A novel test using dried blood spots for the chromatographic assay of methadone.
A novel test has been developed for the analysis of methadone in dried blood spot specimens from patients undergoing methadone maintenance treatment. An isocratic reversed-phase high-performance liquid chromatography method with coulometric detection has been optimized for the determination of methadone. The clean-up of dried blood spots was performed by means of an original microextraction by packed sorbent procedure after microwave-assisted extraction of the drug with a suitable solvent. Extraction yields were satisfactory, always being higher than 90.0 %. The calibration curve was linear over the 4-500 ng mL(-1) concentration range. The method had satisfactory sensitivity (limit of quantitation of 4 ng mL(-1)), precision (relative standard deviation less than 5.8 %), selectivity and accuracy (recovery greater than 87.0 %). It was successfully applied to dried blood spot samples collected from heroin-addicted patients undergoing methadone maintenance therapy at dosages between 40 and 240 mg day(-1). The statistical analysis (Bland-Altman plot) showed that the results were in good agreement with those found from the analysis of plasma samples obtained from the same patients. Thus, the method has proved to be suitable for the monitoring of methadone by means of dried blood spots.
Department of Pharmaceutical Sciences, University of Bologna, Via Belmeloro 6, 40126, Bologna, Italy.
Maria Addolorata
MA
Saracino
Chiara
C
Marcheselli
Lorenzo
L
Somaini
Maria Chiara
MC
Pieri
Gilberto
G
Gerra
Anna
A
Ferranti
Maria Augusta
MA
Raggi
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D055664:Electrochemical Techniques; D006801:Humans; D008691:Methadone / Q000097:blood*
D008691:Methadone