Validation of method for rheological characterization of poloxamer 407 hydrogels used for 3D bioprinting

In recent years, the research and development of new dosage forms manufactured by 3D bioprinting technique (3DP) has been increasing. The polymeric materials used in 3DP (bioinks) should possess certain biological as well as mechanical and rheological characteristics. Their rheological behaviour, viscosity, elasticity and plasticity significantly influence the manufacturing process. The determination of rheological properties is essential from the point of view of uniform dispersion of the active substances, stress during controlled extrusion, liquefaction of bioinks during extrusion through the small orifices of printing nozzles, viscoelastic properties for protection against shear stress, thixotropy, the possibility of gelation, etc. Poloxamer 407 (P407) is widely used in different pharmaceutical products, but also shows great potential in 3DP as bioink due to its thermogelling characteristics (Dumortier et al., 2006). The aim of this study was to establish and validate a method for the rheological characterization of P407 hydrogel, as one of the most commonly used biopolymers for 3DP. The paper of Simões at al. (2020) was used as a guide for the validation.