Alginate beads for colon specific delivery of self-emulsifying curcumin

The aim of this study was to develop calcium alginate beads containing self-emulsifying curcumin (SE-Cur) for colon targeting. All formulations were prepared by ionotropic gelation and coated with Eudragit® S-100. The beads were characterized for particle size, drug encapsulation and drug release. Encapsulation efficiency was in the range of 85–98%. The formulations containing a mixture of SE-Cur, 2–4% alginate and 0.1 or 0.3 M calcium chloride could prevent early curcumin release in simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 6.8) and >60% of the drug was released in simulated colonic fluid (pH 7.4) within 12 h, while the total drug release from the beads containing curcumin powder in all media was only 10–20%. The emulsion droplet sizes in simulated colonic fluid were in the range of 120–202 nm. SE-Cur released from the beads showed cytotoxic ability against the human colon adenocarcinoma cell lines (HT-29) with an IC50 of 10 μg/mL. In addition, the reducing power assay (antioxidant activity) was linearly proportional to the concentration of the SE-Cur released. Our results demonstrate the potential use of SE-Cur loaded alginate beads for the delivery of poorly soluble drugs to the colon.

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