Pharmacokinetics of methylphenidate in oral fluid and sweat of a pediatric subject

Correlation Between Methylphenidate and Ritalinic Acid Concentrations in Oral Fluid and Plasma

“…Although it does not reflect the "real-life" situation of chronic dosing in a patient population, we consider the data of this first study of MPH kinetics in oral fluid as promising. Furthermore, these results are supported by the data obtained when developing the analytical assay for oral fluid drug detection (18 ), where the compliance of individuals in treatment with the drug could be verified by oral fluid testing and by the data presented for a pediatric case (20 ). In this latter case, oral fluid measurement of MHP and RA was successfully applied to verify the 4-week compliance of a 12-year-old boy treated with the extended-release drug formulation.…”

“…Conversely, in the case of RA, OF/P ratios under the unity can be easily explained by the acidic nature of this compound, which prevents its excretion in oral fluid. For all these reasons, MPH is the target compound which can be and has to be measured in oral fluid, as has been already shown in a pediatric case (20 ). Furthermore, measurement of MPH in oral fluid appears to be a suitable alternative to plasma analysis.…”

Fenproporex and Amphetamine Pharmacokinetics in Oral Fluid After Controlled Oral Administration of Fenproporex

“…Despite some studies with controlled administration of AMP, methamphetamine (MET), methylphenidate, 3,4-methylenedioxymethamphetamine, and 3,4-methylenedioxyphenyl-2-butanamine to humans, [30][31][32][33]35 and subsequent measure of oral fluid drug concentrations, none has described the pharmacokinetic profile of FEN in oral fluid. According to our results, FEN and AMP could be detected in oral fluid of all 6 volunteers after the administration of a single 25-mg dose of FEN hydrochloride (Fig.…”

“…29 Due to the relative acidity of oral fluid (pH 6.2-7.4) compared with plasma (pH 7.35-7.45), weak bases with low plasmatic protein binding such as AMP (pK a 10.1) and FEN (pK a 7.23) are found in higher concentrations in oral fluid than in plasma, increasing the detectability of this substances. 1,2,[31][32][33][34][35] In general, the ratio between oral fluid and plasma concentrations for AMP is greater than unity, about 2-3 times, 2,14,30,33 showing an advantage in the use of saliva as a biological matrix for the detection of AMP-type stimulants.…”

“…The concentration of AMP-type stimulants in oral fluid usually correlates well with plasma concentration, showing similar pharmacokinetic profiles. 33,35 To the best of the authors' knowledge, the pharmacokinetic profile of FEN and its main metabolite, AMP, in oral fluid has not been described so far. The detection of FEN and AMP in biological fluids such as blood, urine, and gastric contents has already been reported, 1 and the behavior of these analytes in urine has been extensively described by Cody and coworkers.…”