New Analytical Method for Simultaneous Analysis of Losartan and E-3174 by HPLC in Human Plasma: Application in Pharmaceutical Science

Background: Losartan, one of the most frequently used drugs in Heart Failure (HF) treatment, could be modified for its bioavailability (BA) by generic formulations and other factors. Hence, the importance of therapeutic drug monitoring. Objective: Development and validation of a simplified analytical method using HPLC for simultaneous quantification of losartan and E-3174 in human plasma samples. The method was tested for determining the pharmacokinetics parameters of HF patients. Methods: Analytical conditions were optimized using a C18 column (4.6 X 50 mm, 3 μm. Thermo Scientific) at 25ºC. Conditions of mobile phase: a phosphate buffer (0.01M), adjusted to pH 2.5 with phosphoric acid (1M) and Acetonitrile (60:40 v/v). The flow rate was maintained at 1.2 mL/min, on a running time of 5 min and a sample injection volume of 50 μL. Absorbance for measurement of losartan and E-3174 was 200 nm. Pharmacokinetics profiles were determined with Phoenix Win- Nonlin 8.1 software in a non-compartmental model. Results: Analytical method developed and validated in this work is precise and accurate for simultaneous determination of losartan and E-3174 in human plasma samples in a range of 0.02 -10 μg/mL. In HF subjects, lower Tmax and higher Cmax for losartan and E-3174 patent than generic formulation were observed, which can be translated into less biological effect and more time to present it by the generic drug. Conclusion: The pharmacokinetic profile is dependent on the type of formulation studied (generic/ patent) hence the importance of conducting evaluations in our patients to ensure that the expected therapeutic effect is achieved with treatment administered.