Fabrication and characterization of boric acid-crosslinked ethyl cellulose and polyvinyl alcohol films as potential drug release systems for topical drug delivery

In this study, boric acid (BA) is employed as a crosslinking agent to improve the characteristics of two commonly used
polymeric films, ethyl cellulose (EC) and polyvinyl alcohol (PVA), for topical drug delivery applications. The developed films are
characterized by FTIR spectroscopy and SEM analysis. The results show that the surfaces of the prepared films are even and transparent,
except for the BA-modified EC sample. The initial cumulative release for erythromycin (EM) is found to be 0.30 and 0.36 mg/mL for
EC and PVA films, which drops to 0.25 and 0.20 mg/mL after BA crosslinking, respectively, after 1 h at 25 °C. Further, the developed
formulations are stable for 75 days. Also, the antibacterial activity of the developed formulations is investigated against S. aureus (ATCC®
25923™ and ATCC® 29213™). The obtained data confirm that the application of BA as the crosslinking agent extends the release of EM
from EC and PVA polymeric films. The findings of this study suggest that BA-crosslinked EC and PVA films are promising carriers for
controlled topical drug delivery applications