Liquid Chromatographic Determination of Linagliptin in Bulk, in Plasma and in itsPharmaceutical Preparation

In this work, tworeversed-phase liquid chromatographic (RP-LC) methods have been developed for the determination of linagliptin (LNG) based on isocratic elutionusing a mobile phase consisting of potassium dihydrogen phosphate buffer pH (4.6)-acetonitrile(20:80,v/v) at a flow rate of 1 mL min 1. Two detection techniques have been applied either UV detection at 299 nm in the first method or fluorometric detection at 239 nm for excitation and 355 nm for emission in the second method. Chromatographic separation in the two methods was achieved on a Symmetry cyanide column (150 mm×4.6 mm, 5μm). Linearity, accuracy and precision were found to be acceptable over the concentration ranges of 2.5-80 μgmL 1 for LNG in bulk and 2.5-15μg mL 1 for LNG in plasma with the first method and 5-160 μgmL 1 for LNG in bulk with the second method. The optimized methodswere validated and proved to be specific, robust and accurate for the quality control of the cited drug in its pharmaceutical preparation.