Macleod G S, Collett J H, Fell J T
School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Manchester M13 9PL, UK.
J Control Release. 1999 Apr 19;58(3):303-10. doi: 10.1016/s0168-3659(98)00168-0.
Polyelectrolyte complex (PEC) formation between pectin USP and chitosan was investigated by examining the viscosities of supernatant solutions after removal of the precipitated complex. The amount of pectin, relative to chitosan, required for optimal PEC formation increased as the pH of the solution was reduced. At pH values of less than 1.3, there was no evidence for the formation of the PEC. Swelling studies conducted on pectin/chitosan films, showed minimal swelling occurring when the pectin:chitosan weight ratio was optimal for PEC formation, suggesting the formation of the PEC in situ. The permeability of the films to paracetamol as a model compound was dependent on film composition and was markedly increased after exposure to pectinolytic enzymes, used to mimic conditions in the colon. It may be implied from the results that similar formulations, applied as a film coat to tablets, could be used to achieve bimodal drug release with colonic conditions acting as a trigger for an increased rate of release.
通过检测除去沉淀复合物后上清液的粘度，研究了美国药典级果胶与壳聚糖之间聚电解质复合物（PEC）的形成。随着溶液pH值降低，形成最佳PEC所需的果胶与壳聚糖的相对量增加。在pH值小于1.3时，没有形成PEC的证据。对果胶/壳聚糖膜进行的溶胀研究表明，当果胶与壳聚糖的重量比最适合PEC形成时，溶胀最小，这表明PEC是原位形成的。作为模型化合物扑热息痛在膜中的渗透率取决于膜的组成，并且在暴露于用于模拟结肠条件的果胶酶后显著增加。从结果中可以推断，类似的制剂作为片剂的薄膜包衣应用，可用于实现双峰药物释放，结肠条件作为释放速率增加的触发因素。
