Tenofovir Disoproxil
Tenofovir Disoproxil. Nucleotide reverse transcriptase inhibitor prodrug — converted to tenofovir → di-phosphate, a chain-terminator for HIV/HBV… Oral half-life 17 h.
Nucleotide reverse transcriptase inhibitor prodrug — converted to tenofovir → di-phosphate, a chain-terminator for HIV/HBV reverse transcriptase. Backbone of HIV ART + HBV antiviral. Renal proximal tubular toxicity + bone density loss are class concerns; TAF formulation (tenofovir alafenamide) reduces both.
ANALYTE: TENOFOVIR, and the stored half-life is verbatim and explicitly its serum value — "Tenofovir exhibits longer serum (17 hours) and intracellular (>or=60 hours) half-lives than those of nucleoside analogues". NOT THE SOFOSBUVIR SHAPE, and the distinction matters: three species exist, but unlike sofosbuvir inactive dead-end metabolite this plasma analyte is the direct precursor of the active anabolite, with dose-proportional kinetics consistent across healthy and infected subjects. F 0.25 IS UNSOURCED — neither cited paper supports it, and a 25% figure in this literature is a FOOD EFFECT on tenofovir DIPIVOXIL, a different prodrug. Retained only because the resolver default would be worse. ka 0.9 dropped. MASS: the stored weight was tenofovir DISOPROXIL free base while the declared analyte is tenofovir — 80.9 PERCENT HIGH, THE LARGEST MASS DEFECT OF THIS SHAPE FOUND IN THE WHOLE AUDIT. AND HERE IT IS NOT INERT, BECAUSE THE SAME MISMATCH RUNS THROUGH THE DOSE: the stored 300 mg is milligrams of the fumarate salt, of which only about 136 mg is tenofovir moiety, while the verbatim 25 percent bioavailability is defined molar-equivalently — so the model delivers roughly twice the analyte mass it should. THE NINE-FOLD EXPOSURE ERROR DECOMPOSES CLEANLY: about 2.2-fold from that mismatch and about 4.2-fold from an intravenous steady-state volume paired with a terminal half-life. CORRECTING EITHER ALONE MAKES THE DIAGNOSIS LOOK SOLVED WHEN IT IS NOT. THE FEASIBILITY FLOOR FAILS HARD AND INDEPENDENTLY: the label own peak, exposure and peak time sit more than three-fold below the minimum any one-compartment fit permits, so the stored half-life — genuine, verbatim, and TERMINAL — is not the one that carries this drug exposure; the effective value implied by the label own quartet is closer to a quarter of it. ALSO CORRECTED: this record note attributed its bioavailability to a FOOD EFFECT ON TENOFOVIR DIPIVOXIL. That paper exists and says approximately what the note claims, BUT IT IS A NUMERICAL COINCIDENCE AND NOT THE PROVENANCE — the figure is the label absolute bioavailability. No transplant with the alafenamide sibling is possible: that record is unauthored and has no numbers to swap. DOSE MOIETY: THE HALF OF THIS RECORD NINE-FOLD ERROR THAT BATCH 10 IDENTIFIED AND COULD NOT FIX. That pass decomposed the error into roughly 2.2-fold from a prodrug/analyte mass mismatch and roughly 4.2-fold from an intravenous steady-state volume paired with a terminal half-life, and warned that correcting either alone makes the diagnosis LOOK solved when it is not. The mass half is now fixed properly rather than by moving the bioavailability: the dose is milligrams of the FUMARATE salt of a prodrug, of which only 45 percent is tenofovir, while the stored bioavailability is already defined against the tenofovir moiety — so the two compose and neither double-counts. THE DOSE RANGE IS ALSO NORMALISED: its lower bound of 245 was the same tablet expressed as tenofovir DISOPROXIL rather than as its fumarate, so the block was mixing two salt bases in one range. The remaining volume defect is unchanged and still logged.
Pharmacokinetics
- Oral — t½ 17 h · F 25% · Vd 87 L
Sources: PMID:27049055, PMID:15217303