Release studies from lyotropic liquid crystal systems.
A temperature-composition diagram of systems containing the nonionic surfactant polyoxethylene (20) isohexadecyl ether (1) and water was established. Three different anisotropic areas existed over the concentration range 33-80% of 1. Release of salicylic acid from liquid crystalline phases of 1 into aqueous buffer across lipoidal barriers was also studied. Rates of transfer as a function of percent loading from a neat mesophase containing 37% of 1 and also from systems with different molecular packing were determined. Apparent activation energies of transfer from an ordered solvent containing 37% of 1 and from an isotropic medium of the same chemical composition were found to be 33.3 and 9.4 kcal/mol, respectively. These findings suggest a pronounced effect of medium structure on the interfacial resistance of the barrier.
Faculty of Pharmacy, University of Jordan, Amman.
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HG
Ibrahim
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D004058:Diffusion; D004735:Energy Transfer; D008051:Lipid Bilayers / Q000032:analysis*; D000074241:Peanut Oil; D010938:Plant Oils; D011060:Poloxalene; D012459:Salicylates; D020156:Salicylic Acid; D012997:Solvents; D013501:Surface-Active Agents; D013696:Temperature
D008051:Lipid Bilayers; D000074241:Peanut Oil; D010938:Plant Oils; D012459:Salicylates; D012997:Solvents; D013501:Surface-Active Agents; D011060:Poloxalene; D020156:Salicylic Acid