Bactericidal efficacy of 5 per cent povidone iodine cream in Pseudomonas aeruginosa burn wound infection

Abstract

A new topical antiseptic agent, 5 per cent polyvinylpyrrolidone-iodine (PVP-I) cream, with altered physicochemical properties, incorporated in a different carrier base has proved in vivo to be more effective in controlling burn wound infections than 10 per cent PVP-I ointment. Important biodynamic properties of the new formulation have not, however, been elucidated in vivo. Hence the need for a controlled study to evaluate the bioavailability of the active component after penetration through burn eschar; the bactericidal efficacy of the cream and determination of the bactericidal time of the cream in comparison with 10 per cent PVP-I ointment. A modified Walker burn wound model was used to define the rate of trans-eschar penetration, biodynamic availability and bactericidal efficacy 5 per cent povidone iodine cream in established Pseudomonas aeruginosa burn wound infection. In vitro penetration confirmed the effective diffusion of PVP-I cream through 1.5 mm eschar within 6 h. A single topical application of PVP-I cream resulted in a 98.8 per cent (6.088 × 10 9 c.f.u./g of tissue to 7.367 × 10 7 c.f.u./g of tissue) reduction in intra-eschar viable organisms within 18 h after application. A second topical application of PVP-I cream at 18 h resulted in a total reduction of 99.8 per cent in viable organisms (2.90 × 10 9 c.f.u./g of tissue to 7.009 × 10 6 c.f.u./g of tissue) within 48 h. Comparing the in vitro bactericidal time of povidone iodine ointment with cream against Pseudomonas aeruginosa, Staphylococcus aureus and a Klebsiella pneumoniae revealed that the PVP-I cream killed organisms ten-fold more quickly than the ointment. It is concluded that 5 per cent PVP-I in an oil/water emulsion cream base is very effective in terms of rapid trans-eschar penetration, rapid killing and sustained antibacterial effect.