Pharmacokinetics, Bioequivalence, and Safety Evaluation of Two Formulations of Losartan Potassium Tablets USP 100 mg under Fasting Conditions

This study was designed to evaluate the bioequivalence of Losartan Potassium Tablets USP 100 mg, developed by Caplin Point Laboratories Ltd., India, compared with COZAAR® (Losartan Potassium Tablets USP 100 mg) manufactured by Merck Sharp & Dohme LLC, Chile. Conducted under fasting conditions, this open-label, randomized, two-treatment, three-sequence, three-period, single-dose, crossover, semi-replicate study aimed to assess pharmacokinetic parameters and the safety profile of both formulations in healthy adult human subjects. A total of 39 participants were enrolled, with 30 completing all study phases. Blood samples were collected at 28 predefined time points in each study period and analyzed for plasma concentrations of Losartan and its active metabolite, carboxylic acid, using a validated bioanalytical method. Key pharmacokinetic metrics such as Cmax, AUC0-t, and AUC0-∞ were determined, and the log-transformed data were subjected to statistical analysis. Results demonstrated that the 90% confidence intervals of the test/reference ratio for Cmax (82.57%–117.03%), AUC0-t (98.11%–107.46%), and AUC0-∞ (98.09%–107.37%) were all within the predefined bioequivalence acceptance range of 80.00%–125.00%. These findings established bioequivalence between the test and reference formulations. Safety evaluations revealed five adverse events among four subjects, all of which were mild to moderate and resolved completely without sequelae. In conclusion, the study confirms that Losartan Potassium Tablets USP 100 mg by Caplin Point Laboratories Ltd. is bioequivalent to COZAAR® and is well-tolerated under fasting conditions. These results support the potential for the test product to serve as a cost-effective and accessible therapeutic alternative for managing hypertension.