Excipients are usually defined as the nonactive ingredients that are mixed with pharmacologically active compounds to form medicines, particularly tablets. The behavior and effectiveness of many drugs are governed in part by excipients. Some ingredients are used to ensure that a preparation has great crushability and therefore is easy to manufacture in tablet and capsule forms. Others give tablets a sweet taste. Still other excipients may ensure slow release of the drug or provide great compressibility so that a pill can be made smaller. Excipients also can improve a drug's general efficacy, safety, stability, and storage. The main categories of excipients include:
Public awareness and safetyThe trend toward greater public awareness of food additives and ingredients has led inevitably to greater attention to pharmaceuticals. Consumers are becoming increasingly curious about which substances are used in the manufacture of drugs. The result has been a growing interest in excipients and a drive to establish standards for quality and control.
In the United States, the use of excipients is controlled by the US Pharmacopeial Convention, an independent body that publishes and maintains the United States Pharmacopeia and National Formulary, which contain the monographs (i.e., standards) with which excipients must comply.
In the European Union, a similar system is in place. Excipients must conform to monographs that are published in the European Pharmacopoeia, although US standards are accepted where no European monograph exists. Japan also has its own monographs governing the use of excipients, published in either the Japanese Pharmacopoeia or Japanese Pharmaceutical Excipients.
Significant efforts are being made to harmonize international standards of monographs to pave the way for easy and fast development and approval of excipients, but this goal is still some way off. In the short to medium term, pharmaceutical companies face increased costs resulting from the various testing procedures that must be applied to the same products serving different areas of the world.
Regulatory developments are one of the major agents of change in the excipients industry. The most recent are the guidelines from the International Pharmaceutical Excipients Council (IPEC) and the Pharmaceutical Quality Group (PQG). IPEC is a global organization representing producers, suppliers, and end users of excipients. The body has three divisions in Europe, Japan, and the United States, each of which focuses on local regulations concerning the excipients market, as well as on new research and business practices. PQG is an association that publishes monographs and provides training and information for quality professionals within the pharmaceutical industry.
One of the most important aspects of the guidelines is their focus on "one-up–one-down" traceability. This means that companies at each level of the supply chain must be able to trace where their materials or supplies came from and where their products have ended up. This means pharmaceutical companies will have to find more resources for administration and documentation to achieve this traceablility.
Though the guidelines currently are voluntary, they provide much of the focus of current thinking on manufacturing practices for excipients. Implementing them is a must for companies that wish to stay competitive and not be left behind on safety and public-health grounds. Pharmaceutical companies must implement quality procedures that at least meet, if not exceed, the legal requirements. The guidelines also represent an opportunity to move toward a common set of standards that can be applied to excipients.