Floating gellan gum-based in situ gels containing curcumin for specific delivery to the stomach

Abstract

Keywords: Curcumin, Gastroretentive systems, Gellan gum, In situ gelling, Solid dispersion

Objectives: Curcumin has been used for several decades to treat gastric ulcers and other digestive disorders. To overcome the poor aqueous solubility and to prolong the gastric residence time of curcumin, a novel floating gellan gum-based in situ gel with incorporated curcumin-PVP K-30 solid dispersions was developed.

Methods: The solvent evaporation method was used to prepare the curcumin-PVP K-30 solid dispersions. The in situ gelling systems, was composed of a gellan gum as the base polymer, HPMC K4M as an added polymer, calcium carbonate and curcumin PVP K-30 solid dispersions. The developed formulations were evaluated for their floating abilities and drug release properties.

Results: The curcumin PVP K-30 solid dispersions (ratio 1:10) improved the curcumin solubility by approximately 4000 times higher than for curcumin powder. The X-ray diffraction study indicated that the curcumin solid dispersions were in an amorphous form. After incorporation of the solid dispersions into the in situ gelling systems, dark orange liquid preparations for oral use were obtained. The liquid floated within 5 to 7 s and its floating was maintained for more than 24 h in the test medium. The amount of curcumin released from the floating gel was between 50 to 80 % within 8 h depending on the polymer composition. The incorporation of HPMC K4M at concentrations of 1% and 2% w/v was found to retard the release of curcumin.

Conclusion: The floating gellan gum-based in situ gel incorporating curcumin as a solid dispersion was successfully developed. The selected formulation (G2) comprised 0.5 % w/v gellan gum, 0.5% w/v calcium carbonate, 0.25% w/v sodium citrate and a 0.55% w/v of curcumin solid dispersion. The results demonstrated that the newly formulated in situ gelling systems had the potential to be used for the stomach-specific drug delivery of a poorly water soluble substance such as curcumin.