Environmental risk assessment of metformin and its transformation product guanylurea. I. Environmental fate.

Metformin (MET) is a pharmaceutical with very high use worldwide that is excreted in unchanged form, leading to concern about potential aquatic life impacts associated with MET, and its primary transformation product guanylurea (GUU). This study presents, in two companion papers, a risk assessment following internationally accepted guidelines of MET and GUU in surface water based on literature data, previously unpublished studies, and a new degradation test that resolves conflicting earlier results. Previous studies have shown that MET is removed during sewage treatment, primarily through transformation to GUU.

Environmental risk assessment of metformin and its transformation product guanylurea: II. Occurrence in surface waters of Europe and the United States and derivation of predicted no-effect concentrations.

Metformin (MET), CAS 1115-70-4 (Metformin hydrochloride), is an antidiabetic drug with high usage in North America and Europe and has become the subject of regulatory interest. A pharmaceutical industry working group investigated environmental risks of MET. Environmental fate and chronic effects data were collated across the industry for the present risk assessment.

A risk-based approach to managing active pharmaceutical ingredients in manufacturing effluent.

The present study describes guidance intended to assist pharmaceutical manufacturers in assessing, mitigating, and managing the potential environmental impacts of active pharmaceutical ingredients (APIs) in wastewater from manufacturing operations, including those from external suppliers. The tools are not a substitute for compliance with local regulatory requirements but rather are intended to help manufacturers achieve the general standard of "no discharge of APIs in toxic amounts." The approaches detailed in the present study identify practices for assessing potential environmental risks from APIs in manufacturing effluent and outline measures that can be used to reduce the risk, including selective application of available treatment technologies.