The influence of pH on the solubility of miconazole and its effect on survival of c. albicans

Abstract

The in-vitro activity ofmiconazole against Candida albicans (NCPF 3262) was investigated using Time- survival curves. An HPLC assay was also developed to produce a pH-solubility profile which showed that miconazole solubility varied from (2.5 ±0.3) mg/L at pH 12 to (28.9 ± 0.6) mg/L at pH 5. Time survival curve determinations demonstrated a relationship between miconazole concentration and the area under the curve (AUC). In controlled conditions using buffered aqueous solutions of miconazole (8 mg/L), a change in pH from 8 to 5 resulted in an increase in the antifungal activity of miconazole. Experiments performed in buffered YNB using the same concentration of miconazole showed that a change in pH from 7 to 5 resulted in a decrease in miconazole antifungal activity. Such results indicate that apart from the well known inhibitory effects that the growth media have on azole activity, pH at which tests were performed may also influence growth of C. albicans in batch culture.