Development of LC-MS Method for Characterization of Drotaverine Hydrochloride Impurities

A novel, simple and rapid reversed-phase liquid chromatography mass spectrometric method (LC-MS) was developed and subsequently used for the characterization of Drotaverine hydrochloride (DRH) and its impurities. The separation was achieved in 22 minutes on Merck Purosphere STAR RP-18e (250 x 4.6) mm, 5 µm column in gradient mode with flow rate 1.5 mL/min. 0.05 M ammonium acetate buffer pH 3.0 and a mixture of acetonitrile and methanol 85:15 v/v  was used as mobile phase A and mobile phase B, respectively. Detection was carried out at the optimum wavelength of 280 nm using a photodiode array/triple quadrupole mass detectors. The retention time of Drotaverine was found about 7 minutes. Specificity of the method was established by blank solution and the extreme degraded sample was used for the detection of impurity masses. The impurities detected under mass detector were further ionized for their daughter ions.