Exploring solid lipid nanoparticles to enhance the oral bioavailability of curcumin

Scope: Curcumin, a molecule with pluripharmacological properties, was loaded into solid lipid nanoparticles (SLNs) with a view to improve its oral bioavailability (BA). Methods and results: Curcumin-loaded solid lipid nanoparticles (C-SLNs) with an average particle size of 134.6 nm and a total drug content of 92.33 +/- 1.63% was produced using a microemulsification technique. The particles were spherical in shape, with high drug entrapment of 81.92 +/- 2.91% at 10% drug loading. The in vitro release was predominantly by diffusion phenomenon and was prolonged up to 7 days. No significant variation in particle size and curcumin content of C-SLNs was observed, upon storage, over a period of 12 months at 5 +/- 3 degrees C. In vivo pharmacokinetics performed after oral administration of C-SLNs (50, 25, 12.5 and 1 mg/kg dose) and (free) solubilized curcumin (C-S; 50 mg/kg), using a validated LC-MS/MS method in rat plasma revealed significant improvement (at p < 0.05) in BA (39 times at 50 mg/kg; 155 times at 1 mg/kg; and, 59 and 32 times at 12.5 and 25 mg/kg, respectively) after administration of C-SLNs at all the doses with respect to C-S. Conclusions: Enhanced and reliable BA will help in establishing its therapeutic usefulness especially for neurodegenerative and cancerous disorders in humans.