scholarly journals Phase separation in an aqueous quaternary system

1970 ◽  
Vol 117 (1) ◽  
pp. 85-89 ◽  
Author(s):  
Elizabeth Edmond ◽  
A. G. Ogston
Keyword(s):  
Phase Separation ◽  
Polyethylene Glycol ◽  
Sodium Chloride ◽  
Critical Point ◽  
Osmotic Coefficient ◽  
Water System ◽  
Dextran Sulphate ◽  
Interaction Coefficients ◽  
Chloride Water ◽  
Thermodynamic Equations

(1) We have measured the incompatible phase separation that occurs in a polyethylene glycol–sodium dextran sulphate–sodium chloride–water system and have determined a critical point. (2) We have measured the activity coefficients of sodium chloride in critical-point concentrations of polyethylene glycol and sodium dextran sulphate respectively, and the osmotic coefficient of sodium dextran sulphate at the critical-point concentration. (3) With use of the relevant thermodynamic equations for a quaternary ionic system, we have determined the interaction coefficients between polyethylene glycol and dextran sulphate and between polyethylene glycol and sodium chloride. The former could be due mainly to volume exclusion, but the latter is too large to be explained on that basis.

Salt activity and osmotic pressure in connective tissue. I. A study of solutions of dextran sulphate as a model system

1973 ◽  
Vol 183 (1073) ◽  
pp. 399-419 ◽  
Keyword(s):  
Sodium Chloride ◽  
Connective Tissue ◽  
Osmotic Pressure ◽  
Supporting Electrolyte ◽  
Suitable Model ◽  
Dextran Sulphate ◽  
Wide Range ◽  
Chloride Water ◽  
Gel Phase ◽  
Polyelectrolyte Solutions

1. The use of gel osmometry for osmotic pressure measurements on polyelectrolyte solutions is discussed, with special reference to the effect of interaction of low molecular weight supporting electrolyte with the gel, and to the effect of penetration of the gel phase by a small multivalent fraction of a polydisperse polyelectrolyte. 2. Measurements are reported of sodium chloride activity and of osmotic pressure for the system sodium dextran sulphate + sodium chloride + water. 3. The results agree well, over a wide range of concentration, with an extended version (Wells 1973) of the Manning (1969) theory of polyelectrolyte solutions. 4. Dextran sulphate is considered to be a suitable model for connective tissue proteoglycan. The colloid osmotic pressures for proteoglycan solutions under physiological conditions are calculated in order to obtain an estimate of the internal osmotic pressure of cartilage. The effects of variations in the composition of the proteoglycan, and hence of its charge density, are examined.

Conductivity of Sodium Chlorate-Sodium Chloride-Water System at High Temperature

1970 ◽  
Vol 117 (2) ◽  
pp. 279 ◽  
Author(s):  
R. A. Crawford ◽  
W. B. Darlingron ◽  
L. B. Kliever
Keyword(s):  
High Temperature ◽  
Sodium Chloride ◽  
Water System ◽  
Sodium Chlorate ◽  
Chloride Water

Development, Evaluation and Optimization of Osmotic Controlled Tablets of Aceclofenac for Rheumatoid Arthritis Management

2019 ◽  
Vol 9 (1) ◽  
pp. 29-36
Author(s):  
Bijaya Ghosh ◽  
Niraj Mishra ◽  
Preeta Bose ◽  
Moumita D. Kirtania
Keyword(s):  
Rheumatoid Arthritis ◽  
Polyethylene Glycol ◽  
Sodium Chloride ◽  
Cellulose Acetate ◽  
Hydroxypropyl Methylcellulose ◽  
Release Profile ◽  
Polyethylene Glycol 400 ◽  
Permeable Membrane ◽  
Cumulative Release ◽  
The Core

Objective: Rheumatoid arthritis is a dreaded disease, characterized by pain, inflammation and stiffness of joints, leading to severe immobility problems. The disease shows circadian variation and usually gets aggravated in early morning hours. Aceclofenac, a BCS Class II compound is routinely used in the treatment of pain and inflammation associated with rheumatoid arthritis. The objective of this study was to develop an osmotic delivery system of Aceclofenac that after administration at bedtime would deliver the drug in the morning hours. </P><P> Methods: A series of osmotically controlled systems of aceclofenac was developed by using lactose, sodium chloride and hydroxypropyl methylcellulose K100M as osmogens. Cellulose acetate (2% w/v in acetone) with varying concentrations of polyethylene glycol-400 was used as the coating polymer to create semi permeable membrane and dissolution was carried out in 290 mOsm phosphate buffer. Formulation optimization was done from four considerations: cumulative release at the end of 6 hours (lag time), cumulative release at the end of 7 hours (burst time), steady state release rate and completeness of drug release. </P><P> Results: A formulation having swelling polymer hydroxypropyl methylcellulose in the core and lactose and sodium chloride as osmogens, polyethylene glycol-400 (16.39 %) as pore former, with a coating weight of 5% was a close fit to the target release profile and was chosen as the optimum formulation. Conclusion: Aceclofenac tablets containing lactose, HPMC and sodium chloride in the core, given a coating of cellulose acetate and PEG-400 (5% wt gain), generated a release profile for optimum management of rheumatoid arthritic pain.

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