title: Clinical investigation of topical antimicrobials in healthy volunteers.
abstract: OBJECTIVE
  To evaluate the antibacterial activity, onset of action, and duration of action of four topical antimicrobial gels containing cetrimide, bacitracin, polymyxin B sulfate, and a placebo gel.
  
  
  METHODS
  Multiples (1 x, 2x, 4x, 8x) of minimally inhibitory in vitro drug concentrations were formulated in a gel vehicle. Antibacterial activity was evaluated using a scrub-wash methodology on artificially inoculated skin over an 8-hour study period.
  
  
  METHODS
  Healthy volunteers with intact forearm skin participated in the study. A standardized culture of Staphylococcus aureus NCTC 6571 was applied to four areas on each forearm, randomly assigned topical treatments were applied, and sites were sampled at predetermined time intervals using a surfactant wash fluid.
  
  
  METHODS
  Recovered bacteria were quantitated, allowing a comparison of antibacterial activity.
  
  
  RESULTS
  Two-way and one-way ANOVA and a Scheffe test confirmed significant differences in antibacterial effect between the formulations containing 4 and 8 times the minimally inhibitory in vitro concentrations and placebo (p < 0.05). Duration of action was similar for all preparations; however, onset appeared to be faster with the formulations containing 4 and 8 times minimally inhibitory in vitro concentrations.
  
  
  CONCLUSIONS
  The two topical preparations containing 4 and 8 times the minimally inhibitory in vitro concentrations of cetrimide, bacitracin, and polymyxin B sulfate demonstrated significant antibacterial activity and may have potential for further clinical investigations.
authors.affiliation: Department of Pharmacy, University of Sydney, New South Wales, Australia. jane@pharms114.pharm.su.oz.au
authors.forename: J H
authors.initials: JH
authors.lastname: Langford
authors.forename: S
authors.initials: S
authors.lastname: Benrimoj
mesh_terms: D000287:Administration, Topical; D000328:Adult; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000494:pharmacology*; D001414:Bacitracin / Q000008:administration & dosage / Q000494:pharmacology*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005782:Gels; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D011112:Polymyxin B / Q000008:administration & dosage / Q000494:pharmacology*; D011897:Random Allocation; D012867:Skin / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D000891:Anti-Infective Agents, Local; D002593:Cetrimonium Compounds; D005782:Gels; D001414:Bacitracin; D011112:Polymyxin B; D000077286:Cetrimonium