scholarly journals Preparation and Characterization of Large Unilamellar Vesicles Mixed With Trimethylchitosan (TMC): The Effect of Polyelectrolyte Concentration

2018 ◽  
Vol 12 (1) ◽  
pp. 134-139
Author(s):  
S.M. Van Der Merwe ◽  
N. Bouropoulos ◽  
D.A. Katsamenis ◽  
O.L. Lampou ◽  
D.G. Fatouros
Keyword(s):  
Phase Transition ◽  
Nuclear Magnetic Resonance ◽  
Differential Scanning Calorimetry ◽  
Unilamellar Vesicles ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Mucosal Delivery ◽  
Large Unilamellar Vesicles ◽  
Potential Use

Background: The effect of different concentrations of the absorption enhancer Trimethyl Chitosan (TMC) to the physicochemical properties of Large Unilamellar Vesicles (LUV) comprised of L-a-Phospahtidyl Choline (PC) were investigated in the current study. Methods: The Degree of Quartenization (DQ) of trimethylchitosan was assessed with nuclear magnetic resonance (1H NMR). The vesicles were characterized by means of Dynamic Light Scattering (DLS), ζ-potential, Differential Scanning Calorimetry (DSC) and Contact Angle Goniometry (CAG) measurements. Results: The data showed that the surface charge of the PC liposomes was significantly altered as a function of the TMC concentration, giving evidence of presence of the polyelectrolyte to the liposome’s membrane. Varying the concentration of TMC affected the phase Transition Temperature (Tm) of the lipid, verifying the miscibility of the polyelectrolyte with the lipid bilayer. The association of the polymer with the liposomes was related to the amount of the polyelectrolyte present, reflecting changes to the wettability of the dispersion as measured by CAG. Conclusion: The results demonstrated that presence of TMC significantly modified the physical properties of liposomes. Such systems might have a potential use for mucosal delivery (e.g. nasal route of administration).

scholarly journals Synthesis and characterization of solid 2-methoxycinnamylidenepyruvic acid

2008 ◽  
Vol 33 (4) ◽  
pp. 61-68 ◽  
Author(s):  
C. T. de Carvalho ◽  
A. B. Siqueira ◽  
E. Y. Ionashiro ◽  
M. Pivatto ◽  
M. Ionashiro
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Differential Scanning Calorimetry ◽  
Infrared Spectroscopy ◽  
Magnetic Resonance ◽  
Molecular Geometry ◽  
Synthesis And Characterization ◽  
Scanning Calorimetry ◽  
Purity Determination

The 2-methoxycinnamylidenepyruvic acid (2-MeO-HCP) was synthesized and characterized for nuclear magnetic resonance (¹H and 13C NMR), mass spectrometry (MS), Infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The application of DSC for purity determination is well documented in literature and is used in the analysis of pure organic compounds. The molecular geometry and vibrational frequencies of 2-MeO-HCP have been calculated.

Characterization of Main-Chain Liquid Crystal Elastomers by Using Differential Scanning Calorimetry (DSC) Method

2015 ◽  
Vol 1123 ◽  
pp. 69-72 ◽  
Author(s):  
Supardi ◽  
Y. Yusuf ◽  
Harsoyo
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Basic Principle ◽  
Main Chain ◽  
Scanning Calorimetry ◽  
Mechanical Effects ◽  
Liquid Crystal Elastomers ◽  
Dsc Method

We performed an experiment to characterize the four samples of main chain liquid crystal elastomers (MCLCEs) by using differential scanning calorimetry (DSC) method. Basic principle of this method is that difference in the amount of heat required to increase the temperature of the sample and reference is measured as a function of temperature. The temperature between the sample and reference is maintained nearly the same throughout the experiment. There were four samples with different concentrations of crosslinker we have taken, namely 8%, 12%, 14%, and 16%. The results showed that the phase transition from nematic to isotropic obtained by this method had correlation with their thermo-mechanical effects.

1H nuclear magnetic resonance, differential scanning calorimetry, and electrical conductivity studies on the phase transitions of pentylammonium chloride and the cationic self-diffusion in its rotator phase

1988 ◽  
Vol 66 (8) ◽  
pp. 1961-1969 ◽  
Author(s):  
Shigehiko Iwai ◽  
Ryuichi Ikeda ◽  
Daiyu Nakamura
Keyword(s):  
Phase Transition ◽  
Electrical Conductivity ◽  
Differential Scanning Calorimetry ◽  
Room Temperature ◽  
Stable Phase ◽  
Scanning Calorimetry ◽  
Nmr Studies ◽  
Self Diffusion ◽  
H Nmr ◽  
Rotator Phase

Measurements of 1H nmr, differential thermal analysis, and differential scanning calorimetry have revealed that solid pentylammonium chloride, cooled rapidly from room temperature, forms a mixture of the stable and metastable low-temperature phases below the phase transition temperature, Ttr (238 K). The sample annealed just below Ttr for 3 h was shown to consist of a single stable phase down to about 100 K, indicating the existence of a time-consuming phase transition taking place successively just below the normal transition. In the rotator phase obtainable above Ttr (257 K), 1H nmr studies proved the presence of axial rotation of the whole cation about the long axis, similar to n-paraffins in their rotator phase. Above room temperature, the onset of the translational self-diffusion of the cations within 2D planes in the layer structure of the rotator phase was detected by measuring the temperature dependence of electrical conductivity as well as 1H T1 and T1p. 2D self-diffusion constants and diffusional correlation times evaluated from the electrical conductivity observed between room and the melting temperatures indicate that the 2D cationic diffusion near the melting point is as fast as 3D self-diffusion in usual plastic crystals. Cationic motions in the two different rotator phases α and α′ are compared.

