A robust theoretical approach to analyze the diffusion of natural and synthetic wound antimicrobials through polyethylene glycol hydrogel using obstruction theory

In this work, a theoretical approach based on the obstruction theory is proposed to estimate the diffusion characteristics associated with the natural and synthetic wound antimicrobials through polyethylene glycol (PEG) hydrogel matrix. The simulation outcomes have been compared with the free volume theory based model which has been reported in our earlier study. The influence of the skin layer on the predicted parameters is also investigated. The results show that the obstruction theory based model is able to distinguish between the diffusion kinetics of the natural and synthetic antimicrobials for the considered range of molecular weights and PEG matrix configuration. The diffusion time of the therapeutic formulations through the hydrogel is found to vary in the range of 2.7–7.2 h. The predicted time scale is comparable with the real-time treatment window which would aid in preventing the formation of biofilm in wounds. Gentamicin is observed to take 4.2 h to completely diffuse out of the hydrogel matrix, while its diffusion period is increased by 95 times in the presence of the 1 mm thick skin layer. The diffusivity values of the antimicrobial compounds estimated using the obstruction theory are noted to be consistently higher than that of the free volume theory. This study seems to be clinically significant as the computational approaches to analyze the diffusivity of drugs in the hydrogel matrices are essential for the therapeutic decision making during wound treatment. [Display omitted]