The anti-inflammatory agent glucocorticoid is one of the most effective and widely-used drugs for various kinds of inflammatory diseases. However, it has serious side effects, including suppression of host defense mechanisms against microbial infections. Therefore, more efficient delivery methods of glucocorticoids are required for various types of inflammatory diseases. For clinical use films containing glucocorticoids have been developed for oral inflammatory diseases, including mucosal lesions in the oral cavity. Very recently we succeeded in preparing mucoadhesive hydroxypropyl cellulose (HPC)-film containing more than 100 mg/cm 2 of beclomethasone dipropionate (BDP). Before conducting clinical research on this film, the effects of application of this film on oral infection were examined in an animal model, since it is well known that glucocorticoids predispose to oral or pharyngeal Candida infection. [1][2][3][4][5][6] In our previous papers, a murine oral candidiasis model 6) or an esopharynxial model 7) were used, allowing the examination of the effects of topical application of mucoadhesive films.In the present study, we examined the effects of BDP-and neutrophil-Candida interactions in vitro, as well as the level to which oral application of BDP-containing HPC-film predisposes towards oral candidiasis in this murine model.
MATERIALS AND METHODS
Film PreparationThe film was composed of one layer of HPC (150-400 cP; Wako Pure Chemical Industries, Ltd., Osaka, Japan) as the base component. To prepare BDP-containing film, BDP (Wako) was first dissolved in ethanol, HPC added, and then ethanol added to give a final volume of 30 ml per 0.9 g HPC. A 10-ml aliquot of this solution was cast using a graduated pipette at a rate of 10 ml/4 min into a flat round Teflon dish of diameter 75 mm and then dried on a clean bench overnight. These dried films were then cut into circles of diameter 30 mm for the release study or into rectangles of 0.6 cmϫ0.5 cm for the oral candidiasis study in mice.Release of BDP from the Film Measurement of BDPrelease from the BDP-containing films was performed as follows. A dissolution apparatus was modified from the original construction of Okamoto et al.8) Briefly, a 10-ml beaker was used as the receptor compartment and a piece of sample film (3-cm diameter) attached to the inner wall of the beaker using double-sided tape, to produce the donor side. An 0.1 M phosphate buffer (PB) (pH 7.0) was then added to the beaker, which was maintained at 37°C and stirred at a constant speed using a magnetic bead. Aliquots (100 ml each) were withdrawn at preset times (1, 2, 3, 4, 5, and 30 min), and then the amount of BDP released estimated using an HPLC system (Shimadzu Co., Ltd., Kyoto, Japan) equipped with a UV detector (wavelengthϭ254 nm). To maintain a constant volume and sink conditions in the experiment, the removed solution was replaced each time with 100 ml of 0.1 M PB prewarmed to 37°C. The cumulative amount of drug release per 1 cm 2 of BDP film was then calculated. Each experiment was perf...