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Updated: May 12, 2026

Green Synthesis, Characterization, Encapsulation, and Measurement of the Release Potential of Novel Alkali Lignin Micro-/Submicron Particles
Published on: March 1, 2024
Design and in vitro evaluation of a novel polymeric excipient for buccal applications
Flavia Laffleur1, Gul Shahnaz, Ziba Islambulchilar
1Center for Molecular Biosciences Innsbruck, Department of Pharmaceutical Technology, Institute of Pharmacy, Leopold-Franzens-University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria.
Background:
The objective of this study was to develop and evaluate a more effective mucoadhesive thiomer for buccal drug-delivery systems.
Methods:
2-iminothiolane was covalently attached to a chitosan backbone. A preactivation step followed, mediated by 6,6´dithionicotinamide, thiol groups were modified by disulfide bonds formation. Mucoadhesion studies were performed on buccal mucosa. In addition, water-uptake capacity, disintegration, release and cytotoxicity studies were completed.
Results:
The obtained chitosan-thiobutylamidine conjugate displayed 647.4 ± 85.23 µmol/g immobilized thiol groups. Due to the preactivation, approximately 60% of thiol groups were modified by formation of disulfide bonds. Chitosan-thiobutylamidine-mercaptonicotinamide displayed 1.8-fold higher stability and 1.6-fold higher mucoadhesive properties, respectively. The release study demonstrated a 1.4-fold more prolonged drug release compared with corresponding thiomers.
Conclusion:
According to these results, preactivated thiomers demonstrate an improved stability and increased mucoadhesive properties. Therefore, they seem to be advantageous for buccal administration over corresponding thiomers and chitosan.
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