Thymoquinone loaded lipid nanocapsule dispersion: two methods of preparation, characterization and in vitro evaluations for oral administration

This work explores two methods to encapsulate Thymoquinone (TQ) into lipid nanocapsules (LNCs) for oral administration. TQ was added during the phase inversion temperature method (TQ-LNCs-1) or to unload LNCs dispersion (TQ-LNCs-2). LNCs were evaluated for mean diameter, polydispersity index (PDI), zeta-potential, drug loading (DL), drop tensiometer, storage stability, in vitro stability in simulated gastrointestinal fluids (SGIF), and intestinal permeability across Caco-2 cells. TQ-LNCs-1 and TQ-LNCs-2 produced NPs (58.3 +/- 3.7 nm and 61.5 +/- 3.5 nm, respectively), with a DL of 8.7 +/- 0.2 and 7.7 +/- 0.6 mg/mL of suspension, respectively. For both, less than 14% of TQ was released in SGIF, and a minor increase in TQ intestinal permeability with LNCs compared to free TQ was observed. TQ-LNCs represented a promising formulation for oral delivery of TQ. Encapsulation of TQ by adding it at LNCs dispersion can be extended for further drugs.