Nalidixic acid의 Eudragit RL Microencapsulation에 관한 연구

Abstract

Microencapsulation of Nalidixic acid using Eudragit RL, which is a copolymer synthesized from acrylic and methcrylic acid esters containing, was investigated. The preparation is based on dispersion of acetone containing the drug in liquid paraffin. Aluminium tristearate was used as an additive for the preparation of microcapsules. Good reproducibility in microcapsule preparation was observed. The microcapsules obtained were uniform and free-flowing particles. The dissolution rates of Nalidixic acid from the these microcapsules considerably decreased as compared with that from Nalidixic acid powder and Nalidixic acid - Eudragit RL solid dispersions. The release of Nalidixic acid increased with increasing percentage of aluminium tristearate added to the microcapsules. The surfaces of microcapsules containing a small amount of aluminium tristearate were relatively smooth in contrast to those of microcapsules containing a large amount of aluminium tristearate.;Acetone/Liquid paraffin system을 사용한 oil phase에서 solvent evaporation process에 의해 요로감염증에 사용되는 nalidixic acid를 함유하는 Eudragit RL microcapsule과 Eudragit RL에 의한 고체분산계를 조제하였다. Microcapsule조제시 분리분산제로 aluminium tristearate를 1.45%, 4.35%, 7.25%, 10.15% 첨가하여 구상 성형성과 정립성이 좋은 microcapsule을 조제하였으며, pH 6.8 Buffer 용액에서의 용출속도는 고체분산계 또는 ualidixic acid powder에 비해 현저히 지연되었다. 또 첨가된 aluminium tristearate의 양을 증가시킴에 따라 particle size는 작아졌고 nalidixic acid의 용출은 증가하였다. 전자현미경 관찰결과 aluminium tristearate를 가장 소량 첨가한 mierocapsule(1.45%)의 경우 표면이 가장 치밀하였고, 첨가량을 증가시킬수록 microcapsule의 표면은 거칠어졌다.