CPhI Expert Comments on Role of Excipients

Although experts in the past suggested that “high-tech” excipients would be developed and that other excipients would be commoditized, the regulatory environment does not encourage the development of new excipients, says Brian Carlin, member of the CPhI Expert Panel and the United States Pharmacopeial Convention Excipient Expert Committee, in the newly released CPhI Annual Report 2017. Only three new chemical entity excipients have been introduced in the past 20 years, and, in the report, Carlin blames this dearth of pharma-specific excipients on what he calls double jeopardy: “a new chemical entity excipient incurs the cost of safety studies, but there is no regulatory mechanism for review and approval as a pharmaceutical excipient.” Using a new excipient in a new product, in which it will be reviewed as part of the drug application, is a risk that can be difficult to convince pharma companies to take.

Another problem occurs when companies rely merely on an excipient’s compliance with a compendial standard. Carlin notes that excipients are complex, and pharmacopeial specifications do not determine an excipient’s fitness for use in a particular application. In addition, some excipient attributes might change over time. He suggests that excipient manufacturers should be more involved with identifying and addressing these concerns. On the other hand, he notes that drug product manufacturers are the ones responsible for excipient quality.

Multivariate modeling is an improved way to provide assurance of quality, notes Carlin. “Monitoring drift in raw material properties provides both early warning and a degree of oversight over the supplier,” he says. He predicts that excipient suppliers will be able to differentiate themselves by being able to support multivariate monitoring.