Fungicidal, Corrosive, and Mutational Effects of Polyhexamethylene Biguanide Combined with 1-Bromo-3-chloro-5,5-dimethylimidazolidine-2,4-dione.

Background: The disinfectants polyhexamethylene biguanide (PHMB) and 1-bromo-3-chloro-5,5-dimethylimidazolidine-2,4-dione (BCDMH) each have limitations. So far, their combined usage has not been examined. In this study, the fungicidal activity of combined disinfectant using PHMB and BCDMH, named PB, against Candida albicans was evaluated.

Methods: Suspension quantitative fungicidal test and viable fungi count were used to test fungicidal effects against C. albicans . Coupon corrosion testing was used to evaluate disinfectants' corrosive effects on stainless steel, copper, and aluminum. The mouse lymphoma assay was used to detect mutations induced by PB.

Results and Discussion: Fungicidal activity of the combination of 40 mg/L PHMB and 40 mg/L BCDMH was comparable to, or even better than, those of 600 mg/L PHMB or 640 mg/L BCDMH alone. The combination of 400 mg/L PHMB and 400 mg/L BCDMH exhibited good fungicidal effects in field applications. The combination of 100 mg/L PHMB and 100 mg/L BCDMH did not have corrosive effects on stainless steel and no mutagenic effect was observed under the test conditions.

Conclusions: The combination of PHMB and BCDMH has strong fungicidal effects and little metal corrosive and mutagenic effect and can be used as one suitable fungicide for wide household and industrial applications, including shipping containers.