Wan L S, Chui W K
Department of Pharmacy, Faculty of Science, National University of Singapore, Kent Ridge Crescent.
J Microencapsul. 1995 Jul-Aug;12(4):417-23. doi: 10.3109/02652049509087254.
Microspheres were formed when a solution of cellulose phthalate was extruded into 30% glacial acetic acid solution. Sulphonamides entrapped in such microspheres leached into the hardening solution because they dissolved freely in the acetic acid solution. This resulted in poor loading efficiency of the sulphonamides in the microspheres. When mixtures of sulphaguanidine and sulphathiazole in various drug ratios were microencapsulated by this method, the observed drug ratios were found to be markedly changed. This was attributed to the difference in solubility of the two sulphonamides in acid such that their extent of diffusion into the hardening solution was not similar. NSAIDS such as ibuprofen and mefenamic acid which are acidic and more hydrophobic in nature are less soluble in acetic acid. These drugs were retained better in the microspheres during the hardening process and the loading efficiency was consequently improved. In cases where mixture of the NSAIDS were encapsulated, the drug ratios showed little deviation from the theoretical values. This study shows that loading of the CAP microspheres is dependent on the solubility of the drugs in acetic acid. When more than one drug is required to be microencapsulated, the drug ratio may change if the drugs have different solubility in acetic acid.
将邻苯二甲酸纤维素溶液挤入30%的冰醋酸溶液中时会形成微球。包封在这种微球中的磺胺类药物会渗入硬化溶液中，因为它们能自由溶解于醋酸溶液。这导致磺胺类药物在微球中的负载效率较低。当用这种方法对磺胺脒和磺胺噻唑按不同药物比例的混合物进行微囊化时，发现观察到的药物比例有明显变化。这归因于两种磺胺类药物在酸中的溶解度差异，使得它们扩散到硬化溶液中的程度不同。像布洛芬和甲芬那酸这类本质上呈酸性且疏水性更强的非甾体抗炎药在醋酸中的溶解度较低。在硬化过程中，这些药物在微球中保留得更好，因此负载效率得到了提高。在对非甾体抗炎药混合物进行包囊的情况下，药物比例与理论值的偏差很小。这项研究表明，醋酸纤维素酞酸酯微球的负载取决于药物在醋酸中的溶解度。当需要对一种以上药物进行微囊化时，如果药物在醋酸中的溶解度不同，药物比例可能会发生变化。
