Hot Melt Extrusion Technique for Developing Pharmaceutical Co-crystals: A Review

In the era of pharmaceutical research and development, the most challenging aspect is to enhance the physicochemical properties of drugs. Hot Melt Extrusion (HME) is a solvent-free, one-step, continuous, scalable, and industrially feasible method for developing pharmaceutical co-crystals. Co-crystallization, as a technique, has gained significant attention for its potential to modify various physicochemical properties of drugs like solubility, stability, compressibility, permeability, taste masking, and therapeutic efficacy. We determine the characteristic features of HME and explore published literature using the keywords, HME, co-crystals, and PAT, in databases, such as PubMed, Google Scholar, ScienceDirect, and Research Gate. The present review embarks on a detailed journey through the multifaceted domain of HME and its pivotal role in co-crystal development. The process parameters, such as temperature, extruder type, screw configuration, screw speed, and feed rate, are involved in determining the characteristics of the co-crystals produced. Additionally, the review explores the role of materials, including Active Pharmaceutical Ingredients (APIs), plasticizers, polymers, and other pharmaceutical aids, underlining their impact on co-crystal development. The existing literature on HME and its application for pharmaceutical co-crystal production is comprehensively surveyed. The review highlights the utility of Process Analytical Technology (PAT) in realtime process control. The role of HME in the future of pharmaceutical co-crystal development is discussed, making this review essential for researchers and industry professionals alike.