Seshagiri Rao JVLN

A rapid and sensitive LC-MS/MS method for the quantification of nebivolol using d4- nebivolol as internal standard has been developed and validated. The nebivolol and d4- nebivolol were extracted by liquid- liquid extraction using tert-butyl ethyl ether and separated on Kromasil 100-5C 4.6x100mm column using a mixture of 0.1% formic acid in 5 mM ammonium acetate, methanol and acetonitrile at composition of (20:20:60 v/v) at a flow rate of 0.5 mL/min. Detection involved an API-4000 LC-MS/MS with electrospray ionization in the positive mode.  The method was validated as per the FDA guidelines and shown to provide an intra and inter day precision and accuracy within the acceptable limit with in a run time of 3.0 min. The proposed method can adopt for the regular bioequivalence study analysis and also can easily adoptable for clinical drug monitoring due to its simplicity and ruggedness.

This paper describes a simple, rapid and sensitive bioanalytical method based on liquid chromatography / tandem mass spectrometry (LC–MS/MS) for the determination of integrase inhibitor raltegravir in human plasma samples. Carbamazepine was used as an internal standard (IS). Analyte and the internal standard were extracted from 200 µL of human plasma via solid phase extraction. The chromatographic separation was achieved on a C18 column by using a mixture of acetonitrile and 0.1% formic acid (90:10, v/v) as the mobile phase at a flow rate of 0.8 mL/min. The calibration curve obtained was linear (r2 ³ 0.99) over the concentration range of 20.1–4007 ng/mL. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 2.0 min for each sample made it possible to analyze more number of samples in short time, thus increasing the productivity. The proposed method was found to be applicable to pharmacokinetic studies in humans.

  A rapid and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay method has been developed and fully validated for simultaneous quantification of two lipid lowering agents rosuvastatin and fenofibric acid in human plasma. Lovastatin was used as an internal standard. Analytes and the internal standard were extracted from human plasma by liquid-liquid extraction technique using a 50:50, v/v mixture of ethyl acetate and diethyl ether. The reconstituted samples were chromatographed on a C18 column by using a 80:20, v/v mixture of acetonitrile and 0.1% formic acid as the mobile phase at a flow rate of 1.0 mL/min. The calibration curve obtained was linear (r2 ³ 0.99) over the concentration range of 0.10-80.00 ng/mL for rosuvastatin and 50-9003 ng/mL for fenofibric acid. The multiple reaction monitoring mode was used for quantification of ion transitions at m/z 482/258, 319/233 and 405/199 for the rosuvastatin, fenofibric acid and the internal standard, respectively. The results of the intra-day and inter-day precision and accuracy study results were well within the acceptable limits. A run time of 3.0 min for each sample made it possible to analyze more than 300 plasma samples per day. The proposed method was successfully applied for the determination of the fenofibric acid in real time plasma samples for pharmacokinetic studies. Key words: Rosuvastatin, Fenofibric acid, human plasma, LC-MS/MS quantification, Pharmacokinetics.