Synthesis and Characterizations of a Rod-Like Liquid Crystal TBO16A

2011 ◽  
Vol 181-182 ◽  
pp. 135-138
Author(s):  
Qing Lan Ma ◽  
Bao Gai Zhai ◽  
Rui Xiong ◽  
Yuan Ming Huang
Keyword(s):  
Molecular Structure ◽  
Nuclear Magnetic Resonance ◽  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Liquid Crystal ◽  
Scanning Calorimetry ◽  
Absorption Data ◽  
H Nmr ◽  
Smectic A ◽  
Smectic A Phase

A rod-like liquid crystal (LC) N,N-(terephthalaldehyde) bis (4-n-hexadecyloxyaniline) (TBO16A) was synthesized and investigated by nuclear magnetic resonance (NMR), fourier transform infrared (FTIR), differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and ultraviolet-visible (UV-vis) spectrophotometry. The FTIR,1H NMR and UV-vis absorption data confirmed the molecular structure of TBO16A. Our results demonstrated that the TBO16A can form enantiotropic smectic A phase.

Synthesis and characterization of 4-chloromethylstyrene polymers containing bulky organosilicon groups

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Kazem Dindar Safa ◽  
Mirzaagha Babazadeh
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Gel Permeation Chromatography ◽  
Synthesis And Characterization ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Gel Permeation ◽  
Covalently Linked ◽  
C Nmr

Abstract The homopolymer of 4-chloromethylstyrene and its copolymers with styrene (in 1:3 and 1:1 mole ratio) were synthesized by bulk and solution freeradical polymerisations, respectively, at 70±1°C using α,α'-azoisobutyronitrile as an initiator. Highly sterically hindered tris(trimethylsilyl)methyl (Tsi) substituents were then covalently linked to the obtained homopolymer and copolymers. The polymers were characterized by IR, 1H NMR and 13C NMR, differential scanning calorimetry (DSC) and gel permeation chromatography. DSC showed that incorporation of Tsi substituents in the side chains of homopolymer and copolymers increases the rigidity of the polymers and, subsequently, their glass transition temperature.

Characterization of a label system formed by large unilamellar vesicles for its potential use in the design of electrochemical biosensors

2018 ◽  
Vol 140 ◽  
pp. 105-113 ◽  
Author(s):  
Marcos E. Farías ◽  
M. Alejandra Luna ◽  
Ana M. Niebylski ◽  
N. Mariano Correa ◽  
Patricia G. Molina
Keyword(s):  
Electrochemical Biosensors ◽  
Unilamellar Vesicles ◽  
Large Unilamellar Vesicles ◽  
Label System ◽  
Potential Use

Gelatin and Glycerine-Based Bioadhesive Vaginal Hydrogel

2020 ◽  
Vol 17 (4) ◽  
pp. 303-311
Author(s):  
Roberta Cassano ◽  
Federica Curcio ◽  
Delia Mandracchia ◽  
Adriana Trapani ◽  
Sonia Trombino
Keyword(s):  
Differential Scanning Calorimetry ◽  
Inflammatory Process ◽  
Vaginal Mucosa ◽  
Vaginal Infection ◽  
Scanning Calorimetry ◽  
Time Intervals ◽  
Site Specific ◽  
Release Studies ◽  
Hiv Seropositive

Aim: The work’s aim was the preparation and characterization of a hydrogel based on gelatin and glycerine, useful for site-specific release of benzydamine, an anti-inflammatory drug, able to attenuate the inflammatory process typical of the vaginal infection. Objective: The obtained hydrogel has been characterized by Electronic Scanning Microscopy (SEM) and Differential Scanning Calorimetry (DSC). In addition, due to the precursor properties, the hydrogel exhibits a relevant mucoadhesive activity. Methods: The swelling degree was evaluated at two different pHs and at defined time intervals. In particular, phosphate buffers were used at pH 6.6, in order to mimic the typical conditions of infectious diseases at the vaginal level, particularly for HIV-seropositive pregnant women, and pH 4.6, to simulate the physiological environment. Results: The obtained results revealed that the hydrogel swells up well at both pHs. Conclusion: Release studies conducted at both pathological and physiological pHs have shown that benzydamine is released at the level of the vaginal mucosa in a slow and gradual manner. These data support the hypothesis of the hydrogel use for the site-specific release of benzydamine in the vaginal mucosa.

Sign in / Sign up

Export Citation Format

Share Document