Direct compression tablet containing 99% active ingredient – a tale of spherical crystallization
Direct compression (DC) is the easiest and most cost-effective process for tablet manufacturing, since it only involves blending and compression. However, active pharmaceutical ingredients (API) generally exhibit poor mechanical and micromeritic properties, which necessitate dilution and the use of high percentage of excipients to enable a robust DC manufacturing process. Consequently, drug loading in DC tablets is usually low (typically < 30%, w/w). In this study, spherical crystallization by the quasi-emulsion solvent diffusion method was used to engineer a poorly flowing model compound, ferulic acid (FA), to attain superior mechanical properties, particle size distribution, and morphology. The engineered FA particles enabled the successful development of DC tablets containing 99% FA, which is in sharp contrast to the maximum 10% FA loading using as-received FA. The record high API loading in this work illustrates the potential for spherical crystallization to overcome low drug loading when developing a tablet product using the DC manufacturing process.