title: Physicochemical characterization of molecular assemblies of miltefosine and amphotericin B.
abstract: This study describes the interactions between two amphiphilic molecules with antileishmanial activity, amphotericin B (AmB) and miltefosine [hexadecylphosphocholine (HePC)], the latter being effective by the oral route. The effect of HePC on the aggregation state of AmB in aqueous solution and the interactions between the two agents were monitored using absorption spectroscopy and circular dichroism. Structural characterization of the mixed aggregates formed in water by dynamic light scattering (DLS) and cryofracture electron microscopy was performed. At concentrations above its critical micelle concentration, HePC was shown to interact with AmB, leading to an increase in the proportion of AmB in its monomeric form as a result of a micellar solubilization mechanism with a capacity of 26 +/- 3 mmol of AmB solubilized/mol of HePC, that is, nearly 40 molecules of HePC per molecule of AmB in the mixed micelles. These were revealed as individual and spherical aggregates close to 10 nm in diameter by both electron microscopy and DLS. Such a micellar formulation provides a new AmB-based system which might be useful in delivering AmB orally for visceral leishmaniasis bitherapy.
authors.affiliation: Laboratoire de Physico-chimie, Pharmacotechnie et Biopharmacie, UMR CNRS 8612, Univ Paris-Sud 11, Faculté de Pharmacie, IFR 141, Châtenay-Malabry, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Ménez
authors.forename: Philippe
authors.initials: P
authors.lastname: Legrand
authors.forename: Véronique
authors.initials: V
authors.lastname: Rosilio
authors.forename: Sylviane
authors.initials: S
authors.lastname: Lesieur
authors.forename: Gillian
authors.initials: G
authors.lastname: Barratt
mesh_terms: D000666:Amphotericin B / Q000737:chemistry*; D000981:Antiprotozoal Agents / Q000737:chemistry*; D016503:Drug Delivery Systems / Q000379:methods*; D004347:Drug Interactions; D008823:Micelles; D008854:Microscopy, Electron; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000737:chemistry; D012995:Solubility; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D000981:Antiprotozoal Agents; D008823:Micelles; D013501:Surface-Active Agents; D010767:Phosphorylcholine; C039128:miltefosine; D000666:Amphotericin B