g, hydroxypropyl, per mole of glucopyranose. For example when a hydroxypropyl-β-cyclodextrin has DS=14, the MS is 14/7 or 2. Thus, the “molar substitution of the β-cyclodextrin by hydroxypropyl groups”, as used in this specification, means the average number of hydroxypropyl substituents attached to each glucopyranose unit in the cyclodextrin.

(9) Pharmaceutical formulation, as used in this specification, means any formulation intended for therapeutic or prophylactic treatment. Pharmaceutical formulations according to the present invention can be in solid or liquid state.

(10) β-cyclodextrin, as used in this specification, means any cyclodextrin comprising 7 (α-1,4)-linked α-D-glucopyranose units, e.g.

(11) ##STR00006##

(12) Hydroxypropyl-β-cyclodextrin, as used in this specification, means any β-cyclodextrin monomer comprising at least one hydroxypropyl substituent attached to a hydroxyl group on the cyclodextrin. Hydroxypropyl-β-cyclodextrin is abbreviated as HPβCD.

(13) The hydroxypropyl substituent as used in this specification is meant to embrace several different substituents including: —CH.sub.2—CH.sub.2—CH.sub.2OH —CH.sub.2—CHOH—CH.sub.3 —CHOH—CH.sub.2—CH.sub.3 —CHOH—CHOH—CH.sub.3 —CHOH—CH.sub.2—CH.sub.2OH —CH.sub.2—CHOH—CH.sub.2OH —CHOH—CHOH—CH.sub.2OH

(14) One example of a hydroxypropyl-3-cyclodextrin could be represented:

(15) ##STR00007##
wherein R=—CH.sub.2—CH.sub.2—CH.sub.2OH

(16) 2-hydroxypropyl-β-cyclodextrin, as used in this specification, means any β-cyclodextrin monomer comprising at least one 2-hydroxypropyl substituent attached to a hydroxyl group on the β-cyclodextrin. 2-hydroxypropyl-β-cyclodextrin is abbreviated 2-HPβCD. One example of a 2-hydroxypropyl-β-cyclodextrin could be represented as on the following figure:

(17) ##STR00008##
wherein R=—CH.sub.2—CHOH—CH.sub.3.

(18) Whenever pH is mentioned in respect of a formulation according to the present invention, e.g. in respect of formulation having a pH within a specified range, it is to be understood that the formulation is in liquid form if not otherwise stated. “pH of 3-8” is meant to include pH 8.0, pH 7.5, 7.0, pH 6.5, pH 3.0. Further included is any pH between any of these; e.g. pH 5.23, pH 3.35, pH 7.39 etc.

(19) “pH of 4-7” is meant to include pH 4.0, pH 5.5, pH 6.0, pH 7.0. Further included is any pH between any of these; e.g. pH 4.23, pH 5.35, pH 5.39 etc.

(20) “Water for injection” as used herein is substantially pure and sterile water, e.g. water purified by distillation or a purification process that is equivalent or superior to distillation in the removal of chemicals and microorganisms. “Ultrapure water” is water with conductivity below 0.055 μS and pH in the range from 5.0 to 7.0 and is used in the following examples as a substitute for “water for injection”.

(21) “Stabilizing effect” as used herein is a reduction of the level of impurities in solid or liquid formulations formulated according to the parameters described in the claims, in comparison to the formulations which are not manufactured within the same parameters.

(22) “Stabilized pharmaceutical formulations” are formulations in which voriconazole degrades in lower extent when formulations are exposed to stability testing at elevated temperature in comparison to the non-stabilized formulations in which decomposition of voriconazole is greater under the same stability testing conditions.

EXAMPLES

(23) The voriconazole formulations were prepared in the following manner: first 2-hydroxypropyl-β-cyclodextrin was dissolved in the appropriate vehicle in concentration of 160 mg/mL and then voriconazole was added to the solution in a concentration of 10 mg/mL. After preparation, liquid formulations were filled in vials and subsequently lyophilized.

