雷公藤甲素-甘草次酸复方微乳的制备及其理化性质和体外释药特性研究

目的:建立雷公藤甲素-甘草次酸复方微乳的含量测定方法,优化其处方,并考察其理化性质及体外释药特性。方法:采用超高效液相色谱法测定雷公藤甲素-甘草次酸复方微乳的含量,色谱柱为ACQUITY UPLC BEH C18,流动相为0.1%甲酸水溶液-乙腈(梯度洗脱),流速为0.4mL/min,柱温为40℃,检测波长为218 nm,进样量为5μL。采用水滴定法绘制伪三元相图,以油相、表面活性剂、助表面活性剂为指标优化处方;采用体外释放试验考察所制微乳的体外释放特性。结果:雷公藤甲素、甘草次酸的检测质量浓度线性范围分别为1~40μg/mL(r=0.999 7)、10~400μg/mL(r=0.999 8);定量限分别为0.5、0.8μg/mL,检测限分别为0.1、0.2μg/mL;精密度、稳定性、重复性试验的RSD均小于2%;加样回收率分别为100.32%~101.15%(RSD=0.36%,n=6)、99.78%~101.42%(RSD=0.59%,n=6)。最优处方为以中链甘油三酯为油相,聚乙二醇羟基硬脂酸酯为表面活性剂,无水乙醇为助表面活性剂,水为水相,四者质量比为8∶28∶14∶50。所制微乳为水包油型,外观透明澄清,其平均粒径为(62.38±3.44)nm,平均多分散指数为0.096±0.001,平均黏度为(26.84±1.10)mPa·S。所制微乳在24 h内的雷公藤甲素、甘草次酸累积释放度分别为99.8%、99.7%(pH 2.0的磷酸缓冲盐溶液中),99.3%、99.4%(pH 7.4的磷酸缓冲盐溶液中),98.9%、98.4%(pH 9.0的磷酸缓冲盐溶液中);单方微乳中的雷公藤甲素和甘草次酸释放均快于复方微乳。结论:所建含量测定方法操作简便、准确;所得优化处方稳定、可行;所制雷公藤甲素-甘草次酸复方微乳较单方微乳具有更好的缓释作用。

Study on Preparation of Triptolide-glycyrrhetic Acid Compound Microemulsion and Its Physicochemical Properties and in vitro Release Characteristics

OBJECTIVE:To establish content determination method of Triptolide-glycyrrhetic acid compound microemulsion,optimize the formula and investigate its physicochemical properties and release rate in vitro.METHODS:The content of Triptolideglycyrrhetic acid compound microemulsion was determined by UPLC.The determination was performed on ACQUITY UPLC BEH C18 column with mobile phase consisted of 0.1%formic acid aqueous solution-acetonitrile(gradient elution)at the flow rate of 0.4 mL/min.The column temperature was 40℃.The detection wavelength was set at 218 nm,and sample size was 5μL.Pseudo-ternary phase diagrams were drawn by water titration method.Using oil phase,surfactants and co-surfactants as index,the formula was optimized,and in intro release characteristics was investigated by in vitro release test.RESULTS:The linear range of triptolide and glycyrrhetinic acid were 1-40μg/mL(r=0.999 7)and 10-400μg/mL(r=0.999 8),respectively.The limits of quantitation were 0.5 and 0.8μg/mL;the limits of detection were 0.1 and 0.2μg/mL.RSDs of precision,stability and reproducibility tests were all less than 2%.Average recoveries were 100.32%-101.15%(RSD=0.36%,n=6),99.78%-101.42%(RSD=0.59%,n=6).The optimal formula included that medium chain triglyceride as oil phase,polyethylene glycol hydroxy stearate as surfactants,ethanol as co-surfactants,water as water phase,the proportion of them was 8∶28∶14∶50.The obtained microemulsion was O/W type,being transparent and clear,with average diameter,average polydispersity index and average viscosity of(62.38±3.44)nm,0.096±0.001 and(26.84±1.10)mPa·S.Within 24 h,cumulative release rates of triptolide and glycyrrhetinic acid in obtained microemulsion were 99.8%and 99.7%(in PBS pH 2.0),99.3%and 99.4%(in PBS pH 7.4),98.9%and 98.4%(in PBS pH 9.0),respectively.Triptolide and glycyrrhetinic acid released faster in the single microemulsion than in the compound microemulsion.CONCLUSIONS:Established content determination method is simple and stable.The optimized formula is stable and feasible.Obtained iriptolide-glycyrrhetinic acid compound microemulsion show better sustained-release effect than sigle microemulsion.