Aggregation and Morphological Aptitude of Drug-Based Ionic Liquids in Aqueous Solution

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Pharmaceutical Chemistry

Background:

• Ionic liquids (ILs) are tunable solvents with unique properties.
• Traditional ILs often use simple inorganic counterions.
• Incorporating pharmaceutically active ions offers new functionalities.

Purpose of the Study:

• To synthesize and characterize novel drug-based ionic liquids (DF-ILs).
• To investigate the impact of replacing inorganic anions with diclofenate (DF-) on IL properties.
• To explore the aggregation behavior and interfacial characteristics of these new ILs.

Main Methods:

• Synthesis of 1-alkyl-3-methylimidazolium diclofenate ([C_nmim][DF]) ionic liquids.
• Small-angle neutron scattering (SANS) and transmission electron microscopy (TEM) for aggregate structure.
• Isothermal titration calorimetry (ITC) and conductivity measurements for thermodynamics.
• Pyrene fluorescence to probe local polarity and packing.

Main Results:

• DF-ILs show a 300-fold lower critical aggregation concentration than chloride analogues.
• Synergistic interactions between [C_nmim]+ and DF- were observed, enhancing hydrophobicity.
• Improved interfacial properties were noted compared to chloride-based ILs.
• Vesicle formation was observed, even for shorter alkyl chains like [C₆mim][DF].

Conclusions:

• Replacing inorganic anions with active pharmaceutical anions significantly modifies IL interfacial and bulk properties.
• Drug-based ILs demonstrate superior aggregation behavior and potential for self-assembly.
• These findings open avenues for designing advanced functional materials and drug delivery systems.