PRECLINICAL PHARMACOKINETICS OF ALFUZOSIN FORMULATIONS IN RABBITS BY HPLC

Abstract

The objective of the current study was the pre-clinical evaluation of alfuzosin in rabbits. A simple, specific and simple HPLC method has been developed for estimation of Alfuzosin with 100μL of rabbit plasma using Doxazosin as an internal standard (IS). The Waters HPLC with PDA detector at 245 nm. A simple protein precipitation extraction process with acetonitrile was used to extract Alfuzosin and IS (Doxazosin) from rabbit plasma. The total run time was 3.00 min and the elution of Alfuzosin and Doxazosin occurred at 1.49 min and 2.14 min, this was achieved with a mobile phase consisting of buffer : acetonitrile (60:40, v/v) at a flow rate of 0.80 mL/min on a Inertsil C 8 (150 x 4.6 mm, 5 μm) column. Buffer was prepared by mixing 0.02 M potassium dihydrogen orthophosphate and 1mL triethyl amine in 1000 mL and it was adjusted to (pH-3.5) with ortho phosphoric acid. The developed method was validated in rabbit plasma with a lower limit of quantitation of 0.05 μg/mL for Alfuzosin. A linear response function was established for the range of concentrations 0.05 to 5.0 μg/mL (r > 0.998) for Alfuzosin. The intra and inter-day precision values for Alfuzosin met the acceptance criteria as per FDA guidelines. Alfuzosin was stable in a set of stability studies viz., bench-top, auto-sampler and freeze/thaw cycles. This method is free from interference from the plasma blank or solvents used during the optimization. The current fast track assay method was successfully applied for the oral pharmacokinetic studies of 10 mg extended release tablets of Alfuzosin Hydrochloride and its in vivo evaluation with reference formulations.