Scientist discovers molecule migration from label to drug

The discovery could have an impact on future label varnish selection

While analysing stability data of a particularly potent drug stored inside an HDPE bottle, a scientist at US contract manufacturer Metrics discovered an unexpected trend.

Deanna Williamson found that a benzophenone molecule, a compound that is often used in the varnish coating of a bottle’s label, had travelled through the label and the bottle before coming to rest on a tablet inside.

Although the pharmaceutical industry has long been aware of the ability of some molecules to migrate and this particular molecule was not toxic at the levels seen in Williamson’s stability data, she was concerned about the discovery.

‘In this situation, the active ingredient was an agent that needed to be measured using an especially sensitive analytical method,’ she said.

‘Someone making a typical OTC drug product may not employ the same sensitive level of testing, so it's probable that the levels of benzophenone present in those products would go undetected during the course of routine stability monitoring.’

The research has implications for the pharmaceutical industry. If benzophenone is migrating onto drugs but is undetected because routine monitoring does not catch it, what does that mean for patients?

‘These compounds may have been present all along but, unless you’re looking past a milligram level, you won’t see them,’ said Williamson.

‘At a minimum, this research could have an impact on one’s choice of label varnish, especially in potent products.’

Williamson, quality control group leader at Metrics, presented details of this discovery at the American Association of Pharmaceutical Scientists (AAPS) annual conference.

Started as an analytical laboratory in 1994, Metrics has evolved into a provider of quality pharmaceutical formulation development; first-time-in-man (FTIM) formulations; clinical material manufacturing (CTM) for Phase I, II and III trials; commercial manufacturing; and analytical method development and validation services.