Yomota C, Miyazaki T, Okada S
National Institute of Health Sciences, Osaka, Japan.
Yakugaku Zasshi. 1994 Apr;114(4):257-63. doi: 10.1248/yakushi1947.114.4_257.
In the dissolution test of tablets prepared by the direct compression of chitosan with 10% sodium alginate (NaAlg), the release of theophylline was extended independently of the medium pH. The drug release mechanism of the tablet was investigated by measuring the dissolution behavior of such excipients as chitosan and NaAlg. It was shown that at the lower pH the drug release was accompanied with the dissolution of chitosan, while at the neutral pH it was controlled by the gelation and dissolution of NaAlg. Further more by the oral administration of the tablet to beagle dogs, the sustained release of theophylline was also confirmed by some bioavailability parameters. Thus the chitosan tablet with 10% NaAlg was expected to be a pH-independent sustained release dosage form.
在对壳聚糖与10%海藻酸钠（NaAlg）直接压片制备的片剂进行溶出度测试时，茶碱的释放得到延长，且与介质pH无关。通过测量壳聚糖和NaAlg等辅料的溶出行为来研究该片剂的药物释放机制。结果表明，在较低pH值时，药物释放伴随着壳聚糖的溶解，而在中性pH值时，药物释放受NaAlg的凝胶化和溶解控制。此外，通过对比格犬口服该片剂，一些生物利用度参数也证实了茶碱的缓释效果。因此，含10% NaAlg的壳聚糖片剂有望成为一种pH值无关的缓释剂型。
