Edition: BP 2025 (Ph. Eur. 11.6 update)
Action and use
Dopamine receptor antagonist; neuroleptic.
DEFINITION
Levomepromazine Injection is a solution of Levomepromazine Hydrochloride in Water for Injections.
The injection complies with the requirements stated under Parenteral Preparations and with the following requirements.
Content of levomepromazine hydrochloride, C19H24N2OS,HCl
95.0 to 105.0% of the stated amount.
IDENTIFICATION
To a volume of the injection containing 50 mg of Levomepromazine Hydrochloride add 2 mL of 1M sodium hydroxide, shake, extract with 15 mL of ether and allow to separate. Wash the ethereal layer with 5 mL of water, filter through phase-separating paper (Whatman 1 PS is suitable) containing anhydrous sodium sulfate, evaporate the ether to dryness and dry the residue at 100° for 3 hours. The infrared absorption spectrum of the dried residue, Appendix II A, is concordant with the reference spectrum of levomepromazine (RS 404).
TESTS
Acidity
pH, 4.0 to 5.0, Appendix V L.
Related substances
Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions protected from light.
(1) Dilute a volume of the injection, if necessary, with sufficient of a mixture of 95 volumes of methanol and 5 volumes of diethylamine to produce a solution containing 0.5% w/v of Levomepromazine Hydrochloride.
(2) Dilute 1 volume of solution (1) to 100 volumes with a mixture of 95 volumes of methanol and 5 volumes of diethylamine and further dilute 1 volume to 2 volumes with the same solvent mixture.
(3) 0.005% w/v of levomepromazine sulfoxide BPCRS in a mixture of 95 volumes of methanol and 5 volumes of diethylamine.
CHROMATOGRAPHIC CONDITIONS
(a) Use a TLC silica gel GF254 plate.
(b) Use the mobile phase, maintained at 35°, as described below.
(c) Apply 10 μL of each solution.
(d) Develop the plate to 15 cm.
(e) After removal of the plate, allow it to dry in air and examine under ultraviolet light (254 nm).
MOBILE PHASE
5 volumes of diethylamine, 10 volumes of acetone and 85 volumes of toluene.
LIMITS
In the chromatogram obtained with solution (1):
any spot corresponding to levomepromazine sulfoxide is not more intense than the spot in the chromatogram obtained with solution (3) (1%);
any other secondary spot is not more intense than the spot in the chromatogram obtained with solution (2) (0.5%).
Disregard any spot remaining on the line of application.
ASSAY
Carry out the following procedure protected from light. Dilute a volume of the injection containing 0.1 g of Levomepromazine Hydrochloride to 100 mL with water and dilute 1 volume of this solution to 25 volumes with water. Immediately measure the absorbance of the solution at the maximum at 302 nm, Appendix II B, using water in the reference cell. Measure the absorbance of a 0.004% w/v solution of levomepromazine maleate BPCRS in water and calculate the content of C19H24N2OS,HCl from the absorbances obtained using the declared content of C19H24N2OS,C4H4O4 in levomepromazine maleate BPCRS. Each mg of C19H24N2OS,C4H4O4 is equivalent to 0.8207 mg of C19H24N2OS,HCl.
STORAGE
Levomepromazine Injection should be protected from light.
