Research Lab, GIET School of Pharmacy, NH-5, Rajahmundry, India.
Curr Drug Deliv. 2010 Jan;7(1):93-7. doi: 10.2174/156720110790396436.
Most of the floating systems have an inherent drawback of high variability in the GI transit time, invariably affecting the bioavailability of drug. An attempt has been made to develop floating drug delivery system for improving the drug bioavailability by prolongation of gastric residence time of famotidine in stomach. The floating microballoons were prepared using polymer Eudragit L-100 by solvent evaporation and diffusion technique. The prepared famotidine loaded microspheres were characterised for drug loading, entrapment, encapsulation efficiency, particle size distribution, surface morphology, differential scanning calorimetry, test for buoyancy, in-vitro release and in-vivo antiulcer studies. The results showed an increased drug loading, encapsulation and entrapment efficiency. The thermogram of the DSC showed that the drug was encapsulated in amorphous form and SEM studies revealed the discrete, spherical shaped spheres with rough surface and presence of holes on floating microspheres due high entrapment of PEG which are responsible for drug release and floating ability. The sizes of spheres were found between 20-120 microm which exhibited prolonged release (In-vitro > 8 h) and remained buoyant for > 10 h. The mean particle size increased and the drug release rate decreased at higher Eudragit L-100 polymer concentration. The in-vivo results showed significant antiulcer property of famotidine loaded microspheres when compared to control and standard group of rats by using pyloric ligation method. The mean volume of gastric secretion, mean pH and mean total acid for formulation treated group was calculated as 3.45+/-0.88 ml, 5.65+/-0.74, and 114.15+/-1.80 mEq/L respectively.
大多数漂浮系统都存在胃肠道转运时间高度变化的固有缺点，这不可避免地会影响药物的生物利用度。本研究试图通过延长法莫替丁在胃中的滞留时间来开发用于改善药物生物利用度的漂浮药物递送系统。采用溶剂蒸发扩散技术，以聚合物 Eudragit L-100 为载体，制备漂浮微球。对载有法莫替丁的微球进行载药量、包封率、包封效率、粒径分布、表面形态、差示扫描量热法、漂浮试验、体外释放和体内抗溃疡研究。结果表明，载药量、包封率和包封效率均有所提高。DSC 图谱显示药物以无定形形式包封，SEM 研究表明，由于高 PEG 包封率，漂浮微球呈现离散的、球形、粗糙表面和存在孔，这是药物释放和漂浮能力的原因。球的大小在 20-120 微米之间，表现出延长的释放（体外>8 小时），并保持漂浮>10 小时。随着 Eudragit L-100 聚合物浓度的增加，平均粒径增加，药物释放速率降低。与对照组和标准组大鼠相比，采用幽门结扎法，载有法莫替丁的微球具有显著的抗溃疡作用。制剂处理组的平均胃分泌量、平均 pH 值和总酸度分别为 3.45+/-0.88ml、5.65+/-0.74 和 114.15+/-1.80mEq/L。
