Pharmaceutics

Author: Zou Lijia
Editor-in-Chief: Xu Xiaojie et al.
Publisher:
Publishing Date: 2002-06-01
Features:
Content Summary
This book primarily introduces the characteristics, uses, and preparation processes of various common dosage forms, including liquid preparations, injectables, tablets, powders, pills, suppositories, films, granules, and aerosols. It also covers relevant knowledge of pharmacokinetics and biopharmaceutics. The content is rich and highly practical, suitable for pharmacy programs in general higher vocational colleges, as well as for reference by other pharmacy professionals.
Excerpt:
(1) Drugs and Medicines
A drug refers to substances used to prevent, treat, or diagnose diseases in humans and animals, as well as those that affect human physiological functions. Drugs can be categorized into two main types based on their origin: natural drugs and synthetic drugs. A medicine, on the other hand, refers to substances used to prevent, treat, or diagnose human diseases, with the purpose of regulating physiological functions, and is specified with indications, dosage, and administration methods. This includes traditional Chinese medicinal materials, prepared Chinese medicinal materials, Chinese patent medicines, chemical raw materials and their preparations, antibiotics, biochemical medicines, radioactive medicines, serum vaccines, blood products, and diagnostic medicines. Therefore, drugs and medicines are not entirely equivalent concepts. The scope of drugs is much broader than that of medicines, and not all disease-preventing or treating substances are medicines.
(2) Dosage Forms
A dosage form refers to the form in which a drug is processed for preventive or therapeutic use (abbreviated as "dosage form"). It generally denotes the category of drug preparations, such as tablets, injectables, and ointments. Different drugs can be formulated into the same dosage form, such as ascorbic acid tablets and antitoxin tablets. Conversely, a single drug can also be formulated into multiple dosage forms, such as ephedrine hydrochloride tablets, ephedrine hydrochloride injections, and ephedrine hydrochloride nasal drops.
(3) Preparations
A preparation refers to a pharmaceutical preparation with a certain specification, formulated from raw drugs according to a widely used and stable prescription as specified in pharmacopoeias, drug standards, or prescription manuals. Preparations can be directly used for clinical treatment or prevention of diseases (e.g., penicillin injections, ascorbic acid tablets), or used as raw materials for other preparations or formulations (e.g., fluid extracts, tinctures). Preparations are primarily manufactured in pharmaceutical factories but can also be prepared in hospital preparation rooms. The science that studies the theory, technology, and methods of preparation production is called pharmaceutics.
(4) Formulations
A formulation refers to a pharmaceutical preparation specifically prepared for a particular patient or a certain disease according to a physician's prescription. Formulations have clear targets, dosages, and administration methods and can be directly administered to patients. The preparation of formulations is generally carried out in hospital preparation rooms. The science that studies the preparation, use, and related technologies and theories of formulations is called. Due to the similarities in the principles and techniques of formulation preparation and preparation production, these two aspects are often discussed together and collectively referred to as pharmaceutics. Currently, the preparation of formulations is rarely conducted in hospital pharmacy departments in China, so this book covers limited content on.
(5) Patent Medicines
A patent medicine refers to a pharmaceutical preparation formulated from raw drugs according to a prescription with proven efficacy, stable properties, and widespread application, with a certain dosage form and specification. Its characteristics include generally being given popular names (e.g., pain-relieving tablets, cooling oil, pain-relieving plasters, forsythia tablets), and clearly indicating its effects, dosage, and administration methods. The production and sale of patent medicines must be approved by pharmaceutical regulatory authorities.
(6) Toxic Drugs
A toxic drug refers to a medicine with a strong pharmacological effect, where the therapeutic dose is close to the toxic dose, and improper use can lead to poisoning or death. Examples include atropine, digitoxin, and arsenic trioxide.
