- British Pharmacopoeia Volume III
- Formulated Preparations: Specific Monographs
Tioconazole Cream |
Antifungal.
Tioconazole Cream contains Tioconazole in a suitable basis.
The cream complies with the requirements stated under Topical Semi-solid Preparations and with the following requirements.
95.0 to 105.0% of the stated amount.
A. Carry out the method for thin-layer chromatography, Appendix III A, using a silica gel F254 precoated plate (Merck silica gel 60 F254 plates are suitable) and, as the mobile phase, the upper layer obtained from a mixture of 40 volumes of glacial acetic acid, 40 volumes of water and 80 volumes of 4-methylpentan-2-one. Apply separately to the plate 10 µL of each of the following solutions. For solution (1) add to a quantity of the cream containing 10 mg of Tioconazole 3 mL of n-hexane and 10 mL of dichloromethane, mix with the aid of ultrasound for 5 minutes and centrifuge. Shake 3 mL of the lower layer with 9 mL of 0. 5m sulfuric acid and centrifuge the aqueous layer. To 6 mL of the supernatant liquid add 1 mL of 8m sodium hydroxide, shake with 2 mL of dichloromethane, centrifuge and use the lower layer. Solution (2) contains 0.1% w/v of tioconazole BPCRS in dichloromethane. After removal of the plate, allow it to dry in air and examine under ultraviolet light (254 nm). The principal spot in the chromatogram obtained with solution (1) corresponds to the spot in the chromatogram obtained with solution (2).
B. In the Assay, the chromatogram obtained with solution (1) shows a peak with the same retention time as the principal peak in the chromatogram obtained with solution (2).
Mix 10 g with 10 mL of carbon dioxide-free water. The pH of the suspension is 4.0 to 7.0, Appendix V L.
Carry out the method for liquid chromatography, Appendix III D, using the following solutions. For solution (1) add 40 mL of the mobile phase to a quantity of the cream containing 10 mg of Tioconazole, shake until fully dispersed, dilute to 50 mL with the mobile phase, mix and filter through a glass microfibre filter (0.2 µm). For solution (2) dilute 1 volume of solution (1) to 200 volumes with the mobile phase. Solution (3) contains 0.20% w/v of tioconazole impurity standard BPCRS in the mobile phase.
The chromatographic procedure may be carried out using (a) stainless steel column (25 cm × 4.6 mm) packed with octadecylsilyl silica gel for chromatography (5 µm) (Hypersil ODS is suitable), (b) a mixture of 1 volume of 0.005m tetrabutylammonium dihydrogen orthophosphate adjusted to pH 7.4 with 2m ammonia and 4 volumes of methanol as the mobile phase with a flow rate of 1.0 mL per minute and (c) a detection wavelength of 218 nm.
The test is not valid unless the chromatogram obtained with solution (3) closely resembles the reference chromatogram supplied with tioconazole impurity standard BPCRS.
In the chromatogram obtained with solution (1) the areas of any peaks corresponding to tioconazole impurities A, B and C are not greater than the area of the principal peak in the chromatogram obtained with solution (2) (0.5% of each).
Carry out the method for liquid chromatography, Appendix III D, using the following solutions. Prepare solution (1) in the same manner as that described for solution (1) under Related substances. Solution (2) contains 0.020% w/v of tioconazole BPCRS in the mobile phase.
The chromatographic conditions described under Related substances may be used.
Calculate the content of C16H13Cl3N2OS in the cream using the declared content of C16H13Cl3N2OS in tioconazole BPCRS.