Investigation of the Effect of Addition of Chitosan Nanoparticles and Diclofenac Sodium on Gelatin / Polyvinyl Alcohol Pain Relief Patch

In the current study, fabrication and characterization of a biodegradable skin patch with controlled release of sodium diclofenac was reported. Gelatin and polyvinyl alcohol were considered the main part of the patch, and nanochitosan was selected as an agent for improving physical and mechanical properties and controlling the drug release.  Furthermore, diclofenac sodium was loaded into the polymer as a pain relief agent. The total weight percent of the polymer was selected as 5%. Different samples with weight ratios of gelatin to polyvinyl alcohol of 0.1, 0.25, 0.5, 1, 1.5, 3, and 4.5 were fabricated. The sample's appearance characteristics with a ratio of 3 were the best; therefore, this sample was considered for further characterization. Then different percentages of nanochitosan were added to the polymer substrate. The tensile strength test results showed that the highest strength is obtained in the presence of 1% by weight of nanochitosan. Afterward, different amounts of drugs were added to the gelatin/polyvinyl alcohol/nanochitosan sample. The samples' different properties were examined using the tensile test, drug release test, scanning electron microscopy, swelling test, degradation test, and thermal degradation test. The results showed that good interaction between the components and the uniform distribution of nanoparticles within the samples was achieved. Measurement of drug release rate in samples over 8 hours showed that the release rate was faster at the beginning of the test; furthermore, the drug's maximum loading was 95%. This study's findings can be a preliminary step to prove the potential of gelatin/polyvinyl alcohol/nanochitosan/diclofenac sodium compound as a pain relief skin patch.