Temazepam pharmacokinetics and molecular data

Pharmacokinetics
In a single and multiple dose absorption, distribution, metabolism, and excretion (ADME) study, using 3H labeled drug, Temazepam was well absorbed and found to have minimal (8%) first pass metabolism. There were no active metabolites formed and the only significant metabolite present in blood was the O-conjugate. The unchanged drug was 96% bound to plasma proteins. The blood level decline of the parent drug was biphasic with the short half-life ranging from 0.4-0.6 hours and the terminal half-life from 3.5-18.4 hours (mean 8.8 hours), depending on the study population and method of determination. Metabolites were formed with a half-life of 10 hours and excreted with a half-life of approximately 2 hours. Thus, formation of the major metabolite is the rate limiting step in the biodisposition of Temazepam. There is no accumulation of metabolites. A dose-proportional relationship has been established for the area under the plasma concentration/time curve over the 15-30 mg dose range. Temazepam was completely metabolized through conjugation prior to excretion; 80%-90% of the dose appeared in the urine. The major metabolite was the O-conjugate of Temazepam (90%); the O-conjugate of N-desmethyl Temazepam was a minor metabolite (7%). Return to top