Capillary microsampling in clinical studies: opportunities and challenges in two case studies.

Capillary microsampling of 15 μl whole blood from fingersticks or heelsticks was used to collect pharmacokinetic (PK) samples from pediatric subjects in two projects. In a mebendazole multisite study in Ethiopia and Rwanda in subjects between 1 and 16 years old, complete PK profiles (7 timepoints) could be obtained, although some of the fingerstick samples were contaminated by the dosing formulation. In a multisite study with a respiratory syncytial virus drug in children between 1 and 24 months old, sparse PK sampling was done (2 samples). All samples were successfully analyzed even though some capillaries were not properly filled. CMS shows potential for PK sampling in pediatrics but may need further optimization.