摘要
Novel mixed polymeric micelles formed by biocompatible polymers,mPEG-PLA and Pluronic P105,were fabricated and used as a nanocarrier to solubilize the poorly soluble anesthetic drug propofol.Propofol was added directly to an aqueous solution of mPEG-PLA/Pluronic P105 mixed micelles and stirred into a micellar solution.The average particle size and size distribution of micelles were evaluated by the dynamic light scattering technology.Drug loading content,encapsulation efficiency and free drug concentration were determined by using ultracentrifugation and lyophilization.In vitro release characteristic of propofol formulation was investigated by dialysis method.The physical stability of mixed micelles was also assessed under storage condition（4 oC） after six months.Sleep-recovery studies in male Sprague-Dawley rats,at a dose of 10 mg/kg were performed to compare the pharmacodynamic profiles of propofol in mixed micelles with that of commercial lipid emulsion（CLE）.The results indicated that solubilization of propofol in the mixed micelles was more efficient than that in mPEG-PLA alone.Micelles with the optimized composition of mPEG-PLA/Pluronic P105/Propofol（10：4：5,w/w/w） had particle size of about 90 nm with narrow distribution（polydispersity index of about 0.2）.The content of free propofol in the aqueous phase of mixed micelles was significantly lower than that in CLE（P〈0.05）.There was no remarkable differences for particle size,polydispersity index,and free drug concentration when the mix micelles were stored at 4 oC for six months,suggesting that the propofol-loaded mixed micelles were stable for at least six months.The accumulative release of mixed micelles was significantly higher than that of CLE at the corresponding time points,suggesting that quick release rate for mixed micelles might produce favorable pharmacological effect.No significant differences in the unconsciousness time and recovery time of righting reflex were observed between the mixed micelles and CLE（P〉0.05）.In conclusion,the mixed micelle of mPEG-PLA and pluronic copolymer may be a promising candidate for intravenous delivery of propofol in clinic.
采用生物相容性聚合物胶束材料聚乙二醇-聚乳酸(mPEG-PLA)和普朗尼克P105(P105),构建了全新的混合胶束体系,用于提高难溶性麻醉药—丙泊酚的溶解度。相对于单纯由mPEG-PLA构建的载药胶束,该载药混合胶束能有效提高药物溶解度。最优化处方为mPEG-PLA:P105:丙泊酚=10:4:5(w/w/w),粒径约为90nm,多分散指数为0.2左右。载药混合胶束中游离药物浓度显著低于市售品脂肪乳(P<0.05)。此混合胶束于4oC条件下放置6个月,其粒径、多分散指数、游离药物浓度和载药量均无明显变化,说明4oC条件下该体系在6个月内是稳定的。混合胶束在各时间点的体外释放百分率显著高于市售品脂肪乳,这可能有利于更快发挥药效。睡眠/苏醒试验结果表明,混合胶束、单一胶束以及市售品脂肪乳的翻正反射消失时间和恢复时间没有显著性差异(P>0.05)。上述结果表明该混合胶束有望成为静脉给药系统应用于临床。
基金
National Development of Significant New Drugs(New Preparation and New Technology,Grant No. 2009zx09310-001)
the National Basic Research Program of China (973 program,Grant No. 2009CB930300)
