of administration (one being that used in man). Results provide a guide to the maximum tolerated doses in subsequent chronic. toxicity tests，aid selection of dose levels，and identify target organs.
The main aim of the subsequent sub-acute toxicity tests is to determine whether or not the drug candidate is adequately tolerated after administration to animals for a prolonged period as a guide to possible adverse reactions in man. Two to four week (daily dosing) studies are required，using the same route of administration as in man，in two species (one non-rodent)prior to administration of the compound to man. Three dose levels are usually necessary:the low daily dose should be a low multiple of the expected therapeutic dose，and the highest dose should demonstrate some toxicity.
A general guide for the evaluation of new chemical entities would be that toxicology studies of a minimum duration of 14 days are required to support single-dose exposure of a new drug candidate in normal volunteers in Phase 1. Toxicology studies of 30 days duration are required to support clinical studies of 7 to 10 days duration. Clinical studies of greater than 7 to 10 days up to 30 days duration require the support of at least 90 days toxicology studies. These requirements illustrate the need to plan ahead in drug development. The duration and approximate timings for future clinical trials need to be considered well in advance in order to schedule and conduct the appropriate toxicology studies to support the clinical program and avoid any delays.
Two types of safety test are used to detect the ability of the drug candidate to produce tumours in man. The first are short-term in vitro genotoxicity tests，for example bacterial tests. The second are long-term animal carcinogenicity studies which are conducted in mice and rats;their length of often 2 years covers a large part of the lifespan of the animal. Mice and rats are used because of their relatively short life span，small size，and ready availability.
Also，knowledge，which has accumulated concerning spontaneous diseases and tumours② in particular strains of these species，helps greatly in the interpretation of‘ results.
Long-term toxicology and carcinogenicity studies are conducted in order to obtain approval to test and finally to market a product for chronic administration to man. These studies may need to start during the late preclinical/ early clinical phase in order to `support' the subsequent clinical program. Long-term toxicity studies will normally include toxicity studies of six and twelve months duration in two species (one non-rodent).Any toxicity previously detected may be investigated more closely，for example extra enzymes looked at in blood samples.
Reproductive toxicology is that part of toxicology dealing with the effect of compounds on reproduction-fertility，foetal abnormalities，post-natal development. Prior to clinical studies in women of child-bearing age，regulatory authorities require teratology data from two species (normally rat and rabbit)as well as clinical data from male volunteers. No reproductive data are required prior to clinical studies in male subjects. The effects of 59 compounds on reproduction differ with the period of the reproductive cycle in which exposure takes place and studies are designed to look at these phases. Teratology`'' studies are designed to detect foetal abnormalities，fertility studies to investigate the compounds' effect on reproductive performance，And peri- and post-natal studies to study the development of pups.
Selected from F. D. King，’Medicinal Chemistry Principles and Practice ’ the Royal Society of Chemistry Thomas , Graham House G. B. , 1994.
5单元 药物研发（I） 1。简介
药品开发是一个非常复杂的过程，需要一个协调和沟通不同功能之间的群体广泛很大。它是昂贵的，特别是在临床开发的后期阶段，在研究涉及的数百名病人。据估计，目前约2.3亿美元（1987美元）的新药开发成本，并采取介于7和10多年的临床前开发阶段开始，首先市场（不包括监管滞后）。药物开发是一项高风险业务，虽然利率不断上升，大约只有每十个新的化学研究在人类首次实体开展会不会成为一个产品。作为候选药物的进步，通过发展'的失败降低风险hurdles'are克服前进的道路上。失败的典型原因包括不可接受的毒性，缺乏有效性，或不能提供比其他竞争产品的优点
（图1）。
损耗率的新化学实体
（竞争性考试的）进入发展。平均 只有约400 ^ 1000我在化合物 合成进入发展。
原因的罗富国教育学院的发展终止 （不包括抗感染药） 1：缺乏疗效 2：药代动力学 3：动物毒性 4：杂项
5：在人的不良影响 6：商业上的原因
图。 1磨损率和终止的原因 2。发展规划
候选药物是否有可能提供有竞争力优势的评估首先需要强调的地方有一个产品'的
目标，目标产品或配置文件集。应特别注意支付给竞争者形成差异。这已成为55个，并与有限的处方，医疗费用，以及药物经济学（本章稍后讨论）日益重视更为关键。
配置文件将确定一个目标指示（县），将候选药物开发以及诸如每日一次给药的目标，起效更快的行动，更好地侧比主要竞争对手效应特征。目标配置文件可以通过完善和发展为移动和候选药物的候选药物或竞争对手成为可用的新数据修改。合乎逻辑的下一个步骤是确定发展战略，例如，有适应症先发展，哪些国家向市场为目标的药物，然后确定要达到的核心监管机构的批准和商业成功的临床研究。
本章将描述一个成功的新药开发所需的主要活动。所有这些活动，其中许多是相互依存，需要认真规划和协调。速度与高品质的数据收集到的市场是成功的关键。该活动确定的时间会去登记被称为项目管理方面，关键路径，路径。这是非常重要的计划和准备，并在研究开始监控和管理问题，以确保关键路径如期进行。增加经济压力和竞争强度，重要的是企业，探讨如何缩短这一关键路径。并行运行的活动，或重叠研究，这将通常按顺序运行，往往涉及的风险增加，节省时间，但分红可以使这种战略值得的。
用于药物开发的一个新的关键路径通常贯穿初步合成的化合物，亚急性毒性研究，然后临床计划。图表显示了一个典型的候选药物的关键路径上的活动图所示。 2。
化学化学合成路线的选择试验厂，规模和稳定性测试制造工厂生产 急性及亚急性毒理学毒理学长期和再现毒理学 第一阶段会期临床阶段微光分析数据和报告相低压回顾 监管意见书和临床试验申请更新准备提交管理局 甲基丙烯酸/新药审批管理 上市后Surverillance 药物临床前，临床和商业配方 发展和稳定的测试准备标签
