HIGH-PERFORMANCE THIN LAYER CHROMATOGRAPHIC METHOD FOR THE SIMULTANEOUS QUANTITATION OF LOPINAVIR AND RITONAVIR IN TABLET FORMULATION

The present work describes a simple, accurate and precise HPTLC method for simultaneous quantitation of ritonavir (RVR) and lopinavir (LVR) in tablet formulation. Chromatographic separation of both drugs was performed on precoated aluminum plates, silica gel 60 F254 as the stationary phase and the solvent system consisted of toluene: ethyl acetate: methanol: glacial acetic acid in the ratio of 6.5:2.5:0.5:0.5(v/v/v/v). Densitometric evaluation of the separated zones was performed at 266 nm. The two drugs were satisfactorily resolved with Rf values of 0.242 0.03 and 0.413 0.02 for RVR and LVR, respectively. The accuracy and reliability of the method was assessed by evaluation of linearity (400-2000 ng/spot for RVR and 1600-8000 ng/spot for LVR), precision (intra-day RSD 0.16-0.38% and inter-day RSD 0.21-0.60 % for RVR and intra-day RSD 0.35-0.58 % and inter-day RSD 0.26-0.55 % for LVR) and recovery (99.54 0.62 % for RVR and 100.45 0.65 % for LVR), in accordance with ICH guidelines.