It appears that the formula exhibits diffusion-controlled drug release mechanism, but the % of release suggests stronger association between the drug and the hydrogel matrix. Try fitting the dissolution data to other mathematical models to get a better analysis for the release mechanism
By using the model Korsmeyer-peppas in the diffusion studies I obtain the coefficient of release rate. However, I was wondering if I can simply determine by a slope of % released vs time the diffussion rate?