Conversion of Chitosan to Facilitate Preparation of Chitosan Carboxylic Salt with Moisture Absorption-Retention Abilities

2011 ◽  
Vol 396-398 ◽  
pp. 2193-2197
Author(s):  
Bao Feng Lin ◽  
Wei Wang ◽  
Yan Ming Li ◽  
Xing Quan Liang ◽  
Yu Min Du
Keyword(s):  
Salicylic Acid ◽  
Carboxylic Acid ◽  
13C Nmr ◽  
Water Solubility ◽  
Moisture Absorption ◽  
Food Preservation ◽  
Solution Properties ◽  
Ft Ir ◽  
First Time ◽  
Better Than

Different chitosan carboxylic salts were successfully prepared via a simple way using chitosan and oxalic, fumaric, salicylic acid for the first time. The characterizations of the salts were evaluated by FT-IR, 13C NMR, 1H NMR, elemental analysis, XRD. The solution properties and moisture absorption-retention abilities of the salts were compared with chitosan. The result indicated that chitosan and carboxylic acid were combined with salt bond. The properties of the salts were related to the type of carboxylic acid added and the formation of salt bond. The water-solubility, wetting effect and moisture-retention absorption abilities of the salts were better than chitosan. They therefore have the potential to substitute for chitosan for easy use as coating in food preservation.

scholarly journals SYNTHESIS OF FLAVANONE-6-CARBOXYLIC ACID DERIVATIVES FROM SALICYLIC ACID DERIVATIVE

2012 ◽  
Vol 12 (1) ◽  
pp. 70-76 ◽  
Author(s):  
Muhammad Idham Darussalam Mardjan ◽  
Retno Ambarwati ◽  
Sabirin Matsjeh ◽  
Tutik Dwi Wahyuningsih ◽  
Winarto Haryadi
Keyword(s):  
Salicylic Acid ◽  
Carboxylic Acid ◽  
Acid Derivative ◽  
Ring Closure ◽  
Hydroxybenzoic Acid ◽  
Fries Rearrangement ◽  
Acetophenone Derivatives ◽  
Ft Ir ◽  
Benzaldehyde Derivatives ◽  
Derivatives Of

Synthesis of flavanone-6-carboxylic acid derivatives had been conducted via the route of chalcone. The synthesis was carried out from salicylic acid derivative, i.e. 4-hydroxybenzoic acid, via esterification, Fries rearrangement, Claisen-Schmidt condensation and 1,4-nucleophilic addition reactions. Structure elucidation of products was performed using FT-IR, 1H-NMR, GC-MS and UV-Vis spectrometers. Reaction of 4-hydroxybenzoic acid with methanol catalyzed with sulfuric acid produced methyl 4-hydroxybenzoate in 87% yield. The acid-catalyzed-acetylation of the product using acetic anhydride gave methyl 4-acetoxybenzoate in 75% yield. Furthermore, solvent-free Fries rearrangement of methyl 4-acetoxybenzoate in the presence of AlCl3 produced 3-acetyl-4-hydroxybenzoic acid as the acetophenone derivatives in 67% yield. Then, Claisen-Schmidt condensation of the acetophenone and benzaldehyde derivatives of p-anisaldehyde and veratraldehyde in basic condition gave 2'-hydroxychalcone-5'-carboxylic acid derivatives  in 81 and 71 % yield, respectively. Finally, the ring closure reaction of the chalcone yielded the corresponding flavanone-6-carboxylic acids in 67 and 59% yield, respectively.

scholarly journals PHYTOCHEMICAL STUDY OF THE ARIAL PARTS OF Cleome rutidosperma DC PLANT

2010 ◽  
Vol 8 (3) ◽  
pp. 459-462 ◽  
Author(s):  
S. M. Mizanur Rahman ◽  
Serajum Munira ◽  
M. Amzad Hossain
Keyword(s):  
Spectral Analysis ◽  
Carboxylic Acid ◽  
Petroleum Ether ◽  
13C Nmr ◽  
Mass Spectral Data ◽  
Phytochemical Study ◽  
Mass Spectral ◽  
New Compounds ◽  
First Time ◽  
Cleome Rutidosperma

