Polyhydroxyalkanoates as Promising Materials in Biomedical Systems

Polyhydroxyalkanoates (PHAs) are the natural polymers that have been a subject of a significant research interest in the past few decades. The PHAs (natural as well as their synthetic analogs) as biodegradable and biocompatible polymers were studied intensively for biomedical applications, that is, scaffolds for tissue engineering. Drug-loaded implants or scaffolds based on these polyesters were also used in the drug release systems. Drug delivery systems should provide an optimal release profile of an active compound that allows to increase therapeutic effect, decrease side effects, and improve patient convenience and compliance. Therefore, recently, the increasing interest is focused on the use of PHA as drug carriers because of significant improvement in the bioavailability of bioactive substances. Recent developments introduced such strategies as conjugation of the drug with low-molecular-weight poly(3-hydroxybutyrate) or preparation of PHA particles loaded with the drug. On the contrary, there is a growing interest in functionalized PHA technology. The advancement of these strategies allows to obtain the targeting systems based on the chemical modification, for example, by folic acid attachment or biosynthesis of targeting proteins on the PHA particle surface. In addition, the PHAs were presented as materials that could be used in transdermal administration of bioactive substances for medical or cosmetic purposes. The development of novel functionalized PHAs has opened new possibilities to combine good biocompatibility of PHA-based drug delivery systems with improved drug loading and release properties, targeting, or imaging possibilities. Further progress in PHA-based drug delivery systems is expected because of the combination of excellent biocompatibility of these biopolymers and strong beneficial effect on drug administration.

Keywords: Polyhydroxyalkanoates, Poly(3-hydroxybutyrate), Drug delivery systems, Implants, Polymeric nanoparticles, Conjugate.