Methylphenidate for Treating ADHD: A Naturalistic Clinical Study of Methylphenidate Blood Concentrations in Children and Adults With Optimized Dosage.

Background: Methylphenidate (MPH), along with behavioral and psychosocial interventions, is the first-line medication to treat attention-deficit hyperactivity disorder (ADHD) in Sweden. The dose of MPH for good symptom control differs between patients. However, studies of MPH concentration measurement in ADHD treatment are limited.

Determination of methylphenidate and ritalinic acid in blood, plasma and oral fluid from adolescents and adults using protein precipitation and liquid chromatography tandem mass spectrometry--a method applied on clinical and forensic investigations.

A validated, accurate and sensitive LC-MS/MS method for determination of racemic methylphenidate and its metabolite ritalinic acid has been developed. The analytes were quantified by tandem mass spectrometry operating in positive electrospray ionization mode with multiple reaction monitoring. Blood, plasma and oral fluid samples of 100μl were prepared by simple precipitation with 200μl of an aqueous solution of zinc sulphate in methanol.