Reed Kenneth, Li Amy, Wilson Britney, Assamoi Tetchi
Department of Pharmaceutical, Social and Administrative Sciences, Belmont University College of Pharmacy , Nashville, Tennessee.
J Ocul Pharmacol Ther. 2016 Nov;32(9):574-582. doi: 10.1089/jop.2016.0084. Epub 2016 Sep 9.
The purpose of this study was to determine if the addition of calcium gluconate to gellan solution results in a stronger gel structure on initial exposure to tear fluid due to the displacement of calcium from the gluconate ion by tear monovalent cations (Na, K).
Test solutions of gellan and gellan-calcium gluconate were mixed thoroughly with simulated tear fluid (STF) at a 5:1 ratio. The resulting gel was measured for viscosity at 32°C-36°C.
The addition of optimized amounts of calcium gluconate to gellan formulations resulted in gellan-calcium gluconate-STF gels of higher strength (statistically significant) than when gellan alone was mixed with STF. Gellan experimental preparations demonstrated thixotropic behavior both before and after addition of STF.
It appears possible to enhance the initial in situ gel-forming properties of gellan by adding a divalent cation bound to an ion exchange molecule or resin. Optimal amounts of polyvinylpyrrolidone (PVP) appear to be effective in slowing timolol release when added to gellan and calcium gluconate solutions.
本研究的目的是确定在结冷胶溶液中添加葡萄糖酸钙是否会由于泪液中的单价阳离子（钠、钾）将葡萄糖酸离子中的钙置换出来，从而在初次接触泪液时形成更强的凝胶结构。
将结冷胶和结冷胶 - 葡萄糖酸钙的测试溶液按5:1的比例与模拟泪液（STF）充分混合。在32°C - 36°C下测量所得凝胶的粘度。
向结冷胶配方中添加优化量的葡萄糖酸钙，得到的结冷胶 - 葡萄糖酸钙 - STF凝胶比单独将结冷胶与STF混合时强度更高（具有统计学意义）。结冷胶实验制剂在添加STF之前和之后均表现出触变性。
通过添加与离子交换分子或树脂结合的二价阳离子，似乎有可能增强结冷胶的初始原位凝胶形成特性。当添加到结冷胶和葡萄糖酸钙溶液中时，最佳量的聚乙烯吡咯烷酮（PVP）似乎能有效减缓噻吗洛尔的释放。
