Metformin hydrochloride

PBT assessment

PBT assessment: overall result

Reference

Name:

Metformin hydrochloride

Type of composition:

legal entity composition of the substance

State / form:

solid: bulk

Reference substance:

Metformin hydrochloride

PBT status:

the substance is not PBT / vPvB

Justification:

Metformin HCl is highly water soluble and has a very low octanol-water partition coefficient. It is thus not likely to accumulate in biotic tissues or to sorb to organic material. In aerobic aquatic systems, the compound dissipated steadily from the water phase via degradation and adsorption to sediment. Based on the DT50 value of 14.2 days in the river system, metformin HCl is considered to be biodegradable in aerobic aquatic systems (river).

In general, metformin HCl has a very low hazardous potential on aquatic organisms. In acute aquatic toxicity tests, metformin HCl did not cause any adverse effects to fish (Lepomis macrochirus) and only weak effects to invertebrates (Daphnia magna). Chronic toxicity testing with aquatic organisms also resulted in either no (Desmodesmus subspicatus, Daphnia magna, Danio rerio) or weak (Lemna minor) adverse effects at the concentrations tested. The lowest NOEC from aquatic toxicity studies was the 34d-NOEC of >=12 mg/L obtained in the Early life stage test with Danio rerio. For effects on sediment organisms, the 28d-NOEC for Chironomus riparius was 31.25 mg/L The Phase II Tier A and B fate and effects analyses for the different environmental compartments (surface water, ground water, sewage treatment plant, sediment, bioaccumulation and terrestrial compartment) did not result in a risk for any of the compartments. Therefore, it can be concluded that metformin HCl does not pose an environmental risk