Dileep M. Bhosale

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.

A novel, simple, rapid and stability-indicating reversed-phase ultra performance liquid chromatographic and mass spectrometric method was developed and subsequently validated for quantitation of Efavirenz (EFV) from drug substance matrix. The separation was achieved in 2.5 minutes on Waters ACQUITY UPLC BEH C18 (50 x 2.1) mm, 1.7µm column in isocratic mode with flow rate 0.4 mL/min. Mobile phase used was 0.01 M ammonium acetate buffer pH 7.5 and acetonitrile in ratio 50:50 v/v. Detection was carried out at the maximum wavelength of 247 nm using a photodiode array detector. The retention time of Efavirenz was found 1.8 minutes. Specificity of the method was established on drug substance by hydrolytic and oxidative stress conditions. Validation of analytical method was carried out as per the current ICH guidelines for linearity, recovery, precision, limit of detection, limit of quantification and robustness parameters.