Curcumin containing monoolein aqueous dispersions: A preformulative study

• Curcumin (CR) can be solubilized in monoolein aqueous dispersions (MAD).
• Different emulsifiers result in different inner structures in the disperse phase.
• Monoolein/poloxamer/sodium cholate mixture (MCP) results in the highest CR encapsulation.
• MCP maintains CR stability for 6 months.
• Xanthan gum based MAD better control CR fluxes with respect to plain gel and liquid MAD.

The present study describes the production and characterization of monoolein aqueous dispersions (MAD) as drug delivery systems for curcumin (CR).MAD based on monoolein and different emulsifiers have been produced and characterized. Morphology and dimensional distribution have been investigated by Cryogenic Transmission Electron Microscopy (cryo-TEM), X-ray and Photon Correlation Spectroscopy (PCS).Monoolein in different mixtures with sodium cholate, sodium caseinate, bentonite and poloxamer resulted in heterogeneous dispersions constituted of unilamellar vesicles, cubosomes and sponge type phases, depending on the employed components, as found by cryo-TEM and X-ray studies. CR was encapsulated with entrapment efficiencies depending on the MAD composition, particularly the highest was reached in the case of monoolein/poloxamer/sodium cholate mixture. The same mixture was able to maintain CR stability also after 6 months.CR release modalities were in vitro investigated in order to mimic a possible subcutaneous administration of MAD. It was found that MAD constituted of monoolein/poloxamer and monoolein/poloxamer/sodium cholate mixtures were able to sustain CR release.MAD viscous vehicles were produced by xanthan gum.CR percutaneous absorption has been studied in vitro using excised human skin membranes [stratum corneum epidermis (SCE)] mounted into Franz cells. It was found that fluxes (Fn) of CR incorporated in MAD are influenced by the presence of monoolein based nanosystems. In particular xanthan gum based MAD better control CR diffusion from MAD.