Ritthidej Garnpimol C, Phaechamud Thawatchai, Koizumi Tamotsu
Faculty of Pharmaceutical Sciences, Department of Industrial Pharmacy, Chulalongkorn University, 10330, Bangkok,
Int J Pharm. 2002 Jan 31;232(1-2):11-22. doi: 10.1016/s0378-5173(01)00894-8.
Chitosan salt films were prepared by casting method using acetic, citric, formic, glycolic, lactic, malic and propionic acids as solubilizers. The films were then exposed to moist heat at 60 degrees C and 75% relative humidity for several time intervals. The influence of moist heat treatment on their physicochemical characteristics was investigated. All freshly prepared films were soluble in deionized water and HCl buffer solution. Chitosan citrate film also dissolved in phosphate buffer solution. After treatment, the percentage of water sorption and dissolution of chitosan films in three media were gradually decreased. Longer alkyl group and less carboxyl and hydroxyl groups in the molecule of organic acid resulted in lower percentage of water sorption and dissolution of treated films. The FT-IR spectra revealed that there was amide formation between chitosan and organic acids after treatment especially in chitosan acetate and propionate films. However, the absorption peaks of ammonium ['NH3+] and free carboxylate groups were still remained in treated chitosan citrate and malate films. Change in the degree of crystallinity from powder X-ray diffractogram and thermal characteristic from DSC thermogram were also related to the water sorption and dissolution of films.
采用流延法，以乙酸、柠檬酸、甲酸、乙醇酸、乳酸、苹果酸和丙酸作为增溶剂制备壳聚糖盐薄膜。然后将薄膜在60℃和75%相对湿度条件下进行多次湿热处理。研究了湿热处理对其物理化学特性的影响。所有新制备的薄膜均能溶于去离子水和盐酸缓冲溶液。壳聚糖柠檬酸盐薄膜也能溶于磷酸盐缓冲溶液。处理后，壳聚糖薄膜在三种介质中的吸水率和溶解率逐渐降低。有机酸分子中较长的烷基以及较少的羧基和羟基导致处理后薄膜的吸水率和溶解率较低。傅里叶变换红外光谱表明，处理后壳聚糖与有机酸之间形成了酰胺，尤其是在壳聚糖乙酸盐和丙酸盐薄膜中。然而，处理后的壳聚糖柠檬酸盐和苹果酸盐薄膜中仍保留着铵离子['NH3+]和游离羧酸盐基团的吸收峰。粉末X射线衍射图中结晶度的变化以及差示扫描量热图中热特性的变化也与薄膜的吸水率和溶解率有关。
