乙基纤维素水分散体包衣微丸的体外释药特性研究

以乙基纤维素水分散体Ａｑｕａｃｏａｔ和Ｓｕｒｅｌｅａｓｅ为包衣材料，流化床包衣制备盐酸苯丙醇胺缓释微丸，研究微丸在不同ＰＨ介质中的释药特性和微丸释药机制。结果表明，Ｓｕｒｅｌｅａｓｅ包衣微丸的体外释放度不受介质ＰＨ影响，而未热处理的Ａｑｕａｃｏａｔ包衣微丸可能出现ＰＨ依赖性药现象，通过包衣后热处理或增塑剂的选择可以避免这一现象。包衣微丸体外释药机制为：渗透压驱动作用下药物通过衣膜的扩膜。

Study on Drug Release Characteristics from Aqueous Ethylcellulose Dispersion Coated Pellets

Phenylpropanolamine hydrochloride (PPA) sustained release pellets were developed in fluid bed with two aqueous ethylcellulose dispersion(Aquacoat and Surelease). Drug release characteristics in different medium pH as well as drug release mechanism from pellets were studied. Results showed that PPA release from Surelease coated pellets was independent of medium pH. But the release from Aquacoat coated pellets may be pH dependent, and faster release occurs at higher pH values. Further studies showed that pH dependency can be avoided by curing process and reasonable plasticizer. PPA release mechanism was indicated to be diffusion controlled accompanied by osmotic pumping effects.