title: Solution properties of amitriptyline and its partitioning into lipid bilayers.
abstract: Solution properties of a drug and its partitioning into lipid bilayers were studied for drug extraction using several different techniques, such as surface tension, zeta potential, ultra filtration and UV-Vis spectroscopy. From the surface tension study it was found that the presence of salt makes the drug molecules more surface-active. Zeta potential revealed the adsorption of the drug into the liposome bilayers to be governed mostly by electrostatic forces. The drug retention volume was expressed as a capacity factor, K, and that was normalized with respect to the amount of the immobilized phospholipids. The K-values for the positively charged drug on the liposomes decreased in the presence of phosphate buffer due to the presence of the oppositely charged ions. The above methods can thus be used to understand the mechanism of drug-membrane interaction and quantification of drug absorption into liposomes.
authors.affiliation: NSF IUCR Center for Advanced Studies in Novel Surfactants, Langmuir Center for Colloid and Interfaces, Columbia University, New York, NY 10027, USA. nd157@yahoo.com
authors.forename: Namita
authors.initials: N
authors.lastname: Deo
authors.forename: T
authors.initials: T
authors.lastname: Somasundaran
authors.forename: P
authors.initials: P
authors.lastname: Somasundaran
mesh_terms: D000639:Amitriptyline / Q000737:chemistry*; D000929:Antidepressive Agents, Tricyclic / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004530:Egg Yolk; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry; D008956:Models, Chemical; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry; D013053:Spectrophotometry; D013499:Surface Properties; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D000929:Antidepressive Agents, Tricyclic; D007477:Ions; D008051:Lipid Bilayers; D008081:Liposomes; D010713:Phosphatidylcholines; D010743:Phospholipids; D000639:Amitriptyline