Evolution of Solid Dispersion Technology: Solubility Enhancement Using Hydroxypropyl Methylcellulose Acetate Succinate: Myth or Reality?

Poorly aqueous soluble active pharmaceutical ingredients are highly risky development candidates and remain a concern of pharmaceutical industries in drug discovery and development processes. Pharmaceutical industries are putting significant efforts into the target identification and lead candidate development using combinatorial chemistry. About 40% of compounds arising from combinatorial screening are poorly water soluble. Pharmaceutical industries evolved over this challenge by coming up with reproducible and scalable particle size reduction or by identifying alternate morphs. Another important area where pharmaceutical industries are working is solid dispersion technology. With the emergence of the hot-melt extrusion and spray drying approach, many molecules have been brought to the market using solid dispersion technology from the discovery phase by improving bioavailability and thereby efficacy. Although the solid solution technology in the last 60 years evolved from eutectic mixtures, solid dispersions using water-soluble polymers, and enteric polymers especially hydroxypropyl methylcellulose acetate succinate (HPMCAS), still there is no preformulation tool to identify correct polymer or polymer combination at the early stage of development. Thus, this leads to the urgent need to focus on the design and development of third-generation solid dispersions for the unmet needs of the industries and society.