Surface crosslinking for delayed release of proxyphylline from PHEMA hydrogels.

Area of Science:

• Materials Science
• Pharmaceutical Sciences
• Biomedical Engineering

Background:

• Delayed release systems are crucial for chronotherapeutics, colon-specific delivery, and oral delivery of peptides/proteins.
• Surface crosslinking has previously been shown to modify poly(vinyl alcohol) (PVA) hydrogel release profiles, reducing burst release.

Purpose of the Study:

• To demonstrate the feasibility of delayed release of proxyphylline from poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels using surface crosslinking.
• To investigate the mechanisms behind delayed release and optimize parameters for controlled drug delivery.

Main Methods:

• Surface crosslinking of PHEMA hydrogels with varying reagent concentrations and exposure times.
• In vitro drug release studies of proxyphylline from modified PHEMA hydrogels.
• Morphological analysis of PHEMA hydrogels during swelling and drug release.

Main Results:

• Surface crosslinking significantly delayed proxyphylline release from PHEMA hydrogels.
• Reduced or eliminated initial burst release was observed.
• Near zero-order release kinetics were achieved by optimizing crosslinking parameters.

Conclusions:

• Surface crosslinking is an effective strategy for achieving delayed release of proxyphylline from PHEMA hydrogels.
• The formation of highly crosslinked surface layers and subsequent ruptures contribute to delayed release.
• Controlled surface crosslinking offers a viable method for developing advanced drug delivery systems with tailored release profiles.