Inhibitory activity of the diphosphate metabolites of adefovir, tenofovir, and PMEO-DAPym against HSV DNA.

aFour separate experiments were carried out in which three non-radiolabeled dNTPs were present at 100 µM and the fourth dNTP was radiolabeled and present at 1 to 3.2 µM depending on the nature of the [3H]dNTP. The 50% inhibitory concentration was defined as the drug metabolite concentration required to inhibit HSV DNA polymerase-catalysed DNA synthesis by 50%, using different (radiolabeled) dNTPs as direct competing substrates. As the primer/template, gapped calf thymus DNA was used.