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Published on: March 1, 2018
Usefulness of sweat testing for the detection of methylphenidate after fast- and extended-release drug
Emilia Marchei1, Magí Farré, Ricardo Pardo
1Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanitá, Rome, Italy.
Abstract:
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.
Insights
Methylphenidate (MPH) can be detected in sweat patches following both fast-release and extended-release formulations. Sweat patch analysis offers a noninvasive method for monitoring MPH use and misuse.
Area of Science:
- Pharmacology
- Analytical Chemistry
- Forensic Toxicology
Background:
- Methylphenidate (MPH) is a widely prescribed medication for attention-deficit hyperactivity disorder (ADHD).
- Previous studies have detailed MPH and ritalinic acid (RA) excretion in oral fluid and plasma.
- The pharmacokinetics of MPH in sweat remain less understood.
Purpose of the Study:
- To investigate the excretion profile of methylphenidate (MPH) and its metabolite ritalinic acid (RA) in sweat.
- To compare MPH excretion following administration of fast-release and extended-release formulations.
- To evaluate the potential of sweat patch analysis for noninvasive drug monitoring.
Main Methods:
- Administration of single oral doses of fast-release (10 mg) and extended-release (20 mg) MPH to male subjects.
- Collection of sweat samples using adhesive patches applied to the back at timed intervals.
- Quantification of MPH and RA in sweat patches using liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS).
Main Results:
- Methylphenidate (MPH) was detected in sweat patches after administration of both fast-release and extended-release MPH.
- For fast-release MPH, MPH appeared in sweat within 2 hours, with a mean total excretion of 0.02 mg (0.08% of dose).
- For extended-release MPH, MPH appeared in sweat within 5 hours, with a mean total excretion of 0.04 mg (0.18% of dose).
- Ritalinic acid (RA) was not detected in sweat samples.
Conclusions:
- Sweat patch analysis can detect methylphenidate (MPH) following oral administration of both fast- and extended-release formulations.
- The total amount of MPH excreted in sweat is low, but detectable.
- Measuring MPH in sweat patches presents a viable, noninvasive alternative to urine testing for monitoring drug use and misuse.
