Tang Jingling, Sun Jin, Cui Fude, Zhang Tianhong, Liu Xiaohong, He Zhonggui
Department of Biopharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China.
Drug Deliv. 2008 Nov;15(8):477-84. doi: 10.1080/10717540802039089.
Self-emulsifying drug delivery systems (SEDDS) are mixtures of oils, surfactants, and cosurfactants, which are emulsified in aqueous media under conditions of gentle stirring and digestive motility that would be encountered in the gastrointestinal tract. We found that SEDDS could efficiently improve oral absorption of the sparingly soluble drugs by rapid self-emulsification and subsequently dispersion in the absorption sites. Ginkgo biloba extract (GBE) has become a widely used herbal remedy for increasing cognitive function in elderly people. The main purpose of our work is to prepare SEDDS for improving oral absorption of GBE. Pseudoternary phase diagrams were constructed to identify the efficient self-emulsification region, and particle size distributions of resultant emulsions were determined. The optimized formulation for bioavailability assessment consisted of 45% Tween 80-Cremophor EL35 (1:1, w/w), 10% 1, 2-propanediol, and 45% ethyl oleate. The mean droplet size distribution of the optimized SEDDS was approximately 100 nm when diluted with 500-fold volume of the distilled water. The in vitro dissolution rates of the active components of GBE SEDDS form were significantly faster than those of the GBE tablets. After single oral administration of 800 mg GBE as SEDDS or tablets to fasted dogs, the relative bioavailability of SEDDS for bilabolide and ginkgolide A and B was 162.1, 154.6, and 155.8% compared with the reference tablets, respectively. Our results suggested the potential and promising use of SEDDS for the efficient delivery of the sparingly soluble drugs or traditional Chinese medicines, such as GBE by oral administration.
自乳化药物递送系统（SEDDS）是油、表面活性剂和助表面活性剂的混合物，在胃肠道中温和搅拌和消化蠕动的条件下，它们在水性介质中乳化。我们发现，SEDDS可通过快速自乳化并随后分散在吸收部位来有效提高难溶性药物的口服吸收。银杏叶提取物（GBE）已成为一种广泛用于提高老年人认知功能的草药。我们工作的主要目的是制备用于改善GBE口服吸收的SEDDS。构建伪三元相图以确定有效的自乳化区域，并测定所得乳液的粒径分布。用于生物利用度评估的优化配方由45%吐温80-聚氧乙烯蓖麻油EL35（1:1，w/w）、10% 1,2-丙二醇和45%油酸乙酯组成。用500倍体积的蒸馏水稀释后，优化的SEDDS的平均液滴尺寸分布约为100 nm。GBE SEDDS剂型中活性成分的体外溶出速率明显快于GBE片剂。将800 mg GBE以SEDDS或片剂形式单次口服给予禁食犬后，与参比片剂相比，SEDDS对银杏内酯和银杏苦内酯A和B的相对生物利用度分别为162.1%、154.6%和155.8%。我们的结果表明，SEDDS在口服给药高效递送难溶性药物或中药（如GBE）方面具有潜在且有前景的应用。
