Two-Stage Supramolecular Self-Assembly-Directed Collagen-Peptide-Decorated Liposomal Complexes of Curcumin Microspheres with Enhanced Solubility and Bioavailability.

Green formulations of phytonutrients with enhanced solubility and bioavailability are of great significance in nutrition therapy. In the present contribution, we hypothesized that the collagen peptides could be a safe, natural, food-grade, and cost-effective functional agent for the surface decoration and stabilization of liposomes in powder form and hence a "green" solution for the oral delivery of phytonutrients. The present study reports a two-stage supramolecular self-assembly-directed process for the preparation of collagen peptide-decorated liposomal complexes of curcumin (CCL) [10% (w/w)] as microspheres (125 ± 25 μm) with improved solubility (1.46 × 10 5 -fold) and sustained-release properties under gastrointestinal pH conditions. The molecular self-assembly of collagen peptides around the lipid bilayers and the various noncovalent interactions and conformational changes leading to the supramolecular assembly to act as a matrix for the encapsulation of lipid vesicles of curcumin were clear from the spectroscopic studies (UV-vis, fluorescence, FTIR, and circular dichroism). Further investigation of pharmacokinetics following a randomized double-blinded controlled trial on healthy volunteers ( n = 15) demonstrated that the oral administration of 2.5 g of CCL sachet (250 mg of curcumin) enhanced the plasma concentration ( C max : 118 vs. 4.3 ng/mL), the elimination half-life (4.2 vs. 0.7 h), and bioavailability as per the area under the curve over 12 h [AUC 0-12h (CCL) = 506·8 vs. AUC 0-12h (C95) = 9.47 (53-fold)], when the plasma concentration of curcumin was estimated with triple quadruple tandem mass spectrometry (UPLC-ESI-MS/MS).