Efficient mechanochemical complexation of various steroid compounds with α-, β- and γ-cyclodextrin

• Cyclodextrins/steroids inclusion complexes are easily formed in ball mills.
• Solid state grinding enhances the interaction between cyclodextrins and steroids.
• DSC was used to confirm the formation of inclusion complexes.
• Cyclodextrins/steroids 2:1 ratio gave high encapsulation efficiency (77–96%).

Mechanochemical technology enables solvent-free micronized solid dispersions and efficient molecular host–guest inclusion complexes to be formed in matrices which contain cyclodextrins (CDs). This type of complexation has been studied using α-, β- and γ-cyclodextrin with the dual aims of improving overall solubility and enhancing the bioavailability of common steroid compounds, such as cholic acids and β-sitosterols or lowering cholesterol content in products of animal origin. Several parameters have been studied and optimized: CD/compound molar ratio (1:1, 1:2, 2:1 and 3:1) in function of the cavity sizes of the three different CDs, milling time (from 5 to 40 min) and rotation speed (from 100 to 300 rpm). DSC (differential scanning calorimetry) analyses have revealed that inclusion complexes were efficiently formed after 40 min milling (200 rpm) for β-CD/cholesterol and β-CD/ugrsodeoxycholic acid (encapsulation efficiency 96% and 77% respectively). Besides steroid encapsulation/vehiculation, the mechanochemical technique may pave the way for new ideas in solventless steroid extraction from vegetal matrices with CDs.

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