Structure characterization and construction analysis of a calcium-vitamin D3 co-delivery aqueous solution system based on α-cyclodextrin/casein phosphopeptide

A aqueous co-delivery system for calcium ions (Ca 2+ ) and vitamin D 3 (VD 3 ) was developed to achieve their co-loading and synergistic release. The quaternary complex α-cyclodextrin-VD 3 @casein phosphopeptide‑calcium chelate (α-CD-VD 3 @CPP-Ca 2+ ), prepared from α-CD-VD 3 and CPP-Ca 2+ , exhibited a particle size of 419.46 ± 1.52 nm and a zeta potential of −28.39 ± 1.21 mV. Spectroscopic analysis revealed that α-CD-VD 3 and CPP-Ca 2+ were associated via hydrogen bonds and van der Waals forces. The complex showed good dispersibility in aqueous solution and enhanced stability across different pH values and salt ion environments. In vitro release experiments indicated that the complex remained stable in simulated gastric fluid (SGF) and achieved high release efficiencies of 78.39 % for VD 3 and 84.12 % for Ca 2+ in simulated intestinal fluid (SIF). This study provides an effective solution for improving the synergistic utilization of VD 3 and Ca 2+ .