Comparison of Dried Blood Spots Versus Conventional Plasma Collection for the Characterization of Efavirenz Pharmacokinetics in a Large-Scale Global Clinical Trial—The ENCORE1 Study

Background: The aim of this study was to determine the utility of dried blood spots (DBS) compared with conventional plasma collection methods for characterization of efavirenz pharmacokinetics, in the setting of a large-scale, global clinical trial (ENCORE1). Methods: Six hundred thirty patients were recruited from 38 sites and had single matched whole blood DBS and plasma samples (mid-dose interval) taken at weeks 4 and 12 of treatment. In addition, a subgroup of patients underwent intensive DBS and plasma sampling (0–24 hours) to provide full-profile data for pharmacokinetic parameters. Efavirenz concentrations were determined by validated high-performance liquid chromatography–mass spectrometry methods. A DBS-predicted plasma concentration was derived and linear regression and Bland–Altman plots were used to compare DBS-predicted plasma concentrations with that of measured plasma concentrations. Results: Efavirenz DBS and plasma concentrations were significantly correlated (R2 = 0.904, P
Source: Therapeutic Drug Monitoring - Category: Drugs & Pharmacology Tags: Short Communication Source Type: research