Comparison of the bactericidal efficacy and in vitro cytotoxicity of Lavasept (R) and Prontosan (R)

Lavasept (R) and Prontosan (R) were compared using identical concentrations of the active agent polihexanide contained in both preparations regarding their bactericidal effectiveness in the quantitative suspension test and their cytotoxicity on mice fibroblasts, to obtain a statement regarding the coergism of polihexanide with the additives Macrogolum resp. undecylenamidopropyl betaine that are different in both preparations. In higher polihexanide concentrations the addition of undecylenamidopropyl betaine leads to a better bactericidal effectiveness of the preparation Prontosan (R), against P. aeruginosa, but at the same time to a decrease of the in vitro cytotoxicity of up to 50% depending on the concentration-time relationship. Comparing the IC50 there is a difference of approximately 28%. With lower concentration and longer exposure time this effect is reduced and with exposure times > 1 min there is partly even the tendency towards a better effectiveness of the combination preparation consisting of polihexanide and Macrogolum. As a cause for this phenomenon, an interaction among the constituents polihexanide with undecylenamidopropyl betaine resp. Macrogolum can be discussed. The effectiveness of both preparations towards S. aureus is not different from each other. Because Lavasept (R) is used in a maximum application concentration of 0.04% polihexanide, and for chronic wounds the reduced application concentration of 0.02% is recommended, but the application concentration of polihexanide in Prontosan (R) is 0.1%, regarding the use solutions the combination of polihexanide and Macrogolum is to be appraised as being less cytotoxic and therefore more compatible with wounds than undiluted Prontosan (R). For experimental support of this assumption further investigations are necessary.