Levomepromazine Tablets
Action and use
Dopamine receptor antagonist; neuroleptic.
Definition
Levomepromazine Tablets contain Levomepromazine Maleate.
Content of levomepromazine maleate, C19H24N2OS,C4H4O4
95.0 to 105.0% of the stated amount.
Identification
3 volumes of water, 7 volumes of anhydrous formic acid and 90 volumes of di-isopropyl ether.
The chromatogram obtained with solution (1) shows a spot remaining on the line of application and a spot which is similar in position to the principal spot 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 levomepromazine maleate, C19H24N2OS,C4H4O4, in the medium from the absorbances obtained and using the declared content of C19H24N2OS,C4H4O4 in levomepromazine maleate BPCRS. The amount of levomepromazine maleate released is not less than 60% of the stated amount.
Related substances
Carry out the method for thin-layer chromatography, Appendix III A, protected from light using the following solutions.
5 volumes of diethylamine, 10 volumes of acetone and 85 volumes of toluene.
Any secondary spot in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (2) (0.5%).
Assay
Carry out the following procedure protected from light. Weigh and powder 20 tablets. To a quantity of the powdered tablets containing 50 mg of Levomepromazine Maleate add 15 mL of 0.2m methanolic ammonia, stir for 2 minutes, filter and collect the filtrate. Repeat the extraction with a further 3 successive 15-mL quantities of 0.2m methanolic ammonia, grinding the residue with a glass rod before extraction. Dilute the combined filtrates to 100 mL with 0.2m methanolic ammonia, mix and dilute 10 volumes of the solution to 100 volumes with methanol and further dilute 10 volumes of this solution to 100 volumes with the same solvent. Measure the absorbance of this solution at the maximum at 254 nm, Appendix II B, using methanol in the reference cell. Measure the absorbance of a 0.0005% w/v solution of levomepromazine maleate BPCRS in 0.002m methanolic ammonia at the same wavelength using methanol in the reference cell and calculate the content of C19H24N2OS,C4H4O4 in the tablets using the declared content of C19H24N2OS,C4H4O4 in levomepromazine maleate BPCRS.
Storage
Levomepromazine Tablets should be protected from light.