Controlled drug release is a demand for many pharmaceutics to become useful. This can be achieved in different ways, for example by having a coating that surrounds a unit containing the drug. The transport of the drug can be controlled by creating pores in the coating via addition of pore forming agents. This presentation summarizes and demonstrates the ability of using the phase separation of bio-based polymers to achieve pores. We used a mixture of the cellulose derivatives hydroxypropyl cellulose (a water-soluble polymer) and ethylcellulose (water- insoluble polymer) and dissolved these polymers in an organic solvent (ethanol). During the coating process, the dry content increases, which leads to that the two polymers undergo spinodal decomposition. Upon exposure to aqueous medium the water-soluble polymer dissolves and is transport out from the coating, where the remaining coating contains a porous structure. The pore structure depends on the phase separation, which is sensitive to the ratio between water-soluble and water-insoluble polymers, the molecular weights of the polymers, the process conditions during the coating etc. It was concluded that the drug release rate correlated to the pore structure, and where we were able to simulate the permeability and drug release rate.

Control of drug release rate by phase separation of cellulose derivatives

ACS Spring Meeting 2021

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