A study on melanin affinity of 14C-trimethoprim in male Mol:WIST and Mol:PVG rats.

: Hooded (Mol:PVG) and albino (Mol:WIST) rats were used to study the distribution pattern of 14C-trimethoprim by whole body autoradiography. Accumulation of radioactivity was demonstrated in the uveal tract of the eye and the pigmented parts of the skin in the hooded rats. No radioactivity was present in the corresponding tissues in the albino rats. This difference in the distribution pattern was interpreted to reflect binding to melanin of 14C-trimethoprim and/or its metabolites.