Abstract:
OBJECTIVE To prepare genistein-loaded MePEG-PLGA nano-micelle and study its physicochemical properties. To investigate the release characterization
in vitro and study the pharmacokinetic characteristics of genistein nano-micelle after single dose in rats. METHODS Genistein nano-micelle was prepared by modified spontaneous emulsification solvent diffusion method, then its physicochemical properties including entrapment efficiency, drug loading, average diameter and Zeta potential were studied. The in vitro release was studied by dynamic dialysis method and the release behavior was fitted with different equations. Put freeze-dried GEN-loaded micelle at 4 ℃ for six months to investigate the changes of the entrapment efficiency and drug loading. The plasma concentrations of Genistein at different time were determined by a developed and validated HPLC method after i.v. administration. The pharmacokinetic parameters were acquired with DAS 2.0 software and analyzed using SPSS 17.0 statistic software. RESULTS The entrapment efficiency, drug loading and average diameter of the prepared nano-micelle were (84.43±2.93)%, (2.63±0.91)% and (63.75±4.12)nm, respectively. The release behavior of the lyophilized Gen nano-micelle was well-fitted to Weibull equation. The entrapment efficiency and drug loading had no significant difference after stored at 4 ℃ for six months. After i.v. administration of Genistein nano-micelle and Genistein emulsion 40 mg·kg
-1, the main pharmacokinetie parameters were as follows: AUC
0-t were (99.46±4.77)mg·L
-1·h and (57.51±1.37)mg·L
-1·h,
t1/2 were (7.48±1.15)h and (4.95±1.15)h,
Cmax were (16.03±1.20)mg·L
-1 and (16.73±1.10)mg·L
-1, CL were (0.36±0.02)L·h
-1·kg
-1 and (0.67±0.02)L·h
-1·kg
-1. CONCLUSION The genistein nano-micelle was spherical with narrow size distribution and high entrapment efficiency, the genistein nano-micelle possess the properties of sustained release with good stability. Compared with reference injection, the nano-micelle can significantly improve the pharmacokinetic behavior of genistein.