Regardless of whether it’s prescription or over-the-counter, the ingredients on a drug product label typically include one, maybe two, active pharmaceutical ingredients (APIs). The rest of the list is comprised of “inactive” ingredients (excipients) which in reality are far from inactive. Their functions range from helping to guarantee the stability and bioavailability of the API to the drug product’s manufacturability to its texture and taste. Because of the multiple roles they play in drug product formulations, excipient quality is as important as that of the API, so standards are needed to ensure their purity and reliability.
- How can you, as a manufacturer, be confident in the quality of the excipients you get from your suppliers?
- How can you, as a research scientist, be sure you’ll have the excipients you’ll need to formulate the new therapeutics you’re developing?
- How can you, as a consumer, have confidence in the quality of the drugs you’re using or giving to your family?
Without quality standards, you can’t.
Benefits and challenges of globalization
With vast, multi-national supply networks, there’s no shortage of sources from which pharmaceutical manufacturers can purchase excipients. Manufacturers of excipients have differences in their raw materials, production processes, the scale of manufacture and their location, any of which can contribute to variability in the quality and purity of an excipient as well as its physicochemical properties.
Not only do the substances that serve as excipients in pharmaceuticals come from a multitude of global sources, they may also be used for a wide range of purposes in other industries. Polyethylene glycol (PEG), for example, is used in pharmaceuticals as a solvent, surfactant, ointment, and tablet and capsule lubricant. It is also used as a solvent for ink in some printers and is a main ingredient in paintball fills. Variation in the chemistry, origin and manufacture of materials may be acceptable for printer ink and paintballs, but not for pharmaceuticals.
Variability may be acceptable for products such as printer in and paintballs, but not pharmaceuticals. Making quality standards for excipients is critical to ensuring consistent drug quality.
Excipient quality management
To verify the quality, purity and authenticity of the materials used as excipients, drug manufacturers implement quality and risk management systems that can be validated and audited to detect adulteration. They monitor their own facilities and can check the organizations in their supply chains using well-characterized third-party verification systems. Such systems and processes further mitigate risk through independent, unbiased assessments to verify consistent excipient quality.
Documentary and reference standards are used as part of the quality management process to evaluate the integrity of the excipients used in drug products. Using precisely defined testing procedures and acceptance criteria, excipients’ physicochemical properties are measured against well characterized substances to confirm their identity, purity, and quality. Pharmaceutical manufacturers use USP standards to comply with FDA requirements and demonstrate their commitment to consumers by safeguarding the quality and reliability of drug products in the marketplace.
Every step in the pharmaceutical manufacturing process, from raw materials through packaging and distribution of the final product, presents a point at which quality could be compromised. Documentary and reference standards as well as process and product verification procedures are all valuable tools to safeguard quality along the entire manufacturing and distribution chain, reducing risks to patients and consumers. Variability may be acceptable for products such as printer ink and paintballs, but not pharmaceuticals, making quality standards for excipients critical to ensuring consistent drug quality. USP is committed to supporting these efforts with standards that help ensure the quality and benefit of medicines.