S-protected thiolated chitosan: Synthesis and in vitro characterization

Abstract

Highlights► Synthesis of a novel mucoadhesive thiolated chitosan with protected thiol groups. ► The novel conjugate exhibited promising mucoadhesive features. ► In vitro cytotoxicity of the new conjugate was evaluated and found to be non-toxic. ► Swelling behavior of the polymer decreased with the increase of protection. ► Enhanced cross linking within the novel conjugate resulted in improved stability.

Design and application of chitosan microspheres as oral and nasal vaccine carriers: an updated review

“…In the second step, the thiol group of thiolated chitosan was protected by the formation of disulfide bonds with aromatic thiol-bearing ligands. The S-protected thiolated chitosan exhibited improved mucoadhesivity, enhanced permeation effect, inhibited efflux pump, bioavailability, and controlled release profile compared to the corresponding thiolated and unmodified polymers, 109,127,128 demonstrating that TCMs prepared using S-protected thiolated chitosan are a promising chitosan-based mucoadhesive polymer for the development of various mucosal vaccine delivery systems.…”

“…[109][110][111][112][113][114] Among various thiomer-based carriers, thiolated CMs (TCMs) are highly popular because of their strong mucoadhesiveness and ability to control and extend drug release profiles with improved permeation ability. [115][116][117][118][119] TCMs can be prepared by immobilizing the thiol-bearing chain on the polymeric backbone of chitosan ( Figure 3).…”

“…126 Recently, Bernkop-Schnurch et al performed several studies using aromatic thiol-bearing ligands for the synthesis of S-protected thiolated chitosan and evaluated their efficacy as mucosal drug delivery carriers. 109,127,128 To prepare the S-protected thiolated chitosan, the thiol-bearing ligand was covalently attached to chitosan as the first step of modification. In the second step, the thiol group of thiolated chitosan was protected by the formation of disulfide bonds with aromatic thiol-bearing ligands.…”

Mucoadhesive polymers in ophthalmic therapy

“…There are two ways for the stabilization of thiolated polymers in solution: 1) the use of reducing agents (antioxidants) or 2) thiol group protection by already−formed disulfide bonds (Marschutz and Bernkop-Schnürch, 2002;Bernkop-Schnürch et al, 2003;Dünnhaupt et al, 2012).…”

“…In earlier studies, this type of protection was performed with pyridyl sulfhydryl (Dünnhaupt et al, 2012), 6-mercaptonicotinamide (Dünnhaupt et al, 2012, 2-mercaptonicotinamide (Wang et al, 2012;Hintzen et al, 2013) or 3-methyl-1-phenylpyrazole-5-thiol (Müller et al, 2013). Thanks to the addition of these protective agents, the thiolated polymers have improved stability and mucoadhesive, enzyme-inhibitory, permeation-enhancing and efflux-pump inhibiting properties (Dünnhaupt et al, 2012).…”