Characterization of enteric-coated capsules filled with colchicine loaded zein nanoparticles for colon delivery

In this study, we developed a dual pH and time-dependent formulation for targeted colonic release, aiming at minimizing adverse effect and enhancing anticancer efficacy of colchicine in the treatment of colorectal cancer.

To achieve this, colchicine was loaded in zein nanoparticles (Col-Z NP) which were further optimized and encapsulated in Eudragit S100 coated capsules. A full factorial design was employed to determine the optimal condition for preparation of Col-Z NP.

The optimized Col-Z NPs exhibited a spherical shape with particle size of 104.3 ± 1.6 nm, polydispersity index of 0.27 ± 0.01, zeta potential of 29.0 ± 0.1 mV, encapsulation efficiency of 59.8 ± 4.8%, release efficiency over 8 h of 45.5 ± 2.7%, and drug loading of 13.0 ± 0.0%. No notable difference in cytotoxicity was observed between free colchicine and Col-Z NPs at comparable concentrations. The cellular uptake study showed more uptake for coumarin 6 loaded Z NPs compared to free coumarin 6. Colchicine release from coated capsules was restricted to around 3% in gastric medium and increased to about 8% in simulated intestine medium, respectively.

Results suggest that Eudragit S100 coated capsules containing Col-Z NP could be effective delivery system for colchicine to target colorectal tumors.