Curcumin, the fat-soluble active ingredient and major compound of curcuminoids contained in the curcuma root, is known for its physiological low absorption and bioavailability. Various formulations and galenic technologies are currently available on the market. In this study, the product tested was provided as a soft gelatin capsule containing curcuminoids in an oily matrix mixed with phospholipids (oil/phospholipids [PL]-based, no new technologies applied or artificial excipients added). This was intended to improve bioavailability of curcuminoids as well as to mimic the natural digestion process of fat-soluble substances. In particular, the oral bioavailability of curcuminoids in the oil/PL-based formulation was compared with the pure curcuminoids extract alone (reference product), in a randomized, cross-over, single oral dose study design. Twelve healthy subjects were administered 200 mg curcuminoids under fasting conditions. Pharmacokinetic parameters were analyzed from individual concentration-time curves of total curcuminoids, as well as the curcumin metabolite tetrahydrocurcumin (THC). Results showed significantly higher AUC0-8h levels after the intake of the oil/PL-based formulation for total curcuminoids (205.60 vs. 112.50 ng/mL*h, P = .0001) as well as for THC (347.30 vs. 118.90 ng/mL*h, P < .0001) in comparison to the pure curcuminoids extract. Cmax was also significantly higher for both parameters analyzed (total curcuminoids: 47.54 vs. 21.16 ng/mL, P = .0001; THC: 96.69 vs. 29.83 ng/mL, P < .0001). In addition, the uptake kinetic of total curcuminoids was significantly fastened with the oil/PL-based curcuminoids formulation compared with the pure curcuminoids extract (P = .0446). These data suggest an improved impact on curcuminoids uptake of the oil/PL-based formulation and confirms its good tolerability.
Keywords: bioavailability; curcumin; curcuminoids; phospholipid.