Correlation between in vitro and in vivo erosion behaviour of erodible tablets using gamma scintigraphy

In vitro and in vivo erosion behaviour of erodible tablets consisting of glyceryl behenate and low-substituted hydroxypropylcellulose manufactured using three different methods: direct compression (DC), melt granulation (MG) and direct solidification (DS) was investigated. In vitro erosion behaviour was studied using gravimetric and scintigraphic methods. For scintigraphic investigations, the radiolabel was adsorbed onto activated charcoal and incorporated into tablets at a concentration that did not affect the erosion profile. A clinical study was carried out in six healthy volunteers using gamma scintigraphy. Tablet erosion was affected by the preparation method and was found to decrease in the order of preparation method, DC > MG > DS tablets. The mean in vivo onset time for all tablets (DC: 6.7 ± 3.8 min, MG: 18.3 ± 8.1 min, DS: 67 ± 18.9 min) did not differ significantly from in vitro onset time (DC: 5.3 ± 1 min, MG: 16.8 ± 3.9 min, DS: 61.8 ± 4.7 min). The mean in vivo completion times were found to be 36.6 ± 9.7 (DC tablets), 70 ± 18.3 min (MG tablets) and 192.5 ± 39.9 min (DS tablets). Among the three different erodible tablets, MG tablets showed the highest correlation between in vitro and in vivo mean erosion profile and suggested a potential platform to deliver controlled release of water-insoluble compounds.