Master thesis : Formulation and evaluation of carboxymethyl chitosan-based biomaterials for indications in degenerative pathologies (including introduction to research methodology)

Abstract

Osteoarthritis affects hundreds of millions of people worldwide and no disease-modifying therapy is currently available. KiOmed Pharma has developed KiOmedine®, a CE-marked intra-articular injectable formulation based on carboxymethyl chitosan (CsC), whose prolonged clinical effects remain only partially understood. This master’s thesis addresses three methodological development needs in the characterisation of CsC-based biomaterials: a visualisation tool for CsC in joint tissues, experimental data on the influence of CsC on collagenase activity, and an analytical method for assessing the homogeneity of CsC microbead formulations in pre-filled syringes.

Fluorescent labelling was achieved through EDC-mediated covalent coupling of fluorescein to CsC, followed by purification. Collagenase activity was evaluated using a FALGPA-based spectrophotometric assay. Homogeneity assessment of microbead syringes was explored by screening four analytical approaches : extrusion force measurement, turbidimetry, spectrophotometry and rheology.

The optimised labelling protocol produced a strong fluorescence signal, although the labelling efficiency and its impact on polymer properties warrant further investigation. Neither CsC nor the complete injectable formulation showed any measurable influence on collagenase activity under the tested conditions. Among the methods evaluated, rheology was the only technique capable of reliably detecting intra-syringe variations in microbead content, with complex viscosity proving particularly sensitive to subtle concentration differences.

Together, these results provide a methodological foundation for the further characterisation and development of CsC-based biomaterials in the context of degenerative joint diseases, with direct relevance to the biological understanding of KiOmedine® and to the development of microbead-based injectable products.