Wetting properties of bile salt solutions and dissolution media. 2000

P E Luner
Division of Pharmaceutics, College of Pharmacy, University of Iowa, Iowa City, Iowa 52242, USA. paul-luner@uiowa.edu

The objective of this study was to determine the extent to which specific bile salt solutions and compendial dissolution media differ in their ability to wet a model surface. Solutions were examined in the concentration range of bile salts found in the gastrointestinal tract and at pH values approximating those of the stomach and small intestine. Wetting was evaluated from measurement of the surface tension of the solutions and contact angles of sessile drops on poly(methyl methacrylate). Compendial dissolution media had higher surface tensions and contact angles than bile salt solutions at 10 mM. Individual bile salts at 10 mM varied in surface tension lowering and contact angles. The contact angle-concentration profiles achieved plateau values at 2.5 mM. Dewetting was observed at low bile salt concentrations at pH 7.5. Calculated adhesion tension and interfacial tension were consistent with this behavior. The effect was attributed to the influence of the substrate surface charge on the orientation of the adsorbed bile salt molecule. Adhesion tension profiles showed that from low (<0.5 mM) to moderate (2 mM) concentrations preferential bile salt adsorption to the liquid-vapor interface occurred, but at higher values (>2 mM) the preference shifted toward the solid-liquid interface. These results have implications in the design of physiologically based dissolution media.

UI MeSH Term Description Entries
D007202 Indicators and Reagents Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499) Indicator,Reagent,Reagents,Indicators,Reagents and Indicators
D000465 Algorithms A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task. Algorithm
D001647 Bile Acids and Salts Steroid acids and salts. The primary bile acids are derived from cholesterol in the liver and usually conjugated with glycine or taurine. The secondary bile acids are further modified by bacteria in the intestine. They play an important role in the digestion and absorption of fat. They have also been used pharmacologically, especially in the treatment of gallstones. Bile Acid,Bile Salt,Bile Salts,Bile Acids,Acid, Bile,Acids, Bile,Salt, Bile,Salts, Bile
D012996 Solutions The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed) Solution
D013500 Surface Tension The force acting on the surface of a liquid, tending to minimize the area of the surface. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed) Interfacial Force,Interfacial Tension,Surface Tensions,Tension, Surface,Tensions, Surface
D013816 Thermodynamics A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed) Thermodynamic
D014906 Wetting Agents A surfactant that renders a surface wettable by water or enhances the spreading of water over the surface. Wetting Agent,Agent, Wetting,Agents, Wetting
D019904 Polymethyl Methacrylate Polymerized methyl methacrylate monomers which are used as sheets, moulding, extrusion powders, surface coating resins, emulsion polymers, fibers, inks, and films (From International Labor Organization, 1983). This material is also used in tooth implants, bone cements, and hard corneal contact lenses. PMMA,Polymethylmethacrylate,Acron,Acrylic Bone Cement,CMW Bone Cement,Implast,Kallocryl K,Lucite,Methyl Acrylic Plastic,Palacos R,Palavit,Perspex,Plexiglas,Plexiglass,Poly(methyl methacrylate),Polymethyl Methacrylate, Isostatic,Polymethyl Methacrylate, Simplex Opaque,Polymethyl Methacrylate, Surgical Simplex Bone Cement, Ammonium Salt,Polymethyl Methacrylate, Surgical Simplex P,Polymethyl Methacrylate, Syndiostatic,Polymethylmetacrylate,Sol,Superacryl,Isostatic Polymethyl Methacrylate,Methacrylate, Polymethyl,Methacrylate, Syndiostatic Polymethyl,Syndiostatic Polymethyl Methacrylate
Copied contents to your clipboard!