A Simple Liquid Chromatographic Method for the Determination of Tenofovir in Rat Plasma and Its Application to Pharmacokinetic Studies

The objective of this study was to develop and validate a novel, simple, and selective high-performance liquid chromatographic (HPLC) method with photodiode array detector for the estimation of tenofovir in rat plasma, which can be utilized in analyzing the pharmacokinetic samples from rats. Prior to analysis, an optimized protein precipitation technique was used to extract tenofovir from plasma. The mobile phase for this method comprised of 10 mM ammonium acetate buffer (pH 4) and methanol in the ratio of 97:3 v/v. Chromatographic separation of tenofovir was achieved using Spincotech C-18G enabled column (250 x 4.6 mm, 5 mu m). Tenofovir was monitored at a wavelength of 260 nm, and the calibration curve was linear in the range of 250-4000 ng mL(-1) (R-2 = 0.999). High recovery obtained after extraction (97%-101%) of plasma samples precluded the use of an internal standard. Validation studies were performed as per the standard guidelines, and the developed method was accurate, precise, and selective for the determination of tenofovir in the rat plasma. The stability studies performed during the sample pretreatment process and sample storage conditions did not show a quantifiable degradation of tenofovir. Further, this method was able to estimate tenofovir and determine its pharmacokinetic parameters, post IV bolus administration in male Wistar rats. The pharmacokinetic profile of tenofovir followed one compartmental open model.