Usefulness of sweat testing for the detection of methylphenidate after fast- and extended-release drug administration: a pilot study.
The pharmacokinetics of methylphenidate (MPH), a prescription amphetamine derivative used in the treatment of attention-deficit hyperactivity disorder, has been amply described in conventional biological matrices. Recently, the excretion of MPH and its principal metabolite, ritalinic acid (RA) in oral fluid and plasma after a single drug administration has been described. The aim of this study was to describe the excretion of MPH and RA in sweat after the administration of a single dose of either fast-release or extended-release MPH. Three male subjects received 2 simultaneous oral doses of 10 mg fast-release MPH, and 1 male subject received one dose of 20 mg extended-release MPH. Sweat patches were applied to the back of each participant and removed at timed intervals. MPH and RA were determined in patches using a previously validated liquid chromatography-electrospray ionization mass spectrometric method. MPH was detected in sweat after the administration of fast- and extended-release formulations. For the fast-release formulation, MPH appeared in the sweat patches 2 hours after administration with a maximum of 15.9 nanogram per patch, reached after 24 hours. Mean total MPH excreted was 0.02 mg (about 0.08% of the administered dose). For the extended-release formulation, MPH appeared in the sweat 5 hours after administration and reached a maximum of 34.3 nanogram per patch after 24 hours. Mean total MPH excreted was 0.04 mg (about 0.18% of the administered dose). RA was not detected in either of the sweat patches probably because of its acidic properties. Measuring MPH in sweat patches can be a viable alternative to urine testing for noninvasive monitoring of use and misuse of the drug.
Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanitá, Rome, Italy.
Emilia
E
Marchei
Magí
M
Farré
Ricardo
R
Pardo
Oscar
O
Garcia-Algar
Manuela
M
Pellegrini
Roberta
R
Pacifici
Simona
S
Pichini
D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000032:analysis* / Q000493:pharmacokinetics; D003692:Delayed-Action Preparations; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000032:analysis* / Q000493:pharmacokinetics; D010865:Pilot Projects; D015813:Substance Abuse Detection / Q000379:methods*; D013542:Sweat / Q000737:chemistry*; D055815:Young Adult
D000697:Central Nervous System Stimulants; D003692:Delayed-Action Preparations; D008774:Methylphenidate; C009189:ritalinic acid