title: Interaction of the local anaesthetic heptacaine with dipalmitoylphosphatidylcholine liposomes: a densimetric study.
abstract: Interaction of the local anaesthetic heptacaine, monohydrochloride of [2-(heptyloxy)-phenyl]-2-(1-piperidinyl)-ethyl ester of carbamic acid, with multilamellar dipalmitoylphosphatidylcholine (DPPC) liposomes in aqueous solution with high excess of water has been studied by means of density measurements in the scanning regime in the main phase transition region. The anaesthetic decreased the temperature of main phase transition. The molar partition coefficients of heptacaine between aqueous phase, liquid crystal and gel phases of DPPC have been determined from a combination of phase transition data obtained by densimetry with a DPPC/heptacaine phase diagram published in the literature. The saturation of heptacaine concentration in liposomes has been observed at higher total amount of anaesthetic. The partial specific volume of heptacaine located in DPPC bilayers is slightly lower than in the aqueous phase.
authors.affiliation: Institute of Experimental Physics of Slovak Academy of Sciences, Department of Biophysics, Kosice, Slovakia. bano@saske.sk
authors.forename: M
authors.initials: M
authors.lastname: Bánó
authors.forename: O
authors.initials: O
authors.lastname: Pajdalová
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D000779:Anesthetics, Local / Q000737:chemistry*; D055592:Biophysical Phenomena; D001703:Biophysics; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D008081:Liposomes; D010880:Piperidines / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water
chemical_list: D000779:Anesthetics, Local; D008081:Liposomes; D010880:Piperidines; D014867:Water; D015060:1,2-Dipalmitoylphosphatidylcholine; C013549:heptacaine