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.
