title: pH of preparations affecting the on-off drug penetration behavior through the thermo-responsive liquid crystal-embedded membrane.
abstract: A liquid crystal (cholesteryl oleyl carbonate, COC)-embedded membrane with a controlled rate and higher reversibly thermo-responsive function was successfully fabricated by the vacuum filtration method. The aim of this study was to investigate the effect of the pH of aqueous solutions and gel preparations on the penetration of salbutamol sulfate through this thermo-responsive COC-embedded membrane. The results indicate that the on-off switching penetration behavior of salbutamol sulfate through the COC-embedded membrane in response to a repeatedly exchanging temperature cycle (10 <=> 25 degreesC) is not influenced by the pH of the medium. However, the pH-dependent ionization of salbutamol and the viscosity of the gel base, as well as the interaction between salbutamol and carbopol, might change the amount and the rate of salbutamol sulfate that penetrates across this COC-embedded membrane.
authors.affiliation: Department of Medical Research and Education, Veterans General Hospital-Taipei, Taipei, China. SYLIN@ISC1.VGHTPE.GOV.TW
authors.forename: S Y
authors.initials: SY
authors.lastname: Lin
authors.forename: K S
authors.initials: KS
authors.lastname: Chen
authors.forename: Y Y
authors.initials: YY
authors.lastname: Lin
mesh_terms: D000180:Acrylic Resins; D002152:Calorimetry, Differential Scanning; D003460:Crystallization; D004058:Diffusion; D004337:Drug Carriers; D005374:Filtration; D005782:Gels; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D011145:Polyvinyls; D012996:Solutions
chemical_list: D000180:Acrylic Resins; D004337:Drug Carriers; D005782:Gels; D008567:Membranes, Artificial; D011145:Polyvinyls; D012996:Solutions; C006912:carboxypolymethylene