Applying liquisolid technique to enhance curcumin solubility: a central composite design study

Turmeric, specifically its curcuminoids such as curcumin (C₂₁H₂₀O₆), possesses extensive therapeutic benefits including anti-inflammatory, anticancer, and anti-aging properties. However, curcumin’s clinical effectiveness is significantly limited by its hydrophobic nature, leading to poor bioavailability. This study aims to enhance the solubility and bioavailability of curcumin through the development of liquisolid compact dispersion formulations. To address curcumin’s limited water solubility (3.12 mg/l at 25 °C) and high oil–water partition coefficient (\(\text{log}Kow=3.29\)), we employed a central composite design (CCD) to optimize liquisolid compact dispersion formulations. The optimization focused on the tablet’s physical properties, such as hardness, disintegration time, and dissolution rate at 30 min. Critical formulation components included Tween 80 as the liquid vehicle and Aerosil 200 as the coating material, serving as independent variables in the optimization process. The optimized formulation, containing 30 mg of Tween 80 and 75 mg of Aerosil 200, significantly improved curcumin’s dissolution rate. Experimental results confirmed the formulation’s effectiveness, with a marked reduction in the time to dissolve 63.2% of the drug to 165 min, compared to 300 min for conventional formulations. Differential scanning calorimetry and Fourier-transform infrared spectra indicated a transformation of curcumin into a non-crystalline state and the formation of hydrogen bonds with Tween 80, contributing to enhanced solubility. This study successfully demonstrates a viable strategy to enhance the bioavailability of curcumin through liquisolid compact dispersion formulations. By addressing the solubility challenges of curcumin, this technique presents a significant advancement in improving the clinical applicability of BCS class II and IV drugs, potentially benefiting a wide range of therapeutic applications.

Graphical abstract

Graphical representation of optimizing curcumin liquisolid formulation using central composite design (CCD) methodology