Two new compounds were identified as 2-ethyl-cyclohex-2-ene-6-hydroxy-methylene-1-carboxylic acid and 3b-hydroxy-lup-20(29)-en-28-oic acid, respectively, from the petroleum ether extracts of Cleome rutidosperma plant. These two constituents is the first time occurrence in this plant. The structures of the two different type of compounds are elucidated with the help of UV, IR, 1H-NMR, 13C-NMR, COSY, DEPT 90, DEPT 135 and mass spectral data.   Keywords: Cleome rutidosperm DC; isolation; spectral analysis

scholarly journals Preparation and Evaluation of Eudragit® L100 Nanoparticles LoadedImpregnated with KT Tromethamine Loaded PVA -HEC Insertions forOphthalmic Drug Delivery

2019 ◽  
Vol 9 (4) ◽  
pp. 593-600
Author(s):  
Ghobad Mohammadi ◽  
Shahla Mirzaeei ◽  
Shiva Taghe ◽  
Pardis Mohammadi
Keyword(s):  
Drug Delivery ◽  
Moisture Absorption ◽  
Drug Loading ◽  
Polymer Concentration ◽  
Hydroxyethyl Cellulose ◽  
Moisture Loss ◽  
Physiochemical Parameters ◽  
Ft Ir ◽  
First Time ◽  
Preparation And Evaluation

Purpose: The purpose of the present study was to improve the ocular delivery for ketorolactromethamine (KT) used to treat inflammation of the eye.Methods: Eudragit nanoparticles loaded with KT were prepared and incorporated in polyvinylalcohol (PVA) and hydroxyethyl cellulose (HEC) films. Nanoparticles were characterized byFourier transform-infrared (FT-IR), scanning electron microscopy (SEM). Physicochemicalproperties and encapsulation effciency were investigated for nanoparticles. Also, the insertswere evaluated for their physiochemical parameters like percentage moisture absorption,percentage moisture loss, thickness and folding endurance.Results: Mean particle size and zeta potential were in range of 153.8-217 nm and (-10.8) -(-40.7) mV, respectively. The results show that the use of a surfactant has not led to any majorchange on drug loading. The loading increases with the amount of polymer. The insert had athickness varying from 0.072 ± 0.0098 to 0.0865 ± 0.0035 mm. The thicknesses of the insertsand the folding endurance increased with the total polymer concentration. The physicochemicalproperties showed that the Eudragit® L-100 nanoparticles loaded PVA-HEC films could be aneffective carrier for KT.Conclusion: For the first time, inserts of Eudragit nanoparticles were successfully prepared forophthalmic drug delivery system to prevent frequent drug administration and enhance patientcompliance.<br />

Development of a Hydroxypropyl-β-Cyclodextrin Complex for Improving Water Solubility and Reducing Skin Sensitivity of Salicylic Acid

2014 ◽  
Vol 1004-1005 ◽  
pp. 919-923
Author(s):  
Yi Qing Huang ◽  
Qiang Xia
Keyword(s):  
Salicylic Acid ◽  
Water Solubility ◽  
Release Mechanism ◽  
Burst Release ◽  
Temperature Dependent ◽  
Cyclodextrin Complex ◽  
Skin Sensitivity ◽  
Release Studies ◽  
Ft Ir ◽  
Enthalpy And Entropy Changes

The present work reports on complexation of hydroxypropyl-β-cyclodextrin (HP-β-CD) with salicylic acid (SA) by vacuum evaporation and inclusion behavior confirmed by FT-IR, OM and SEM. Complex stoichiometry, release mechanism and skin sensitivity were evaluated. The results showed that SA could be encapsulated into cyclodextrin at the ratio of 1:1. Negative values of Gibbs free energy, enthalpy and entropy changes indicated a feasible, spontaneous and exothermic process. Release studies evidenced a burst release in first 2 h, followed by a sustained release and the release rate was temperature-dependent. Furthermore, an improved water solubility and significant reduced irritation effect of SA could be obtained by HP-β-CD.

