Phase separation of cellulose derivatives during hot-melt extrusion – an enabler for the development of next-generation of pharmaceutics

The development of solid oral pharmaceutics faces these challenges:The new drugs have lower water-solubility than before, giving lower bioavailabilityThe cost for pharmaceutics must decreaseThe patients´ compliance must increaseThe emissions of greenhouse gases must decreaseInitial experiments in our research group have shown that the cost-efficient hot-melt extrusion (HME) process of model drugs and binary polymer blends gave amorphous solid dispersions (ASDs), a common way to increase bioavailability.

These formulations showed also extended drug release because phase-separation occurred during the extrusion step and the drug became mainly distributed in one of the polymer domains.

This Ph.D. student project will focus on the phase-separation mechanism of the bio-based cellulose derivatives, the most common pharmaceutical-approved polymers, and correlate the size of the phase-domains, determined by SEM and X-ray methods developed within the project, to the Hansen solubility parameters (HSP) for the polymers and model drugs.

The hypotheses are that larger phase-separated domains will be found for extruded binary polymer blends with larger distances in the Hansen space, and a higher amount of drug molecules will be found in the polymer phase with the most similar HSP.

This will control the drug release rate since drug molecules distributed in the more hydrophilic polymers phases will release faster. Our project thus aims to meet all the challenges mentioned above.