PART 3 INDUSTRIAL PHARMACY
Unit 11 Tablets (The Pharmaceutical Tablets Dosage Form)
Role in Therapy
    The oral route of drug administration is the most important method of administering drugs for systemic effects. Except in cases of Insulin therapy，the parenteral route is not routinely used for self-administration of medications. The topical route of administration has only recently been employed to deliver drugs to the body for systemic effects，with two classes of marketed products: Nitroglycerin酯 for the treatment of angina心绞痛 and scopolamine莨菪胺 for the treatment of motion sickness晕动病，指晕车、晕船等. Other drugs are certain to follow，but the topical route of administration is limited in its ability to allow effective drug absorption for systemic drug action. The parenteral route of administration is important in treating medical emergencies in which a subject is comatose昏迷的 or cannot swallow，and in providing various types of maintenance therapy for hospitalized patients. Nevertheless，tablet defectsit is probable that at least 90 % of all drugs used to prod
uce systemic effects are administered投药，给药 by the oral route. When a new drug is discovered，one of the first questions a pharmaceutical company asks is whether or not drug can be effectively administered for its intended effect by the oral route. If it cannot，the drug is primarily relegated to被降级到 administration in a hospital setting or physician's office. If patient self- administration cannot be achieved，the sales of the drug constitute only a small fraction of what the market would be otherwise. Of drugs that are administered orally，solid oral dosage forms represent the preferred class of product. The reasons for this preference are as follows. Tablets and capsules represent unit dosage forms in which one usual dose of the drug has been accurately placed. By comparison相比之下， liquid oral dosage forms，such as syrups，suspensions，emulsions，solutions，and elixirs，are usually designed to contain one dose of medication in 5 to 30 ml. The patient is then asked to measure his or her own medication using a teaspoon，
第三部分 工业药剂学
第11单元 药片 (医药的片剂剂型)
在中的作用
口服给药途径是通过给药获得全身作用效果中最重要的方法。除了胰岛素疗法之外，肠外给药途径通常不用于（病人的）自主性用药。而局部给药途径则是在最近才被用来把药物送到体内从而产生全身作用。这种途径有两种上市产品：用于心绞痛的酯和用于晕动病的莨菪胺。今后肯定还会有其他的药物相继出现，但是局部给药的途径在有效的药物吸收从而获得全身物作用方面仍有其局限性。在病人处于昏迷状态或病人不能吞咽的医疗急救处理中，肠外给药途径是很重要的，同时它也给住院的病人提供了各种不同类型的维持疗法。然而，可能至少有90%的被用于产生全身作用的药物是通过口服的途径给药的。当一种新的药物被研发出来的时候，制药公司问的第一个问题就是这种药物能否有效地通过口服给药途径来达到预期的效果。如果不能，那么这种药物就要被降级到医院或者医生的办公室里。如果病人的自主用药不能实现，那么（这种）药物的销量就会是能实现病人的自主用药的药物销量的很少一部分。在所有通过口服来给药的药物当中，固体口服制剂是（人们）偏爱的产品种类。其原因如下：药片和胶囊代表着单元剂量的形式，其中通常已经放置好了一个剂量的药物。相应地，液体口服制剂，比如说糖浆、悬浮液、乳剂、溶液和酏剂，则通常被设计成在5-30 ml （液体中）包含一个剂量的药物。病人会被要求用茶匙、调羹或
其他测量装置来衡量他自己的用药量。病人自己用药时这种剂量测量方法，其误差范围通常
tablespoon， other measuring device. Such dosage measurements are typically in error by a factor ranging from 20 %to or 50% when the drug is self-administered by the patient.
    Liquid oral dosage forms have other disadvantages and limitations when compared with tablets. They are much more expensive to ship (one liquid dosage weighs 5 g or more versus 0. 25 to 0. 4 g for the average tablet)，and breakage or leakage during shipment is a more serious problem with liquids than with tablets. Taste masking of the drug is often a problem (if the drug is in solution even partially). In addition，liquids are less portable便携的，轻便的 and require much more space per number of doses on the pharmacist's shelf. Drugs are in general less stable (both chemically and physically) in liquid form than in a dry state and expiration dates截止日期 tend to be shorter. Careful attention is required to assure保证 that the product will not allow a heavy microbiologic微生物学的 burden to develop on standing or under normal conditions of use once opened(preservation requirements储存要求).There are basically three reasons for having liquid dosage forms of
a drug:(1)The liquid form is what the public has come to expect for certain types of products (e. g. cough medicines).(2) The product is more effective in a liquid form (e. g.，many adsorbents and antacids). (3) The drug(s) are used fairly commonly by young children or the elderly，who have trouble swallowing the solid oral dosage forms.
Properties
    The objective of the design and manufacture of the compressed tablet is to deliver orally the correct amount of drug in the proper form at or over the proper time and in the desired location，and to have its chemical integrity protected to that point. Aside from the physical and chemical properties of the medicinal agent (s)to be formulated into a tablet，the actual physical design，manufacturing process，and complete chemical makeup of the tablet can have a profound深远的 effect on the efficacy功效 of the drug(s) being administered.
    A tablet should be an elegant讲究的，优良的，上等的 product having its own identity while being
在20%-50%之间。
液体口服制剂和药片相比还有其弊端和局限性。它们运输起来更昂贵（一剂量液体制剂重5 g 或者更多，而普通的药片只重0.25-0.4 g ），而且对于液体制剂来说，在运输过程中的破坏和泄漏相对于药片而言也是一个更为严重的问题。药物味道的掩蔽通常也是个问题（如果说药物在溶液中溶解，甚至只是部分溶解）。另外，液体也比较不易携带，而且同样数目的剂量，液体制剂在医生的药架上占据的空间（比药片）要多得多。液体形式的药物通常比处于干燥状态的药片不稳定（不仅在化学上，物理上也是），而且其有效期也相对较短。（人们）需要小心注意以确保产品在储存或正常的拆封使用条件下，不会有严重的微生物负担（保存要求）。制造液体形式的药物有三个基本的原因：1、对于某些类型的产品（例如止咳药），液体剂型已经逐渐成为人们期望的形式了。2、液体形式的药品更有效（例如许多吸附剂和抗酸剂）。3、（液体制剂）药物在小孩儿和老年人中运用相当普遍，对他们来说，吞咽固体的口服制剂有些困难。
性质
设计和制造压缩片剂的目的是要通过口服把正确数量的药物以适当的形式，在适当的时间送达期望的位置，在此之前还要保护药物的化学完整性（不受破坏）。除了被加进药片当中的
药物组分的物理和化学性质之外，药片实际的物理结构设计、制造过程和完整的化学组成都对药物的功效有深远的影响。
药片应当是一种优良的产品，有其自身的特点，同时不能有诸如缺损、裂隙、褪、污染之类的缺陷；应该能经得住机械撞击的考验，这些撞击在药片的生产、包装、装运和分发过程
free of defects such as chips，cracks， discoloration变褪，contamination不纯，污染，and the like; should have the strength to withstand the rigors of mechanical shocks encountered in its production， packaging，shipping，and dispensing分配分发; and should have the chemical and physical stability to maintain its physical attribute属性，特质 over time. Pharmaceutical scientists now understand that various physical properties of tablets can undergo change under environmental or stress conditions，and that physical stability， through its effect on bioavailability in particular，can be of more significance and concern in some tablet systems than chemical stability.

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