Enhanced water-solubility and mucoadhesion of N,N,N-trimethyl-N-gluconate-N-homocysteine thiolactone chitosan

Preparation and Properties of Minocycline-Loaded Carboxymethyl Chitosan Gel/Alginate Nonwovens Composite Wound Dressings

“…According to the different substitution sites of carboxymethyl groups, carboxymethyl chitosan can be divided into three types: N , O -carboxymethylated chitosan, O -carboxymethylated chitosan and N -carboxymethylated chitosan. Carboxymethyl chitosan biomaterials can be fabricated in neutral water medium, thus maintaining the activity of active substances such as small molecule drugs, proteins and cells, which expands the application range of chitosan [23,24,25,26]. Meanwhile, carboxymethyl chitosan possesses better sustained and controlled drug release performance [27,28,29,30].…”

Preparation and Characterization of Novel Cationic Chitosan Derivatives Bearing Quaternary Ammonium and Phosphonium Salts and Assessment of Their Antifungal Properties

“…As shown in Figure 2 , the signals at 3.0–5.0 ppm are assigned to the protons of glucosamine unit of chitosan and the peak at 2.0 ppm is assigned to the methyl protons of the N -acetyl group [ 7 , 11 ]. Compared with the peaks of chitosan, the 1 H-NMR spectrum of compound 1 shows a prominent –N + (C H 3 ) 3 peak at 3.1 ppm [ 31 , 32 ] along with the resonance peak at 4.4 ppm corresponding to the methylene protons of –COC H 2 Cl group [ 27 , 29 ]. Compared to compound 1 , it can be clearly seen from the 1 H-NMR spectra of chitosan derivatives 2a and 2b in Figure 2 that the characteristic resonance at 4.4 ppm for –COC H 2 Cl weakens greatly while new signals appear at 1.2-2.7 ppm in compound 2a , which are assigned to the protons of methyl and methylene moieties, and the resonances at 7.5–8.0 ppm are responded to the phenyl protons in compound 2b [ 18 , 32 ].…”

“…In contrast to chitosan, chitosan derivatives undergo a major weight loss from about 190 °C to 300 °C and 65–71% of their masses are decomposed up to 800 °C. In the second stage, the temperatures at the maximum degradation rate values of chitosan and chitosan derivatives 1 , 2a and 2b are 315, 236, 233 and 237 °C, respectively, which indicates that chemical modification has a significant influence on the thermal stability of chitosan which may be due to the introduction of functional groups, which can break the intramolecular and intermolecular hydrogen bonding interaction and destroy the crystalline structure of the chitosan molecule [ 31 , 33 , 34 ]. Besides, in the third stage, the temperatures at the maximum degradation rate values registered at 405 °C and 389 °C for chitosan derivatives 2a and 2b , respectively.…”

“…It is highly soluble in acidic solutions (pH < 6.5) due to the protonation of the primary amine [ 12 , 35 ]. After trimethylation of chitosan, chitosan derivative 1 showed higher water solubility because of the high hydrophilicity of its quaternary ammonium groups [ 16 , 31 ]. Meanwhile, the introduction of quaternary phosphonium moieties into chitosan derivative 1 further improves the water solubility, especially at alkaline pH (pH > 8.0).…”

Synthesis, characterization, and antifungal evaluation of novel 1,2,3-triazolium-functionalized starch derivative

“…The decomposition temperature starts at 200°C and the highest decomposition rate is observed at 254°C, and the total weight loss in this stage is 65%. It is quite conspicuous that further modification might lead to lower thermal stability [39,40]. The introduction of functional groups has a significant influence on its thermal stability, and it is due to the changed crystalline structure of starch, especially through the loss of hydrogen bonding between starch chains [18].…”