Characterization and in vitro degradation of poly(octadecanoic anhydride)

Area of Science:

• Polymer Chemistry
• Materials Science
• Biomaterials

Background:

• Polymeric materials are crucial in various applications, requiring tailored degradation properties.
• Understanding polymer erosion mechanisms is key to designing materials for specific uses, such as in controlled drug delivery or temporary implants.

Purpose of the Study:

• To synthesize and characterize Poly(octadecanoic anhydride) (POA).
• To investigate the in vitro degradation behavior of POA in different pH conditions.
• To compare the degradation characteristics of POA with other poly(anhydride)s like poly(sebacic anhydride) (PSA).

Main Methods:

• Synthesis of POA via melt polycondensation.
• Characterization using Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and wide angle X-ray diffraction (WAXD).
• In vitro degradation studies in phosphate buffer at pH 7.4 and acidic conditions (pH 5.98) at 37°C, analyzed by weight loss and Scanning Electron Microscopy (SEM).

Main Results:

• POA degradation involves both surface erosion (moving front) and bulk erosion (porous shell).
• POA shows a very slow degradation rate in acidic conditions (1.64% weight loss over 20 days).
• POA completely degrades within 18 days in basic buffer (pH 7.4), exhibiting higher crystallinity and a slower hydrolytic rate compared to PSA.

Conclusions:

• POA presents a unique, tunable degradation profile suitable for applications requiring controlled erosion.
• Its slow degradation in acidic media and complete degradation in basic media offer potential for pH-responsive biomaterials.
• POA's properties, including higher crystallinity and slower hydrolysis than PSA, make it a promising alternative poly(anhydride).