ENTECAVIR 0.5 mg
Each film-coated tablet contains.
Colour: Titanium Dioxide IP & Red Oxide of Iron
- Oral film-coated tablet
Mechanism of action
Entecavir is an antiviral drug.Entecavir a guanosine nucleoside analogue with activity against HBV reverse transcriptase (rt).is efficiently phosphorylated to the active triphosphate form which has
an intracellular half-life functionally inhibits all three activities of the HBV reserve transcriptase:
Base priming.(2) reverse transcription of the negative strand from the pregenomic messenger
RNA and (3) synthesis of the positive strand of HBV DNA Entecavir in phosphate is a weak inhibitor
Of cellular DNA polymerases α β and δ and mitochondrial DNA polymerase gamma with K, values
Ranging from 18 to<160 Γm.Antiviral Activity.Entecavir inhibited HBV DNA synthesis(50%
Reduction, EC) at a concentration of 0.004 ΓM in human HepG2 cells transfected with wild-type HBV.The median EC value for entecavir against lamivudine-resistant HBV (rtl 180M, Tm204v)
Was 0.026 ΓM.(range 0.010 to 0.059 ΓM) The co-administration of HIV nucleoside/ nucleotide
Reverse transcriptase inhibitors (NRTIs) with entecavir is unlikely to reduce the antiviral efficacy
Of entecavir against HBV or of any of these agents against HIV,in HBV combination assays in cell culture,abacavir,didanosine,lamivudine,stavudine,tenofovir or zidovudine were not antagonistic to the cell culture anti-HIV activity of these six NRTIs or emtricitabine at concentrations greater than 100 time C max of entecavir using 1 mg dose.
Antiviral Activity against HIV
Analysis of the inhibitory activity of entecavir against a panel of laboratory and clinical HIV type 1(HIV-1) isolates using a variety of cells and assay conditions yielded EC50 values ranging from
0.026 to >10 ΓM; the lower EC50 values were observed when decreased levels of virus were
Used in the assay.in cell culture entecavir selected for an M1841 substitution in HIV variants
Containing the M184V substitution showed loss of susceptibility to entecavir.
The single- and multiple-dose pharmacokinetics of entecavir were evaluated in healthy subjects And subjects with chronic HBV infection. Absorption.following oral administration in healthy Subjects, entecavir peak plasma concentration occurred between 0.5 and 1.5 hours.following
Multiple daily doses ranging from 0.1to 1.0 mg.CMAX and area under the concentration-time curve (AUC) at steady state increased in proportion to dose.Steady state was achieved after 6 to 10 days of once-daily administration with approximately 2-fold accumulation.for a 0.5 mg oral
Dose, CMAX at steady state was 4.2ng/ML.and trough plasma concentration (C1rough) was 0.3 ng/ML.for a 1mg oral dose. CMAX at steady state was 4.2ng/ML and trough plasma concentration( CMAX ) was 0.3 ng/ml for a 1 mg oral dose CMAX was 8.2ng/ml and C1rough was 0.5ng.ml.Effects of Food on Oral Absorption: Oral administration of 0.5 mg of entecavir with a
Standard high-fat meal (945 kcal,54.6 g fat)or a light meal(379 kcal.8.2 g fat) resulted in a delay
In absorption (1.0-1.5 hours fed versus 0.75 hours fasted).a decrease in AUC of 18-20%[see DOSAGE ANDADMINISTRATION].