Synthesis of Novel Bis-pyrazoles via Electrophilic Cyclization

2019 ◽  
Vol 16 (6) ◽  
pp. 511-516
Author(s):  
Adnan Cetin
Keyword(s):  
13C Nmr ◽  
Cyclization Reaction ◽  
Electrophilic Cyclization ◽  
Pyrazole Derivatives ◽  
Spectral Analyses ◽  
Mass Spectral ◽  
Palladium Catalyzed ◽  
Ft Ir ◽  
Reaction Compound

Efficient steps towards the synthesis of novel (phenyl)(1&#039;-aryl-1,5,5&#039;-triphenyl[3,3&#039;-bi-1Hpyrazol]- 4-yl)methanones 4a-e were developed. The procedure starts from 1-(4-benzoyl-1,5-diphenyl- 1H-3-pyrazolyl)-3-phenyl-2-propyn-1-one (2) which was synthesized by a palladium catalyzed crosscoupling reaction. Compound 2 reacted with various hydrazines to give (E)-(phenyl)[1,5-diphenyl-3- [3-phenyl-1-(2-arylhydrazono)-2-propyn-1-yl]-1H-4-pyrazolyl]methanones E-3a-e. The bis-pyrazole derivatives 4a-e were synthesized from electrophilic cyclization reaction of &#945;,&#946;-acetylenic hydrazones E-3a-e and copper(I) iodide. All synthesized compounds were characterized by FT-IR, 1H, 13C NMR and Mass spectral analyses.

scholarly journals Kinetical Study, Thermo-Mechanical Characteristics and Recyclability of Epoxidized Camelina Oil Cured with Antagonist Structure (Aliphatic/Aromatic) or Functionality (Acid/Amine) Hardeners

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2503
Author(s):  
Chiara Di Mauro ◽  
Aratz Genua ◽  
Alice Mija
Keyword(s):  
Disulfide Bonds ◽  
Mechanical Characteristics ◽  
Dicarboxylic Acids ◽  
Thermomechanical Properties ◽  
Chemical Recycling ◽  
Camelina Oil ◽  
Ft Ir ◽  
Tan Δ ◽  
The Individual ◽  
First Time

In an attempt to prepare sustainable epoxy thermosets, this study introduces for the first time the idea to use antagonist structures (aromatic/aliphatic) or functionalities (acid/amine) as hardeners to produce reprocessable resins based on epoxidized camelina oil (ECMO). Two kinds of mixtures were tested: one combines aromatic/aliphatic dicarboxylic acids: 2,2′-dithiodibenzoic acid (DTBA) and 3,3′-dithiodipropionic acid (DTDA); another is the combination of two aromatic structures with acid/amine functionality: DTBA and 4-aminophenyl disulfide (4-AFD). DSC and FT-IR analyses were used as methods to analyze the curing reaction of ECMO with the hardeners. It was found that the thermosets obtained with the dual crosslinked mechanism needed reduced curing temperatures and reprocessing protocols compared to the individual crosslinked thermosets. Thanks to the contribution of disulfide bonds in the network topology, the obtained thermosets showed recycling ability. The final thermomechanical properties of the virgin and mechanical reprocessed materials were analyzed by DMA and TGA. The obtained thermosets range from elastomeric to rigid materials. As an example, the ECMO/DTBA704-AFD30 virgin or reprocessed thermosets have tan δ values reaching 82–83 °C. The study also investigates the chemical recycling and the solvent resistance of these vitrimer-like materials.

scholarly journals Homopiperazine (Hexahydro-1,4-diazepine)

Molbank ◽  
10.3390/m1200 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1200
Author(s):  
R. Alan Aitken ◽  
Dheirya K. Sonecha ◽  
Alexandra M. Z. Slawin
Keyword(s):  
13C Nmr ◽  
Title Compound ◽  
Coupling Constants ◽  
15N Nmr ◽  
Time Data ◽  
Nmr Spectrum ◽  
X Ray ◽  
First Time

