Oligoethylene Phosphoramidate-Based Kinase Inhibitor Prodrugs - Solubility, Enzyme Inhibition, and Hydrolysis

Area of Science:

• Medicinal Chemistry
• Drug Discovery
• Cancer Therapeutics

Background:

• Kinase inhibitors are crucial cancer therapeutics, but poor water solubility limits their efficacy.
• Oligo ethylene glycol (OEG) chains can improve drug solubility, but controlled cleavage is needed for therapeutic action.
• The length of OEG chains significantly impacts solubility and binding affinity of drug conjugates.

Purpose of the Study:

• To investigate the impact of oligo ethylene glycol (OEG) chain length on the water solubility of kinase inhibitors.
• To synthesize and evaluate drug-OEG conjugates using a pH-labile phosphoramidate linker.
• To understand the relationship between OEG chain length, solubility, enzyme inhibition, and pH-induced hydrolysis.

Main Methods:

• Synthesis of a library of drug-OEG conjugates for Ceritinib, Crizotinib, Palbociclib, and Ribocilib with varying OEG repeat units (n=2, 3, 4, 8).
• Assessment of water solubility for synthesized drug-OEG conjugates.
• Evaluation of enzyme inhibition activity and pH-induced hydrolysis kinetics.

Main Results:

• A maximum in water solubility was observed for OEG chain lengths of n=3 or n=4 repeat units.
• Small variations in OEG chain length (n) significantly influenced water solubility.
• Other properties, such as enzyme inhibition, remained relatively comparable across different OEG chain lengths.

Conclusions:

• Oligo ethylene glycol (OEG) chain length is a critical factor in optimizing the water solubility of kinase inhibitors.
• The pH-labile phosphoramidate linker facilitates the development of soluble drug conjugates with tunable properties.
• Targeted OEG chain length optimization can enhance the delivery and efficacy of kinase inhibitor cancer therapeutics.