The Criticality Of Excipient Purity

Excipient purity is critical in all applications of drug formulation. Typically, the more sensitive or reactive an API, the more critical excipient purity becomes. When evaluating or choosing any excipient, however, purity should always be a priority. Excipient impurities can directly impact the stability of the drug active and its performance, which in turn will lead to poor bioavailability, and affect the end product’s pharmacokinetics and pharmacodynamics. Side effects associated with excipient impurity are breakdown of the API and poor performance, and impurities in even the simplest formulation can lead to a failed end product.

George J. Rizzo is Research Team Leader – Health Care, Technical Applications and Product Development at Croda Inc.

The pharmaceutical industry takes the issue of excipient purity very seriously and must keep up to date with the changes issued by governing bodies that regulate APIs and materials used in drug formulation. The FDA, the US Pharmacopeia, the European Pharmacopeia and the Japanese Pharmacopeia are the main governing bodies and are heavily involved with regards to limits of usage of the excipient per route of entrance into the body for specific applications. These bodies are constantly making improvements to monographs to ensure that patient safety is a first priority.

Improving excipients to ensure purity is a heavily involved process that begins with being aware of what issues are relevant to drug formulators. Once a problem is identified, a corrective plan is established in the research and development laboratories to physically solve and correct the problem at hand. Once a solution has been obtained, the work is then transferred to the commercial side for mass production, which is achieved on the commercial scale by putting in place good process controls and quality systems that ensure high purity material is produced on a consistent basis.