Simultaneous axial and radial swelling studies from 2D stereozoom images of tablet compacts composed of superdisintegrants

Abstract

Swelling-based disintegration is considered important for drug release from tablets and can be modified with excipients called tablet disintegrants. Swelling of tablets occurs axially and radially, and most researchers have observed both these events separately using 2D images. In the current work, we have studied these events simultaneously instead of separately under a stereozoom microscope for tablet compacts composed of high proportions of disintegrants (sodium starch glycolate, SSG and croscarmellose sodium, CCS), using water as the disintegrating medium. A hypothesis is proposed for the measurements of radial and axial swellings from a single 2D image, as horizontal lengths based on trigonometric functions for a right-angle triangle. All predicted axial and radial lengths (as per proposed hypothesis) are found validated with respect to vernier calliper measurements for dry-tablet compacts with a minute error of 3.809%. The axial swelling is approximately fivefolds more than that of radial swelling on the basis of normalised lengths. No particular trend can be spotted exclusively in favour of a superdisintegrant; however, the CCS-based tablets have shown higher swelling as compared to SSG-based tablets. From the current studies, it is evident that both axial and radial dimensions are obtainable from single 2D stereozoom images and can be successfully implemented for swelling studies of tablets.