LC-MS/MS determination of cinacalcet enantiomers in rat plasma on Chirobiotic V column in polar ionic mode: application to a pharmacokinetic study.

A simple and selective polar ionic liquid chromatography-tandem mass spectrometric method for separation and determination of cinacalcet enantiomers in rat plasma was developed and validated. The chromatographic separation was accomplished on a Chirobiotic V column packed with vancomycin as a chiral stationary phase using 2.5 mm ammonium formate in 100% methanol as a mobile phase in an isocratic mode of elution at a flow rate of 1.

RP-HPLC separation and ESI-MS, 1H, and 13C NMR characterization of forced degradants including process related impurities of carisbamate: method development and validation.

A stability indicating reversed phase HPLC method was developed and validated for determination of process related impurities and forced degradants of carisbamate (CRS) in bulk drugs. Carisbamate when subjected to acid/base hydrolysis, H2O2 oxidation, photolysis and thermal stress significant degradation was observed during acid/base hydrolysis and the degradants were isolated and characterized by ESI-MS, (1)H and (13)C NMR. MS/MS and 2D-NMR (COSY and HSQC) studies revealed the possible isomerization of CRS under stress conditions.

High-performance liquid chromatographic determination of anti- hypertensive drugs on dried blood spots using a fluorescence detector--method development and validation.

A selective and sensitive high-performance liquid chromatography method with fluorescence detection for simultaneous determination of irbesartan, losartan and valsartan on dried blood spots (DBS) has been developed and validated. It involves solvent extraction of a punch of DBS followed by reversed-phase liquid chromatography on a Lichrospher(®) 100 RP-18e column. Fluorescence detection was performed at 259 and 385 nm as excitation and emission wavelengths, respectively.