Potentials and challenges in self-nanoemulsifying drug delivery systems

Introduction: A significant number of new chemical entities (almost 40%), that are outcome of contemporary drug discovery programs, have a potential therapeutic promise for patient, as they are highly potent but poorly water soluble resulting in reduced oral bioavailability. Self-nanoemulsifying drug delivery systems (SNEDDS) have emerged as a vital strategy to formulate these poorly soluble compounds for bioavailability enhancement.

Areas covered: The review gives an insight about potential of SNEDDS with regards to oral drug delivery. The effect of various key constituents on formulation of SNEDDS and their applications in oral drug delivery is also discussed. Various aspects of formulation, characterization and biopharmaceutical aspects of SNEDDS are also been explored. The choice and selection of excipients for development of SNEDDS is also discussed.

Expert opinion: The ability of SNEDDS to present the drug in single unit dosage form either as soft or hard gelatin capsule with enhanced solubility maintaining the uniformity of dose is unique. With the ease of large-scale production, high drug-loading capacity, improvement in release behavior of poorly water-soluble drugs and improvement of oral bioavailability, SNEDDS have emerged as preferable system for the formulation of drug compounds with bioavailability problems due to poor aqueous solubility.     

葛根素自微乳给药系统的制备及其质量评价

目的 研究葛根素自微乳给药系统的处方工艺。方法 通过溶解度试验、油和表面活性剂配伍试验,以及伪三元相图的绘制,筛选葛根素自微乳的处方组成;通过粒径、载药量和自微乳化时间优化了葛根素自微乳处方;并对葛根素自微乳的理化性质和稳定性进行了考察。结果 葛根素自微乳处方中油相为中链甘油三酯（19.0%）、油酸（19.0%）,表面活性剂为聚山梨酯80（19.0%）、聚氧乙烯蓖麻油（19.0%）,助表面活性剂为1, 2-丙二醇（19.0%）,葛根素（5.0%）。自微乳化后粒径为（17.28±0.24）nm,自微乳化时间小于120 s;室温留样6个月,该自微乳性状、质量分数、粒径和自微乳化时间均无明显变化。结论 所制备的葛根素自微乳粒径小、稳定性好,符合良好自微乳制剂的要求。     

Interaction of a Self-Emulsifying Lipid Drug Delivery System with the Everted Rat Intestinal Mucosa as a Function of Droplet Size and Surface Charge

Purpose. To investigate the interaction of positively charged self-emulsifying oil formulations (SEOF) following aqueous dilution as a function of resulting emulsion droplet charge and size with rat everted intestinal mucosa, adherent mucus layer and Peyer's patches, using cyclosporine A (CsA) as a lipophilic model drug. Methods. Droplet size determination (TEM technique) and -potential measurements were used to characterize the resulting emulsions. For the ex vivo interaction study, the well-known rat intestine everted sac technique was used in combination with confocal microscopy. Results. The positively charged oil droplets formed by SEOF dilutions at ratios of 1/50 and 1/10 elicited the stronger interaction with the mucosal surface. The positive charge of the smaller droplets was more readily neutralized, and even reversed in aqueous solutions containing moderate subphysiological mucin concentrations. Parameters such as droplet size, negativity of the epithelial mucosa potential and presence of the mucus layer on the epithelial surface affected drug mucosa uptake and the adhesion of the positively charged droplets to the rat intestinal mucosa. Conclusions. The enhanced electrostatic interactions of positively charged droplets with the mucosal surface are mostly responsible for the preferential uptake of CsA from the positively charged droplets as compared to negatively charged droplets irrespective of the experimental conditions used. The increased uptake of the CsA from the negatively charged oil droplets was consistent with the dilution extent, as expected, whereas in the positively charged droplets, an intermediate droplet size range was identified resulting in optimum drug uptake and clearly suggesting that drug uptake was not consistent with either dilution extent or droplet size.     

基于相同载体体系的中药成分自乳化制剂的制备及其体外透皮吸收特性考察

目的:制备同时适合于黄芩素、黄连素及大蒜素3种中药成分的自乳化载体体系,并考察这3种自乳化制剂的体外透皮吸收效果。方法:采用饱和溶解度法、伪三元相图法、正交试验筛选最佳的空白处方组成及基质用量。以Franz扩散池和离体大鼠皮肤进行体外透皮吸收试验,采用HPLC分别测定3种自乳化制剂中黄芩素、黄连素及大蒜素的累积透皮渗透量,并分别与黄芩素散剂、黄连素散剂及大蒜素散剂进行比较。结果:最佳处方为油酸乙酯-聚氧乙烯氢化蓖麻油40-聚乙二醇400载体体系,所形成的自乳化制剂粒径适宜,其微观形态呈较规整的球形。透皮吸收10 h,黄芩素、黄连素及大蒜素3种自乳化制剂的药物透皮速率分别为6.898 6,7.600 4,190.040μg·cm~(-2)·h~(-1),累积透皮渗透量分别为71.38,85.54,1 795.16μg·cm~(-2)。结论:成功制备了不同种类中药成分均能使用的自乳化载体体系,且该自乳化制剂的体外透皮吸收效果良好,可为后续中药复方自乳化制剂的制备及其透皮给药吸收研究提供实验依据。     

青蒿素自乳化制剂的制备及其在家兔体内的药动学研究

目的:制备青蒿素自乳化系统,并对家兔体内药动学过程进行考察.方法:通过绘制相图并结合溶出度试验,以形成乳剂的乳化程度和乳化时间为指标,应用正交试验设计筛选最佳处方.用高效液相色谱法测定青蒿素的血药浓度,以青蒿素原料药作对照,比较家兔体内的药动学参数.结果:青蒿素自乳化系统主要由青蒿素、吐温-85 、油酸乙酯、乙醇组成.青蒿素自乳化制剂与青蒿素原料药在家兔体内平均滞留时间分别为4.750 h和4.628 h,家兔药动学研究结果表明,青蒿素自乳化系统口服后能很大程度上提高生物利用度.结论:自乳化制剂可以显著提高青蒿素的体外溶出及体内吸收.     

