N-Nitroso compound contaminants in prescription and nonprescription drugs.

73 pharmaceutical products, consisteing of both prescription and over-the-counter drugs have been analyzed by gas chromatography-thermal energy analysis (GC-TEA) and high-pressure liquid chromatography-thermal energy analysis (HPLC-TEA) for the presence of N-nitroso compound contaminants. The methods used were designed to detect both volatile and non-volatile N-nitroso compounds at levels down to 1 ng/g (1 ppb). Results presented here indicate that N-nitroso compound impurities are absent from the majority of the products tested. However, for 3 of the drugs, our analysis suggests the possible presence of N-nitroso compounds at levels up to 81 ng/g (81 ppb). The identity of the suspect N-nitroso compounds have not yet been established. In the case of the over-the-counter drugs, two of these have been shown to contain TEA responsive materials (126 ppb, 406 ppb), that may appear to be O-nitroso compounds rather than N-nitroso.