Properties of κ-carrageenan aerogels prepared by using different dissolution media and its application as drug delivery systems

Highlights

• Kappa-carrageenan aerogel materials were successfully prepared by dissolution into ionic liquids.
• Dissolution into ionic liquids allows for a lower volume shrinkage with repercussions on the porosity of the aerogels.
• Aerogel matrixes prepared by dissolution into ionic liquids showed to not reduce Caco-2 cell viability.
• Controlled release of tetracycline from kappa-carrageenan matrixes was achieved at pH 7.4.
• The synthesized matrixes are promissory to be used on biocompatible controlled delivery formulations.

This work reports the synthesis of kappa-carrageenan aerogels using different dissolution and crosslinking media in order to evaluate its effects on the textural properties of the matrixes and further on the drug loading and release performance. The different aerogel samples were produced through the dissolution of the biopolymer in water with addition of potassium salts as crosslinking agents and, in two different ionic liquids (ILs) derived from imidazolium ion, being further dried with supercritical CO₂.

The samples were characterized by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), Nitrogen Adsorption-Desorption Analysis, Thermogravimetry (TGA) and Differential Scanning Calorimetry (DSC). The synthesized samples presented surface areas similar to the carrageenan aerogels being their structure constituted mainly by meso and macropores. The absence of ionic liquid in samples was demonstrated by DSC analysis and was corroborated by the cytotoxicity assays which revealed that cellular viability in Caco-2 cells was preserved.

Tetracycline was used as a model drug and loaded in two of the prepared aerogels samples. The release experiments were performed with the composites to test in vitro drug release at physiologic pH. With a higher macroporosity, the kappa-carrageenan aerogel prepared by dissolution into ionic liquid showed a higher loading capacity than the one prepared by dissolution into water and a slightly higher release rate. The matrixes were considered to present a good potential to be used as biocompatible carriers on drug controlled delivery.

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Article Information: Daniela A. S. Agostinho, Ana I. Paninho, Teresa Cordeiro, Ana V. M. Nunes, Isabel M. Fonseca, Carolina Pereira, Ana Matias, Márcia G. Ventura; Materials Chemistry and Physics, 2020.