Fyfe C A, Blazek A I
Department of Chemistry, University of British Columbia, Vancouver, Canada.
J Control Release. 1998 Mar 2;52(1-2):221-5. doi: 10.1016/s0168-3659(97)00217-4.
In recent studies, NMR imaging has been used to investigate the swelling of hydroxypropylmethylcellulose (HPMC) tablets and to determine polymer concentration distributions in the swollen matrix. The total amount of polymer in the system was computed from these distributions and was up to 35% greater than the known weight of HPMC in the tablet. This deviation was traced to the presence of air bubbles in the swollen matrix which occupied a significant volume previously assumed to be occupied by polymer and water. When the air in the tablet was removed by vacuum, the swollen gel contained no evidence of air bubbles and the calculated total polymer weights from the HPMC distributions were equal to the amount of HPMC in the tablet.
在最近的研究中，核磁共振成像已被用于研究羟丙基甲基纤维素（HPMC）片剂的溶胀情况，并确定溶胀基质中聚合物的浓度分布。根据这些分布计算出系统中聚合物的总量，该总量比片剂中已知的HPMC重量高出35%。这种偏差可追溯到溶胀基质中存在气泡，这些气泡占据了先前假定由聚合物和水占据的大量体积。当通过真空去除片剂中的空气时，溶胀凝胶中没有气泡迹象，并且根据HPMC分布计算出的聚合物总重量与片剂中HPMC的量相等。
