The functional attributes of co-processed excipients in direct compression

The pharmaceutical industry is increasingly adopting co-processed excipients as alternatives to conventional excipients in tablet manufacturing despite certain regulatory challenges. Co-processing of excipients was designed to optimize physical powder properties such as flowability, compressibility, and compactibility, which are critical attributes for efficient tablet production, especially by means of direct compression. This review summarizes the various preparation methods of co-processed excipients and comprehensively discusses the role of co-processed excipients over conventional pharmaceutical excipients in enhancing tablet formulation as well as tablet manufacturing efficiency and consistency due to their improved functionality. Furthermore, the functionality and enhancement of performance of co-processed excipients are discussed on the three levels of solid substances, namely the molecular, particle and bulk levels. It further evaluates the effectiveness of co-processed excipients in addressing common formulation challenges such as moisture, lubricant sensitivity and strain rate sensitivity.