title: Extraction and Analysis of Methadone in Exhaled Breath Condensate Using a Validated LC-UV Method.
abstract: OBJECTIVE
  A combined microextraction and separation method is presented for the determination of methadone in exhaled breath condensate (EBC) which is a promising non-invasive biological component for monitoring drug concentrations.
  
  
  METHODS
  In this work, dispersive liquid-liquid microextraction (DLLME) and ultrasonic liquid-liquid microextraction (ULLME) procedure coupled with a validated liquid chromatography method were used for analysis of methadone in EBC collected using an in-house cold trap setup. The method has been validated according to the FDA guidelines using EBC-spiked samples and tested on a number of EBC samples collected from patients.
  
  
  RESULTS
  The best DLLME conditions involved the use of a disperser solvent of methanol (1 mL), extraction solvent of chloroform (200 mL), EBC sample pH of 10.0 and centrifugation at 6000 rpm for 5 minutes. The conditions for ULLME were 150 mL of chloroform and the samples were sonicated for 4 minutes. The method was validated over the concentration range of 0.5-10 mg/L-1 in EBC. Inter- and intra-day precision and accuracy were less than 5 % where the acceptable levels are less than 20%. Furthermore, the validated method was successfully applied for the determination of methadone in patients' EBC samples.
  
  
  CONCLUSIONS
  The outcomes indicate that the developed LC-UV combined with DLLME and/or ULLME extraction methods can be employed for the extraction and separation of methadone in EBC samples.
authors.affiliation: Tuberculosis and Lung Disease Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Khoubnasabjafari
authors.forename: Khalil
authors.initials: K
authors.lastname: Ansarin
authors.forename: Vahid
authors.initials: V
authors.lastname: Jouyban-Gharamaleki
authors.forename: Vahid
authors.initials: V
authors.lastname: Panahi-Azar
authors.forename: Ali
authors.initials: A
authors.lastname: Shayanfar
authors.forename: Laya
authors.initials: L
authors.lastname: Mohammadzadeh
authors.forename: Abolghasem
authors.initials: A
authors.lastname: Jouyban
mesh_terms: D000328:Adult; D001944:Breath Tests / Q000379:methods*; D002853:Chromatography, Liquid; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D059627:Liquid Phase Microextraction; D008297:Male; D008691:Methadone / Q000032:analysis* / Q000302:isolation & purification*; D008875:Middle Aged; D015394:Molecular Structure; D014465:Ultrasonics; D014466:Ultraviolet Rays
chemical_list: D008691:Methadone