The effect of ageing on the long-term stability of FAPG ointments stored at room temperature was studied. The stability studies lasted for one and a half years. Rheological and differential scanning calorimeter (DSC) measurements were chosen as testing methods. Furthermore, the mechanism by which drug release rates may be altered will be described. It was confirmed that the viscosity of ointment increases with faster cooling rates at constant stirring rate, but the viscosity decreases below initial level after one and half years' storages. The release rates of norfloxacin were inversely proportional to the viscosity of ointments. The DSC analysis indicated that the ingredient of base, PEG 6000, will precipitate more as the cooling rate increased. After storages, PEG 6000 crystal may gradually dissolve in PG and that results in apparent alteration of viscosity. 本研究主要是探討FAPG軟膏以不同的製備條件製造，在室溫下貯存時，老化因素對軟膏長期安定性的影響。安定性實驗總計進行一年六個月，所採行的檢測方法分別為流變學評估與熱分析；進一步，有關藥物釋出速率改變的可能機轉亦一併於文中加以探討。結果證實，在相同的攪拌速率下，軟膏的黏稠度隨冷卻速率的加快而增加，但軟膏經一年半的貯藏後，其黏稠度比新鮮製備時來得低；且norfloxacin的藥物釋出速率則與軟膏的黏稠度成反比。經熱分析的結果指出，基劑的組成份PEG 6000在軟膏中的析出量會隨冷卻速率增加而增加，經過貯存以後，PEG 6000的結晶會逐漸溶解於丙二酮當中，導致軟膏黏稠度的改變。
