Understanding the Effect of Diluents on Powder Flow and Tablet Properties of Poorly Compressible Black Pepper Extract...

The application of black pepper extract in dietary supplement formulations is often limited by its inherently poor compressibility, which renders direct compression into tablets problematic. Therefore, the selection of appropriate diluents to enhance the compressibility of black pepper extract is essential. This study employed an augmented simplex lattice design comprising three diluents: microcrystalline cellulose (MCC) PH102, spray-dried lactose (SDL), and dibasic calcium phosphate (DCP). The powder flowability of the black pepper aqueous extract, both alone and in combination with the specified diluents, was evaluated using various parameters: angle of repose, bulk density, tapped density, compressibility index, and Hausner ratio. Subsequently, 600 mg tablet formulations containing 100 mg of black pepper aqueous extract were prepared under a compression pressure of 1500 psi, and the physical characteristics of the resulting tablets, including hardness, friability, and disintegration time (DT), were measured. The findings indicated that SDL exhibited superior flowability compared with MCC and DCP. For tablet formulations, MCC emerged as the most effective diluent, demonstrating optimal parameters: high hardness, low friability, and minimal DT. Specifically, the optimal tablet formulation achieved a hardness ranging from 8.63 to 9.04 kgf, with friability between 0.07% and 0.29%, and DT between 2.73 and 4.42 min. Verification of these results demonstrated predictive accuracy with low residual values. In summary, this investigation highlights the pivotal role of diluents in enhancing the compressibility and overall tablet characteristics of black pepper aqueous extract. Among the evaluated diluents, MCC PH102 proved to be the most effective in promoting the desired tablet properties, thereby facilitating the direct compression of this otherwise poorly compressible substance.