title: An observational study of blood concentrations and kinetics of methyl- and propyl-parabens in neonates.
abstract: OBJECTIVE
  Systemic exposure to parabens in the neonatal population, in particular propyl-parabens (PPB), remains a concern. Blood concentrations and kinetics of methyl-parabens (MPB) and PPB were therefore determined in neonates receiving medicines containing these excipients.
  
  
  METHODS
  A multi-centre, non-interventional, observational study of excipient-kinetics in neonates. 'Dried Blood Spot' samples were collected opportunistically at the same time as routine samples and the observations modelled using a non-linear mixed effects approach.
  
  
  RESULTS
  A total of 841 blood MPB and PPB concentration data were available for evaluation from 181 pre- and term-neonates. Quantifiable blood concentrations of MPB and PPB were observed in 99% and 49% of patients, and 55% and 25% of all concentrations were above limit of detection (10 ng/ml), respectively. Only MPB data was amenable to modelling. Oral bioavailability was influenced by type of formulation and disposition was best described by a two compartment model with clearance (CL) influenced by post natal age (PNA); CL PNA<21 days 0.57 versus CL PNA>21 days 0.88 L/h.
  
  
  CONCLUSIONS
  Daily repeated administration of parabens containing medicines can result in prolonged systemic exposure to the parent compound in neonates. Animal toxicology studies of PPB that specifically address the neonatal period are required before a permitted daily exposure for this age group can be established.
authors.affiliation: Department of Pharmacy, University Hospitals of Leicester, Leicester, UK, hussain.mulla@uhl-tr.nhs.uk.
authors.forename: H
authors.initials: H
authors.lastname: Mulla
authors.forename: S
authors.initials: S
authors.lastname: Yakkundi
authors.forename: J
authors.initials: J
authors.lastname: McElnay
authors.forename: I
authors.initials: I
authors.lastname: Lutsar
authors.forename: T
authors.initials: T
authors.lastname: Metsvaht
authors.forename: H
authors.initials: H
authors.lastname: Varendi
authors.forename: G
authors.initials: G
authors.lastname: Nellis
authors.forename: A
authors.initials: A
authors.lastname: Nunn
authors.forename: J
authors.initials: J
authors.lastname: Duncan
authors.forename: H
authors.initials: H
authors.lastname: Pandya
authors.forename: M
authors.initials: M
authors.lastname: Turner
mesh_terms: D000284:Administration, Oral; D001682:Biological Availability; D002626:Chemistry, Pharmaceutical; D003198:Computer Simulation; D059788:Dried Blood Spot Testing; D004334:Drug Administration Schedule; D004739:England; D004957:Estonia; D005079:Excipients / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood; D008657:Metabolic Clearance Rate; D008954:Models, Biological; D017711:Nonlinear Dynamics; D010226:Parabens / Q000009:adverse effects / Q000493:pharmacokinetics*; D018570:Risk Assessment; D047929:Term Birth / Q000097:blood
chemical_list: D005079:Excipients; D010226:Parabens; C015358:methylparaben; C006068:propylparaben