Effect of human serum on the in vitro anti-HIV-1 activity of 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT) derivatives as related to their lipophilicity and serum protein binding.

Several derivatives of 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT) were examined for their inhibitory effects on the replication of human immunodeficiency virus type 1 (HIV-1) in MT-4 cells in the presence of various concentrations (10-50%) of human serum (HS). Although all HEPT derivatives proved to be highly potent inhibitors of HIV-1 in the presence of 10% fetal bovine serum, some of them were less inhibitory to HIV-1 replication in the presence of HS. The HEPT derivatives were found to be highly bound to HS proteins. Both the anti-HIV-1 activity and HS protein binding of the compounds appeared to be related to their lipophilicity.