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3046805 
Journal Article 
Effect of ethanol, propylene glycol and glycerol on the interaction of methyl and propyl p-hydroxybenzoate with Staphylococcus aureus and Pseudomonas aeruginosa 
Darwish, RM; Bloomfield, SF 
1997 
Yes 
International Journal of Pharmaceutics
ISSN: 0378-5173
EISSN: 1873-3476 
IPA/98/1137272 
147 
1 
51-60 
English 
WOS:A1997WR40100006 
IPA COPYRIGHT: ASHP To determine the mechanisms by which different cosolvents exert their effect on the antibacterial activity of the paraben esters, cosolvents ethyl alcohol (ethanol), propylene glycol, and glycerin (glycerol) were used to increase aqueous concentrations of methylparaben (methyl-p-hydroxybenzoate) and propylparaben (propyl-p-hydroxybenzoate) above their saturation solubility. The increased aqueous concentration of parabens in cosolvent solutions was associated with increased antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, but the extent of this effect increased with increasing hydrophobicity of the cosolvent. Addition of cosolvents to aqueous solutions of parabens caused a reduction in octyl alcohol (octanol)/water partitioning and a reduction in the uptake of the parabens by the cells, the extent of reduction increasing as cosolvent hydrophobicity increased. The addition of cosolvents also potentiated cell membrane damage as evidenced by leakage of radiolabelled phosphate from paraben-treated cells, but the extent of the damage was correlated with increasing hydrophobicity of the cosolvent. 
parabens; Co-solvent; preservation; membrane damage