Tenofovir alafenamide
Tenofovir alafenamide is a novel [tenofovir] prodrug developed in order to improve renal safety when compared to the counterpart [tenofovir disoproxil]. Both of these prodrugs were first created to cover the polar phosphonic acid group on tenofovir by using a novel oxycarbonyloxymethyl linkers to improve the oral bioavailability and intestinal diffusion. Tenofovir alafenamide is an alanine ester form characterized for presenting low systemic levels but high intracellular concentration. It has been reported to produce a large antiviral efficacy at doses ten times lower than tenofovir disoproxil. Tenofovir alafenamide is indicated to treat chronic hepatitis B, treat HIV-1, and prevent HIV-1 infections.  Tenofovir alafenamide was developed by Gilead Sciences Inc and granted FDA approval on 5 November 2015.