title: Optimising concentrations of antimicrobial agents in pharmaceutical preparations: Case of an oral solution of glycerol and an ophthalmic solution containing cysteamine.
abstract: BACKGROUND
  In the context of current distrust of antimicrobial preservatives, the quantities of these substances in two pharmaceutical formulas were studied: an ophthalmic solution of cysteamine preserved benzalkonium chloride at 1mg/5mL and Glycerotone(®) preserved with sorbic acid at 0.1g/100g. The purpose of this work was to verify that a reduction of the quantities of preservative continues to fulfil the requirements for antimicrobial preservation.
  
  
  METHODS
  The Test of efficacy of antimicrobial preservation, section 5.1.3 of the 8th edition of the European Pharmacopoeia, was carried out on each formulation prepared with decreasing quantities of preservative.
  
  
  RESULTS
  The results show that formulations whose preservative concentration was reduced by a factor of four remained compliant with standards. It is to be noted that in formulas without preservative, fungal growth was observed in both the solution of Glycerotone(®) and the ophthalmic solution containing cysteamine.
  
  
  CONCLUSIONS
  Although there is no question that an antimicrobial preservative is necessary, the quantity of preservative can be reduced without deteriorating the quality of the pharmaceutical product but the minimal effective concentration remains to be determined.
  
  
  CONCLUSIONS
  The formulations of many pharmaceutical products should therefore be examined in order to limit the quantities of preservative while continuing to guarantee patient's safety.
authors.affiliation: DL, AGEPS, 7, rue du Fer-à-Moulin, 75005 Paris cedex, France. Electronic address: aurelie.chw@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Chan Hew Wai
authors.affiliation: DL, AGEPS, 7, rue du Fer-à-Moulin, 75005 Paris cedex, France.
authors.forename: P
authors.initials: P
authors.lastname: Becasse
authors.affiliation: DL, AGEPS, 7, rue du Fer-à-Moulin, 75005 Paris cedex, France.
authors.forename: S
authors.initials: S
authors.lastname: Tworski
authors.affiliation: DIP, AGEPS, 7, rue du Fer-à-Moulin, 75005 Paris cedex, France.
authors.forename: D
authors.initials: D
authors.lastname: Pradeau
authors.affiliation: DL, AGEPS, 7, rue du Fer-à-Moulin, 75005 Paris cedex, France.
authors.forename: V
authors.initials: V
authors.lastname: Planas
mesh_terms: D000891:Anti-Infective Agents, Local / Q000737:chemistry*; D001419:Bacteria / Q000187:drug effects; D001548:Benzalkonium Compounds / Q000008:administration & dosage / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D003543:Cysteamine / Q000737:chemistry / Q000494:pharmacology*; D004340:Drug Contamination / Q000517:prevention & control; D005658:Fungi / Q000187:drug effects; D005990:Glycerol / Q000737:chemistry / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009883:Ophthalmic Solutions / Q000737:chemistry*; D011310:Preservatives, Pharmaceutical / Q000737:chemistry / Q000494:pharmacology*; D013011:Sorbic Acid
chemical_list: D000891:Anti-Infective Agents, Local; D001548:Benzalkonium Compounds; D009883:Ophthalmic Solutions; D011310:Preservatives, Pharmaceutical; D003543:Cysteamine; D005990:Glycerol; D013011:Sorbic Acid
keywords: Acide sorbique; Benzalkonium chloride; Chlorure de benzalkonium; Conservateurs; Multidose preparations; Patient safety; Preservative; Préparations multidoses; Sorbic acid; Sécurité du patient