Interaction of chlorpromazine with phospholipid membranes. An EPR study of membrane surface potential effects.
The interaction of chlorpromazine (CPZ) with artificial membranes (egg-yolk phosphatidylcholine liposomes) has been studied. Measurements of the surface electric potential, which is modified in the presence of the ionized form of the drug, were obtained by electron paramagnetic resonance spectroscopy (EPR) using a positively charged amphiphilic spin-probe. This probe partitions between the aqueous and lipidic phases depending on the surface potential and on the structural state of the membrane. The surface potential was measured as a function of drug concentration in the range where the spectral line-shapes are not affected by the incorporation of the drug. From these experimental results and through an appropriate formalism we obtain information on the binding of the drug to the lipid bilayer and on the ionization of the drug in the lipidic phase.
Anteneodo
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Centro Brasileiro de Pesquisas Físicas/CNPq, RJ, Rio de Janeiro, Brazil.
Bisch
P M
PM
Marques
J F
JF
D001665:Binding Sites; D055592:Biophysical Phenomena; D001703:Biophysics; D002746:Chlorpromazine / Q000737:chemistry / Q000494:pharmacology*; D004578:Electron Spin Resonance Spectroscopy; D066298:In Vitro Techniques; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry; D008564:Membrane Potentials; D008567:Membranes, Artificial; D008956:Models, Chemical; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D013499:Surface Properties
D008051:Lipid Bilayers; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D010743:Phospholipids; D002746:Chlorpromazine