A simple, sensitive, selective, rapid, rugged, reproducible and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used for quantitative estimation of rizatriptan (RZ) in human plasma using rizatriptan-d 6 (RZD6) as internal standard (IS). Chromatographic separation was performed on Ascentis Express RP Amide C18, 50 9 4.6 mm, 2.7 lm column with isocratic mobile phase composed of 10 mM ammonium formate:acetonitrile (20:80 v/v) at flow rate of 0.5 mL min -1 . RZ and RZD6 were detected with proton adducts at m/z (amu) 270.2 ? 201.2 and 276.1 ? 207.1, respectively, in multiple reaction monitoring (MRM) positive mode. Liquid-liquid extraction was used and validated over a linear concentration range of 0.1-100.0 ng mL -1 with correlation coefficient r 2 C 0.9981. The limit of quantification (LOQ) and limit of detection (LOD) were found to be 0.1 ng mL -1 and 12.5 fg, respectively. Intra-and inter-day precision were within 1.7-3.1% and 2.8-3.7%, and accuracy within 96.0-101.7% and 99.7-101.4% for RZ. Drug was found to be stable throughout three freeze-thaw cycles. The method was successfully employed for analysis of plasma samples following oral administration of RZ (10 mg) in 25 healthy Indian male human volunteers under fasting conditions.

In this study, authors developed a simple, sensitive and specific liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for quantification of Amisulpride in human plasma using Amisulpride-d5 as an internal standard (IS). Chromatographic separation was performed on Zorbax Bonus-RP C18, 4.6 × 75 mm, 3.5 μm column with an isocratic mobile phase composed of 0.2% formic acid:methanol (35:65 v/v), at a flow-rate of 0.5 mL/min. Amisulpride, Amisulpride-d5 was detected at m/z 370.1→242.1 and 375.1→242.1. The drug and the IS were extracted by a liquid-liquid extraction method. The method was validated over a linear concentration range of 2.0–2500.0 ng/mL for Amisulpride with a correlation coefficient of (r2) ≥ 0.9982. This method demonstrated intra- and inter-day precision within 0.9 to 1.7 and 1.5 to 2.8 % and intra- and inter-day accuracy within 98.3 to 101.5 and 96.0 to 101.0 % for Amisulpride. Amisulpride was found to be stable at 3 freeze–thaw cycles, bench top and auto sampler stability studies. The developed method was successfully applied to a pharmacokinetic study.

A reversed phase high performance liquid chromatography (RP-HPLC) method was developed, validated and used for the quantitative determination of rabeprazole sodium (RP) and itopride hydrochloride (IH), from its tablet dosage form. Chromatographic separation was performed on a Phenomenex C18 column (250 mm × 4.6 mm, 5 μm), with a mobile phase comprising of a mixture of 50 mM ammonium acetate buffer and methanol (20:80v/v), pH 4.5 adjusted with acetic acid, at a flow rate of 1.3 mL/min with detection at 286 nm. Separation was completed in less than 10 min. As per International Conference on Harmonization (ICH) guidelines the method was validated for linearity, accuracy, precision, limit of quantitation and limit of detection. Linearity of RP was found to be in the range of 37.5-375 μg/mL and IH was found to be in the range of 5-50 μg/mL. The correlation coefficients were 0.9997 and 0.9995 for RB and IH respectively. The accuracy of the developed method was found to be 98.6-100.7 for RP and 99.42 -100.81 for IH. The experiment shows the developed method is free from interference of excipients. It indicates the developed RP-HPLC method is simple, linear, precise and accurate and it can be conveniently adopted for the routine quality control analysis of the tablet dosage form.