title: Temporally controlled drug delivery systems: coupling of pH oscillators with membrane diffusion.
abstract: A novel approach to modulate the release of a drug or an active ingredient that avoids the need for external power sources or electronic controllers is described. By changing the pH of a solution relative to the pKa, a drug, enhancer, or solubilizer may be rendered charged or uncharged. Because only the uncharged form of a drug can permeate across lipophilic membranes, a temporally modulated delivery profile may be obtained with a pH oscillator in the donor solution. Ionizable permeants have a buffer capacity, so the feasibility of coupling the mixed Landoldt pH oscillator with membrane diffusion of nicotine or benzoic acid is demonstrated for a single oscillation.
authors.affiliation: Ciba-Geigy Corporation, Ardsley, NY 10502, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Giannos
authors.forename: S M
authors.initials: SM
authors.lastname: Dinh
authors.forename: B
authors.initials: B
authors.lastname: Berner
mesh_terms: D001565:Benzoates / Q000737:chemistry; D019817:Benzoic Acid; D016503:Drug Delivery Systems; D006863:Hydrogen-Ion Concentration; D008433:Mathematics; D008567:Membranes, Artificial; D013464:Sulfuric Acids / Q000737:chemistry; D013885:Thiosulfates; D013997:Time Factors
chemical_list: D001565:Benzoates; D008567:Membranes, Artificial; D013464:Sulfuric Acids; D013885:Thiosulfates; D019817:Benzoic Acid; C033158:sulfuric acid