Methods
Prospective study (1/2021–12/2021) in 32 enterally fed preterm infants (28 0/7–32 0/7 weeks gestation). Patients were randomized to receive enterally a single dose of 2.7 mg/kg D9-choline-equivalent as D9-choline chloride, D9-phosphoryl-choline, D9-glycerophosphorylcholine (D9-GPC) or D9-1-palmitoyl-2-oleoyl-PC(D9-POPC), followed by blood sampling at 1 + 24 h or 12 + 60 h after administration. Plasma concentrations were analyzed by tandem mass spectrometry. Results are expressed as median (25th/75th percentile).