The aim of this study was the synthesis and evaluation of an entirely S-protected thiolated silicone as novel hydrophobic mucoadhesive and skin adhesive. 2-[(2-Amino-2-carboxyethyl)disulfanyl]nicotinic acid was covalently attached to a poly(dimethylsiloxane)-graft-polyacrylate via amide bond formation. Adhesive properties were determined via the rotating cylinder method and tensile studies on porcine small intestinal mucosa besides on porcine abdominal skin. Rheological characteristics were evaluated on a cone-plate rheometer. The S-protected thiolated silicone exhibited 128 ± 18 μmol immobilized 2-mercaptonicotinic acid per gram of polymer and showed a 5.9-fold extended time of mucosal adhesion compared with the unmodified silicone on the rotating cylinder. With a 2.3-fold higher maximum detachment force and a 1.7-fold higher total work of adhesion tested on porcine small intestinal mucosa, the S-protected thiolated silicone is superior to the unmodified silicone. Furthermore, using porcine abdominal skin, a 2.4-fold higher maximum detachment force and a 4.4-fold higher total work of adhesion obtained for the S-protected thiolated silicone outlines the preferentially adhesion to skin. Triggered by N-acetyl-L-cysteine liberated thiol groups form interchain and intrachain disulfide bonds within the polymer (6.7% m/v) causing a 23.0-fold increase in dynamic viscosity (ƞ). In parallel, the elastic modulus (G') and the viscous modulus (G") increased 39.2-fold and 8.1-fold, respectively.
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http://dx.doi.org/10.1016/j.xphs.2019.04.003 | DOI Listing |
Int J Pharm
May 2024
Center for Chemistry and Biomedicine, Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria. Electronic address:
Aim: This study aims to design chemically crosslinked thiolated cyclodextrin-based hydrogels and to evaluate their mucoadhesive properties via mucosal residence time studies on porcine small intestinal mucosa and on porcine buccal mucosa.
Methods: Free thiol groups of heptakis(6-deoxy-6-thio)-β-cyclodextrin (β-CD-SH) were S-protected with 2-mercaptoethanesulfonic acid (MESNA) followed by crosslinking with citric acid. Cytotoxicity was assessed by hemolysis as well as resazurin assay.
ACS Omega
February 2024
Center for Chemistry and Biomedicine, Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria.
This study aimed at designing an S-protected thiolated β-cyclodextrin (β-CD) exhibiting enhanced mucoadhesive properties. The native β-CD was thiolated with phosphorus pentasulfide resulting in a thiolated β-CD (β-CD-SH) and subsequently S-protected with 2-mercaptoethanesulfonate (MESNA) to form β-CD-SS-MESNA. The structure of the novel excipient was confirmed by H NMR and Fourier-transform infrared spectroscopy.
View Article and Find Full Text PDFACS Biomater Sci Eng
December 2023
Center for Chemistry and Biomedicine, Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
Nanoemulsions can be tuned toward enhanced gastro-intestinal retention time by incorporating thiolated surfactants into their surface. Tailoring the chemical reactivity of the thiol headgroup has major influence on mucoadhesive features of the nanoemulsion. Two generations of thiolated surfactants were synthetically derived from PEG-40-stearate featuring either a free thiol group or an S-protected thiol group.
View Article and Find Full Text PDFACS Appl Mater Interfaces
August 2023
Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
Chitosan (Ch) and different Ch derivatives have been applied in tissue engineering (TE) because of their biocompatibility, favored mechanical properties, and cost-effectiveness. Most of them, however, lack cell adhesive properties that are crucial for TE. In this study, we aimed to design an S-protected thiolated Ch derivative exhibiting high cell adhesive properties serving as a scaffold for TE.
View Article and Find Full Text PDFPharmaceuticals (Basel)
June 2023
Department of Pharmacology and Toxicology, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
Mucoadhesive nanosized crystalline aggregates (NCs) can be delivered by the gastrointestinal, nasal, or pulmonary route to improve retention at particular sites. Itopride hydrochloride (ITH) was selected as a drug candidate due to its absorption from the upper gastrointestinal tract. For drug localization and target-specific actions, mucoadhesive polymers are essential.
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