(24) The following hydroxypropyl beta cyclodextrins were used for preparation of voriconazole formulations: 1. 2-hydroxypropyl-β-cyclodextrin with molar substitution=0.65 2. 2-hydroxypropyl-β-cyclodextrin with molar substitution=0.63 3. 2-hydroxypropyl-β-cyclodextrin with molar substitution=0.87

(25) All formulations were analyzed immediately after lyophilization and then subjected to stability testing at the elevated temperature (40° C.±2° C./75%±5% RH). Analyses of formulations were done at defined time points and during the storage finished product vials were kept in inverted position.

(26) Except pH, content of impurities was analyzed at each specified time point using validated HPLC methods.

(27) The results of the study and conclusions are presented in text and Tables that follow.

Example 1

(28) The composition was prepared according to the above described procedure and as a vehicle ultrapure water was used. Stability of finished product was tested at 40° C./75% RH in inverted position (taken as a worst case) during 1 month. The results are shown in Table 1.

(29) Table 1. Impurity profile and respective pH values of Voriconazole and 2-hydroxypropyl-β-cyclodextrin formulation prepared using 2-hydroxypropyl-β-cyclodextrin of molar substitution equal to 0.65 (ultrapure water was used as solvent).

(30) TABLE-US-00001 TABLE 1 Formulation: Voriconazole and 2-hydroxypropyl-β- cyclodextrin formulation (MS of 2HPβCD = 0.65) in Ultrapure water Storage Condition: 2 weeks 1 month 40° C./ 40° C./ TESTS START 75% RH IP 75% RH IP pH 8.9  8.6 8.6 Related substances (%) 1-(2,4-difluorophenyl)-2- 0.08 1.2 1.8 (1H-1,2,4-triazol-1-yl) ethanone 4-ethyl-5-fluoropyrimidine 0.07 1.2 1.9 ((2RS,3SR)-2-(2,4- <LOQ <LOQ <LOQ difluorophenyl)-3 -(pyrim- idin-4-yl)-1-(1H-1,2,4-tri- azol-1-yl)butan-2-ol) (2RS,3RS)-2-(2,4- <LOQ  0.30  0.45 Difluorophenyl)-3-(5- fluoropyrimidin-4-yl)-1-(1H- 1,2,4-triazol-1-yl)butan-2-ol Total Impurities 0.20 2.6 4.2 Total impurities = sum of specified and unspecified impurities

(31) From above presented results it can be seen that found level of impurities after two weeks of storage at 40° C./75% RH was rather high. Obtained pH values measured in all samples was in the range from 8.6 to 8.9, which implies that pH of formulation higher than 8 destabilizes the active compound.

Example 2

(32) The compositions were prepared according to the above described procedure, and as a vehicle different buffers were used. The stability of finished products was tested at 40° C./75% RH in inverted position (taken a s a worst case) during 1 month. The results are shown in Table 2.

(33) Table 2. Impurity profiles and respective pH values of voriconazole and 2-hydroxypropyl-β-cyclodextrin formulations prepared using 2-hydroxypropyl-β-cyclodextrin of molar substitution equal to 0.65 dissolved in different buffers with pH value adjusted in the range from 3.8 to 7.2 subjected to stability testing at elevated temperature.

