Formulation-Dependent Extrudability of Highly Filled Alginate System for Vaginal Drug Delivery

Area of Science:

• Materials Science
• Biomedical Engineering
• Pharmaceutical Sciences

Background:

• Hydrogels are versatile materials for drug delivery.
• Incorporating solid fillers can enhance hydrogel properties.
• Alginate hydrogels offer tunable characteristics for biomedical applications.

Purpose of the Study:

• To investigate alginate-based hydrogels filled with metronidazole (MTZ) for extrusion-based drug delivery.
• To analyze the impact of alginate and MTZ content on rheological properties, stability, and drug dissolution.
• To establish correlations between composition and material properties for predictive modeling.

Main Methods:

• Preparation of alginate-based hydrogels with varying alginate and metronidazole (MTZ) concentrations using internal gelation with CaCO3.
• Rheological characterization of precursor suspensions and hydrogels.
• Assessment of hydrogel stability in acetate buffer (pH 4.5).
• Evaluation of MTZ dissolution and release kinetics.

Main Results:

• Precursor solutions exhibited shear-thinning behavior, intensified by higher alginate concentrations.
• Addition of MTZ above saturation concentration significantly increased viscosity and introduced yield stress.
• Formulations maintained extrudability despite increased viscosity.
• MTZ particles influenced viscoelastic behavior but not crosslinking.
• Alginate concentration dictated hydrogel stability and MTZ release/dissolution.

Conclusions:

• Alginate-metronidazole hydrogels demonstrate tunable rheological properties and stability for extrusion-based drug delivery.
• Compositional control is key for optimizing hydrogel performance in drug delivery systems.
• The findings provide a foundation for developing predictive models for highly filled hydrogel systems.