Study of the Tableting Properties of MCR, a Newly Coprocessed Cellulose-based Direct Compression Excipient

In this work, the aim was to coprocess and evaluate a new cellulose-based direct compression tableting excipient (MCR) of improved functionalities by granulation and slugging from locally extracted microcrystalline cellulose and regenerated cellulose (CRC).

Model tablet formulations of metronidazole (MZ) as a model of nonfreely flowing and directly incompressible active pharmaceutical ingredient were designed to study the tableting properties of MCR.

The results showed that the optimum concentration of CRC needed to produce excipient of accepted flow properties and high compression characteristics was 20% w/w. MCR performed better than the parent components either singly or in a simple binary mixture. MZ tablets of enhanced mechanical properties and fast disintegrating and dissolving rates were compressed from MCR. The crushing strength (H) and the disintegration rate constant (k_d) increased from 3.76 to 11.08 kg and from 0.92 to 13.1×10^-3 s^-1 for the tablets made with 50% w/w MCR, respectively.

Both the H and k_d values of a given MZ tablet batch were found to be functions of the total number of bonding sites (α) available in the excipient in the given batch. MCR was unfortunately sensitive to magnesium stearate. The obtained result revealed that MCR is a successful complementary direct compression excipient.