Abstract

Although for decades it has been well known that certain chemicals can be mutagenic and/or carcinogenic (1,2), control of such chemicals as impurities in pharmaceutical products has come under the scrutiny of both the regulators and the pharmaceutical industry, only rather recently, with the issuance of the draft EMA (European Medicines Agency) genotoxic impurity guideline in 2004 (3). The discussions surrounding the viracept (nelfinavir mesylate) incident that occurred in 2007 significantly increased the overall awareness of genotoxic impurities and highlighted both the potential risk of genotoxic impurities to patient safety and the pharmaceutical business (4). The problem was caused by contamination of ethyl mesylate (EMS) in some lots of the HIV drug. As a result, safety concerns were raised, and Roche, the manufacturer of viracept, recalled the drug from the market and spent millions of dollars on toxicological studies of EMS (5–10).