Nimodipine Tablets
Action and use
Calcium channel blocker.
Definition
Nimodipine Tablets contain Nimodipine. They are coated.
Content of nimodipine,C21H26N2O7
95.0 to 105.0% of the stated amount.
Identification
40 volumes of ethyl acetate and 60 volumes of cyclohexane.
The spot due to nimodipine is greyish-violet.
The principal spot in the chromatogram obtained with solution (1) corresponds in position and colour to that in the chromatogram obtained with solution (2).
The principal spot in the chromatogram obtained with solution (3) appears as a single, compact spot.
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 nimodipine, C21H26N2O7, in the medium from the absorbances obtained and using the declared content of C21H26N2O7 in nimodipine BPCRS.
The amount of nimodipine released is not less than 85% of the stated amount.
Related substances
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
13 volumes of acetonitrile, 26 volumes of tetrahydrofuran and 60 volumes of water.
The test is not valid unless, in the chromatogram obtained with solution (4), the resolution factor between the peaks due to nimodipine and nimodipine impurity A is at least 1.5 and the symmetry factor of the peak due to nimodipine is not more than 2.0.
In the chromatogram obtained with solution (1):
the area of any peak corresponding to nimodipine impurity A is not greater than the area of the principal peak in the chromatogram obtained with solution (3) (0.5%);
the area of any other secondary peak is not greater than the area of the principal peak in the chromatogram obtained with solution (2) (0.2%);
the sum of the areas of any secondary peaks other than any peak corresponding to impurity A is not greater than 2.5 times the area of the principal peak in the chromatogram obtained with solution (2) (0.5%).
Disregard any peak with an area less than 0.25 times the area of the principal peak in the chromatogram obtained with solution (2) (0.05%).
Assay
Weigh and powder 20 tablets. Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
The chromatographic conditions described under Related substances may be used.
The test is not valid unless, in the chromatogram obtained with solution (3), the resolution factor between the peaks due to nimodipine and nimodipine impurity A is at least 1.5, and the symmetry factor of the peak due to nimodipine is not more than 2.0.
Calculate the content of C21H26N2O7 in the tablets using the declared content of C21H26N2O7 in nimodipine BPCRS.
IMPURITIES
The impurities limited by the requirements of this monograph include those listed under Nimodipine.