Ofner C M, Schott H
J Pharm Sci. 1986 Aug;75(8):790-6. doi: 10.1002/jps.2600750814.
The swelling rate and the equilibrium swelling of gelatin (type B) were studied by casting warm gelatin solutions into films, cutting them into short rectangular strips after gelation, drying them, and measuring the weight gain on immersion in buffer solutions as a function of time. The process variables investigated included concentration of the gelatin casting solutions, the thickness, drying conditions, age and residual moisture content of the film strips, the chemical nature and concentration of the buffers in the swelling solutions, and the temperature of these solutions at a constant pH of 7.0 (1.9 pH units above the isoionic point). The swelling kinetics followed a second-order equation. The initial swelling rate and the equilibrium swelling of the amorphous portion of the gelatin strips (which was somewhat smaller than the total observed swelling) were calculated from a linearized form of the rate equation. Of the factors investigated, the equilibrium swelling was increased most strongly when the temperature of the swelling solution was raised from 20 to 25 degrees C. Strip thickness was the predominant factor governing the rate of swelling, which was inversely proportional to the thickness. Conditions leading to slower drying and longer storage times promoted more extensive crystallization, thereby increasing the density of the gelatin strips and reducing their swelling rate.
通过将温热的明胶（B型）溶液浇铸制成薄膜，凝胶化后将其切成短的矩形条，干燥并测量其在缓冲溶液中浸泡时的重量增加随时间的变化，研究了明胶（B型）的溶胀速率和平衡溶胀。所研究的工艺变量包括明胶浇铸溶液的浓度、薄膜条的厚度、干燥条件、薄膜条的老化程度和残余水分含量、溶胀溶液中缓冲剂的化学性质和浓度以及在pH值为7.0（比等离子点高1.9个pH单位）时这些溶液的温度。溶胀动力学遵循二级方程。根据速率方程的线性化形式计算明胶条非晶部分的初始溶胀速率和平衡溶胀（略小于观察到的总溶胀）。在所研究的因素中，当溶胀溶液的温度从20℃升高到25℃时，平衡溶胀增加最为显著。条带厚度是控制溶胀速率的主要因素，溶胀速率与厚度成反比。导致干燥较慢和储存时间较长的条件促进了更广泛的结晶，从而增加了明胶条的密度并降低了其溶胀速率。
