USE OF A NEW ASSAY TECHNIQUE FOR QUANTIFICATION OF ANTIFUNGAL ACTIVITY OF NYSTATIN INCORPORATED IN DENTURE LINERS

Denture-induced stomatitis with concurrent candidal infection is the m ost commonly encountered intraoral abnormality among individuals who w ear dentures. The institutionalized elderly demonstrate increased susc eptibility and could benefit from its management with a fungicidal den ture liner. As an integral part of the prosthesis, the efficacy of the fungicidal liner would be independent of patient compliance and/or nu rsing involvement and would provide a predictable therapeutic modality . In this study a ''slant agar assay'' was developed to evaluate the i n vitro antimycotic activity of Visco-gel and Lynal liners impregnated with various concentrations of nystatin over a 14-day period in nonaq ueous and aqueous environments. The results were as follows: preparati ons incorporating higher concentrations of nystatin resulted in greate r inhibition of Candida albicans growth; Visco-gel liner-nystatin prep arations exhibited a greater fungicidal activity than equivalent Lynal preparations; loss of potency by all of the reline-nystatin preparati ons consisted of an initial rapid loss between days 0 and 2, followed by a plateau during which the preparations gradually continued to lose inhibitory activity; and 1 million units of nystatin were necessary t o maintain an adequate level of antifungal activity in an aqueous envi ronment, where the liners demonstrated decreasing antifungal activity proportional to the duration of exposure to water.