Assessment of Pharmacokinetic Parameters of Daidzein-Containing Nanosuspension and Nanoemulsion Formulations After Oral Administration to Rats

Background and ObjectivesDaidzein has several biological effects such as antioxidation, anti-inflammation, chemoprevention, and anticancer effects. The aim of this study was to evaluate the impact of nano-formulations (nanoemulsion-NE and nanosuspension-NS) prepared to increase the oral bioavailability of daidzein, a poorly water-soluble isoflavone, on the pharmacokinetic parameters of daidzein in rats. MethodsA high-performance liquid chromatography-ultraviolet (HPLC-UV) method was successfully developed for daidzein analysis in rat plasma. The pharmacokinetics studies of the nano-sized formulations, compared to coarse daidzein suspension, were carried out in the rats by a single oral dose at 10 mg/kg (n = 6/group). Area under the plasma concentration-time curve from time zero to extrapolation to time infinity (AUC0–∞), maximum plasma concentration (Cmax), time to reach maximum plasma concentration (tmax), and elimination half life (t1/2) values for coarse daidzein suspension, daidzein-NS, and daidzein-NE were estimated by a non-compartmental analysis.ResultsThe AUC values of daidzein-NE and daidzein-NS were approximately 2.62 and 2.65 times higher than that of coarse daidzein suspension, respectively (p < 0.05). Relative bioavailability (Frel) (%) values of daidzein following oral administration of nanosuspension or nanoemulsion formulations were about 265.6% and 262.3%, respectively.ConclusionIt revealed that nanoscale size is an important factor to overcome any dissolution rate barriers to oral bioavailability of the low water-soluble compound. Nanoemulsion and nanosuspension formulations are beneficial dosage forms to increase the oral bioavailability of Biopharmaceutical Classification System (BCS) Class II and Class IV compounds.