Self-emulsifying preconcentrates of daidzein-phospholipid complex: design, in vitro and in vivo appraisal

Self-emulsifying phospholipid-complex preconcentrates (SEPPs) were fabricated to improve oral bioavailability of daidzein (DAI), an anticancer drug with challenging amphiphobic nature and extensive presystemic metabolism. DAI-phosphatidylcholine complex was prepared to enhance DAI lipophilicity and loading in SEPPs. The physicochemical characteristics and the pharmacokinetic behavior in rats were studied. Surfactant-free SEPP (plain DAI:Phosal 53MCT complex) was monodisperse upon aqueous dilution with nanorange globule size (485 ± 15 nm). Compared with drug suspension, it showed enhanced drug release and 2.38-fold enhanced oral bioavailability with minimized drug-induced intestinal irritation. Addition of 30% surfactant/co-surfactant mixture did not show any significant difference in drug release rate or absorption profile. The highly safe surfactant-free SEPP could be an effective approach to improve DAI oral bioavailability.