Hsieh D S, Rhine W D, Langer R
J Pharm Sci. 1983 Jan;72(1):17-22. doi: 10.1002/jps.2600720105.
Theoretical and experimental analyses demonstrate that a hemispheric polymer-drug matrix laminated with an impermeable coating, except for an exposed cavity in the center face, can be used to achieve zero-order release kinetics. Hemispheric systems for low molecular weight drugs were prepared by heating and compressing polyethylene and drug (sodium salicylate) in a brass mold. Hemispheric systems for high molecular weight drugs were prepared by casting ethylene-vinyl acetate copolymer and protein in a hemispheric mold at -80 degrees, followed by a two-step drying procedure (-20 and 20 degrees). In both systems, cavities were made in the center face of the hemispheres and the remainder of the matrices coated with an impermeable material. Zero-order release for 60 days at a rate of 0.5 mg/day was achieved from polymer matrices containing bovine serum albumin (mol. wt. 68,000).
理论和实验分析表明，除了中心面有一个暴露的腔体之外，由不透性包衣层压的半球形聚合物-药物基质可用于实现零级释放动力学。通过在黄铜模具中加热和压缩聚乙烯与药物（水杨酸钠）来制备用于低分子量药物的半球形系统。通过在-80℃的半球形模具中浇铸乙烯-醋酸乙烯酯共聚物和蛋白质，然后进行两步干燥程序（-20℃和20℃）来制备用于高分子量药物的半球形系统。在这两种系统中，在半球的中心面制造腔体，并用不透性材料包被基质的其余部分。含有牛血清白蛋白（分子量68,000）的聚合物基质以0.5毫克/天的速率实现了60天的零级释放。
