scholarly journals Study of the diffusion process in films sodium salt of carboxymethyl cellulose – drug

2021 ◽  
Vol 21 (4) ◽  
pp. 382-390
Author(s):  
Anzhela S. Shurshina ◽  
◽  
Elena I. Kulish ◽  
Keyword(s):  
Surface Modification ◽  
Water Vapor ◽  
Calcium Chloride ◽  
Sodium Salt ◽  
Diffusion Coefficients ◽  
Prolonged Release ◽  
Relaxation Processes ◽  
Diffusion Mode ◽  
Sorption Of Water Vapor ◽  
Amikacin Sulfate

The transport properties of medicinal films based on sodium salt of carboxymethylcellulose and the antibiotic amikacin sulfate have been studied in this work. It has been shown that the process of sorption of water vapor by such films and the release of a drug from them proceeds in an abnormal diffusion mode, which is explained by the slowdown of relaxation processes in glassy polymers, which include the sodium salt of carboxymethylcellulose. An increase of the amount of the introduced drug is accompanied by a regular decrease in the diffusion coefficients of both the process of sorption of water vapor and the release of amikacin from the films. It is noted that the formed films of sodium salt of carboxymethylcellulose-amikacin sulfate dissolve in water during the day and do not provide a prolonged release of the drug. To reduce the solubility of the films in water, the surface modification of the polymer film with calcium chloride has been carried out. It has been found that the modification does not lead to a change in the diffusion mode, but is accompanied by a regular change in the diffusion coefficients – the longer the formed films were kept in a calcium chloride solution, the lower the diffusion coefficients of the sorption of water vapor by medicinal films and the diffusion coefficients of the release of the drug amikacin from the film. It is argued that the surface modification of polymer films based on the sodium salt of carboxymethylcellulose is an effective way of imparting to them the effect of prolonging the release of a drug.

Sorption of water vapor on poly-s-carboxymethyl-l-cysteine and its sodium salt

1976 ◽  
Vol 56 (1) ◽  
pp. 132-137 ◽  
Author(s):  
Shoichi Ikeda ◽  
Kaoru Tanemura ◽  
Akira Kojima
Keyword(s):  
Water Vapor ◽  
Sodium Salt ◽  
Sorption Of Water Vapor

Diffusion Phenomena of the Oxygen and Nitrogen in Niobium by Mechanical Spectroscopy

2010 ◽  
Vol 297-301 ◽  
pp. 1346-1353
Author(s):  
Odila Florêncio ◽  
Paulo Sergio Silva ◽  
Carlos Roberto Grandini
Keyword(s):  
Diffusion Coefficients ◽  
Short Range ◽  
Annealed Sample ◽  
Relaxation Processes ◽  
Torsion Pendulum ◽  
Mechanical Spectroscopy ◽  
Interstitial Diffusion ◽  
Relaxation Parameters ◽  
Low Concentrations ◽  
Diffusion Phenomena

The short-range diffusion phenomenon (Snoek Effect) was investigated by mechanical spectroscopy measurements between 300 K and 650 K, in a polycrystalline niobium sample, containing oxygen and nitrogen, using a torsion pendulum. Experimental spectra of anelastic relaxation were obtained under three conditions: as-received sample; annealed sample and subsequently annealed in an oxygen atmosphere for three hours at 1170 K in partial pressure of 5x10-5mbar. The experimental spectra obtained were decomposed in elementary Debye peaks and the anelastic relaxation processes were identified. With anelastic relaxation parameters and the lattice parameters, the interstitial diffusion coefficients of the oxygen and nitrogen in niobium were calculated for each kind of preferential occupation (octahedral and tetrahedral). The results were compared with the literature data, and confirmed that the best adjustment is for the preferential occupation octahedral model for low concentrations of interstitial solutes, but at higher concentration of oxygen were observed deviations of experimental data for the interstitial diffusion coefficients of oxygen in niobium when compared with the literature data, this could be related to the possible occurrence of a double occupation of interstitial sites in the niobium lattice by oxygen interstitials.

scholarly journals Diffusion coefficients and electrical conductivities for calcium chloride aqueous solutions at 298.15K and 310.15K

2008 ◽  
Vol 54 (2) ◽  
pp. 192-196 ◽  
Author(s):  
Ana C.F. Ribeiro ◽  
Marisa C.F. Barros ◽  
Ana S.N. Teles ◽  
Artur J.M. Valente ◽  
Victor M.M. Lobo ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Calcium Chloride ◽  
Diffusion Coefficients ◽  
Electrical Conductivities

The Sorption of Water Vapor by Activated Charcoals. IV. Isothermals in Absense of Foreign Gases (Static Method)

1929 ◽  
Vol 33 (11) ◽  
pp. 1682-1693 ◽  
Author(s):  
A. J. Allmand ◽  
P. G. T. Hand ◽  
J. E. Manning ◽  
D. O. Shiels
Keyword(s):  
Water Vapor ◽  
Static Method ◽  
Sorption Of Water Vapor

scholarly journals Water Vapor Sorption Characteristics of Calcium Chloride-Anodized Alumina Composites

2016 ◽  
Vol 49 (3) ◽  
pp. 274-279 ◽  
Author(s):  
Yuji Suwa ◽  
Mikio Kumita ◽  
Ryotaro Noki ◽  
Akio Kodama ◽  
Yoshio Otani
Keyword(s):  
Water Vapor ◽  
Calcium Chloride ◽  
Water Vapor Sorption ◽  
Vapor Sorption ◽  
Alumina Composites ◽  
Sorption Characteristics

Sorption of Water Vapor by Vermiculite and Its Silica

1942 ◽  
Vol 34 (4) ◽  
pp. 506-508 ◽  
Author(s):  
L. A. Spitze ◽  
L. A. Hansen
Keyword(s):  
Water Vapor ◽  
Sorption Of Water Vapor

Phosphorus diffusion in silicon; influence of annealing conditions

2001 ◽  
Vol 669 ◽  
Author(s):  
J. S. Christensen ◽  
A. Yu. Kuznetsov ◽  
H. H. Radamson ◽  
B. G. Svensson
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficients ◽  
Activation Energies ◽  
Boron Diffusion ◽  
Diffusion Mode ◽  
Phosphorus Diffusion ◽  
Annealing Conditions ◽  
Boron Doped ◽  
Arrhenius Dependence ◽  
P Diffusion

ABSTRACTPhosphorus diffusion has been studied in both pure epitaxially grown silicon and Cz silicon, with a substantial amount of impurities like oxygen and carbon. Anneals have been performed in different atmospheres, N2 and dry O2, as well as in vacuum, at temperatures between 810 – 1100°C. Diffusion coefficients extracted from these anneals show no difference for the P diffusion in the epitaxially grown or the Cz silicon. The diffusion coefficients follow an Arrhenius dependence with the activation energy Ea=2.74±0.07 eV and a prefactor D0 = (8±5)×10−4 cm2/s. These parameters differ considerably from the previously reported and widely accepted values (3.66 eV and 3.84 cm2/s, respectively). However, vacuum anneals of the same samplesresult in values close to this 3.6 eV diffusion mode. Furthermore, control anneals of boron doped samples, with similar design as the phosphorus samples, suggest the same trend for boron diffusion in silicon – lower versus higher values of activation energies for nitrogen and vacuum anneals, respectively. These results are discussed in terms of the concentration of Si self-interstitials mediating the diffusion of phosphorus and boron.

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