Hyaluronan, a linear glycosaminoglycan (GAG) can be found as extracellular matrix component in connective, epithelial and neural tissues. It delivers mechanical stability, acts as water reservoir and lubricant and plays a multifaceted role in wound healing processes.
The photochemical crosslinking of chemically modified hyaluronan derivatives bearing e. g. (meth)acrylate functions, leads to stable, soft and highly cytocompatible hydrogels. Depending on the degree of hyaluronan (meth)acrylation and GAG concentration both the mechanical properties and degradation rates of the resulting gel-like materials can be adjusted in a wide range.
Hyaluronan with exceptionally high molecular weight, shows great ability to produce ultrathin fibers using electrospinning processes to form non-woven fleeces with high surface to weight ratio.
Various drugs can be integrated in such electrospun fleeces showing suitable mechanical properties for various soft tissue applications.
In our studies beta blockers like timolol were incorporated in both types of hyaluronan materials. We were interested in developing novel drug delivery systems (DDS) with controlled sustained release usable in ophthalmological applications (glaucoma therapy). We investigated different routes of timolol integration in hydrogels and electrospun fibers based on ionic interactions or covalent attachment of suitable timolol prodrugs. To stabilize hyaluronan carriers against aqueous surroundings various in-process and post-process treatment methods were tested. The degradation behavior of our hyaluronan systems is tuneable from few days to several months and can be adapted to the need of applications. Release profiles of timolol from generated DDS were investigated showing significant differences depending of the used structure, mode of drug incorporation and processing method emphasizing such hyaluronan based materials for the development of well adapted application-specific DDS.
Overall, both classical hydrogel but also electrospun fleece systems based on hyaluronan materials exhibit great potential for various medical applications including drug delivery devices and soft tissue engineering.