Determination of flurazepam and its hydroxyethyl and dealkyl metabolites by some packed and capillary ECD‐GLC methods: Application to pharmacokinetic studies

Abstract

SummaryA sensitivegas-liquid chromatographicassay was developedfor plasma determinations of flurazepam (F), N1 -desalkylflurazepam (DF), and Nl-hydroxyethylflurazepam (HF). The internal standards used were delorazepam for F and DF and 1 a-hydroxymidazolam for HF. Following extraction and derivatization for HF, these compounds were analyzed by ECD-GLC, using either glass packed columns (poly A 103 for F and DF, OV 225 for HF) or CP-SiI 5 capillary columns for DF and HF. The detection limit of the packed-column assay was approximately 3 ng/ml for HFand DF, and 5 ng/ml for F; with capillary GLC analysis, the sensitivity limit for HF and DF was lower than 1 ng/mbThese methods were used for pharmacokinetic investigations after i.v. administration of these compounds.