Delavirdine (U 90152) is a potent, highly specific and orally active non-nucleoside reverse transcriptase inhibitor (NNRTI). Delavirdine selectively inhibits HIV-1 reverse transcriptase (RT) ( IC 50 =0.26 μM) over DNA polymerase α (IC 50 =440 μM) and polymerase δ (IC 50 >550 μM). Delavirdine is an inhibitor of HIV-1 replication and can can be used for the study of AIDs.