Effect of emulsion forms on the preservative efficacy of phenol, cresol and chlorocresol in formulated oil-water system was evaluated. 1g each of formulated oil-water system was dispersed in 9ml sterile peptone water containing 0.25% Tween 80 to aid solubility of the cream. This was challenged with 0.1ml of 0.5MacFarland standard equivalent overnight grown culture of Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus (all clinical isolates) with 1ml sample of the resulting mixture taken at 0 hr, 6 hr, 12 hr, 24 hr, 7 days, 14 days and 28 days seeded in Mueller-Hinton agar medium and incubated at 37oC for 24 hours. Chlorocresol displayed the best efficacy of all the three phenolic agents tested in all the O/W cream used for the study while the action displayed by the 3 phenolics examined in W/O creams varies with the organism used for the challenge test. Since the activity of the 3 phenolic preservatives differs both in W/O and O/W creams examined, it follows that emulsion type can affect the activity of preservative.
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