Ward Adam, Brown Benedict, Walton Karl, Timmins Peter, Conway Barbara R, Asare-Addo Kofi
Department of Pharmacy, University of Huddersfield, Huddersfield HD1 3DH, UK.
EPSRC Future Metrology Hub, University of Huddersfield, Huddersfield HD1 3DH, UK.
Pharmaceutics. 2020 Nov 28;12(12):1162. doi: 10.3390/pharmaceutics12121162.
Hydrophilic matrix systems can be found in a wide range of extended release pharmaceutical formulations. The main principle of these systems is that upon contact with water, the hydrophilic component swells to form a hydrated gel layer which controls drug release. The following work demonstrates an explorative study into the use of dissolution imaging and focus variation microscopy with hydrophilic polymers. This study investigated the surface properties of xanthan gum (XG), polyethylene oxide (PEO), and hypromellose (hydroxypropyl methylcellulose, HPMC) compacts with each of these three hydrophilic polymers from one of each classification of natural, semi-synthetic, or synthetic polymer using a focus variation instrument. The auto correlation length (S) showed all surface profiles from the compacts displayed a value below 0.1 mm, indicating that only high frequency components (i.e., roughness) were considered and that the analysis had been successful. The developed interfacial area ratio (S) displayed values below 5% in line with ISO guidelines for all the polymers studied with their texture aspect ratio values (S) > 0.5, indicating uniformity of the surfaces of the produced compacts. Of the various parameters studied, areal material ratio (S2) predicted XG to wet and hydrate quicker than PEO, with PEO also wetting and hydrating quicker than the HPMC. The dissolution imaging and initial swelling studies proved to concur with the findings from the areal material ratio (S2) parameter, suggesting porosity was not an indicator for the ease with which water ingress occurs. This study suggests the S surface parameter to potentially predict wetting and initial hydration of hydrophilic polymers, however care should be taken as this study consists of a selected number of hydrophilic polymers.
亲水性基质系统可在多种缓释药物制剂中找到。这些系统的主要原理是，与水接触时，亲水性成分会膨胀形成水合凝胶层，从而控制药物释放。以下工作展示了一项关于亲水性聚合物在溶出成像和聚焦变化显微镜中的应用的探索性研究。本研究使用聚焦变化仪器，研究了来自天然、半合成或合成聚合物每一类中的一种的三种亲水性聚合物（黄原胶（XG）、聚环氧乙烷（PEO）和羟丙甲纤维素（羟丙基甲基纤维素，HPMC））压片的表面性质。自相关长度（S）表明，压片的所有表面轮廓显示的值均低于0.1毫米，这表明仅考虑了高频成分（即粗糙度），且分析是成功的。所开发的界面面积比（S）显示的值低于5%，符合ISO指南对所有研究聚合物的要求，其纹理长宽比（S）>0.5，表明所生产压片表面的均匀性。在所研究的各种参数中，面材料比（S2）预测XG比PEO更快湿润和水合，PEO也比HPMC更快湿润和水合。溶出成像和初始溶胀研究结果与面材料比（S2）参数的结果一致，表明孔隙率不是水进入难易程度的指标。本研究表明，S表面参数可能预测亲水性聚合物的湿润和初始水合情况，不过应谨慎对待，因为本研究仅包含选定数量的亲水性聚合物。
