Collaboration between monitoring authorities, regulatory authorities and test facilities on GLP principles provides confidence in data quality with an emphasis on sound science. GLP: an example of a focused effort that paid off.

The herbicide atrazine has been the subject of numerous studies investigating its potential effects on amphibians. The United States Environmental Protection Agency (EPA) required the atrazine registrant to conduct a tiered study approach. Tier I of the studies involved laboratory studies to determine whether atrazine affects amphibian gonadal development. Several good laboratory practice (GLP) inspections were conducted during the Tier 1 atrazine amphibian study entitled "Response of larval Xenopus laevis to atrazine exposure: assessment of metamorphosis and gonadal morphology". These inspections were conducted on each of the in-life (Phase 1) test facilities (TF), i.e., Wildlife International (WLI) Ltd. (Easton, Md, USA) and the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) (Berlin, Germany). All of the inspections were conducted in conjunction with the EPA GLP monitoring authority (MA), the Office of Enforcement, Compliance and Assurance (OECA) as well as auditors from the regulatory authority (RA) Office of Pesticide Programs (OPP). The inspection of the German facility also included representatives of the German equivalent of OECA. In Phase II of the Tier 1 study, tissue samples collected by both IGB and WLI during Phase I were prepared for histology and reviewed by a veterinary pathologist at the Experimental Pathology Laboratory (Vienna, Virginia, USA). The cooperation between the MA, RA and the TF allowed OPP to ensure the GLP principles were being followed as well as allowing everyone involved to bring up some higher level science issues associated with the study execution.