Tablets prepared by single-step granulation/tabletting: interparticulate binding mechanism and stability.

The binding mechanism of tablets prepared by single-step granulation/tabletting (SSGT), a novel technique for the production of tablets, was evaluated. SSGT yielded hard tablets having a short disintegration time due to their porous, spongelike internal structure. Calculation of the interaction factor and electrical conductance tests confirmed the presence of solid bridges that provided a higher tensile strength to these compacts in comparison to tablets prepared by conventional tabletting techniques. At high relative humidity, moisture sorption and glass-to-rubber transition of the binder (polyvinylpyrrolidone), or condensation of moisture on the internal pore surface, reduced the tensile strength of the SSGT-manufactured tablets. Contrary to tablets prepared by granulation and compression, the SSGT tablets did not harden during storage under conditions of varying relative humidity (alternating the relative humidity every 24 hr between 33% and 75%).