阿立哌唑自乳化释药系统的制备与质量评价

目的 制备阿立哌唑自乳化释药系统（ARP-SEDDSs）以提高药物的口服生物利用度。方法 HPLC法检测ARP在不同的油、表面活性剂和助表面活性剂中的溶解度,根据溶解度确定处方组成;采用伪三元相图筛选SEDDSs的处方比例;通过动态光散射、透射电镜、稀释稳定性和体外溶出对ARP-SEDDSs进行表征;大鼠分别ig给予自制ARP-SEDDSs和ARP混悬液（20 mg·kg^-1）后,HPLC法进行药动学研究,考察大鼠ig ARP-SEDDSs的生物利用度。结果 以油酸作为油相,以聚乙二醇15-羟基硬脂酸酯和异丙醇作为表面活性剂和助表面活性剂,优化得到ARP-SEDDSs处方为油酸-聚乙二醇15-羟基硬脂酸酯-异丙醇为2.0∶5.6∶2.4,载药量为10 mg·g^-1;ARP-SEDDSs经水稀释后可快速形成微乳,在透射电镜下可观察到微乳呈类球形,经动态光散射仪检测其平均粒径为（54.6±2.3）nm,聚合物分散性指数（PDI）为0.201±0.011,Zeta电位（-13.5±0.4）mV;ARP-SEDDSs在pH 6.8磷酸盐缓冲液中10 min的药物溶出度接近100%,远高于阿立哌唑口崩片（约10%）。大鼠体内药动学研究表明,与ARP混悬液相比,ARP-SEDDSs相对生物利用度为248.8%。结论 将ARP制备成自乳化释药系统,有助于药物快速溶出,显著提高了ARP的口服生物利用度。     

促过饱和物质对多西他赛自乳化系统体外释药特性的影响

 目的 研究促过饱和物质对多西他赛自乳化系统（DTX-SEDDS）释药特性的影响。方法 测定DTX-SEDDS的体外溶出度,并考查不同的促过饱和物质,促过饱和物质的不同用量,不同的投药量以及不同的释放介质对DTX-SEDDS体外释药特性的影响。 结果 不同的促过饱和物质如羟丙基甲基纤维素(HPMC)、十二烷基磺酸钠（SDS）、聚维酮（PVPK30）、Avicel RC591中,HPMC的促溶和稳定作用最强;不同厂家同黏度的HPMC对药物溶出影响差异不显著,同浓度不同黏度的HPMC对药物溶出影响有显著性差异,低黏度的好于高黏度HPMC;HPMC的不同用量对DTX-SEDDS体外释药有一定影响;当低黏度HPMC的用量为1%～8%,累积溶出百分率无显著差异,当高黏度HPMC的用量≤0.5%或≥8%时药物溶出明显减少;不同介质对药物溶出影响无显著性差异。推荐自乳化处方中选择加入1%～8%的低黏度HPMC（型号：山东50,山东100或上海K100）效果较好。结论 过饱和物质HPMC可以明显提高DTX-SEDDS的溶出和稳定性,同时可减少自乳化油的用量,可提高自乳化制剂的临床安全性。     

HPLC法测定山楂叶提取物固体自乳化颗粒中牡荆素鼠李糖苷的含量

目的 建立山楂叶提取物固体自乳化颗粒中牡荆素鼠李糖苷含量的测定方法.方法 采用Diamonsil-C18 色谱柱(200 mm×4.6 mm,5μm);四氢呋喃-甲醇-乙腈-2.8％冰醋酸(114∶9∶9∶748)为流动相,检测波长为330 nm,流速为0.8 mL/min.结果 牡荆素鼠李糖苷在19.8～198.0 μg/mL范围内线性关系良好(r=0.9994),平均回收率为100.98％,RSD为1.21％.结论 该方法简便、准确、重复性好,为山楂叶提取物固体自乳化颗粒的质量控制提供参考.     

葛根素固体自乳化微丸的制备研究

目的 制备葛根素固体自乳化微丸.方法 考察葛根素在不同乳化剂、助乳化剂、油相的溶解度,利用伪三元相图法优化自微乳处方;制备含葛根素自微乳软材,采用挤出-滚圆法制备葛根素自乳化微丸;并对葛根素自微乳微丸的释放度及自乳化后的粒径进行考察.结果 葛根素自乳化微丸的处方确定为葛根素-吐温80-甘油-IPM-微晶纤维素-微粉硅胶的质量比为0.7∶4∶4∶2∶70∶30,自乳化微丸溶解乳化后平均粒径为43 nm,40 min时的溶出度约为80％.结论 制备的葛根素自乳化微丸体外溶出度较高,粒径分布较好.     

固体自微乳载体、固体化方法及稳定性研究进展

目的：对国内外近年来固体自微乳的载体、固体化方法及稳定性的研究进展进行综述,为该剂型的进一步研究和开发提供参考。方法：搜集国内外相关文献进行综合分析。结果：新型的载体材料和新的固体化方法可进一步提高固体自微乳的自乳化性能、药物的分散度,提高难溶性药物的溶出度和生物利用度,还可以改善药物的稳定性。结论：固体自微乳制剂具有微乳和固体制剂的双重优势,是非常具有研发前景的新型固体制剂,随着新型载体材料和固体化方法的开发,该剂型将得到广泛的应用。