Single and repeated dose kinetics of the hypnotic agent loprazolam in healthy volunteers.
The pharmacokinetics of loprazolam have been studied in eight healthy male volunteers after single and repeated 2 mg oral doses taken at night, for eight nights. The absorption and disposition of unchanged drug (HPLC-GC assay) and receptor active benzodiazepine-type materials (radioreceptor assay) were examined after the first and eighth dose. Maximum levels of approximately 10 ng ml-1 (range 3.6 to 15.5 ng ml-1) were reached within about 2.5 h after dosing. The post-peak levels declined in a single exponential fashion with an overall mean +/- SD half-life of 7.06 +/- 1.98 h and total areas under the curve ranging from 35.9 to 189.0 ng ml-1 h. There were no statistical differences between the values for the first and eighth doses. There was no evidence to suggest that significant accumulation of parent drug or receptor active benzodiazepine-type materials had occurred, and it is concluded that the kinetics of loprazolam would allow repeated daily doses of 2 mg.
D000328:Adult; D014151:Anti-Anxiety Agents; D001569:Benzodiazepines; D001570:Benzodiazepinones / Q000008:administration & dosage / Q000378:metabolism*; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D006207:Half-Life; D006801:Humans; D007700:Kinetics; D008297:Male; D011869:Radioligand Assay; D011956:Receptors, Cell Surface / Q000378:metabolism; D011963:Receptors, GABA-A; D013997:Time Factors
D014151:Anti-Anxiety Agents; D001570:Benzodiazepinones; D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; D001569:Benzodiazepines; C020168:triazulenone