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Thermoplastic poly(urethane) (TPU) blends allow tunable drug diffusion rates. Above 55% hydrophilic TPU, a continuous network forms, accelerating drug release via water-filled pores.

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Area of Science:

  • Materials Science
  • Polymer Chemistry
  • Drug Delivery Systems

Background:

  • Thermoplastic poly(urethane) (TPU) blends offer tunable properties for drug diffusion.
  • Hydrophilic-hydrophobic mixtures can control water swelling and drug release rates.

Purpose of the Study:

  • Assess drug diffusion rates across varying hydrophilic-to-hydrophobic TPU ratios.
  • Investigate emtricitabine permeability based on TPU mixture ratios.
  • Evaluate the extrusion process's impact on TPU mixing and drug diffusion.

Main Methods:

  • Fabrication of TPU blends with varying hydrophilic content.
  • Measurement of emtricitabine permeability through TPU matrices.
  • Analysis of polymer homogeneity and its correlation with drug diffusion.

Main Results:

  • Emtricitabine permeability showed a 736-fold range across TPU blends, significantly wider than EVA.
  • A sharp 123-fold permeability increase occurred between 50% and 55% hydrophilic TPU.
  • Hydrophilic polymer domains likely form a continuous network above 55% hydrophilic TPU.

Conclusions:

  • Hydrophilic TPU content is a critical factor in controlling drug diffusion rates.
  • A continuous hydrophilic network above 55% facilitates accelerated drug diffusion.
  • Extrusion process had minimal impact on homogeneity and drug diffusion in these TPU blends.