Self-micro emulsifying formulation improved intestinal absorption and oral bioavailability of bakuchiol

Bakuchiol (BAK), isolated from the seeds of Psoralea corylifolia L., recently presents a variety of pharmacologic activities. However, the poor oral bioavailability limits its further development and clinical use. The purpose of this study was to establish a self-microemulsifying (SME) formulation for oral delivery improvement of BAK. The optimized liquid SME formulation was comprised of BAK (40 %), Cremophor RH 40 (30 %) and Labrasol (30 %). The emulsion droplets were spherical in shape, and particle size and zeta potential were determined. The in vitro dissolution test of BAK-SME formulation illustrated faster dissolution rate than the bulk drug. The permeabilities of 40 μg mL^-1 BAK-SME formulation in rat intestinal segments of duodenum, jejunum, ileum and colon were 30.91 × 10^-3, 23.61 × 10^-3, 29.43 × 10^-3 and 23.62 × 10^-3 cm min^-1, respectively, exhibiting 3.99 times in duodenum, 2.59 times in ileum and 2.31 times in colon greater than BAK perfusate. The oral bioavailability of BAK-SME formulation at a dose of 150 mg kg^-1 was determined in rats. The C_max and the AUC_(0-24h) were 515.4 ng mL^-1 and 4,327.2 h ng mL^-1, respectively, which were 1.90 fold and 1.73 fold greater than the value of BAK suspension. All these results clearly stated that BAK-SME formulation performed well-improvement on oral bioavailability of BAK.