Ultra-high-speed liquid chromatography combined with mass spectrometry detection analytical methods for the determination of nitrosamine drug substance-related impurities.

In the present study, five simple, feasible, and sensitive Ultra-high-speed liquid chromatography combined with mass spectrometry detection methods, using electrospray ionization are proposed. These methods were developed and validated for the determination of four different nitrosamine drug substance-related impurities-N-nitrosoacebutolol, N-nitrosobisoprolol, N-nitrosometoprolol, and N-nitrososotalol-in five beta blockers active pharmaceutical ingredients-acebutolol HCl, bisoprolol fumarate, metoprolol tartrate, metoprolol succinate, and sotalol HCl. The proposed methods were validated as per regulatory guidelines. Acquity HSS T3 (3.0 × 100 mm, 1.8 µm) column and formic acid 0.1% in water combined with methanol or acetonitrile were used for chromatographic separation in all methods. The limit of detection and the limit of quantification were found to be in the range of 0.02-1.2 and 2-20 parts per billion, respectively. The accuracy and precision of the five methods have been demonstrated in the working range of each one, giving values of recovery within the range of 64.1%-113.3%, and the regression coefficients (R) were found to be in the range of 0.9978-0.9999. These methods could be used for controlling nitrosamine drug substance-related impurities content for beta blockers drug substances batches manufactured at Moehs group.

Method development and validation study for quantitative determination of nifedipine and related substances by ultra-high-performance liquid chromatography.

A novel stability-indicating reversed phase ultra-high performance liquid chromatography (UPLC) coupled photodiode array gradient method was developed for determination of the nifedipine and related compounds. Furthermore, based on the chromatographic conditions and forced degradation studies performed through the development of the related substances method a UPLC isocratic method was validated for the determination of the assay of this active substance. An Acquity Shield RP18 (50 × 3.0 mm 1.7 µm) column was used for separation of nifedipine and its five potential impurities within 11 min, which is 5-fold less than the official method. A mobile phase consisting of 10 mm ammonium formate (pH 4.5) and methanol, delivered at a flow rate 0.5 mL/min, was employed to achieve a minimum resolution of 2.0 for all consecutive pairs of compounds. The precision value expressed as percentage relative standard deviation for method repeatability and reproducibility was <5.0%. The recoveries for all the related compounds were in the range of 99-105.0%. Linearity was found to be acceptable over the concentration range of 0.25-1.5 µg/mL for nifedipine and its impurities. The limit of quantification for nifedipine was 0.05 µg/mL, which is much less than the European Pharmacopoeia method.