Systematic screening of pharmaceutical polymers for hot melt extrusion processing: a comprehensive review

Abstract

Pharmaceutical research, whether industrial or academic, has attempted to adopt approaches most efficient for the development of innovations. With the abundance of literature and growth of modern techniques available to minimize the number of trials, research is becoming more systematic by the day. Screening and selection of polymers for a pharmaceutical formulation can be challenging, considering the variety of polymers available and under development. Multiple considerations and experimentations are required to select a polymer to attain the target product profile. In this review, a stepwise discussion of techniques useful to screen and select polymers suitable for hot melt extrusion processing are explored and reported. First of all, selecting a range of polymers available for certain formulation types, for example, immediate release or modified release. Secondly, the screening of these selected polymers based on their physical and chemical properties as these properties should be in line with the active pharmaceutical ingredients (APIs) and the processing limitations of the equipment. Finally, selecting polymers using theoretical models such as solubility parameters and Flory Huggins modeling. Utilization of these three steps before proceeding to experimental methods will minimize the use of resources and provide a higher degree of accuracy towards the development of efficient, stable, and consistent products.

Keywords: Flory Huggins modeling; Hot melt extrusion; Mechanical properties; Polymer screening; Solubility parameters; Thermal properties.