Cysteinylprolyl ester-mediated drug release from a lipid-drug conjugate

Area of Science:

• Medicinal Chemistry
• Drug Delivery Systems
• Bioconjugation Chemistry

Background:

• Lipidation of small-molecule drugs can extend circulation half-life via albumin binding.
• Existing methods for drug release often require non-physiological conditions.
• Developing self-immolative linkers for controlled drug release is crucial for therapeutic efficacy.

Purpose of the Study:

• To modify the cysteinylprolyl ester (CPE) system for self-immolative linker applications.
• To enhance the release of gemcitabine from a lipid-gemcitabine conjugate under physiological conditions.
• To investigate the potential of this system for extending the biological activity of high-clearance drugs.

Main Methods:

• Modification of the CPE system by incorporating a methyl group at the α-position of cysteine.
• Synthesis of lipid-gemcitabine conjugates with the modified CPE linker.
• Evaluation of gemcitabine release kinetics in the presence of bovine serum albumin and/or 2-mercaptoethanesulfonic acid.

Main Results:

• The modified CPE system, Ac-Gly-(α-Me)Cys(SH)-Pro-gemcitabine, significantly promoted gemcitabine release compared to the unmodified version.
• A lipid-gemcitabine conjugate (16) demonstrated gentle and continuous gemcitabine release under physiological conditions.
• The system shows promise for improving the pharmacokinetic profiles of various high-clearance drugs.

Conclusions:

• The α-methylated CPE system functions as an effective self-immolative linker for controlled drug release.
• This approach facilitates drug release under physiological conditions, enhancing therapeutic potential.
• The developed linker strategy is applicable to a range of high-clearance drugs, including nucleic acid and prostacyclin derivatives.