Determination of the anxiolytic agent 8-chloro-6-(2-chlorophenyl)-4H-imidazo-[1,5-alpha] [1,4]-benzodiazepine-3-carboxamide in whole blood, plasma or urine by high-performance liquid chromatography.
A rapid, sensitive and specific high-performance liquid chromatographic (HPLC) assay was developed for the determination of 8-chloro-6-(2-chlorophenyl)-4H-imidazo-[1,5-alpha]-[1,4]-benzodiazepine-3-carboxamide [I] and its 4-hydroxy metabolite, 8-chloro-6-(2-chlorophenyl)-4-hydroxy-4H-imidazo-[1,5-alpha] [1,4]-benzodiazepine-3-carboxamide [II] in whole blood, plasma or urine. The assay for both compounds involves extraction into diethyl ether-methylene chloride (70:30) from blood, plasma, or urine buffered to pH 9.0. The overall recoveries of [I] and [II] are 92.0 +/- 5.4% (S.D.) and 90.3 +/- 4.9% (S.D.), respectively. The sensitivity limit of detection is 50 ng/ml of blood, plasma, or urine using a UV detector at 254 nm. The HPLC assay was used to monitor the blood concentration-time fall-off profiles, and urinary excretion profiles in the dog following single 1 mg/kg intravenous and 5 mg/kg oral doses, and following multiple oral doses of 100 mg/kg/day of compound [I].
Chapter III Whole Blood Sample Clean-Up for Chromatographic Analysis
Publisher Summary This chapter discusses the general strategies for blood sample handling for various drugs and presents an example of measurement of cyclosporine. It also describes the metabolites of cyclosporine. Cyclosporine proved to be a good example because blood level measurement is of high clinical impact and the whole spectrum of sample preparation strategies has been applied for cyclosporine determination. Developing an adequate sample preparation method several factors must be considered: (1) the chemical properties of the constituents in question, and (2) the biological matrix. The substance of interest must be extracted from its biological matrix prior to chromatographic analysis. Proteins and other macromolecules may interfere with detection and columns may get plugged or rapidly inactivated. A good extraction procedure should be reproducible with little loss of the material of analytical interest. It should be rapid and allow several samples to be analyzed in a short period of time and it should be inexpensive. Because of better handling the use of plasma or serum as biological matrix is preferable over blood. Plasma and serum is produced by removing the cellular components of blood by centrifugation or natural clotting.
A study of diazepam (Valium) for induction of anaesthesia.
DIAZEPAM (Valium| is one of the most interesting drugs to have been introduced for a long time. It has been used widely for the treatment of anxiety, muscle spasm, and as a tranquillizing-sedative agent. Its anticonvulsant properties have been found valuable in status epilepticus, and anaesthetists have found the sedation it produces useful in the course of regional anaesthesia. Some antiarrhythmic properties also have been ascribed to the agent, 1 and these, together with its hypnotic and analgesic effects, had led to increasing use of the drug in cardioversion. In 1966 McClish ~ reported on the use of diazepam as an induction agent in place of intravenous barbiturates, and shortly after our study had been started, Fox, Wynands, and Bhambhami ~ compared diazepam with thiopental for induction. Quite recently another paper on the subject has been published by Baker. 4 The present study was undertaken in an attempt to elucidate the usefulness of the drug for that purpose in standard operative procedures on a homogeneous group of patients, using a standard anaesthetic technique for maintenance of anaesthesia.