Rheological aspects of the flow of thermosensitive chitosan systems during injection application

The aim of this paper was to conduct preliminary instrumental tests to determine the possibility of injection applications for thermosensitive chitosan systems, including injection needles and application conditions. Among the many biomedical and pharmaceutical applications of chitosan, the minimally invasive thermosensitive scaffolds that form in vivo are an interesting solution. Despite many studies on colloidal chitosan systems undergoing sol-gel phase transition, almost no studies have examined their injectability. It has been stated that the use of acetic acid as a solvent reduces the forces needed for injection. Moreover, the key impact of injection temperature was determined. Storing the medium at room temperature before the injectability test led to a decrease in the value of forces needed for injection. The obtained results are discussed based on the change of the rheological properties of the chitosan hydrogels.