title: Interactions Between Peptide and Preservatives: Effects on Peptide Self-Interactions and Antimicrobial Efficiency In Aqueous Multi-Dose Formulations.
abstract: OBJECTIVE
  Antimicrobial preservatives are known to interact with proteins and potentially affect their stability in aqueous solutions. In this systematic study, the interactions of a model peptide with three commonly used preservatives, benzyl alcohol, phenol and m-cresol, were evaluated.
  
  
  METHODS
  The impact on peptide oligomerization was studied using GC-MALS, SEC-MALS and DLS, antimicrobial efficiency of different formulations were studied using the Ph. Eur. antimicrobial efficacy test, and the molecular adsorption of preservative molecules on reversible peptide oligomers was monitored using NMR.
  
  
  RESULTS
  The hydrodynamic radius and molar mass of the peptide oligomers was shown to clearly increase in the presence of m-cresol but less significantly with phenol and benzyl alcohol. The increase in size was most likely caused by peptide self-interactions becoming more attractive, leading to reversible oligomerization. On the other hand, increasing the concentration of peptide in multi-dose formulations led to reduced molecular mobility and decreased antimicrobial efficacy of all preservatives.
  
  
  CONCLUSIONS
  Peptide-preservative interactions not only affect peptide self-interactions, but also antimicrobial efficiency of the preservatives and are thus of significant relevance. Adsorption of preservatives on oligomeric states of peptides is proposed as a mechanism to explain this reduced antimicrobial efficacy.
authors.affiliation: Pharmaceutical Development & Supplies, Pharma Technical Development Biologics Europe (PTDE), F. Hoffmann - La Roche Ltd., Grenzacherstrasse 124, 4070, Basel, Switzerland. petteri.heljo@roche.com.|Division of Pharmaceutical Technology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland. petteri.heljo@roche.com.
authors.forename: P
authors.initials: P
authors.lastname: Heljo
authors.affiliation: Discovery Technologies, Small Molecules Research (SMR), Pharma Research and Early Development (pRED), F. Hoffmann - La Roche Ltd., Basel, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Ross
authors.affiliation: Late Stage Pharmaceutical Development, Genentech Inc., South San Francisco, California, USA.
authors.forename: I E
authors.initials: IE
authors.lastname: Zarraga
authors.affiliation: Pharmaceutical Development & Supplies, Pharma Technical Development Biologics Europe (PTDE), F. Hoffmann - La Roche Ltd., Grenzacherstrasse 124, 4070, Basel, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Pappenberger
authors.affiliation: Pharmaceutical Development & Supplies, Pharma Technical Development Biologics Europe (PTDE), F. Hoffmann - La Roche Ltd., Grenzacherstrasse 124, 4070, Basel, Switzerland.
authors.forename: H-C
authors.initials: HC
authors.lastname: Mahler
mesh_terms: D000327:Adsorption; D000890:Anti-Infective Agents / Q000737:chemistry* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D002626:Chemistry, Pharmaceutical / Q000379:methods; D003408:Cresols / Q000737:chemistry; D005079:Excipients / Q000737:chemistry; D010455:Peptides / Q000737:chemistry* / Q000494:pharmacology*; D011310:Preservatives, Pharmaceutical / Q000737:chemistry*
chemical_list: D000890:Anti-Infective Agents; D003408:Cresols; D005079:Excipients; D010455:Peptides; D011310:Preservatives, Pharmaceutical; C032538:4-cresol
keywords: antimicrobial efficacy; interaction; oligomerization; peptide; preservative