乳酸カルシウムならびにアルギン酸ナトリウムをコーティングした顆粒からの不溶性ゲル形成を応用した薬物放出制御

抄録

We attempted to control drug release from granules by applying a gel formation of calcium lactate (LACa) and sodium alginate (ALNa). The core granules were prepared with theophylline (TP) as a model drug, and LACa and ALNa by the extruding granulation method. The coated granules were prepared by undercoating LACa and overcoating ALNa on the core granules by use of a tumbling fluidized bed granulator. TP release from the core and coated granules was studied. The pore size distributions of the coated granules before and after the dissolution test were measured by mercury intrusion porosimetry. The release profile of TP from the core granules varied depending on the LACa/ALNa ratio. The core granules at the LACa/ALNa ratio of 40/40 maintained their initial granule shape after the dissolution test. The release rate of TP from the coated granules prepared by undercoating LACa and overcoating ALNa at the LACa/ALNa ratio of 40/40 decreased with the increasing ratio of ALNa overcoating layer. This may be due to the increase in the amount of insoluble gel formation with the increasing ratio of ALNa. These results suggest that the present preparation method, applying the water-insoluble gel formation of LACa and ALNa, will be useful to control drug release.