Reactive Fractal Dimension of Scopolamine Bromide Release from Hydrogel

Overview

First-order release kinetics is characterized by a linear dependence of the release rate on thereleased amount of the active ingredient, the triple of the absolute value of the exponent of theexponential function expressing the reactive fractal dimension DR. Scopolamine bromide releasefrom hydroxypropylmethylcellulose hydrogel was first expressed by first-order kinetics with anestimated DR ranging from 2.98–3.00. The employment of an exponential equation with theexponent of release n renders it possible to make an assumption about the mechanism of release.Within a range of n=0.505–0.550, estimated DR=2.46–2.94. In this region, release by means of themechanism of Fick’s diffusion prevails.DR=(3/n) – 3 generally holds true for the relationship betweenboth variables, which makes it possible to use the knowledge gained in the experimental influencingof the exponent of release in the examination of the relationship between the reactive fractaldimension and the mechanism of release of scopolamine bromide from hydrogel. An increase in theexponent of release markedly decreases the corresponding values of reactive fractal dimension.

Key words:
reactive fractal dimension – release kinetics – scopolamine bromide – hydrogel