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Stability of Acetals/Ketals Under Controlled Radical and Ring Opening Polymerization
Brandon Andrade-Gagnon1, Sofia Nieves Casillas-Popova1, Jung Kwon Oh1
1Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada.
Macromolecular Rapid Communications
|July 4, 2025
Summary
This study evaluates acid-labile groups for drug delivery. Benzaldehyde acetal (BzAc) shows stability in atom transfer radical polymerization (ATRP), while cyclohexyl ketal (CyHK) is unstable in both ATRP and ring-opening polymerization (ROP).
Area of Science:
- Polymer Chemistry
- Materials Science
- Drug Delivery
Background:
- Acid-degradable amphiphilic block copolymers (ABPs) are crucial for smart drug delivery systems.
- These polymers release therapeutics in acidic tumor tissues and endo/lysosomes.
- Poly(ethylene glycol)-based ABPs often use acetal and ketal groups, but their stability during polymerization is understudied.
Purpose of the Study:
- To investigate the stability of acetals and ketals under controlled polymerization conditions.
- To establish design principles for acid-degradable ABPs based on acid sensitivity and polymerization stability.
- To correlate hydrolysis rates with drug release kinetics in acidic environments.
Main Methods:
- Synthesis of poly(ethylene glycol)-based ABPs using controlled polymerization techniques.
- Utilizing atom transfer radical polymerization (ATRP) and tin-catalyzed ring-opening polymerization (ROP).
- Evaluating the stability of benzaldehyde acetal (BzAc) and cyclohexyl ketal (CyHK) under these polymerization conditions.
Main Results:
- Benzaldehyde acetal (BzAc) demonstrated stability under ATRP conditions.
- BzAc showed partial stability under tin-catalyzed ROP.
- Cyclohexyl ketal (CyHK) was found to be unstable under both ATRP and ROP conditions.
Conclusions:
- The stability of acid-labile groups varies significantly with polymerization methods.
- BzAc is a promising candidate for acid-degradable ABPs synthesized via ATRP.
- Understanding group stability is essential for designing controlled drug release systems with tunable hydrolysis rates.
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