Bioequivalence model for evaluation of Losartan in human plasma with special reference to drug–metabolite ratio

Losartan and in-vivo active metabolite losartan carboxylic acid (LCA) formation into systemic circulation have been poorly characterized in different races. A bioequivalence study was therefore conducted on healthy male Indian volunteers with 50 mg losartan formulation and unique comparative analysis with other population is presented. Non-compartmental pharmacokinetic analysis elucidated metabolite formation ratio (MR) for losartan: LCA [Cmax = 1.30 and AUC = 0.32] of 50 mg losartan was more varying compared to innovator [Cmax = 0.82 and AUC = 0.22] though bioequivalence requirements were met successfully. This variation was less for losartan 100 mg losartan- hydrochlorothiazide formulation in our previous published bioequivalence study.