Clindamycin Capsules
Action and use
Lincosamide antibacterial.
Definition
Clindamycin Capsules contain Clindamycin Hydrochloride.
Content of clindamycin, C18H33ClN2O5S
90.0 to 110.0% of the stated amount.
Identification
Tests
Related substances
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
45 volumes of acetonitrile and 55 volumes of a 0.68% w/v solution of potassium dihydrogen orthophosphate adjusted to pH 7.5 with a 25% w/v solution of potassium hydroxide.
When the chromatograms are recorded under the prescribed conditions the retention time of clindamycin is about 10 minutes.
The test is not valid unless the chromatogram obtained with solution (3) shows peaks with retention times relative to clindamycin of about 0.4 [Ph Eur impurity A (lincomycin)], about 0.65 [Ph Eur impurity B (clindamycin B)] and about 0.8 [Ph Eur impurity C (7-epiclindamycin)].
In the chromatogram obtained with solution (1):
the area of any peak corresponding to impurity B is not greater than the area of the principal peak in the chromatogram obtained with solution (2) (2%);
the area of any peak corresponding to impurity C is not greater than twice the area of the principal peak in the chromatogram obtained with solution (2) (4%);
the area of any other secondary peak is not greater than half the area of the principal peak in the chromatogram obtained with solution (2) (1%);
the sum of the areas of all the secondary peaks is not greater than 3 times the area of the principal peak in the chromatogram obtained with solution (2) (6%).
Disregard any peak with an area less than 0.025 times the area of the principal peak in the chromatogram obtained with solution (2) (0.05%).
Water
The contents of the capsules contain not more than 7.0% w/w of water, Appendix IX C. Use 1 g.
Assay
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
The chromatographic conditions described under Related substances may be used.
Calculate the content of C18H33ClN2O5S in the capsules using the declared content of C18H33ClN2O5S,HCl in clindamycin hydrochloride EPCRS. Each mg of C18H33ClN2O5S,HCl is equivalent to 0.9209 mg of C18H33ClN2O5S.
Labelling
The quantity of active ingredient is stated in terms of the equivalent amount of clindamycin.
Impurities
The impurities limited by the requirements of this monograph include those listed under Clindamycin Hydrochloride.