Observation of curcumin-loaded hydroxypropyl methylcellulose (HPMC) oleogels under in vitro lipid digestion and in situ intestinal absorption in rats.

Curcumin-loaded nanostructured lipid carriers (Cur-NLCs)-based hydroxypropyl methylcellulose (HPMC) oleogels (Cur-NLCs-HPMC-OGs) were fabricated using a cryogel template. The effect of the HPMC viscosity grade on the oleogel characteristics and in situ intestinal absorption were examined. Highly stable Cur-NLCs were prepared with a mean particle size of 314 nm and polydispersity index of 0.275. Cur-NLCs affected the creamy texture of self-standing Cur-NLCs-HPMC-OGs. The Cur-NLCs were tightly packed as oil droplets in the network of HPMC. However, a high viscosity of HPMC-4000 led to a greater ability to entrap and prevent droplet coalescence compared to a low viscosity of HPMC-400. NLCs promoted the release of free fatty acids during in vitro lipid digestion, whereas HPMC-4000 maintained the strength and durability of oleogels against mechanical and enzymatic breakdown. The in situ loop results revealed higher curcumin absorption by Cur-NLCs-HPMC-OGs than by Cur-HPMC-OGs. HMPC-4000 showed slightly higher curcumin absorption compared to HPMC-400. • Cur-OGs and Cur-NLCs-OGs with HPMC were fabricated for improving curcumin delivery. • Cur-NLCs promoted oil and HPMC network formation to increase loading efficiency. • High-viscosity grade HPMC can entrap and stabilize oil droplets. • Cur-NLCs-HPMC-4000-OGs slowed curcumin release under acidic and neutral conditions. • High-viscosity grade HPMC prevented mechanical and enzymatic breakdown of oleogels. [ABSTRACT FROM AUTHOR]