FREE AND LOADED SWELLING OF SUPERDISINTEGRANTS

Jonas Auditorium

Objective. The objective of this study was to study the behavior of superdisintegrants under free and loaded conditions. Background. Superdisintegrants are characterized by their swelling ratio, which determines their capacity to disintegrate tablets. Swelling ratio is determined by weight or volume of the dry versus swollen sample. While high swelling capacity and slow swelling rate can be successfully measured by weight or volume changes, a high standard deviation is expected when swelling is negligible or very fast. Moreover, the swelling capacity and rate can be changed when isolated particles of the superdisintegrant are dispersed in the swelling medium (free swelling) or compressed into a tablet before exposed to the swelling medium (loaded swelling). We therefore developed a new effective method to measure the swelling pressure of superdisintegrants. Methods. Tablets of three different superdisintegrants were prepared with same hardness and weight. Swelling pressure was determined by the novel probe attached to the Brookfield CT3 texture analyzer; weight selling ratio of the superdisintegrants as particle and tablet was also measured. Results. Under free swelling, Explotab displayed the maximum swelling capacity, while maximum swelling pressure was obtained for Croscarmellose. We also found most water absorbed by explotab was interstitial, while it was bulk absorption for Croscarmellose. Polyplasdone showed almost same free and loaded swelling, the swelling was low and fast, which can be accounted for by its wicking action. Conclusion. Although useful for comparative studies, the free swelling data cannot be used to characterize disintegration power of superdisintegrants in tablets. Grants. NA