Introduction Parabens are widely used as antimicrobial preservatives in medicines given to neonates. Some concerns have been raised about the potential of paraben toxicity. To date there have been no studies of the circulating concentrations of methyl paraben (MPB) in babies. This study aimed to describe the relationship between dose of MPB administered and circulating concentrations using a population pharmacokinetic model.
Methods Neonates in 4 UK and 1 Estonian neonatal units who were prescribed paraben-containing medications were recruited with parental consent. Parabens were assayed in timed, dried blood spots using LCMSMS. The limit of quantification was 20ng/mL.
Results 180 babies provided 841 samples of which 382 (45%) were below the limit of quantification. The mean (range) of observed blood MPB concentrations was 28.4 (10–874) ng/ml. The final kinetic model for MPB included first order absorption and two compartment disposition. Clearance was related to postnatal age (PNA). The model parameters are shown in the Table.
Discussion Routine use of MPB as an excipient in medicinal formulations does not lead to markedly high circulating blood concentrations of MPB in neonates. We cannot exclude accumulation from these data. These findings will contribute to safety assessments and regulatory advice and may indicate that current levels of MPB in formulations are acceptable for young children.