scholarly journals Magneto-sensitive hybrid nanocomposites of water-soluble sodium alginate cross-linked with calcium ions and maghemite

2018 ◽  
Vol 12 (5) ◽  
pp. 452-461 ◽  
Author(s):  
V. V. Spiridonov ◽  
I. G. Panova ◽  
L. A. Makarova ◽  
S. B. Zezin ◽  
A. A. Novakova ◽  
...  
Keyword(s):  
Sodium Alginate ◽  
Calcium Ions ◽  
Water Soluble ◽  
Hybrid Nanocomposites

scholarly journals DESIGN AND EVALUATION OF CONTROLLED-RELEASE OCULAR INSERTS OF BRIMONIDINE-TARTRATE AND TIMOLOL MALEATE

2016 ◽  
Vol 9 (1) ◽  
pp. 79 ◽  
Author(s):  
Preethi G. B. ◽  
Prashanth Kunal
Keyword(s):  
Controlled Release ◽  
Drug Release ◽  
Sodium Alginate ◽  
Calcium Chloride ◽  
Release Kinetics ◽  
Water Soluble ◽  
Moisture Loss ◽  
Timolol Maleate ◽  
Brimonidine Tartrate

<p><strong>Objective: </strong>The current work was attempted to formulate and evaluate a controlled-release matrix-type ocular inserts containing a combination of brimonidine tartrate and timolol maleate, with a view to sustain the drug release in the cul-de-sac of the eye.<strong></strong></p><p><strong>Methods: </strong>Initially, the infrared studies were done to determine the drug–polymer interactions. Sodium alginate-loaded ocuserts were prepared by solvent casting technique. Varying the concentrations of polymer—sodium alginate, plasticizer—glycerine, and cross-linking agent—calcium chloride by keeping the drug concentration constant, made a total of nine formulations. These formulations were evaluated for its appearance, drug content, weight uniformity, thickness uniformity, percentage moisture loss, percentage moisture absorption, and <em>in vitro </em>release profile of the ocuserts. Finally, accelerated stability studies and the release kinetics were performed on the optimised formulation.<strong></strong></p><p><strong>Results: </strong>It was perceived that polymer, plasticizer, and calcium chloride had a significant influence on the drug release. The data obtained from the formulations showed that formulation—F9 was the optimised formulation, which exhibited better drug release. The release data of the optimised formulation tested on the kinetic models revealed that it exhibited first-order release kinetics. <strong></strong></p><p><strong>Conclusion: </strong>It can be concluded that a natural bioadhesive hydrophilic polymer such as sodium alginate can be used as a film former to load water soluble and hydrophilic drugs like brimonidine tartrate and timolol maleate. Among all formulations, F9 with 400 mg sodium alginate, 2% calcium chloride and 60 mg glycerin were found to be the most suitable insert in terms of appearance, ease of handling, thickness, <em>in vitro</em> drug release and stability.</p>

A fluoride selective water-soluble anion receptor based on a 1,2-phenylenediacetic acid and calcium ion dimer

2019 ◽  
Vol 43 (34) ◽  
pp. 13690-13695
Author(s):  
Dae Hyup Sohn ◽  
Nayeon Kim ◽  
Soonmin Jang ◽  
Jongmin Kang
Keyword(s):  
Calcium Ions ◽  
Calcium Ion ◽  
Water Soluble ◽  
Anion Receptor ◽  
Fluoride Ions

The dimeric receptor 1 from 1,2-phenylenediacetic acid and calcium ions recognized fluoride ions almost exclusively in 100% water.

Preparation and swelling behaviour of a novel anti-salt superabsorbent hydrogel based on kappa-carrageenan and sodium alginate grafted with polyacrylamide

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Ali Pourjavadi ◽  
Hossein Ghasemzadeh ◽  
Hossein Hosseinzadeh
Keyword(s):  
Sodium Alginate ◽  
Graft Copolymerization ◽  
Weight Ratio ◽  
Homogeneous Solution ◽  
Water Soluble ◽  
Swelling Kinetics ◽  
Salt Solutions ◽  
Superabsorbent Hydrogel ◽  
Swelling Capacity ◽  
Kappa Carrageenan

Abstract A novel superabsorbent hydrogel was synthesized via crosslinking graft copolymerization of acrylamide (AAm) onto kappa-carrageenan (κC) and sodium alginate (Na-Alg) backbones in a homogeneous solution. Methylenebisacrylamide (MBA) and potassium persulfate (KPS) were applied as water-soluble crosslinker and initiator, respectively. FTIR spectroscopy was used for confirming the structure of the final product. A mechanism for superabsorbent hydrogel formation was also suggested. The parameters affecting the swelling capacity of the synthesized hydrogel, i.e., κC-Alg weight ratio, concentration of AAm, MBA and KPS, as well as reaction temperature were systematically optimized for obtaining maximum absorbency. The swelling capacity of hydrogels was also measured in various salt solutions (LiCl, NaCl, KCl, MgCl2, CaCl2, SrCl2, BaCl2, and AlCl3). Due to their high swelling ability in salt solutions, the hydrogels may be referred to as ‘anti-salt superabsorbent’ polymers. The overall activation energy for the graft copolymerization reaction was found to be 374 kJ/mol. The swelling kinetics of the hydrogels in distilled water and in saline solution (0.9 wt.-% NaCl) was investigated.

scholarly journals Calcium ions and cell fusion. Effects of chemical fusogens on the permeability of erythrocytes to calcium and other ions

1979 ◽  
Vol 182 (2) ◽  
pp. 555-563 ◽  
Author(s):  
A M J Blow ◽  
G M Botham ◽  
J A Lucy
Keyword(s):  
Cell Fusion ◽  
Calcium Ions ◽  
Biological Membranes ◽  
Human Erythrocytes ◽  
Water Soluble ◽  
Chemically Induced

1. Fusogenic and non-fusogenic chemicals were tesetd for their ability to allow 45Ca2+ and 3H2O to enter hen and human erythrocytes. 2. The ratio of 45Ca2+/3H2O in treated cells to that in untreated cells is referred to as the entry ratio. 3. Within 1 min at 37 degrees C both water-soluble and lipid-soluble fusogens increased the value of the entry ratio, which reached maximum values in 5–10 min. 4. Values of the entry ratio in the range of 4–12 were found under conditions that led to cell fusion. 5. Closely related but non-fusogenic chemicals did not significantly alter the entry ratio. 6. The entry ratios for 86Rb+, 22Na+ and 35SO42- were also significantly increased by both lipid-soluble and water-soluble fusogens, though the increases were not as large as those for 45Ca2+. 7. It is suggested that fusogenic compounds increase the permeability of biological membranes to ions, and that an increase in the concentration of intracellular Ca2+ initiates or facilitates events that lead to the chemically induced fusion of erythrocytes.

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