“…A value of >1 describes good tolerability, while a value <1, poor microbial killing combined with high cytotoxicity. 15 Hirsch et al studied commonly used topical antiseptics, to determine their relative efficacy in terms of minimal inhibitory concentrations and their tissue tolerability. Prontosan (B. Braun, Melsungen, Germany) (discussed later), a polyhexamethylene biguanide (PHMB) product available commercially, for instance, demonstrated excellent efficacy at all concentrations of the "generic" tested (1%-20%), while others required higher concentrations to completely inhibit growth.…”