L8 (27) orthogonal array was employed to demonstrate the significant effect of adjuvants and additives in capsule formulations on dissolution rate of Salicylic acid. The dissolution behavior of salicylic acid in corn starch, lactise, microcrystalline cellulose, calcium phosphate dibasic anhydrous, magnesium stearate and with or without amorphous silica, urethane and polysorbate 80 was studied with dissolution equations. It is obvious that microcrystalline cellulose is the most reliable adjuvant, popularily used starch and lactose are the moderate through the dissolution study. Magnesium stearate has notable inhibition effect on dissolution. As magnesium stearate is popularily employed in capsule formulation to facilitate the processing of automatic capsule filling, the unfavorable effect on dissolution and bioavailability should be taken into cautions consideration. 利用L8(27)直交實驗計劃法，檢討賦形劑及添加劑對salicylic acid膠囊劑之溶離速度之影響。salicylic acid受corn starch, lactose, microcrystalline cellulose, calciim phosphate dibasic anhydrous, magnesium stearate. amorphous silica, urethane及polysorbate 80之影響狀態，均加以分析、觀察，並利用溶離方程式加以歸納。salicylic acid 之溶離，以microcrystalline cellulose最優，常用之賦形劑starch及lactose尚佳，magnesium stearate有阻?溶離之作用。因使用高速自動膠囊填充機時，常使用magnesium stearate做滑潤劑，故對於有效成分溶離之影響，必須加以注意。
