title: Influence of dipalmitoylphosphatidylcholine on the dissolution of Brazilian chrysotile.
abstract: It is known that Brazilian chrysotile is rapidly removed from the lungs, but quantitative studies about the influence of lung surfactants on chrysotile dissolution have not been investigated. In this work, the chemical behavior of chrysotile and its dissolution in the presence of dipalmitoylphosphatidylcholine (DPPC) were investigated in physiological conditions. The dissolution was investigated through quantification of magnesium and silicon released by chrysotile. At 37 degrees C, the magnesium concentration is similar to control (without DPPC), which is about 2.0x10(-4)molL(-1), meaning that the dissolution process is not affected by the presence of this surfactant. The same was observed for silicon. The silicon concentration released by chrysotile is similar in all media tested. It is known that the dissolution mechanisms of brucite and tridymite layers are different. From our results, we propose that under physiological conditions, the mechanism of brucite dissolution is based on its interaction with hydrogen ions and that the mechanism of tridymite dissolution is based on a hydrolysis process.
authors.affiliation: Universidade Estadual de Campinas, Instituto de Química, CP 6154, 13083-970 Campinas, SP, Brazil.
authors.forename: I B
authors.initials: IB
authors.lastname: Valentim
authors.forename: M H
authors.initials: MH
authors.lastname: Martins
authors.forename: I
authors.initials: I
authors.lastname: Joekes
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D017632:Asbestos, Serpentine / Q000737:chemistry / Q000493:pharmacokinetics*; D008274:Magnesium / Q000378:metabolism; D011663:Pulmonary Surfactants / Q000378:metabolism*; D012825:Silicon / Q000378:metabolism
chemical_list: D017632:Asbestos, Serpentine; D011663:Pulmonary Surfactants; D015060:1,2-Dipalmitoylphosphatidylcholine; D008274:Magnesium; D012825:Silicon