New biodegradable polymers are needed for use in drug delivery systems to overcome the high burst release, lack of sustained release, and acidic degradation products frequently observed in current microparticle formulations. Commercially available poly(lactide-<i>co</i>-glycolide) (PLGA) is often used for particle drug release formulations; however, it is often limited by a large burst release and acidic degradation products. Therefore a new biocompatible and biodegradable tyrosol-derived poly(ester arylate) library has been used to prepare a microparticle drug delivery system which shows sustained delivery of hydrophobic drugs. A continuous flow particle preparation method has been optimized to prepare particles ranging from 60-150 µm in diameter. A range of tyrosol-derived polymers were selected due to their varying physical and thermal properties. A variety of drug solubilizing co-solvents were tested to load model drugs curcumin, dexamethasone, nicotinamide, and acyclovir. Drug encapsulation was highest when drug was loaded as a solid suspension. Hydrophobic drugs curcumin and dexamethasone were successfully loaded up to 50 weight percent (wt.%) and a linear correlation between drug wt.% loaded and particle glass transition temperature was observed. Both curcumin and dexamethasone were visible on the particle surface at 20 wt.% loading and higher. By adjusting the polymer concentration during particle formation, release rates were able to be controlled. Release studies of dexamethasone from a lower concentration formulation showed a biphasic release profile and complete release after 47 days. Particles prepared using a higher polymer concentration showed sustained release for up to 77 days. Comparably, PLGA showed a traditional triphasic release and complete release after 63 days. This novel tyrosol-derived poly(ester arylate) library can be used to develop injectable, long-term release formulations capable of providing sustained drug delivery.

Tyrosol derived poly(ester-arylate)s for sustained drug delivery from microparticles

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.