Rate-dependent mechanical properties of dry blended pharmaceutical powder formulations for tabletting applications

Pharmaceutical tablets are formed using formulations consisting of ingredients such as filler, binder, disintegrant, and active pharmaceutical ingredients. In the present study, these formulations were tested to determine mechanical properties at low to medium pressure regime using a medium pressure (< 10. MPa) flexible boundary cubical triaxial tester. Hydrostatic and conventional triaxial compression tests were conducted at 10 and 20. MPa/min loading rates. Fundamental elastic, elastoplastic, and rate-dependent properties such as bulk modulus, compression index, spring-back index, shear modulus, and failure stress were determined from these tests. The bulk modulus increased linearly in all cases with pressure. At 10. MPa/min loading rate, the bulk modulus value increased with the binder content. The compression index values increased with pressure in all cases of 10 and 20. MPa/min loading rates. At 10. MPa/min, the compression index generally decreased with the binder content. The spring-back index increased with the increase in pressure at both 10 and 20. MPa/min loading rates. At 10. MPa/min, the spring-back value decreased with the binder content. Shear modulus and failure stress values increased with the increase in the confining pressure. The effect of binder on failure stress values was not very prominent. These results were further used to predict the tablet quality parameters.