title: Interactions of antimicrobial compounds with cross-linking agents of alginate dressings.
abstract: OBJECTIVE
  The aim of this study was to investigate the antimicrobial activities of calcium ions and other cross-linking agents of alginate dressings, as well as their compatibility with commonly used topical antimicrobials.
  
  
  METHODS
  The antimicrobial activities of cross-linking agents and antimicrobials (five antibiotics and four antiseptics) were evaluated by the broth dilution method. The interactions between individual cross-linking agents and antimicrobials were evaluated using the chequerboard test against common skin pathogens, Staphylococcus aureus and Pseudomonas aeruginosa.
  
  
  RESULTS
  From the MIC determined, antibiotics were the most active, followed by the antiseptics and cross-linking agents. Calcium ions, which are commonly used to cross-link alginate, exhibited very weak antimicrobial activity and higher fractional inhibitory concentration than the other cross-linking agents. The use of calcium and gentamicin resulted in antagonism against S. aureus. In contrast, aluminium, zinc and copper ions exhibited higher antimicrobial activities but insignificant interactions with the antimicrobials.
  
  
  CONCLUSIONS
  Commonly used topical antimicrobials that are active against the skin pathogens S. aureus and P. aeruginosa could be potentially incompatible with calcium alginate dressings. Copper, zinc and aluminium ions are more suitable cross-linking agents for alginate as they do not show antagonism with the antimicrobials and could impart antimicrobial property to the resultant dressing.
authors.affiliation: Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Republic of Singapore.
authors.forename: Cheong Hian
authors.initials: CH
authors.lastname: Goh
authors.forename: Paul Wan Sia
authors.initials: PW
authors.lastname: Heng
authors.forename: Esther Pei En
authors.initials: EP
authors.lastname: Huang
authors.forename: Benny Kai Hui
authors.initials: BK
authors.lastname: Li
authors.forename: Lai Wah
authors.initials: LW
authors.lastname: Chan
mesh_terms: D000464:Alginates / Q000378:metabolism*; D000535:Aluminum / Q000378:metabolism / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology*; D000891:Anti-Infective Agents, Local / Q000378:metabolism / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D003300:Copper / Q000378:metabolism / Q000494:pharmacology; D003432:Cross-Linking Reagents / Q000378:metabolism / Q000494:pharmacology*; D004347:Drug Interactions; D020723:Glucuronic Acid / Q000378:metabolism; D006603:Hexuronic Acids / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D015032:Zinc / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000464:Alginates; D000900:Anti-Bacterial Agents; D000891:Anti-Infective Agents, Local; D003432:Cross-Linking Reagents; D006603:Hexuronic Acids; D003300:Copper; D020723:Glucuronic Acid; D000535:Aluminum; D015032:Zinc; D002118:Calcium