(34) TABLE-US-00002 TABLE 2 Formulation: Voriconazole and 2-hydroxypropyl-β- Voriconazole and 2- Voriconazole and 2- cyclodextrin hydroxypropyl-β- hydroxypropyl-β- formulation (MS of cyclodextrin formulation cyclodextrin formulation 2-HβCD = 0.65) in (MS of 2-HβCD = 0.65) in (MS of 2-HβCD = 0.65) Citrate buffer with Citrate buffer with pH in Citrate buffer with pH pH adjusted to 7.2 adjusted to 5.5 adjusted to 3.8 Storage Condition: 2 2 1 2 1 TESTS START weeks* START weeks* month** START weeks* month** pH 7.4 7.3 5.7 5.7 5.8 4.1 4.1 4.1 Related substances (%) 1-(2,4-difluorophenyl)- 0.06 1.8 <LOQ 0.19 0.43 <LOQ 0.20 0.46 2-(1H-1,2,4-triazol-1- yl)ethanone 4-ethyl-5- 0.06 1.9 <LOQ 0.19 0.40 <LOQ 0.21 0.42 fluoropyrimidine ((2RS,3SR)-2-(2,4- <LOQ <LOQ <LOQ <LOQ <LOQ <LOQ <LOQ 0.05 difluorophenyl)-3- (pyrimidin-4-yl)-1- (1H-1,2,4-triazol-1- yl)butan-2-ol) (2RS,3RS)-2-(2,4- <LOQ 0.49 <LOQ 0.05 0.11 <LOQ <LOQ 0.07 Difluorophenyl)-3-(5- fluoropyrimidin-4-yl)- 1-(1H-1,2,4-triazol-1- yl)butan-2-ol Total Impurities 0.17 4.2 0.05 0.47 0.98 <LOQ 0.45 1.0 Formulation: Voriconazole and 2- Voriconazole and 2- hydroxypropyl-β- hydroxypropyl-β- cyclodextrin cyclodextrin formulation formulation (MS of (MS of 2-HβCD = 0.65) in 2-HβCD = 0.65) in Succinate buffer with pH Tartarate buffer adjusted to 4.0 with pH adjusted to 4.8 Storage Condition: 2 1 2 1 TESTS START weeks* month** START weeks* month** pH 4.3 4.3 4.3 5.0 5.0 5.0 Related substances (%) 1-(2,4-difluorophenyl)- <LOQ 0.17 0.40 <LOQ 0.16 0.37 2-(1H-1,2,4-triazol-1- yl)ethanone 4-ethyl-5- <LOQ 0.18 0.37 <LOQ 0.17 0.35 fluoropyrimidine ((2RS,3SR)-2-(2,4- <LOQ <LOQ <LOQ <LOQ <LOQ 0.05 difluorophenyl)-3- (pyrimidin-4-yl)-1- (1H-1,2,4-triazol-1- yl)butan-2-ol) (2RS,3RS)-2-(2,4- <LOQ <LOQ 0.06 <LOQ <LOQ 0.09 Difluorophenyl)-3-(5- fluoropyrimidin-4-yl)- 1-(1H-1,2,4-triazol-1- yl)butan-2-ol Total Impurities <LOQ 0.40 0.90 <LOQ 0.44 0.91 Total impurities = sum of specified and unspecified impurities

(35) From obtained results in could be concluded that found level of impurities in formulations with pH adjusted in the range from 3.8 to 5.5 are approximately four times lower than in the voriconazole formulation that was prepared using 2-hydroxypropyl-β-cyclodextrin of molar substitution equal to 0.65 dissolved only in ultrapure water (for comparison please see Table 1). Formulation prepared with citrate buffer and pH adjusted to 7.2 showed significant degradation of active compound when exposed to elevated temperature, implying that formulation is destabilized in slightly alkaline media

Example 3

(36) The compositions were prepared according to the above described procedure, and as a vehicle ultrapure water was used. Stability of finished products was tested at 40° C./75% RH in inverted position (taken as a worst case) during 2 weeks. The results are shown in Table 3.

(37) Table 3. Impurity profiles and respective pH values of Voriconazole and 2-hydroxypropyl-β-cyclodextrin formulations prepared using 2-hydroxypropyl-β-cyclodextrin of molar substitution equal to 0.87 or 0.63 dissolved in ultrapure water and subjected to stability testing at elevated temperature.

