Improving adherence and compliance to inhaled therapy for asthma and COPD may improve treatment outcomes for patients, but techniques that can monitor both of these are lacking. The measurement of drug residues in hair samples may provide a prospective and retrospective record of adherence over time. This study is the first to evaluate the feasibility of analysing hair samples from asthma and COPD patients who are using inhaled therapy. Head hair samples (1 cm length bundle, weighing approx. 10 mg taken for analysis) were collected from patients (n=200) taking one of seven, standard of care, orally inhaled medicines, at a single visit to a clinical unit. Analytes from processed hair samples were analysed using solid phase extraction followed by liquid chromatography–tandem mass spectrometry. The inhaled drugs being tested were detected in 72% of the hair samples analysed (figure), and varied in the ease of detection. In some samples, drugs were detectable but at levels below the limit of quantification. Drug concentrations may be influenced by dose administered, frequency, hair colour, and the use of hair treatments. This is the first demonstration that inhaled medication can be measured in hair samples from patients taking chronic inhaled medication. Improvements to sensitivity and methodology, to assess drug concentration along the hair length, may allow routine monitoring of adherence and compliance. Funding: GSK (Study 201934)
