title: The stability of thiamine in total parenteral nutrition mixtures stored in EVA and multi-layered bags.
abstract: The compounding of complete total parenteral nutrition (TPN) mixtures into big bags with extended shelf-lives has been made more possible by the introduction of reduced gas permeable bags, using multi-layered plastic laminates. Since this produces a highly reduced chemical environment, the stability of thiamine; which degrades by reduction, may be compromised. It was the purpose of this study to investigate the degradation of thiamine at two different concentrations in TPN mixtures containing different commercial amino acid sources stored for extended periods in EVA or multi-layered bags. Results indicated that thiamine was unstable in mixtures containing Freamine III 8.5%, a metabisulphite-containing amino acid infusion, but was relatively stable in mixtures containing Vamin 14, Aminoplex 12 or Eloamin 15% as the amino acid source. Degradation of thiamine in Freamine III 8.5%-containing mixtures stored in multi-layered bags was more rapid than in EVA bags. Degradation rate was not greatly influenced by thiamine concentration. Results indicate that thiamine is stable in complete TPN mixtures for periods of at least 28 days in multi-layered bags, provided metabisulphite containing amino acid infusions are avoided. The shelf-life of complete mixtures containing Freamine III should be restricted to ensure patient receive minimum acceptable daily thiamine requirements.
authors.affiliation: Medicines Research Unit, University of Derby, Mickleover, Derby, DE3 5GX, UK.
authors.forename: M C
authors.initials: MC
authors.lastname: Kearney
authors.forename: M C
authors.initials: MC
authors.lastname: Allwood
authors.forename: T
authors.initials: T
authors.lastname: Neale
authors.forename: G
authors.initials: G
authors.lastname: Hardy