Ichikawa M, Watanabe S, Miyake Y
Pharmaceutical Research Laboratories, Eisai Company, Ltd., Ibaraki, Japan.
J Pharm Sci. 1991 Nov;80(11):1062-6. doi: 10.1002/jps.2600801113.
A multiple-unit type of oral floating dosage system, (a new type of floating pills which generate carbon dioxide gas) has been prepared in order to prolong the gastric emptying time (GET) of the preparation. The floating ability and the sustained-release characteristics of the system have been elucidated in vitro. The system was composed of sustained-release pills as seeds and double layers on the sustained-release pills. The inner layer was an effervescent layer containing both sodium bicarbonate and tartaric acid. The outer layer was a swellable membrane layer containing mainly polyvinyl acetate and purified shellac. When the system was immersed in water, it formed swollen pills, like balloons, with a density much lower than 1.0 g/mL. The reaction was due to carbon dioxide gas generated by neutralization in the effervescent layer with the diffusion of water through the swellable membrane layer. The system was floating completely within approximately 10 min and approximately 80% remained floating over a period of 5 h irrespective of pH and viscosity of the test medium. While the system was floating, a drug (p-aminobenzoic acid) was released. The release rate of the drug from the system was zero order and depended on the sustained-release characteristics of the sustained-release seeds composing the system. The release rate was not affected by the amount of the swellable membrane layer up to 13% (w/w).
为延长制剂的胃排空时间（GET），制备了一种多单元型口服漂浮给药系统（一种新型能产生二氧化碳气体的漂浮片）。该系统的漂浮能力和缓释特性已在体外得到阐明。该系统由作为核心的缓释片以及缓释片上的双层结构组成。内层是含有碳酸氢钠和酒石酸的泡腾层。外层是主要含有聚醋酸乙烯酯和精制虫胶的溶胀性膜层。当该系统浸入水中时，会形成像气球一样的膨胀片，其密度远低于1.0 g/mL。这种反应是由于泡腾层中通过溶胀性膜层扩散进来的水发生中和反应产生了二氧化碳气体。该系统在大约10分钟内完全漂浮起来，并且在5小时内约80%保持漂浮状态，与测试介质的pH值和粘度无关。当该系统漂浮时，一种药物（对氨基苯甲酸）被释放出来。药物从该系统中的释放速率为零级，并且取决于构成该系统的缓释核心的缓释特性。在溶胀性膜层含量高达13%（w/w）时，释放速率不受其影响。
