Simultaneous analysis of aliskiren and hydrochlorothiazide in pharmaceutical preparations and spiked human plasma by HPTLC

A simple, selective and precise method based on HPTLC has been developed for the simultaneous determination of aliskiren and hydrochlorothiazide in a fixed-dose tablet formulation and human plasma. The chromatography was performed on silica gel 60 GF254 plates, with a mobile phase consisting of methanol-chloroform (6:4, v/v). Densitometric analysis of the analytes was carried out at 225 nm. Under optimized conditions, the Rf values were 0.26 ± 0.02 and 0.71 ± 0.02, and the resulting regression plots were linear (r2 ≥ 0.9997) in the concentration ranges of 1.00-10.0 and 0.10-1.00 μg band−1 for aliskiren and hydrochlorothiazide. The limit of detection and limit of quantitation of the validated method were 0.206 and 0.624 μg band−1 for aliskiren and 0.015 and 0.046 μg band−1 for hydrochlorothiazide, respectively. The % expected content of aliskiren and hydrochlorothiazide in the commercial tablet formulation was 99.2% and 101.3%, respectively. For spiked plasma sample preparation, the analytes and nebivolol internal standard were extracted from 500 μL of plasma sample by solid-phase extraction on LiChrosep® DVB-HL cartridges. The mean extraction recovery of aliskiren and hydrochlorothiazide from human plasma was 87.2% and 76.5%, respectively. In addition, the stability of the analytes in plasma was established under different storage conditions.