(38) TABLE-US-00003 TABLE 3 Formulation: Voriconazole and 2-hydroxypropyl-β- Voriconazole and 2-hydroxypropyl-β- cyclodextrin formulation (MS of 2- cyclodextrin formulation (MS of 2- HPβCD = 0.87) in Ultrapure water HPβCD = 0.63) in Ultrapure water Storage Condition: 2 weeks 2 weeks 40° C./ 40° C./ TESTS START 75% RH IP START 75% RH IP pH 6.9 7.2  7.1 7.3  Related substances (%) 1-(2,4-difluorophenyl)-2- <LOQ 0.22 <LOQ 0.43 (1H-1,2,4-triazol-1-yl) ethanone 4-ethyl-5-fluoro- <LOQ 0.20 <LOQ 0.39 pyrimidine ((2RS,3SR)-2-(2,4- <LOQ <LOQ <LOQ <LOQ difluorophenyl)-3- (pyrimidin-4-yl)-1-(1H- 1,2,4-triazol-1-yl)butan- 2-ol) (2RS,3RS)-2-(2,4- <LOQ 0.05 <LOQ 0.11 Difluorophenyl)-3-(5- fluoropyrimidin-4-yl)-1- (1H-1,2,4-triazol-1- yl)butan-2-ol Total Impurities <LOQ 0.47 <LOQ 0.93 Total impurities = sum of specified and unspecified impurities

(39) Obtained results imply that formulation with 2-HPβCD with higher MS is more stable than the formulation with lower MS, as the level of impurities is twice higher in formulation containing 2-HPβCD with lower molar substitution.

Example 4

(40) The composition was prepared according to the above described procedure, and as a vehicle ultrapure water was used. Stability of finished product was tested at 40° C./75% RH in inverted position (taken as a worst case) during 3 months. The results are shown in Table 4.

(41) Table 4. Impurity profiles and respective pH values of Voriconazole and 2-hydroxypropyl-β-cyclodextrin formulation prepared using 2-hydroxypropyl-β-cyclodextrin of molar substitution equal to 0.87 dissolved in ultrapure water and subjected to stability testing at elevated temperature.

(42) TABLE-US-00004 TABLE 4 Formulation: Voriconazole and 2-hydroxypropyl- β-cyclodextrin formulation (MS of 2-HPβCD = 0.87) in Ultrapure water Storage Condition: 1 M 40° C./ 3 M 40° C./ TESTS START 75% RH IP 75% RH IP pH 6.5  6.4  6.4  Related substances (%) 1-(2,4-difluorophenyl)-2- <LOD 0.35 0.91 (1H-1,2,4-triazol-1-yl) ethenone 4-ethyl-5-fluoropyrimidine <LOD 0.36 0.65 ((2RS,3SR)-2-(2,4- <LOD <LOQ <LOQ difluorophenyl)-3- (pyrimidin-4-yl)-1-(1H- 1,2,4-triazol-1-yl)butan-2-ol) (2RS,3RS)-2-(2,4- <LOQ 0.10 0.15 Difluorophenyl)-3-(5- fluoropyrimidin-4-yl)-1-(1H- 1,2,4-triazol-1-yl)butan-2-ol Total Impurities 0.05 0.87 1.8  Total impurities = sum of specified and unspecified impurities

Example 5

(43) The compositions were prepared according to the above described procedure, and as a vehicle different buffers were used. The stability of finished products was tested at 40° C./75% RH in inverted position (taken a s a worst case) during 3 months. The results are shown in Table 5.

(44) TABLE-US-00005 TABLE 5 Impurity profiles and respective pH values of voriconazole and 2-hydroxypropyl-β-cyclodextrin formulations prepared using 2-hydroxypropyl-β-cyclodextrin of molar substitution equal to 0.63 dissolved in different buffers with pH value adjusted to 4.7 subjected to stability testing at elevated temperature. Formulation: Voriconazole and 2- Voriconazole and 2- Voriconazole and 2- Voriconazole and 2- hydroxypropyl-β-cyclo- hydroxypropyl-β-cyclo- hydroxypropyl-β-cyclo- hydroxypropyl-β-cyclo dextrin formulation dextrin formulation dextrin formulation dextrin formulation (MS of 2-HPβCD = 0.63) (MS of 2-HPβCD = 0.63) (MS of 2-HPβCD = 0.63) (MS of 2-HPβCD = 0.63) in Citrate buffer with in Succinate buffer with in Tartrate buffer with in Acetate buffer with pH adjusted to 4.7 pH adjusted to 4.7 pH adjusted to 4.7 pH adjusted to 4.7 Storage Condition: 3M 3M 3M 3M 40° C./75% 40° C./75% 40° C./75% 40° C./75% TESTS START RH IP START RH IP START RH IP START RH IP pH 4.9  5.0  4.9  5.0  5.0  5.0  5.1  5.1  Related substances (%) 1-(2,4-difluoro-phenyl)-2- <LOQ 1.20 <LOQ 1.28 <LOQ 0.96 <LOQ 1.6  (1H-1,2,4-triazol-1-yl)- ethanone 4-ethyl-5-fluoropyrimidine <LOQ 1.26 <LOQ 1.35 <LOQ 0.95 <LOQ 1.6  ((2RS, 3SR)-2-(2,4- <LOQ <LOQ <LOQ <LOQ 0.05 <LOQ 0.05 <LOQ difluorophenyl)-3- (pyrimidin-4-yl)-1-(1H-1,2, 4-triazol-1-yl)butan-2-ol) (2RS, 3RS)-2-(2,4- <LOQ 0.23 <LOQ 0.23 <LOQ 0.27 <LOQ 0.13 Difluorophenyl)-3-(5- fluoropyrimidin-4-yl)-1- (1H-1,2,4-triazol-1-yl) butan-2-ol Total Impurities 0.07 2.7  0.07 2.9  0.10 2.2  0.05 3.4  Total impurities = sum of specified and unspecified impurities

