Blood and urine specimen collection schedules. Participants in “single-dose only” groups were randomized to one of two schedules (A or B) of specimen collection over a period 70 days. Participants in the “weekly dose” groups were similarly randomized to one of two schedules (C or D); however, the analysis of single-dose pharmacokinetics only included those specimens collected up to and including day 7, preceding administration of the 2nd vitamin D dose.
Roth et al. Nutrition Journal 2012 11:114 doi:10.1186/1475-2891-11-114