The X-ray structure of the title compound has been determined for the first time. Data on its 1H–13C-NMR coupling constants and 15N-NMR spectrum are also given.

scholarly journals Piroxicam Loading onto Mesoporous Silicas by Supercritical CO2 Impregnation

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2500
Author(s):  
Marta Gallo ◽  
Luca Serpella ◽  
Federica Leone ◽  
Luigi Manna ◽  
Mauro Banchero ◽  
...  
Keyword(s):  
Supercritical Co2 ◽  
Water Solubility ◽  
Solid Dispersions ◽  
Mesoporous Silicas ◽  
Incipient Wetness Impregnation ◽  
Pore Blocking ◽  
Physico Chemical ◽  
Adsorption From Solution ◽  
First Time ◽  
Loading Procedure

Piroxicam (PRX) is a commonly prescribed nonsteroidal anti-inflammatory drug. Its efficacy, however, is partially limited by its low water solubility. In recent years, different studies have tackled this problem and have suggested delivering PRX through solid dispersions. All these strategies, however, involve the use of potentially harmful solvents for the loading procedure. Since piroxicam is soluble in supercritical CO2 (scCO2), the present study aims, for the first time, to adsorb PRX onto mesoporous silica using scCO2, which is known to be a safer and greener technique compared to the organic solvent-based ones. For comparison, PRX is also loaded by adsorption from solution and incipient wetness impregnation using ethanol as solvent. Two different commercial mesoporous silicas are used (SBA-15 and Grace Syloid® XDP), which differ in porosity order and surface silanol population. Physico-chemical analyses show that the most promising results are obtained through scCO2, which yields the amorphization of PRX, whereas some crystallization occurs in the case of adsorption from solution and IWI. The highest loading of PRX by scCO2 is obtained in SBA-15 (15 wt.%), where molecule distribution appears homogeneous, with very limited pore blocking.

scholarly journals Effect of Antibacterial Root Canal Sealer on Persistent Apical Periodontitis

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 741
Author(s):  
Zheng Wang ◽  
Ge Yang ◽  
Biao Ren ◽  
Yuan Gao ◽  
Xian Peng ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Therapeutic Effect ◽  
Root Canal ◽  
Apical Periodontitis ◽  
Control Group ◽  
Root Canal Sealer ◽  
Root Canal Filling ◽  
First Time ◽  
Cone Beam Computer Tomography ◽  
Better Than

The infection of Enterococcus faecalis and its interacting microorganisms in the root canal could cause persistent apical periodontitis (AP). Antibacterial root canal sealer has favorable prospects to inhibit biofilms. The purpose of this study was to investigated the antibacterial effect of root canal sealer containing dimethylaminododecyl methacrylate (DMADDM) on persistent AP in beagle dogs for the first time. Persistent AP was established by a two-step infection with Enterococcus faecalis and multi-bacteria (Enterococcus faecalis, Lactobacillus acidophilus, Actinomycesnaeslundii, Streptococcus gordonii). Root canal sealer containing DMADDM (0%, 1.25%, 2.5%) was used to complete root canal filling. The volume of lesions and inflammatory grade in the apical area were evaluated by cone beam computer tomography (CBCT) and hematoxylin-eosin staining. Both Enterococcus-faecalis- and multi-bacteria-induced persistent AP caused severe apical destruction, and there were no significant differences in pathogenicity between them. DMADDM-modified sealer significantly reduced the volume of periapical lesion and inflammatory grade compared with the control group, among them, the therapeutic effect of the 2.5% group was better than the 1.25% group. In addition, E.faecalis-induced reinfection was more sensitive to the 2.5% group than multi-bacteria reinfection. This study shows that root canal sealer containing DMADDM had a remarkable therapeutic effect on persistent AP, especially on E. faecalis-induced reinfection.

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