药物代谢动力学(简称药代动力学)是研究药物在体内吸收、分布、代谢和排泄的量变规律.合理地应用药代动力学原理以及所用药物的动力学特征,有助于拟订给药方案,使药物血清浓度维持在最佳“治疗范围”内.药物吸收、分布、代谢和排泄的速率通常与药物浓度成比例,遵照一级或线性动力学规律.例如,当口服某种药物时,最初胃肠道内的药物浓度较高,则其吸收速率亦较快.当药物开始被吸收后,胃肠道内浓度减低,药 Pharmacokinetics (referred to as pharmacokinetics) is to study the drug absorption, distribution, metabolism and excretion of the law of quantitative changes in the rational use of pharmacokinetic principles and the kinetic characteristics of the drug used to help formulate the drug program , So that the drug serum concentration is maintained within the optimal “therapeutic range.” The rate of drug absorption, distribution, metabolism and excretion is usually proportional to the drug concentration, in line with the first-order or linear kinetics.For example, when oral administration of a drug , The initial high concentration of drug in the gastrointestinal tract, the absorption rate is also faster when the drug began to be absorbed, the gastrointestinal tract concentration decreased, the drug