Interaction between chlorhexidine digluconate and sodium monofluorophosphate in vitro

The aim of the present study was to investigate the compatibility of chlorhexidine digluconate and sodium monofluorophosphate since these agents are potential ingredients in future products in preventive dentistry. Varying combinations of chlorhexidine digluconate and sodium monofluorophosphate in water, covering the possible ranges of clinically relevant concentrations of both compounds, were made, incubated for 24 h and observed for precipitation of insoluble salts. The mixtures were analyzed for presence of free chlorhexidine and monofluorophosphate after incubation. The results showed that chlorhexidine digluconate and sodium monofluorophosphate are not compatible in clinically relevant concentrations. A chlorhexidine-monofluorophosphate salt of low solubility in water is presumably formed.