Fadda Hala M, Hernández María C, Margetson Daniel N, McAllister S Mark, Basit Abdul W, Brocchini Stephen, Suárez Nery
The School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, UK.
J Pharm Sci. 2008 Sep;97(9):3957-71. doi: 10.1002/jps.21292.
Poly(methacrylic acid-methyl methacrylate, 1:2) (Eudragit S) is a commonly used pH-responsive polymer that can facilitate delivery to the ileo-colonic region of the gastrointestinal tract. Different plasticizers have been used to reduce the brittleness of Eudragit S films for the coating of solid dosage forms. To better correlate the dissolution rates of Eudragit S films, we have examined their dielectric response to understand the specific polymer-plasticizer interactions. Solvent cast Eudragit S films were prepared with one of four citrate plasticizers ranging from low to moderate aqueous solubility. Film dissolution was determined using a two-compartment permeation cell. Dielectric properties were measured by thermally stimulated depolarisation currents (TSDC). Secondary relaxations were deconvoluted and identified. The glass transition temperature (T(g)) was measured using TSDC, differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Dissolution of the films was influenced by the solubility and structure of the plasticizers. While no correlation was found among the T(g)'s obtained by TSDC, DSC, and DMA with dissolution time, the low temperature TSDC spectra showed a relationship of the total secondary relaxation area and relaxation of the carboxylic acid functional group with dissolution time. Dielectric secondary relaxations may be a good probe to predict plasticizer influence on dissolution of Eudragit S polymer films.
聚（甲基丙烯酸 - 甲基丙烯酸甲酯，1:2）（尤特奇S）是一种常用的pH响应聚合物，可促进药物输送至胃肠道的回肠 - 结肠区域。不同的增塑剂已被用于降低尤特奇S薄膜的脆性，以用于固体剂型的包衣。为了更好地关联尤特奇S薄膜的溶解速率，我们研究了它们的介电响应，以了解特定的聚合物 - 增塑剂相互作用。用四种具有不同水溶解度（从低到中等）的柠檬酸盐增塑剂之一制备溶剂浇铸的尤特奇S薄膜。使用双室渗透池测定薄膜的溶解情况。通过热刺激去极化电流（TSDC）测量介电性能。对二级弛豫进行反褶积并识别。使用TSDC、差示扫描量热法（DSC）和动态力学分析（DMA）测量玻璃化转变温度（T(g)）。薄膜的溶解受增塑剂的溶解度和结构影响。虽然通过TSDC、DSC和DMA获得的T(g)与溶解时间之间未发现相关性，但低温TSDC光谱显示总二级弛豫面积和羧酸官能团的弛豫与溶解时间之间存在关系。介电二级弛豫可能是预测增塑剂对尤特奇S聚合物薄膜溶解影响的良好探针。
