3D printing has enabled bench-top fabrication of customized bioengineered constructs with intricate architectures. We recently reported the synthesis and extrusion based 3D printing of a solvent-, initiator-, and monomer-free biodegradable low modulus polyester called SC5050. Such synthetic materials can be well characterized to evaluate their efficacy, the toxicity of the implants and their byproducts and the changes in their overall physical, chemical and mechanical properties over the lifetime of these implants. Although, most synthetic materials lack functional and signaling cues for integration into the physiological environment and therefore therapeutics like drugs, biologics, or cells are added to achieve optimum clinical outcomes. Such therapeutics can significantly alter the processing conditions and the physical material properties.  We examine the effect of a commonly used drug called Dexamethasone (Dex) on the 3D printing of the amorphous low modulus SC5050 polyesters. The drug-polymer interaction is characterized by plotting binary phase diagrams using the melting point depression data based on the Flory-Huggins Theory. Moreover, the effect of Dex on the rheology and 3D printing conditions of the SC5050 polyester is analyzed. We conclude that Dex is not soluble in the SC5050 polyester at the relevant 3D printing temperature. The insoluble drug physically reinforces the polymer like filler, and therefore increases the viscosity and shear modulus of the base polymer. The increase in viscosity of the Dex loaded polymer helps retain the 3D printed shape which is shown by image analysis of the 3D printed scaffolds with and without Dex. We also present the effect of the drug composition on the degradation and the rate of drug release from the 3D printed scaffolds. The presence of Dex in the 3D printed scaffolds leads to increased water permeation resulting in accelerated degradation of the SC5050 polyester scaffolds. In conclusion, we analyzed the drug – polymer interaction using temperature – composition phase diagrams and examined the effect of the presence of drug molecules on the extrusion based 3D printing of the amorphous SC5050 polyester.<br/>

Effect of drugs as fillers on the 3D print quality and degradation of a soft amorphous polyester

255th National Meeting (2018)

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