Synthesis and In Vitro Evaluation of Thiolated Carrageenan.

Journal of pharmaceutical sciences (2015-06-04)
Wongsakorn Suchaoin, Sonja Bonengel, Shah Hussain, Christian W Huck, Benjamin N Ma, Andreas Bernkop-Schnürch
ABSTRACT

The aim of this study was to generate and characterize a thiolated carrageenan. Thiolated carrageenan (carrageenan-SH) was synthesized from kappa (κ)- and iota (ι)-carrageenan by bromine replacement of the hydroxyl moieties followed by substitution to thiol groups using thiourea. Thiolated κ- and ι-carrageenan exhibited 176.57 ± 20.11 and 109.51 ± 18.26 μmol thiol groups per gram polymer, respectively. The resazurin test in Caco-2 cells revealed no toxic effect of both thiolated carrageenans at a concentration below 0.1% (w/v). Regarding efflux pump inhibitory effect, cellular accumulation of multidrug-resistance protein 2 substrate, sulforhodamine 101, was 1.38- and 1.35-fold increased in cells treated with thiolated κ- and ι-carrageenan, respectively. Modification of κ- and ι-carrageenan led to 3.9- and 2.0-fold increase in dynamic viscosity of mucus-thiolated carrageenan mixture within 4 h. Furthermore, residence time of κ- and ι-carrageenan-SH on porcine intestinal mucosa was 6.4- and 1.8-fold prolonged, respectively, as demonstrated by rotating cylinder method, indicating improved mucoadhesive properties. Hence, thiolation of carrageenans led to novel pharmaceutical excipients for various applications.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Water, Nuclease-Free Water, for Molecular Biology
Sigma-Aldrich
HEPES, ≥99.5% (titration)
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Water, sterile-filtered, BioReagent, suitable for cell culture
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HEPES, BioPerformance Certified, ≥99.5% (titration), suitable for cell culture
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N,N-Dimethylacetamide, anhydrous, 99.8%
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Triphenylphosphine, ReagentPlus®, 99%
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Resazurin sodium salt, powder, BioReagent, suitable for cell culture
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N-Bromosuccinimide, ReagentPlus®, 99%
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Thiourea, ACS reagent, ≥99.0%
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HEPES buffer solution, 1 M in H2O
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N,N-Dimethylacetamide, ReagentPlus®, ≥99%
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Water, for molecular biology, sterile filtered
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Water, for embryo transfer, sterile-filtered, BioXtra, suitable for mouse embryo cell culture
SAFC
HEPES
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Thiourea, ReagentPlus®, ≥99.0%
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HEPES, BioUltra, for molecular biology, ≥99.5% (T)
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Resazurin sodium salt, certified by the Biological Stain Commission
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HEPES
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N,N-Dimethylacetamide
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Ethanesulfonic acid, 95%
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Triphenylphosphine, polymer-bound, 100-200 mesh, extent of labeling: ~3 mmol/g triphenylphosphine loading
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Water, for cell biology, sterile ultrafiltered
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Sulforhodamine 101
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HEPES, BioXtra, suitable for mouse embryo cell culture, ≥99.5% (titration)
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Triphenylphosphine, ≥95.0% (GC)
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Triphenylphosphine, polymer-bound, 100-200 mesh, extent of labeling: ~3.0 mmol/g loading, 2 % cross-linked with divinylbenzene