In rat the kinetics of flunitrazepam (FNZ) was evaluated by a radiorecepfor assay (RRA) after i.v. administration of 1 mg/kg and after oral administration of 1 and 3 mg/kg. The i.v. kinetics is biexponential and the g.i. absorption is very rapid (with a plasma peak at 0.25 hour) with a good bioavailability (69%); the apparent distribution volume is high, 4.8 L/kg; the half-life is equal to 3.5 hours; the elimination constant is equal to 0.8 h−1; the urinary excretion of FNZ-equivalent is negligible; the plasma total clearance is equal to 3.9 (L/kg)h−1. The concentrations of FNZ-equivalents after oral administration of 1 mg/kg show a peak at the 2-nd hour with a very high concentration in the following organs (in decreasing order): brain, kidneys, heart, liver; after 8 hours no FNZ-equivalents are present in these organs except in the brain, which shows detectable concentrations at the 32-nd hour. The peak concentrations of FNZ-equivalent in brain, kidneys and heart are higher than the corresponding peak concentration in plasma.
Becherucci, C., Palmi, M., Segre, G. (1985). Pharmacokinetics of flunitrazepam in rats studied by a radioreceptor assay. PHARMACOLOGICAL RESEARCH COMMUNICATIONS, 17(8), 733-747 [10.1016/0031-6989(85)90090-6].
Pharmacokinetics of flunitrazepam in rats studied by a radioreceptor assay
Palmi, M.;
1985-01-01
Abstract
In rat the kinetics of flunitrazepam (FNZ) was evaluated by a radiorecepfor assay (RRA) after i.v. administration of 1 mg/kg and after oral administration of 1 and 3 mg/kg. The i.v. kinetics is biexponential and the g.i. absorption is very rapid (with a plasma peak at 0.25 hour) with a good bioavailability (69%); the apparent distribution volume is high, 4.8 L/kg; the half-life is equal to 3.5 hours; the elimination constant is equal to 0.8 h−1; the urinary excretion of FNZ-equivalent is negligible; the plasma total clearance is equal to 3.9 (L/kg)h−1. The concentrations of FNZ-equivalents after oral administration of 1 mg/kg show a peak at the 2-nd hour with a very high concentration in the following organs (in decreasing order): brain, kidneys, heart, liver; after 8 hours no FNZ-equivalents are present in these organs except in the brain, which shows detectable concentrations at the 32-nd hour. The peak concentrations of FNZ-equivalent in brain, kidneys and heart are higher than the corresponding peak concentration in plasma.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/11365/21879
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