Preservative system for topically administrable pharmaceutical compositions

A preserved topically administrable pharmaceutical composition comprising a preservative system wherein the preservative system consists essentially of i) at least one anionic surfactant, ii) one or more pharmaceutically acceptable antifungal acids and iii) one or more pharmaceutically acceptable chelating agents, wherein the the anionic surfactant is selected from the group consisting of:

• wherein:
• R=C8-C24 saturated or unsaturated hydrocarbon;
• X=H or CH3;
• Y=H, (CH2)4NH2 or (CH2)3NHC(NH2)═N+H2;
• and
• M+=H or a pharmaceutically acceptable salt;
• and
• wherein:
• R1=C8-C24 saturated or unsaturated hydrocarbon;
• and
• M+ is as defined above;
• the one or more pharmaceutically acceptable antifungal acids is selected from the group consisting of boric acid;
• benzoic acid;
• salicylic acid;
• sorbic acid;
• lactic acid;
• and acetic acid;
• or a pharmaceutically acceptable salt thereof;
• and
• the one or more pharmaceutically acceptable chelating agents is selected from the group consisting of ethylene diamine tetraacetic acid;
• ethylene glycol-bis-(b-aminoethylether)-N,N,N′,N′-tetraacetic acid;
• 1 ,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid;
• ethylene-N,N′-diglycine;
• and 2,2′-(ethylendiimino)-dibutyric acid;
• or a pharmaceutically acceptable salts thereof provided that the composition does not have a cationic preservative.