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Updated: May 9, 2025

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Published on: August 9, 2022
Solidified ionic liquid-based formulations of metformin with enhanced GI epithelial permeability
Evangelia Tsolaki1, Fiona McCartney2, Anne Marie Healy3
1School of Chemical and Bioprocess Engineering, University College Dublin, Dublin 4, Ireland; SSPC, The Research Ireland Centre for Pharmaceuticals, School of Chemical and Bioprocess Engineering, University College Dublin, Dublin 4, Ireland; EPSRC-SFI Centre for Doctoral Training in Transformative Pharmaceutical Technologies, Ireland.
Solidifying active pharmaceutical ingredient-ionic liquids (API-ILs) using spray-encapsulation improves handling and enhances intestinal drug absorption. This novel approach boosts permeability for poorly bioavailable drugs, overcoming formulation challenges.
Area of Science:
- Pharmaceutical Sciences
- Drug Delivery
- Materials Science
Background:
- Active Pharmaceutical Ingredient-Ionic Liquids (API-ILs) enhance drug permeability but have poor handling properties.
- Lipid-based formulations (LBFs) improve absorption but suffer from low drug loading and stability issues.
- Existing challenges limit the clinical application of API-ILs and LBFs.
Purpose of the Study:
- To develop a method for transforming liquid API-ILs and LBFs into stable, high-loading solid forms.
- To evaluate the efficacy of spray-encapsulated metformin API-IL formulations for enhanced intestinal absorption.
- To investigate the role of permeation enhancers like docusate in solidified formulations.
Main Methods:
- Spray-encapsulation of lipophilic metformin API-ILs and multi-component API-IL solutions with polymers.
- Formulation of solid dosage forms containing metformin, Labrasol®, and docusate.
- In vitro characterization including self-emulsification and drug release studies.
- Ex vivo permeability assessment using rat intestinal mucosa in Ussing chambers.
Main Results:
- Spray-encapsulated solid formulations showed improved handling and self-emulsification properties.
- In vitro release profiles were superior compared to liquid formulations.
- Ex vivo studies demonstrated a 2.3- to 6.3-fold increase in metformin permeability (Papp) for solidified docusate formulations.
- A positive correlation was observed between docusate concentration and enhanced permeability.
Conclusions:
- Solidified API-IL formulations offer a promising strategy to overcome handling and bioavailability challenges.
- Spray-encapsulation provides a viable method for creating high-loading, stable drug delivery systems.
- Docusate-based API-IL formulations significantly enhance intestinal drug permeability, particularly for lipophilic drugs.
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