A new, water-resistant, film-forming, 30-second, one-step application iodophor preoperative skin preparation.

BACKGROUND: A 1-step, film-forming iodophor preoperative skin preparation, Prevail-Fx, was developed. It forms a water-resistant film once dried on skin. To evaluate the partially water-soluble formulation, the testing method was validated with spore-challenge techniques and the efficacy was studied microbiologically and chemically. The importance of method validation and the presence of free iodine as criteria for product evaluation of partially water-soluble or water-insoluble skin preparations are discussed. METHODS: The test methods outlined in the Federal Register, 21 CFR Parts 333 and 369 (Monograph), were used. Twenty-five American Type Culture Collection (Rockville, Md) species of organisms and 25 correspondent clinical isolates were tested in vitro. FDA In the clinical studies, the skin normal flora of the inguinal and abdominal sites were evaluated in a 30-second, single-step application. Betadine (Purdue Frederick Co, Norwalk, Conn) on scrub (7.5%) and Betadine solution (10%) were tested as controls in a 5-minute, 2-step application. RESULTS: Prevail-Fx solution showed a broad spectrum in a minimum inhibitory concentration test. It delivered rapid bactericidal activity in a time-kill test, reducing 5 to 6 log of challenging organism in 3 minutes, as required by the Federal Drug Administration (FDA). In an in vivo clinical test with a single-step, 30-second application, Prevail-Fx effectively reduced greater than 4 log or greater than 3 log of normal skin flora in inguinal and abdominal testing sites, respectively. The bacterial levels remained significantly less than the baseline for 6 to 24 hours. These results meet and exceed the Federal Drug Administration's requirements. The efficacy of Prevail-Fx in a 30-second, single application is as effective as Betadine scrub and Betadine solution applied in a traditional 5-minute, 2-step scrubbing and painting. CONCLUSION: The Prevail-Fx film-forming formulation delivered rapid antimicrobial activity against a broad spectrum of micro-organisms in vitro and a rapid, persistent bactericidal activity in vivo in a 30-second, 1-step application against normal skin flora. This study also found that the spore-challenge validation of the testing methods and the evidence of free iodine are 2 indispensable criteria for the efficacy evaluation of the film-forming iodophor skin preparations.

Povidone iodine gel alcohol: a 30-second, onetime application preoperative skin preparation.

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.

Chlorine dioxide gas sterilization of oxygenators in an industrial scale sterilizer: a successful model.

Artificial organ oxygenators, with large surface areas and complicated structures, were sterilized using chlorine dioxide gas in an industrial scale sterilizer. Bacillus subtilis var. niger ATCC 9372 biological indicators (BI) (10(6) spores/BI) planted in the artificial organs were reproducibly sterilized in a designed cycle schedule with a 30-min dwell time with a chlorine dioxide gas concentration of approximately 30 mg/L in 80 to 85% relative humidity at 30 degrees C. The D value (time required for 90% spore inactivation under specific conditions) was estimated to be 4.4 min. Chlorine dioxide was not detected after post-sterilization aeration. The intravenous median lethal dose (LD50) of chlorine dioxide derivatives, chlorite and chlorate, in rats was found to be 112.8 and 2,228.6 mg/kg, respectively. In an immediate hypersensitivity test, chlorine dioxide gas-treated ovalbumin and bovine serum albumin, unlike ethylene oxide gas-treated proteins, did not cause sterilant-specific IgE-mediated hypersensitivity reactions in rats. Results of an Ames mutagenicity test on chlorine dioxide and on the extracts of the chlorine dioxide gas-exposed oxygenators were negative.

Chlorine Dioxide Gas Sterilization under Square-Wave Conditions.

Experiments were designed to study chlorine dioxide (CD) gas sterilization under square-wave conditions. By using controlled humidity, gas concentration, and temperature at atmospheric pressure, standard biological indicators (BIs) and spore disks of environmental isolates were exposed to CD gas. The sporicidal activity of CD gas was found to be concentration dependent. Prehumidification enhanced the CD activity. The D values (time required for 90% inactivation) of Bacillus subtilis subsp. niger ATCC 9372 BIs were estimated to be 1.5, 2.5, and 4.2 min when exposed to CD concentrations of 30, 15, and 7 mg/liter, respectively, at 23 degrees C and ambient (20 to 40%) relative humidity (RH). Survivor tailings were observed. Prehumidification of BIs to 70 to 75% RH in an environmental chamber for 30 min resulted in a D value of 1.6 min after exposure to a concentration of 6 to 7 mg of CD per liter at 23 degrees C and eliminated survivor tailing. Prolonging prehumidification at 70 to 75% RH for up to 16 h did not further improve the inactivation rate. Prehumidification by ultrasonic nebulization was found to be more effective than prehumidification in the environmental chamber, improving the D value to 0.55 min at a CD concentration of 6 to 7 mg/liter. Based on the current observations, CD gas is estimated, on a molar concentration basis, to be 1,075 times more potent than ethylene oxide as a sterilant at 30 degrees C. A comparative study showed B. subtilis var. niger BIs were more resistant than other types of BIs and most of the tested bacterial spores of environmental isolates.

Mechanism of microwave sterilization in the dry state.

With an automated computerized temperature control and a specialized temperature measurement system, dry spores of Bacillus subtilis subsp. niger were treated with heat simultaneously in a convection dry-heat oven and a microwave oven. The temperature of the microwave oven was monitored such that the temperature profiles of the spore samples in both heat sources were nearly identical. Under these experimental conditions, we unequivocally demonstrated that the mechanism of sporicidal action of the microwaves was caused solely by thermal effects. Nonthermal effects were not significant in a dry microwave sterilization process. Both heating systems showed that a dwelling time of more than 45 min was required to sterilize 10(5) inoculated spores in dry glass vials at 137 degrees C. The D values of both heating systems were 88, 14, and 7 min at 117, 130, and 137 degrees C, respectively. The Z value was estimated to be 18 degrees C.