The use of traditional systemic drug delivery via oral routes has not been successful due to lack of patient compliance. Objective: It is to develop a polymeric device that will enable a constant drug release over several days to treat oral infection. Materials: Ethylene vinyl acetate copolymer( (EVA) Du Pont; Grade 140 W^g), nystatin, doxycycline and diphenhydramine, and dichloromethene. Combinations of nystatin(c)-doxycycline(c) and nystatin(c)-diphenhydramine(c) in equal proportion were studied. Methods: Polymer casting solutions were prepared by dissolving EVA and the drug in the ratio of 7:1 in 70 ml of dichloromethane at 38 ⁰C for 6 hrs. Thin square films of 3x3 cm and 1 mm thickness were cut from the dry sheet obtained by solvent evaporation. Four  samples were extracted for 15 days in a constant volume of 10 ml medium which is replaced daily. Spectral measurements were made to determine the values of l_max for the drugs. The release kinetics were followed using Beckman Duā -70 Spectrophotometer. Results: see table below.

Analysis of the data revealed that among all the individual drugs, diphenhydramine exhibited the highest release rate. Nystatin exhibited 5 times increase in the release rate when combined with doxycycline. This may be interpreted as due to the channels formed in the polymer facilitating faster diffusion process. Conclusion: The  observedenhanced values of drug release rates with reference to nystatin(c) and doxycycline (c) may be attributed to their relative hydrophobic interactions and drug-drug interaction. Less polar medium such as water-ethanol by swelling the polymer, accelerates preferential diffusion of larger molecules nystatin relative to doxycycline. This work is supported by NIH-NIDCR grant T32DE07310.