title: Rapid determination of methadone in plasma, cerebrospinal fluid, and urine by gas chromatography and its application to routine drug monitoring.
abstract: Determination of methadone (MET) in biological fluids can serve to adjust dosages in patients suffering from cancer pain or participating in methadone maintenance programs. We developed a gas chromatographic assay using nitrogen-phosphorus detection. The method involves a single-step extraction from alkalized plasma, cerebrospinal fluid, or urine into n-hexane/isoamyl-alcohol (99/1, v/v). Dextropropoxyphene was used as internal standard. Separation was achieved with a silica SE-52-CB column (13 m x 0.25-mm I.D.). The method was validated for the determination of MET in plasma, urine, and cerebrospinal fluid with a quantification limit of 0.5 ng/mL. The coefficients of variation for within-day and between-day precision were within 10.2 and 14.1%, respectively. Approximately 100 samples can be analyzed by one person in the course of a working day, making the method applicable to routine drug monitoring. The method was demonstrated to be sensitive and accurate for pharmacokinetic studies in plasma, urine, or cerebrospinal fluid.
authors: Department of Experimental and Clinical Pharmacology and Toxicology, University of Erlangen-Nuernberg, Germany.
authors: N
authors: N
authors: Schmidt
authors: R
authors: R
authors: Sittl
authors: K
authors: K
authors: Brune
authors: G
authors: G
authors: Geisslinger
mesh_terms: D002849:Chromatography, Gas; D002908:Chronic Disease; D016903:Drug Monitoring; D006556:Heroin Dependence / Q000097:blood / Q000134:cerebrospinal fluid / Q000652:urine; D006801:Humans; D008691:Methadone / Q000032:analysis* / Q000097:blood / Q000134:cerebrospinal fluid / Q000652:urine; D010146:Pain / Q000097:blood / Q000134:cerebrospinal fluid / Q000652:urine; D011786:Quality Control; D013237:Stereoisomerism
chemical_list: D008691:Methadone