Methadone concentrations in exhaled breath condensate, serum and urine of patients under maintenance treatment

Drug abuse is a serious problem causing health, economical and psycho-social negative outcomes. Methadone is commonly used drug for management of drug addiction. Exhaled breath condensate (EBC) is a promising non-invasive biological sample which attracted more attention in recent years. This work aimed to extend the applicability of a developed preconcentration – liquid chromatographic method for analysis of methadone in serum and urine samples. Drug concentrations in EBC, serum and urine are also investigated for dose-concentration and their inter-correlations. Biological samples were collected from 53 patients receiving methadone and the concentrations were determined using a validated analytical method after a pre-concentration step. Methadone measured in all samples and there are correlations between administered dose of methadone and its serum and urine concentrations. A weak correlation is observed between dose and EBC concentration. Wider variations in EBC concentrations of methadone could be justified concerning a number of affecting parameters such as relative humidity of the collection area and further investigations are required for standardization of EBC as a non-invasive biological sample to be used in clinical practice.