In vitro bactericidal activity of 0.6% povidone-iodine eye drops formulation.

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In vitro bactericidal activity of 0.6% povidone-iodine eye drops formulation.

Eur J Ophthalmol. 2018 Oct 07;:1120672118802541

Authors: Musumeci R, Bandello F, Martinelli M, Calaresu E, Cocuzza CE

PURPOSE: To evaluate the bactericidal activity of a diluted povidone-iodine formulation (0.6%) in comparison with the most used 5% povidone-iodine solution ophthalmic preparation.
METHODS: In vitro bactericidal activity comparison between 0.6% povidone-iodine versus 5% povidone-iodine formulations, against these bacteria: Staphylococcus aureus ATCC 25923, Staphylococcus aureus ATCC 43300, Staphylococcus epidermidis ATCC 12228, linezolid-resistant Staphylococcus epidermidis α99 strain, a clinical isolate, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922.
RESULTS: About 0.6% povidone-iodine formulation was demonstrated to be faster than 5% povidone-iodine preparation in killing Gram-positive as well as Gram-negative bacteria. Against a linezolid-resistant methicillin-resistant Staphylococcus epidermidis strain, 0.6% povidone-iodine formulation showed the best antiseptic efficacy requirement of 3-log10 reduction in bacterial load, if compared with the 5% povidone-iodine formulation.
CONCLUSION: Our investigation has demonstrated that the more diluted 0.6% preparation was more rapidly bactericidal than the 5% povidone-iodine formulation, most probably due to the fact that dilution from 5% to 0.6% increases the amount of free iodine. While our finding must be confirmed by in vivo clinical studies, this fact constitutes an intriguing news for what concerns the use of povidone-iodine eye drops in the ocular surface treatment before intravitreal injections as well as ophthalmic surgery.

PMID: 30295039 [PubMed - as supplied by publisher]