Action and use
Immunostimulant; antihelminthic.
DEFINITION
Levamisole Injection is a sterile solution of Levamisole Hydrochloride in Water for Injections. It may contain suitable colouring matter.
The injection complies with the requirements stated under Parenteral Preparations and with the following requirements.
Content of levamisole hydrochloride, C11H12N2S,HCl
92.5 to 107.5% of the stated amount.
IDENTIFICATION
A. Carry out the method for thin-layer chromatography, Appendix III A, using silica gel G as the coating substance and a mixture of 100 volumes of ethyl acetate, 10 volumes of methanol and 1 volume of 13.5M ammonia as the mobile phase.
Apply separately to the plate 1 μL of each of the following solutions in methanol. For solution (1) dilute a volume of the injection to produce a solution containing 1% w/v of Levamisole Hydrochloride. Solution (2) contains 1% w/v of levamisole hydrochloride BPCRS. After removal of the plate, allow it to dry in air and spray with potassium iodoplatinate solution. The principal spot in the chromatogram obtained with solution (1) corresponds to that in the chromatogram obtained with solution (2).
B. Dilute a volume of the injection containing 0.75 g of Levamisole Hydrochloride to 20 mL with water and add 6 mL of 1M sodium hydroxide. Extract with 20 mL of dichloromethane, discard the aqueous layer and wash the dichloromethane layer
with 10 mL of water. Shake with anhydrous sodium sulfate, filter and evaporate the dichloromethane at room temperature. The melting point of the residue, after drying over phosphorus pentoxide at a pressure of 1.5 to 2.5 kPa at a temperature not exceeding 40°, is about 59°, Appendix V A.
C. The injection is laevorotatory.
D. Yields reaction B characteristic of chlorides, Appendix VI.
TESTS
Acidity
pH, 3.0 to 4.0, Appendix V L.
2,3-Dihydro-6-phenylimidazo[2,1-b]thiazole hydrochloride
Carry out the method for thin-layer chromatography, Appendix III A, using silica gel G as the coating substance and a mixture of 8 volumes of glacial acetic acid, 16 volumes of methanol and 90 volumes of toluene as the mobile phase. Apply separately to the plate 10 μL of each of the following two solutions. For solution (1) dilute a volume of the injection with methanol to produce a solution containing 5.0% w/v of Levamisole Hydrochloride. Solution (2) contains 0.021% w/v of 2,3-dihydro-6-phenylimidazo[2,1-b]thiazole BPCRS in methanol. After removal of the plate, allow it to dry in air and spray with potassium iodoplatinate solution. Any spot in the chromatogram obtained with solution (1) corresponding to 2,3-dihydro-6-phenylimidazo[2,1-b]thiazole is not more intense than the spot in the chromatogram obtained with solution (2) (0.5%).
ASSAY
To a volume of the injection containing 0.75 g of Levamisole Hydrochloride add 50 mL of water and 15 mL of 2M sodium hydroxide, extract with three quantities, of 25, 20 and 15 mL, of chloroform and wash the combined extracts with two 10 mL quantities of water. To the combined extracts add 50 mL of anhydrous acetic acid and carry out Method I for non- aqueous titration, Appendix VIII A, using 1-naphtholbenzein solution as indicator. Each mL of 0.1M perchloric acid VS is equivalent to 24.08 mg of C11H12N2S,HCl.
STORAGE
Levamisole Injection should be protected from light.
