有些药品稳定性差,在贮存中易受光、空气和温湿度等环境因素的影响,药效降低,毒性增高,甚至不能药用。为了保证用药安全、有效,必须给这类药品规定有效期限,也就是按照药品说明书中规定的条件,贮藏保存该药不会发生质量变化的期限。这些药物大致包括以下几类: 一、抗生素系指某些微生物生长过程中产生的代谢产物,其生产可用培养的方法,近年大多采用化学合成 Some drugs have poor stability, are easily affected by environmental factors such as light, air and temperature and humidity during storage, reduce efficacy, increase toxicity, and even can not be used medicinally. In order to ensure the safety and effectiveness of the drug, the expiration date of such drugs must be stipulated, that is, the period of storage and storage of the drug will not change in quality according to the conditions specified in the drug specification. These drugs generally include the following categories: First, the antibiotic refers to the growth of some microorganisms produced metabolites, the production of available culture methods, most of the recent chemical synthesis