Minocycline Tablets
Action and use
Tetracycline antibacterial.
Definition
Minocycline Tablets contain Minocycline Hydrochloride Dihydrate.
Content of minocycline, C23H27N3O7
92.5 to 107.5% of the stated amount.
Identification
A mixture of 6 volumes of water, 35 volumes of methanol and 59 volumes of dichloromethane.
The test is not valid unless the chromatogram obtained with solution (3) shows two clearly separated principal spots.
The principal spot in the chromatogram obtained with solution (1) is similar in position and size to that in the chromatogram obtained with solution (2).
Tests
Dissolution
Comply with the requirements for Monographs of the British Pharmacopoeia in the dissolution test for tablets and capsules, Appendix XII B1.
Calculate the total content of minocycline, C23H27N3O7, in the medium from the absorbances obtained and using the declared content of C23H27N3O7,HCl in minocycline hydrochloride BPCRS. Each mg of C23H27N3O7,HCl is equivalent to 0.9261 mg of C23H27N3O7.
Related substances
Carry out the method for liquid chromatography, Appendix III D, protected from light. Store the solutions at a temperature of 2° to 8° and use within 3 hours of preparation.
A mixture of 25 volumes of a 0.4% w/v solution of sodium edetate, 27 volumes of dimethylformamide and 50 volumes of a 2.8% w/v solution of ammonium oxalate, adjusted to pH 7.0 using a 10.4% w/v solution of tetrabutylammonium hydroxide.
When the chromatograms are recorded using the prescribed conditions the retention time of minocycline is about 15 minutes.
The chromatogram obtained with solution (4) shows a peak with a retention time relative to minocycline of about 0.8 [4-epiminocycline (Ph.Eur. impurity A)].
The test is not valid unless, in the chromatogram obtained with solution (4), the resolution factor between the peaks due to minocycline and 4-epiminocycline is at least 2.0.
In the chromatogram obtained with solution (1):
the area of any peak due to 4-epiminocycline is not greater than the area of the principal peak in the chromatogram obtained with solution (2) (2%);
the area of any other secondary peak is not greater than the area of the principal peak in the chromatogram obtained with solution (3) (1.2%);
the sum of the areas of any such peaks is not greater than the area of the principal peak in the chromatogram obtained with solution (2) (2%).
Disregard any peak with an area less than 0.05 times the area of the principal peak in the chromatogram obtained with solution (2) (0.1%).
Assay
Weigh and powder 20 tablets. Carry out the method for liquid chromatography, Appendix III D, protected from light. Store the solutions at a temperature of 2° to 8° and use within 3 hours of preparation.
The chromatographic conditions described under Related substances may be used.
When the chromatograms are recorded using the prescribed conditions the retention time of minocycline is about 15 minutes.
The chromatogram obtained with solution (3) shows a peak with a retention time relative to minocycline of about 0.8 [4-epiminocycline (Ph.Eur. impurity A)].
The test is not valid unless, in the chromatogram obtained with solution (3), the resolution factor between the peaks due to minocycline and 4-epiminocycline is at least 2.0.
Calculate the content of C23H27N3O7 in the tablets from the chromatograms obtained and using the declared content of C23H27N3O7,HCl in minocycline hydrochloride BPCRS. Each mg of C23H27N3O7,HCl is equivalent to 0.9261 mg of C23H27N3O7.
Labelling
The quantity of active ingredient is stated in terms of the equivalent amount of minocycline.