Enhanced LC-MS/MS determination of alogliptin and metformin in plasma: Application to a pharmacokinetic study

A fast, sensitive and specific LC-MS/MS method was developed for estimation of alogliptin (AG) and metformin (MF) using sitagliptin (SG) as an internal standard (IS). Hypersil Gold column (50 mm × 2.1 mm, 1.9 μm) was used applying gradient elution of acetonitrile and 0.2% formic acid solution. Selected reaction monitoring (SRM), with transitions of 340.33 → 116.32 (m/z), 130.12 → 71.32 (m/z) and 408.12 → 235.24 (m/z), was used to quantify AG, MF and SG (IS), respectively on a triple quadropole mass spectrometer in positive ion mode. Enhanced sample preparation involved direct precipitation and an evaporation technique. As per FDA guidelines, a detailed validation of the method was carried out and the standard curves were found to be linear between 5 and 400 ng mL− 1 for AG and 25-2000 ng mL− 1 for MF. Precision and accuracy results were within the acceptable limits. A short run time of 2.5 min for each sample offered the rapid analysis of high number of human plasma samples per day. Application to a pharmacokinetic study was achieved successfully on Egyptian healthy human volunteers after the approval by the ethical committee. Pharmacokinetic parameters can vary between different races, so the present analysis considered the Egyptian African volunteers to be compared with the results obtained from the other ethnic populations. The applied pharmacokinetic study is considered as a mandatory prerequisite for new drugs registration and approval according to Egyptian Ministry of Health regulations.