Kojima Masazumi, Nakagami Hiroaki
Tokyo Pharmaceutical Research Center, Pharmaceutical Technology Research Laboratories, Daiichi Pharmaceutical Co, Ltd, Edogaea-ku, Japan.
Chem Pharm Bull (Tokyo). 2002 Dec;50(12):1621-4. doi: 10.1248/cpb.50.1621.
The water mobility and diffusivity in the gel-layer of hydrating low-substituted hydroxypropyl cellulose (LH41) tablets with or without a drug were investigated by magnetic resonance imaging (MRI) and compared with those properties in the gel-layer of hydroxypropylmethyl cellulose (HPMC) and hydroxypropyl cellulose (HPC) tablets. For this purpose, a localized image-analysis method was newly developed, and the spin-spin relaxation time (T(2)) and apparent self-diffusion coefficient (ADC) of water in the gel-layer were visualized in one-dimensional maps. Those maps showed that the extent of gel-layer growth in the tablets was in the order of HPC>HPMC>>LH41, and there was a water mobility gradient across the gel-layers of all three tablet formulations. The T(2) and ADC in the outer parts of the gel-layers were close to those of free water. In contrast, these values in the inner parts of the gel-layer decreased progressively; suggesting that the water mobility and diffusivity around the core interface were highly restricted. Furthermore, the correlation between the T(2) of (1)H proton in the gel-layer of the tablets and the drug release rate from the tablets was observed.
通过磁共振成像（MRI）研究了含药或不含药的低取代羟丙基纤维素（LH41）水合片剂凝胶层中的水迁移率和扩散率，并与羟丙基甲基纤维素（HPMC）和羟丙基纤维素（HPC）片剂凝胶层中的这些性质进行了比较。为此，新开发了一种局部图像分析方法，并在一维图中可视化了凝胶层中水的自旋-自旋弛豫时间（T(2)）和表观自扩散系数（ADC）。这些图表明，片剂中凝胶层的生长程度顺序为HPC>HPMC>>LH41，并且在所有三种片剂配方的凝胶层中都存在水迁移率梯度。凝胶层外部的T(2)和ADC接近自由水的T(2)和ADC。相比之下，凝胶层内部的这些值逐渐降低；这表明核心界面周围的水迁移率和扩散率受到高度限制。此外，还观察到片剂凝胶层中(1)H质子的T(2)与片剂的药物释放速率之间的相关性。