(7) Narcotic Drugs
A narcotic drug refers to a medicine that, when used continuously, can easily produce physical dependence and addiction, such as morphine and codeine. Narcotic drugs should be distinguished from anesthetics used in clinical practice, such as ether, chloroform, and procaine, as the latter have anesthetic effects but do not cause addiction and are therefore not classified as narcotic drugs. Toxic drugs and narcotic drugs should be stored in locked cabinets under the supervision of designated personnel, and can only be dispensed with a formal prescription from a designated physician. If the required quantity exceeds the usual amount, the prescribing physician should also sign or stamp the dosage. The labels and colors of toxic drugs and narcotic drugs should also be clearly distinguishable from those of ordinary medicines. Strict adherence to the "Management Measures for Narcotic Drugs" and the "Management Measures for Medical Toxic Drugs," as well as specific regulations implemented by provinces and cities, is required in their purchase, preparation, storage, and use.
(8) Traditional Chinese Medicines
Traditional Chinese medicines generally refer to effective plant medicinal materials used in China based on empirical knowledge (they also include some animal and mineral medicinal materials). Most of them are natural and not listed in classical works.
(9) Chinese Medicine
Chinese medicine refers to natural medicinal materials traditionally used by Chinese physicians, as recorded in classical works, some of which undergo artificial processing before use. Chinese medicine often includes famous traditional Chinese medicine formulations, such as pills,, ointments, and powders.
II. The Tasks of Pharmaceutics
The fundamental task of pharmaceutics is to study how to formulate drugs into appropriate dosage forms to ensure the needs of healthcare are met with high-quality, safe, effective, and stable medicines. The main tasks and development trends of pharmaceutics can be summarized as follows:
(1) Researching Basic Theories and Production Technologies of Pharmaceutics
The study of basic theories in pharmaceutics is of great significance for improving production technology, formulating safe, effective, stable, and convenient medicines. For example, using pharmacokinetic knowledge to predict drug stability and control quality; employing biotechnology for formulation development; utilizing solubilization and co-solvency theories for formulation preparation; using micronization, solid dispersion methods, and microencapsulation to promote and control the rate of drug dissolution and absorption; producing tablets using tablet molding theory and direct compression technology; controlling the quality of dosage forms such as suspensions, emulsions, and ointments using rheological theories; and providing important references for evaluating drug quality, rational drug manufacturing, and rational drug use, etc. It is clear that improving the basic theories of pharmaceutics, especially the research level of dosage form design principles, has significant guiding significance for improving production technology, developing new dosage forms, new products, new processes, and enhancing product quality.
(2) Developing New Dosage Forms and Preparations
With the advancement of science and technology and the continuous improvement of living standards, existing dosage forms and preparations can no longer fully meet people's needs. Common dosage forms such as tablets, injectables, pills, and solutions are difficult to meet requirements such as high efficiency, long duration of action, low side effects, controlled release, and targeted release. Therefore, actively developing new dosage forms is an important task in pharmaceutics today. The focus of pharmaceutical formulation research in foreign countries has shifted from the 1960s, which emphasized formulation technology and apparent quality, to the study of dosage form factors and their relationship with the body. By the late 1980s, formulation research began to shift toward the development and study of novel drug delivery systems (e.g., sustained-release, controlled-release, and targeted formulations) to meet medical needs. New drug delivery systems can enhance drug efficacy, reduce unnecessary high drug concentrations, appropriately extend the duration of drug action in the body, and increase the persistence and selectivity of drug effects to improve therapeutic efficacy and reduce side effects. Currently, China's level of pharmaceutics research still lags behind developed countries, with fewer types of dosage forms and preparation varieties, and limited exportable preparation varieties. Therefore, actively developing new dosage forms and preparations should receive sufficient attention in pharmaceutics research.
(3) Actively Researching and Developing New Pharmaceutical Excipients
In addition to the active pharmaceutical ingredient, pharmaceutical preparations also contain various excipients. Different dosage forms require different excipients. For example, excipients used in tablets differ significantly from those used in ointments, suppositories, etc. The improvement and development of drug dosage forms, the enhancement of product quality, the innovation of production technology and equipment, the application of new technologies, and the research of new dosage forms all require close coordination with various types of pharmaceutical excipients. Although there are many types of pharmaceutical excipients available, they still cannot meet the demand for new excipients in the development of the pharmaceutical preparation industry. In developed pharmaceutical preparation countries, only a few main dosage forms use over 300 types of excipients.