Tritt-Goc Jadwiga, Kowalczuk Joanna, Pislewski Narcyz
Institute of Molecular Physics Polish Academy of Sciences, M Smoluchowskiego 19, 60-179, Poznan, Poland.
J Pharm Pharmacol. 2003 Nov;55(11):1487-93. doi: 10.1211/0022357022133.
Magnetic resonance imaging was used to study the diffusion of a water solution of hydrochloric acid into hypromellose (hydroxypropylmethylcellulose) matrices. Spatially resolved information was obtained about the self-diffusion coefficient and spin-spin relaxation time of solvent protons in the gel layer of hypromellose matrices loaded with different amounts of tetracycline hydrochloride. The data showed the influence of the drug concentration on the diffusion and spin-spin relaxation. Higher drug concentrations in the hypromellose matrix led to greater swelling of the matrix and faster diffusion of the water molecules inside the gel layer of the polymer. The observed differences between the radial and axial diffusion were interpreted in terms of the stresses imposed in the axial direction during the compression of the samples. The spin-spin and diffusion profiles indicated that the diffusion of a water solution of hydrochloric acid into hypromellose, pure and loaded with different amounts of tetracycline hydrochloride, was characterized as a Case II mechanism.
利用磁共振成像技术研究了盐酸水溶液在羟丙甲纤维素基质中的扩散情况。获得了关于不同盐酸四环素负载量的羟丙甲纤维素基质凝胶层中溶剂质子的自扩散系数和自旋 - 自旋弛豫时间的空间分辨信息。数据显示了药物浓度对扩散和自旋 - 自旋弛豫的影响。羟丙甲纤维素基质中较高的药物浓度导致基质膨胀更大，聚合物凝胶层内水分子扩散更快。根据样品压缩过程中轴向施加的应力来解释径向和轴向扩散之间观察到的差异。自旋 - 自旋和扩散分布表明，盐酸水溶液在纯羟丙甲纤维素以及负载不同量盐酸四环素的羟丙甲纤维素中的扩散具有第二类扩散机制的特征。
