Summary
Darunavir is a poorly water-soluble antiretroviral drug whose delivery benefits from being formulated as fine particles and protected from the acidic stomach. This study uses coaxial electrospraying — a single-step technique based on concentric (co-axial) nozzles — to build core–shell nanoparticles in which a core of darunavir nanocrystals is encapsulated within a shell of the enteric polymer Eudragit L100. Feeding separate core and shell solutions through the coaxial nozzle, the authors produced particles that were characterised for morphology, physical state, encapsulation efficiency and in-vitro dissolution. The Eudragit L100 shell acted as a gastro-resistant (enteric) coating, sharply limiting drug release in acidic medium so that release occurs later, at intestinal pH. The work demonstrates coaxial electrospraying as a versatile one-step route to enteric-coated nanoparticulate drug formulations.