Phase-separated polymer blends for controlled drug delivery by tuning morphology

Controlling drug release rate and providing physical and chemical stability to the active pharmaceutical ingredient are key properties of oral solid dosage forms. Here, we demonstrate a formulation strategy using phase-separated polymer blends where the morphology provides a route for tuning the drug release profile. By utilising phase separation of a hydrophobic and a hydrophilic polymer, the hydrophilic component will act as a channelling agent, creating a porous network upon dissolution that will dictate the release characteristics. With ptychographic X-ray tomography and scanning transmission X-ray microscopy we reveal how the morphology depends on both polymer fraction and presence of drug, and how the drug is distributed over the polymer domains. Combining X-ray imaging results with dissolution studies reveal how the morphologies are correlated with the drug release and showcase how tuning the morphology of a polymer matrix in oral formulations can be utilised as a method for controlled drug release. Drug delivery via solid oral dosage requires a controlled release rate and physical and chemical stability of the drug within the formulation. Here, X-ray tomography and spectromicroscopy reveal how the morphology of a phase-separated polymer blend controls drug release.