PURPOSE: A sustained release capsule composition containing guanfacine is provided to optimally and continuously release guanfacine. CONSTITUTION: A sustained release capsule composition contains: 2 wt% of guanfacine； 60-68 wt% of lactose as a diluents； 13-17 wt% of hydroxypropyl methylcellulose as a neutral water-swellable polymer for controlling release； 13-17 wt% of sodium polyacrylate as an anionic water-swellable polymer for controlling release； 2-4 wt% of croscarmellose sodium as a disintegrant； and 0.8-1.2 wt% of magnesium stearate as a lubricant. A method for preparing the capsule composition comprises: a step of mixing the ingredients and pressing the mixture； and a step of filling the prepared sustained release composition in a capsule. [Reference numerals] (AA) Elution rate(%)； (BB) Embodiment 1； (CC) Comparative embodiment 1； (DD) Comparative embodiment 2； (EE) Comparative embodiment 4； (FF) Time(h)본 발명은 구안파신 2 중량%에 희석제로서 유당 60～68 중량%와 중성 수팽윤성 방출 제어용 고분자로서 하이드록시프로필메틸셀룰로스 13～17 중량%, 음이온성 수팽윤성 방출 제어용 고분자로서 폴리아크릴산나트륨 13～17 중량%, 붕해제로서 크로스카멜로스나트륨 2～4 중량% 및 윤활제로서 스테아르산마그네슘 0.8～1.2 중량%를 혼합시켜 제조된 구안파신 서방성 캡슐제 조성물에 관한 것이다.
