Raloxifene HCl (RLX), a selective oestrogen receptor modulator, has low oral bioavailability (<2%) in humans due to its poor aqueous solubility and extensive first-pass metabolism in gut. In this study, we optimised the method of preparation for poly (ε-caprolactone) (PCL) based nanocapsules of RLX by double emulsion method (w/o/w). A hybrid design approach, Plackett-Burman design followed by rotatable central composite design, was used to arrive at the optimised formulation. The optimised formulation was subjected to in vitro and in vivo evaluation. RLX loaded nanocapsules were spherical in shape with particle size less than 200 nm and high encapsulation efficiency (>80%). RLX-loaded nanocapsules showed 2.1-fold increase in oral bioavailability compared to free RLX. IV pharmacokinetic studies indicated that RLX loaded into nanocapsule had significantly low clearance in comparison with free RLX. Designed nanocapsules showed promise as delivery systems to enhance oral bioavailability and in reducing clearance of raloxifene.

Summary. 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 × 4.6 mm, 5 μm). 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.