Objective   To investigate the effect of ambroxol hydrochloride on biofilm and morphology of Candida albicans (C. albicans) in vitro.   Methods   Microtiter plate culture method was used to establish C. albicans (ATCC 90028) biofilm. The abated tetrazolium salt (XTT) reduction assay was performed to quantitatively analyze the effect of ambroxol hydrochloride against C. albicans mature biofilm for 12 h. Microscopic examination with silver staining was conducted to assess the effect

of ambroxol hydrochloride on morpho-logy of C. albicans biofilm.   Results   C. albicans biofilm in vitro was formed on 96-well microtiter plates successfully. XTT reduction assay indicated that the OD

450

values at different concentration of ambroxol hydrochloride (0.625

1.25 and 2.50

5.00 and 7.50 mg/ml) were 0.68±0.04

0.63±0.05

0.52±0.07

0.31±0.05 and 0.11±0.03

respectively. All of these values had significant difference when compared with that of control (0.71±0.07

P0.05). But

when the concentration of ambroxol hydrochloride was 0.625 mg/ml

the OD

450

value was 0.67±0.04

which had no significant difference with that of control (P0.05). After the treatment of ambroxol hydrochloride (2.50

5.00 and 7.50 mg/ml) for 48 h

biofilm structure was destroyed

extracellular matrix was decreased

more single yeast cells were observed.    Conclusion   Ambroxol hydrochloride inhibits mature biofilm of C. albicans in a dose-dependent manner.