High performance liquid chromatography method for the pharmacokinetic study of bicalutamide SMEDDS and suspension formulations after oral administration to rats

Bicalutamide is a non-steroidal antiandrogen and is an oral medication that is used for treating prostate cancer. To evaluate the bioavailability of bicalutamide from bicalutamide self-microemulsifying drug delivery systems (SMEDDS) and bicalutamide suspension formulations, a sensitive, specific reversed-phase high performance liquid chromatographic (HPLC) method using ultraviolet detection was developed and validated for the analysis of bicalutamide (BCT) in rat blood plasma.Letrozole (LZ) was used as the internal standard. The chromatographic separation was achieved on C18 column at 35 °C, with a mobile phase consisting of water: acetonitrile (adjusted to pH 3.0 with 20% o-phosphoric acid) (60:40), at a flow rate of 1.0 mL min−1. Bicalutamide and letrozole were well separated with retention times of 10.9 ± 0.2 and 5.7 ± 0.2 min, respectively. The method was successfully used to determine pharmacokinetics of bicalutamide, following oral administration of bicalutamide suspension and bicalutamide SMEDDS to wistar rats.Significant difference was observed in main pharmacokinetic parameters of tmax, Cmax and AUC0→∞ between SMEDDS and suspension, and a two fold increase in the relative bioavailability of bicalutamide was observed with the SMEDDS compared with suspension formulation. It was concluded that the absorption of bicalutamide from SMEDDS was enhanced.