Storage of Pyrimethamine in Cells in vitro.

Abstract

Binding of pyrimethamine or its active product in monkey kindey tissue culture was demonstrated by challenging treated tissue cultures with Toxoplasma gondii and by microbiological assay with Streptococcus faecalis R. The limits of the storage phenomenon were defined. Chick embryo heart explants, HeLa cells and human intestinal cells also were able to store drug in levels inhibitory to the protozoon. Drug storage in mouse mince and KB cells was less evident and no storage occurred in conjunctival epithelium. Some differences in storage of pyrimethamine were noted in monkey kidney cells of different ages. The ability of cells to store pyrimethamine in vitro suggests an explanation for the prolonged activity of the drug.