title: Microbiological quality of topical drug formulations: efficacy of antimicrobial preservation against Paecilomyces lilacinus.
abstract: BACKGROUND
  Microbiological quality of topical products comprises both, the microbiological purity of the unopened product and the efficacy of the antimicrobial preservation system.
  
  
  OBJECTIVE
  Subsequent to an outbreak of invasive Paecilomyces lilacinus mycosis among patients of an isolation ward, probably caused by a contaminated skin care product, the microbiological quality of different skin care products from the market was investigated.
  
  
  METHODS
  The different products were investigated for their efficacy of antimicrobial preservation in general and especially against P. lilacinus according to a pharmacopoeial routine method slightly adopted for the purpose of this investigation.
  
  
  RESULTS
  The products did partially not comply with the British Pharmacopoeia 1993 test for efficacy of antimicrobial preservation. The antimicrobial preservation systems were less effective against P. lilacinus than against the pharmacopoeial reference germs. The antimicrobial preservation efficacy decreased towards the end of the shelf-life of the product. A decreased P. lilacinus inoculum dose was related to an increased growth of the micro-organisms.
  
  
  CONCLUSIONS
  Topical products are, unless not labelled otherwise, non-sterile preparations and their preservation systems are only tested against pharmacopoeial key micro-organisms. The microbiological behaviour following contamination with other germs remains unknown.
authors.affiliation: Institute of Hospital Pharmacy, University Hospital, Basel, Switzerland.
authors.forename: F P
authors.initials: FP
authors.lastname: Schwarb
authors.forename: B
authors.initials: B
authors.lastname: Gabard
authors.forename: E
authors.initials: E
authors.lastname: Bieli
authors.forename: S
authors.initials: S
authors.lastname: Schwab
authors.forename: C
authors.initials: C
authors.lastname: Surber
mesh_terms: D000287:Administration, Topical; D004304:Dosage Forms; D004340:Drug Contamination / Q000517:prevention & control*; D010143:Paecilomyces / Q000187:drug effects*; D011310:Preservatives, Pharmaceutical / Q000494:pharmacology*
chemical_list: D004304:Dosage Forms; D011310:Preservatives, Pharmaceutical