Plasma versus bone marrow flurazepam concentration in rabbits

Methods for the quantitation of flurazepam in plasma and bone marrow were developed for the purpose of determining the relationship between flurazepam concentrations in both tissues.Albino New Zealand rabbits, given flurazepam in doses of 5, 10, or 20 mg/kg, were sacrificed either one or three hours after drug administration. Flurazepam concentrations in plasma and bone marrow were determined utilizing a gas-liquid chromatograph equipped with an electron capture detector. The average plasma/bone marrow flurazepam ratios were 0.033 ± 0.012 and 0.024 ± 0.012 for rabbits sacrificed one hour and three hours after dosing, respectively. This study showed that a range of plasma flurazepam levels can be estimated from known bone marrow concentrations. The overall mean plasma/bone marrow ratio for all rabbits used in this study was 0.029 ± 0.012 with a range of 0.010 to 0.055.