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3PC-024 Implementation of a strategy to overcome the potential toxic effects of propylene glycol in neonates
  1. R Barbosa1,
  2. S Fraga1,
  3. P Soares1,
  4. F Fernandez-Llimos2,
  5. F Baltazar3,
  6. CM Barbosa4
  1. 1Centro Hospitalar Universitário São João, Serviços Farmacêuticos, Porto, Portugal
  2. 2Faculdade de Farmácia da Universidade do Porto, Laboratório de Farmacologia do Departamento de Ciências do Medicamento, Porto, Portugal
  3. 3Escola de Medicina da Universidade do Minho, Instituto de Investigação em Ciências da Vida e Saúde, Braga, Portugal
  4. 4Faculdade de Farmácia da Universidade do Porto, Laboratório de Tecnologia do Medicamento do Departamento de Ciências do Medicamento, Porto, Portugal


Background and Importance Available evidence on the safety of excipients in compounded formulations is somewhat limited. Contributing to a higher level of evidence seems relevant, particularly regarding compounded formulations for use in neonatology. In a previous study on the presence of problematic excipients in oral compounded formulations, intake above the recommended limits was reported, mainly of propylene glycol (PG), in neonates under 28 days of age.1

Aim and Objectives To implement a strategy aimed at overcoming the potential toxic effects due to the exposure of neonates to PG present in oral compounded formulations.

Material and Methods Evaluation of the composition of compounded formulations regularly used in a neonatal intensive care unit to identify the source of PG.

Assessment of alternatives, considering their preservative power, by calculating the concentration of parabens, and analysing the solubility of the chemical forms of parabens used.

Results The source of the PG in the formulations was the preservative solution used – Paraben Concentrate (B.8).2 As an alternative to B.8, we evaluated three paraben solutions described in the literature, taking into account the respective parabens concentrations, the nature of the solvent and the reported stability. Since the parabens concentrations were at least 100 times lower than that of the B.8, we decided not to adopt any of the solutions described, since this could compromise the preservation of the formulations and, at the time, we were unable to test it.

In an alternative approach, the preparation of a 10% paraben concentrate in water, instead of PG, was implemented. To promote the dissolution of methylparaben and propylparaben (7:3) in water, the respective sodium salts were used. The solution was prepared after calculating the respective equivalent concentrations and ensuring compliance with the solubility data.3

Conclusion and Relevance A water-based, PG-free paraben solution has been developed, suitable for preserving oral compounded formulations. This strategy makes it possible to overcome the potential toxic effects of PG in neonates, thereby increasing the safety of the formulations.

References and/or Acknowledgements 1. Barbosa R, et al. Eur. J. Hosp. Pharm. 2023;30:A178.

2. Barbosa CM (Coord.), Formulário Galénico Português. ANF-CETMED, 2005.

3. Martindale The Complete Drug Reference 40th Edition. Pharmaceutical Press, Vol. A, pag.1826, 2020.

Conflict of Interest No conflict of interest.

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