A case study to investigate the influence of extrusion temperature, 3D printing parameters and the use of antioxidants on the degradation of dexamethasone

The use of 3D printing techniques such as fused deposition modelling (FDM) for the manufacturing of dosage forms has become an interesting research field in pharmaceutics. When using FDM 3D printing, there are usually two temperature events that can have influence on temperature -sensitive drugs and excipients. The aim of this work was to investigate the influence of various parameters on the stability of the active ingredient dexamethasone. For this purpose, active ingredient -containing filaments were produced by hot melt extrusion and the influence of temperature and the presence of antioxidants on drug stability were investigated. Vitamin C, vitamin E and butylated hydroxytoluene were used as antioxidants. If suitable filaments were obtained, these filaments were used to 3D print test objects. In addition to the presence of antioxidants, the influence of printing parameters such as printing temperature, printing speed and print bed temperature on the active ingredient content was investigated. The variation of the temperature during the extrusion process showed an influence on the degradation of dexamethasone. Furthermore, during the investigation of the 3D printed objects, the presence of the antioxidants did not show any positive influence on the drug stability. The printing temperature was identified as a critical process parameter during 3D printing of dexamethasone, while other printing settings like the temperature of the print bed and the printing speed had no detectable influence.