Optimization Of Co-Processed Excipients For Direct Compression Of High-Dose Apis: Comparative Study And Formulation Development

Abstract

Direct compression (DC) remains the most cost-effective and streamlined manufacturing route in solid dosage formulation, yet its application is often limited by the poor mechanical properties of high-dose active pharmaceutical ingredients (APIs). This study investigated the optimization and maximum carrying capacity of the co-processed excipient Prosolv (Silicified Microcrystalline Cellulose) for the direct compression of a high-dose, highly cohesive API with poor flowability and compressibility: Paracetamol (500 mg). The core objective was to bypass traditional granulation steps entirely. Formulations were developed using varying percentages of Prosolv, lubricated with 0.5% magnesium stearate, and subjected to a range of compression forces. The formulations yielded defect-free tablets with satisfactory size and robust compressibility profile; however, this success was exclusively achieved at high excipient concentrations of 50% and 60% Prosolv. These findings challenge the initial hypothesis that standard co-processed excipients can readily accommodate high-dose formulations at low percentages to maintain standard tablet weights. While Prosolv successfully mitigated the poor compaction properties of Paracetamol, the required high excipient load limits its practicality for highdose APIs due to the resulting large tablet size, and the cost of manufacturing the tablets at a large scale with this particular formulation. Consequently, further studies are required to explore alternative coprocessed excipient composites or altered component ratios to optimize direct compression for highdose formulations