Photo-crosslinked anhydride-modified polyester and -ethers for pH-sensitive drug release

Area of Science:

• Polymer Chemistry
• Biomaterials Science
• Drug Delivery Systems

Background:

• Photo-crosslinkable polymers are advantageous for drug delivery, avoiding high processing temperatures.
• Anhydride-based polymers offer tunable degradation properties for controlled release applications.

Purpose of the Study:

• To investigate the hydrolysis and drug release characteristics of novel photo-crosslinkable poly(ether anhydride)s and poly(ester anhydride)s.
• To evaluate the pH-sensitivity of these polymers for controlled drug release.
• To assess the potential of these polymers for colon-targeted drug delivery.

Main Methods:

• Synthesis of carboxylated and methacrylated macromers from poly(ethylene glycol) or polycaprolactone and anhydrides.
• Preparation of photo-crosslinked polymer matrices with varying degradation profiles.
• Hydrolysis studies under different pH conditions (acidic to basic).
• Drug release studies using model drugs lidocaine and vitamin B12 at various pH levels.

Main Results:

• Polymer hydrolysis was pH-sensitive, degrading slowly in acidic conditions and faster in basic conditions.
• Drug release mechanisms varied with drug size: vitamin B12 release was primarily via network degradation, while lidocaine release involved diffusion and swelling.
• Minimal drug release occurred in highly acidic conditions (pH 1.3-2.1), with increased release as pH approached neutral.

Conclusions:

• The synthesized photo-crosslinkable poly(ether anhydride)s and poly(ester anhydride)s exhibit pH-sensitive degradation.
• These polymers demonstrate potential for colon-targeted drug delivery, protecting sensitive drugs in the stomach and releasing them in the intestine.
• The tunable hydrolysis and drug release properties make these polymers suitable for developing advanced drug delivery devices.