Enhanced Pulsatile Drug Release from Injectable Magnetic Hydrogels with Embedded Thermosensitive Microgels

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Nanotechnology

Background:

• Conventional hydrogel drug delivery systems often suffer from short-term stability and limited control over release kinetics.
• Achieving sustained and precisely controlled pulsatile drug release remains a challenge in therapeutic applications.

Purpose of the Study:

• To develop injectable nanocomposite in situ-gelling hydrogels for controlled pulsatile drug delivery.
• To investigate the drug release profiles and long-term stability of these novel hydrogel systems.
• To evaluate the potential of these nanocomposites for physiologically relevant drug delivery.

Main Methods:

• Fabrication of nanocomposite hydrogels incorporating superparamagnetic iron oxide nanoparticles (SPIONs) and thermoresponsive microgels.
• In situ gelation capability assessed for minimally invasive injection.
• Pulsatile drug release studies conducted using a model drug (4 kDa fluorescein-labeled dextran) under varying conditions.
• Evaluation of release over multiple cycles and extended periods (days).
• Assessment of microgel transition temperature optimization for pulsatile release.
• Degradability and cytocompatibility of nanocomposite components were verified.

Main Results:

• The developed nanocomposite hydrogels demonstrated successful in situ gelation for injection.
• A significant ~4-fold enhancement in drug release was achieved during the 'on' state compared to the 'off' state.
• Pulsatile release properties were maintained over multiple cycles and for multiple days, outperforming previous systems.
• Optimal pulsatile release was correlated with microgel transition temperature set just above physiological temperature.
• The nanocomposites exhibited degradability and their components were found to be cytocompatible.

Conclusions:

• Injectable nanocomposite hydrogels containing SPIONs and microgels offer a promising platform for controlled pulsatile drug delivery.
• These materials provide sustained drug release over extended periods, overcoming limitations of existing technologies.
• The demonstrated degradability and cytocompatibility support their potential for safe and effective in vivo applications.