Background: Simplifying and shortening the skin-preparation application procedure is desirable for many reasons, which include labor-cost savings and improved suite utilization. A new formulation, PVP-I Gel Alcohol (PGA) that contains 5% PVP-I and 62% ethanol in gel form, was developed to achieve a shorter preparation time with a rapid and persistent efficacy on a broad spectrum of microorganisms and to minimize the potential for iodine irritation.
Method: The test methods outlined in the Federal Register, 21 CFR Parts 333 and 369, "Tentative Final Monograph for Health-Care Antiseptic Drug Products;" Proposed Rule, 1994 (Monograph), were adapted in this study. Efficacy of PGA was evaluated, both in vitro and in vivo. The in vitro time-kill and minimum inhibition concentration tests were conducted by using 33 strains of aerobic and anaerobic gram-positive bacteria, gram-negative bacteria, yeasts, and antibiotic-resistant bacteria. In the clinical test, the inguinal and abdominal skin sites of human subjects were exposed to PGA for 30 seconds to assess the antimicrobial efficacy on normal skin flora. Betadine PVP-I scrub was tested in a 5-minute application as a control.
Results: The time-kill test showed that PGA delivered a rapid antimicrobial activity--reducing greater than 3 to 8 log microorganisms in 15 seconds in all of the 33 species of microorganisms tested. Within 30 seconds, all challenge organisms were reduced below detection level. Results of the minimum inhibition concentration test showed that PGA demonstrated an equivalent activity to Betadine control under the testing conditions. In the clinical test, PGA was effective in the reduction of greater than 3 log and 2 log of normal skin flora, respectively, in inguinal and abdominal sites in a single-step 30-second application. Bacteria levels remained significantly below the baseline for 6 hours in the primary study and for 24 hours in a secondary study. These results show that the current PGA formulation with a 30-second application delivers an efficacy equivalent to Betadine scrub in a 5-minute application and that the PGA formulation has a long-lasting effect--up to 24 hours.
Conclusion: The PGA formulation delivered rapid and persistent antimicrobial activity against a broad spectrum of bacteria both in vitro and in vivo. PGA is an effective skin-preparation formulation for use in a single-step 30-second application.