Jain Sunil K, Awasthi A M, Jain N K, Agrawal G P
Department of Pharmaceutical Sciences, Dr. H. S. Gour University, Sagar-470 003, India.
J Control Release. 2005 Oct 3;107(2):300-9. doi: 10.1016/j.jconrel.2005.06.007.
Gastroretentive dosage forms have potential for use as controlled-release drug delivery systems. Multiple unit systems avoid the 'all-or-none' gastric emptying nature of single-unit systems. A controlled release system designed to increase its residence time in the stomach without contact with the mucosa was achieved through the preparation of floating microspheres by the emulsion solvent diffusion technique consisting of (i) calcium silicate (FLR) as porous carrier; (ii) repaglinide, an oral hypoglycemic agent; and (iii) Eudragit S as polymer. The effect of various formulation and process variables on the internal and external particle morphology, micromeritic properties, in vitro floating behavior, physical state of the incorporated drug, drug loading and in vitro drug release were studied. The microparticles were found to be regular in shape and highly porous. The release rate was determined in simulated gastro-intestinal fluids at 37 degrees C. The formulation demonstrated favorable in vitro floating and release characteristics. The drug encapsulation efficiency was high. Incorporation of FLR in the microspheres proved to be an effective method to achieve the desired release behavior and buoyancy. The designed system, combining excellent buoyant ability and suitable drug release pattern, could possibly be advantageous in terms of increased bioavailability of repaglinide.
胃滞留剂型有潜力用作控释药物递送系统。多单元系统避免了单单元系统“全或无”的胃排空特性。通过乳液溶剂扩散技术制备漂浮微球实现了一种设计用于增加其在胃中停留时间且不与粘膜接触的控释系统，该微球由以下成分组成：(i) 硅酸钙（FLR）作为多孔载体；(ii) 瑞格列奈，一种口服降糖药；以及(iii) 尤特奇S作为聚合物。研究了各种制剂和工艺变量对内部和外部颗粒形态、粉体学性质、体外漂浮行为、包封药物的物理状态、载药量和体外药物释放的影响。发现微颗粒形状规则且高度多孔。在37℃的模拟胃肠液中测定释放速率。该制剂表现出良好的体外漂浮和释放特性。药物包封效率高。在微球中加入FLR被证明是实现所需释放行为和浮力的有效方法。所设计的系统结合了出色的漂浮能力和合适的药物释放模式，就提高瑞格列奈的生物利用度而言可能具有优势。
