title: Physicochemical characterization and cytotoxic studies of nonionic surfactant vesicles using sucrose esters as oral delivery systems.
abstract: Several nanotechnological solutions for mucosal immunization have been proposed, such as nanoparticles, liposomes, solid lipidic particles, micelles, and surfactant vesicles. In recent years, surfactant vesicles have gained increasing scientific attention as an alternative potential drug delivery system to the conventional liposome. This type of vesicle known as niosomes or nonionic surfactant vesicles (NSVs) has a structure and properties similar to those of liposomes. Both of them can transport hydrophilic drugs by encapsulation in the aqueous inner pool or hydrophobic drugs by intercalation into hydrophobic domains. The aim of this study was to prepare and characterize vesicles formed by sucrose esters as protective systems of bioactive molecules for oral administration. Vesicles were prepared using two commercial products formed by mixtures of mono and diesters S-570 and S-770, respectively. Determined parameters were size and zeta potential; the stability of formulations was tested in presence of increasing concentrations of a surfactant, and at several pH values observed in the gastrointestinal tract. Solubilization experiences showed an initial decrease in size for vesicles of both ester mixtures, samples showed detergent resistance at higher Triton X-100 concentrations. Vesicles showed stability at pH 5-7.4 up to 90 min; however, both formulations showed colloidal instability at pH=2, which corresponds to the isoelectric point of these vesicles. To evaluate the cytotoxicity of both vesicle formulations and separately each pure ester, Caco-2 cells were used. Cytotoxic evaluation indicated that both types of vesicles and free sucrose distearate were safe for Caco-2 viability; however, free sucrose monostearate was toxic for the cells. As a conclusion of these preliminary studies, it can be stated that vesicles formed with mixtures of sucrose esters showed a size in the range of 200 nm maintaining their size when exposed to the action of a surfactant, but showing aggregation at acidic pH.
authors.affiliation: Laboratorio de Tecnología Farmacéutica, Departamento de Ciencias y Tecnologías Farmacéuticas, Universidad de Chile, Sergio Livingstone 1007, Independencia, Santiago, Chile. Electronic address: kvaldes@ciq.uchile.cl.
authors.forename: Karina
authors.initials: K
authors.lastname: Valdés
authors.affiliation: Programa de Nanomedicinas, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Roque Saenz Peña 352, Bernal, Buenos Aires, Argentina.
authors.forename: María José
authors.initials: MJ
authors.lastname: Morilla
authors.affiliation: Programa de Nanomedicinas, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Roque Saenz Peña 352, Bernal, Buenos Aires, Argentina.
authors.forename: Eder
authors.initials: E
authors.lastname: Romero
authors.affiliation: Laboratorio de Tecnología Farmacéutica, Departamento de Ciencias y Tecnologías Farmacéuticas, Universidad de Chile, Sergio Livingstone 1007, Independencia, Santiago, Chile.
authors.forename: Jorge
authors.initials: J
authors.lastname: Chávez
mesh_terms: D000284:Administration, Oral; D018938:Caco-2 Cells; D016923:Cell Death; D002470:Cell Survival / Q000187:drug effects; D055598:Chemical Phenomena; D016503:Drug Delivery Systems; D004952:Esters / Q000008:administration & dosage* / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008081:Liposomes / Q000633:toxicity* / Q000648:ultrastructure; D017830:Octoxynol; D010316:Particle Size; D055672:Static Electricity; D013395:Sucrose / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D013501:Surface-Active Agents / Q000633:toxicity*
chemical_list: D004952:Esters; D008081:Liposomes; D013501:Surface-Active Agents; C018153:sucrose monostearate; C041566:sucrose distearate; D013395:Sucrose; D017830:Octoxynol
keywords: Cytotoxicity; Nonionic surfactant vesicles; Stability; Sucrose stearate