Hansen solubility parameters (HSP) for prescreening formulation of solid lipid nanoparticles (SLN): in vitro testing of curcumin-loaded SLN in MCF-7 and BT-474 cell lines

Abstract

Curcumin, a phenolic compound from turmeric rhizome (Curcuma longa), has many interesting pharmacological effects, but shows very low aqueous solubility. Consequently, several drug delivery systems based on polymeric and lipid raw materials have been proposed to increase its bioavailability. Solid lipid nanoparticles (SLN), consisting of solid lipid matrix and a surfactant layer can load poorly water-soluble drugs, such as curcumin, deliver them at defined rates and enhance their intracellular uptake. In the present work, we demonstrate that, despite the drug’s affinity to lipids frequently used in SLN production, the curcumin amount loaded in most SLN formulations may be too low to exhibit anticancer properties. The predictive curcumin solubility in solid lipids has been thoroughly analyzed by Hansen solubility parameters, in parallel with the lipid-screening solubility tests for a range of selected lipids. We identified the most suitable lipid materials for curcumin-loaded SLN, producing physicochemically stable particles with high encapsulation efficiency (>90%). Loading capacity of curcumin in SLN allowed preventing the cellular damage caused by cationic SLN on MCF-7 and BT-474 cells but was not sufficient to exhibit drug’s anticancer properties. But curcumin-loaded SLN exhibited antioxidant properties, substantiating the conclusions that curcumin’s effect in cancer cells is highly dose dependent.

Keywords:

• Curcumin
• solid lipid nanoparticles
• solubility
• Hansen solubility parameters
• cell viability
• MCF-7 cells
• BT-474 cells

Acknowledgements

The authors would like to thank Prof. Verónica Zea Bermudes and Dr. Mariana Fernandes for the help with measuring the DSC thermograms for this work, Isabel Conceição for assistance and Dr. Andjelka Kovacevic for discussion on the solubility parameters calculations.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Financial support was from Portuguese Science and Technology Foundation (FCT) under references SFRH/BD/60552/2009 and SFRH/BPD/101650/2014 granted to SD. We also acknowledge FCT/MCT and European Funds (PRODER/COMPETE) under the projects M-ERA-NET-0004/2015-PAIRED, UID/AGR/04033/2013 and UID/QUI/50006/2013 co-financed by FEDER, under the Partnership Agreement PT2020.