ABSTRACT
AIMS: The aim of this study was to compare salivary miconazole pharmacokinetics following once daily application of bioadhesive tablets (50 or 100 mg), vs the current treatment with a gel (3 times a day, 375 mg day(-1)). METHODS: A three way cross over study was carried out in 18 healthy subjects (nine males, nine females) with a 1 week washout period between each treatment. Plasma and salivary pharmacokinetics of miconazole were assessed over a 24-h period. RESULTS: In all subjects the tablets gave higher and more prolonged salivary miconazole concentrations than the gel. Thus salivary miconazole AUC(0,24 h) was 37.2 times greater for the 100 mg tablet (90% confidence interval [CI] 22.9, 60.5) and 18.9 times greater for the 50 mg tablet (CI 11.7, 30.6) compared with the gel. Similarly, Cmax was 17.2 times greater (CI 11.8, 25.2) and 7.8 times greater (CI 5.3, 11.4) for the 100 mg tablet and 50 mg tablet, respectively. Comparison of the 100 mg and 50 mg tablets gave ratios of 2.2 and 2.0 for Cmax and AUC(0,24 h), respectively (CI 1.5, 3.2 and 1.2, 3.2). The mean time that salivary miconazole concentrations were above 0.4 micro g ml(-1) (the concentration reached 3 h after application of the oral gel according to published data) or above 1.0 microg ml(-1) (the MIC of some Candida species) was greater for both bioadhesive tablets than for the oral gel (10-14 h vs 1.5 h and 7 h vs 0.6 h). Only 19 plasma samples from eight subjects had concentrations of miconazole above 0.4 micro g ml(-1). Ten of these were taken from five subjects after administration of the gel and nine from three subjects after administration of the tablets. CONCLUSIONS: These data strongly support the further development of miconazole bioadhesive tablets as a sustained release formulation leading to improved antifungal exposure in the buccal cavity. A single daily application should improve compliance, whereas the low systemic absorption of miconazole will alleviate concerns regarding drug interactions and adverse effects.
