Urinary catheters, made of polyurethane, are used in patients for extended periods of time. As a result of a catheter’s location and prolonged use, the catheter is vulnerable to contaminants that lead to infections such as Escherichia coli and Candida spp. A polymer that can prevent the development of these microbes, without compromising the functionality of the catheter, would be an ideal solution to this problem. The purpose of this experiment is to develop a polymer that contains an antimicrobial commonly used to treat the various causes of catheter-induced urinary catheter infections. Polyurethane is the preferred material for catheter production due to its biocompatibility with patients, and, thus, became the material of choice for trials. Sulfathiazole, similarly, has a history of being prescribed to various infections, including UTIs. Sulfathiazole also has the added benefit of being soluble in water, an important factor for testing the concentration of drug releasing from the polyurethane during testing. Samples are created by dissolving sulfathiazole and polyurethane in a solution of dimethylformamide and tetrahydrofuran, then allowing the mixture to mix for 24 hours. The resultant solution is poured into molds, placed in an oven at 370C for 24 hours, and the films are stored in a dessicator. In order to confirm that sulfathiazole can diffuse out of the polyurethane, a portion of the drug-loaded polymer is suspended in an Erlenmeyer flask containing distilled water in a water bath kept at a constant 370C for 24 hours. Every hour, 5 mL of the water in the flask is removed and placed in vials for testing. All the water samples are tested with a Shimazdu UV-2450 spectrometer at 270 nm, the wavelength explicitly cited in a publication on sulfathiazole. Spectrometer readings are compared to the calibration curve made with different concentrations, ranging from 1.25 µg to 100 µg, of sulfathiazole dissolved in distilled water. Two sulfathiazole concentrations, 0.3 wt/wt% and 1.5 wt/wt%, suspended in the polymer were sampled. Both concentrations show similar release mechanisms which follow the Korsemeyer-Peppas kinetic model of diffusion. From the similarity in release rates and kinetic modeling, it seems that the diffusion behavior of sulfathiazole is independent of its concentration. The most important result is that the sulfathiazole is capable of diffusing out of polyurethane at a dependable rate.

Drug delivery mechanism of sulfathiazole in films

253rd National Meeting (2017)

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