(45) When comparing stability testing results presented in Tables 3 & 5 it can be seen that in buffered formulations (pH value in finished product equal to app. 5) containing 2-HPβCD with MS of 0.63, the level of impurities is significantly lower than in the voriconazole formulation containing 2-HPβCD with MS equal to 0.63 dissolved only in ultrapure water. The level of impurities in the later formulation is comparable to the impurities found in the formulation containing 2-HPβCD with MS equal to 0.87.

Example 6

(46) The composition was prepared according to the above described procedure, and as a vehicle ultrapure water was used. pH of formulation was adjusted to 8.5 using 0.1M NaOH prior batch volume make up. The stability of finished product was tested at 40° C./75% RH in inverted position (taken a s a worst case) during 2 weeks. The results are shown in Table 6.

(47) Table 6. Impurity profile and respective pH value of voriconazole and 2-hydroxypropyl-β-cyclodextrin formulation prepared using 2-hydroxypropyl-β-cyclodextrin of molar substitution equal to 0.87 and pH value adjusted to 8.5 with 0.1M sodium hydroxide (NaOH) subjected to 2 weeks stability testing at elevated temperature.

(48) TABLE-US-00006 TABLE 6 Formulation: Voriconazole and 2-hydroxy- propyl-β-cyclodextrin formulation (MS of 2-HPβCD = 0.87) with pH adjusted to 8.5 using 0.1M NaOH Storage conditions: 2 weeks 40° TESTS START C./75% RH IP pH 8.5  8.5  Related substances (%) 1-(2,4-difluorophenyl)-2- 0.05 0.58 (1H-1,2,4-triazol-1-yl)- ethanone 4-ethyl-5-fluoropyrimidine 0.05 0.65 ((2RS,3SR)-2-(2,4-difluorophenyl)- <LOQ <LOQ 3-(pyrimidin-4-yl)-1-(1H- 1,2,4-triazol-1-yl)butan-2-ol) (2RS,3RS)-2-(2,4-Difluorophenyl)- <LOQ 0.22 3-(5-fluoropyrimidin-4-yl)-1- (1H-1,2,4-triazol-1-yl)butan-2-ol Total Impurities 0.10 1.5  Total impurities = sum of specified and unspecified impurities

(49) When comparing above presented results to the results of 2 weeks of stability testing at 40° C./75% RH of the formulation prepared in Ultrapure water without additional pH adjustment (see Table 3 for comparison), it can be seen that found level of impurities in formulation with pH above 8.5 is approximately three times higher. This finding implies that voriconazole in the formulation with pH higher than 8 is less stable and degrades in greater extent.

(50) Still, basic formulation (pH above 8.5) prepared with the 2-HPβCD with MS equal to 0.87 is more stable (level of impurities is twice lower) than the formulation with the similar pH formulated with the 2-HPβCD with MS equal to 0.63 (for comparison, see Table 1).