Solubility Studies of Cyclosporine Using Ionic Liquids

Area of Science:

• Green chemistry
• Materials science
• Pharmaceutical science

Background:

• Cyclosporine A is a vital immunosuppressant drug.
• Traditional purification methods using molecular solvents face limitations due to temperature constraints.
• Ionic liquids (ILs) present a promising alternative for drug solubility and purification.

Purpose of the Study:

• To investigate the solubility of cyclosporine A in various ionic liquids.
• To evaluate the potential of ILs for efficient purification of cyclosporine A.
• To explore the recovery of purified cyclosporine A from ILs.

Main Methods:

• Selection of six ionic liquids based on chemical and physical properties.
• Measurement of cyclosporine A solubility at room and elevated temperatures.
• Purification of cyclosporine A using selected ILs and IL/organic solvent biphasic systems.

Main Results:

• Cyclosporine A showed higher room temperature solubility in 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) compared to acetone.
• Solubility significantly increased with temperature in ILs, offering a wider processing window.
• Purification yielded up to ~93% purity with n-butylammonium acetate ([C4NH3][OAc]), and 95% using a biphasic system.
• Purified cyclosporine A was recovered as an amorphous solid.

Conclusions:

• Ionic liquids, particularly [C2mim][OAc] and [C4NH3][OAc], are effective solvents for cyclosporine A.
• ILs offer advantages over traditional solvents for cyclosporine A purification due to tunable temperature-dependent solubility.
• IL-based systems provide an efficient method for recovering amorphous cyclosporine A.