过去数十年,寻找新药是药学革新的主要途径,与此同时,把药物作用的选择性及持效期作为发展新产品的主要标准。为方便患者,大多数药物所制成的口服剂型,包括片剂、胶囊剂、缓释制剂在体内组织均呈一级动力学过程,不能保持恒定的药物浓度。这些剂型与注射剂和滴眼液一样,都首先很快释出药物到周围组织中,而后速度不断下降持续数小时。这种给药方式有一些缺点,即需频繁用药,甚不方便,而且往往会忘记用药。大多数药物的作用均与浓度有关,提示受体的效应随药物浓度的增加而增强。在大多数情况下,如果血浆中药物浓度保持不变则药物的作用也将保持不变。因而近十年来,注意了对有特定释放速度的剂型和持续释放的剂型的 In the past few decades, finding new drugs has been the main route of pharmaceutical innovation. At the same time, the selectivity and persistence of drug effects have been taken as the main criteria for the development of new products. For the convenience of patients, the oral dosage forms made by most drugs, including tablets, capsules, and sustained-release preparations, exhibit a first-order kinetic process in vivo and do not maintain a constant drug concentration. These formulations, like injections and eye drops, release the drug into the surrounding tissue very quickly, and then continue to drop in speed for hours. This method of administration has some drawbacks, namely frequent medication, inconvenient, and often forget medication. The effect of most drugs is related to the concentration, suggesting that the effect of the receptor increases with increasing drug concentration. In most cases, the effect of the drug will remain unchanged if the plasma drug concentration remains unchanged. In the last decade, therefore, attention has been given to the dosage forms and sustained release dosage forms having a specific release rate