title: Lecithin-linker formulations for self-emulsifying delivery of nutraceuticals.
abstract: Lecithin-linker microemulsions are formulations produced with soybean lecithin in combination with a highly lipophilic (lipophilic linker) and highly hydrophilic (hydrophilic linkers) surfactant-like additives. In this work, lecithin-linker systems were formulated to produce self-emulsifying delivery systems for β-carotene and β-sitosterol. The concentration of the lipophilic linker, sorbitan monooleate, was adjusted to minimize the formation of liquid crystals. The concentration of hydrophilic linkers, decaglyceryl caprylate/caprate and PEG-6-caprylic/capric glycerides, was gradually increased (scanned) until single phase clear microemulsions were obtained. For these scans, the oil (ethyl caprate) to water ratio was set to 1. The single phase, clear microemulsions were diluted with fed-state simulated intestinal fluid (FeSSIF) and produced stable emulsions, with drop sizes close to 200 nm. Using pseudo-ternary phase diagrams to evaluate the process of dilution of microemulsion preconcentrates (mixtures of oil, lecithin and linkers with little or no water) with FeSSIF, it was determined that self-emulsifying systems are obtained when the early stages of the dilution produce single phase microemulsions. If liquid crystals or multiple phase systems are obtained during those early stages, then the emulsification yields unstable emulsions with large drop sizes. An in vitro permeability study conducted using a Flow-Thru Dialyzer revealed that stable emulsions with drop sizes of 150-300 nm produce large and irreversible permeation of β-carotene to sheep intestine. On the other hand, unstable emulsions produced without the linker combination separated in the dialyzer chamber.
authors.affiliation: University of Toronto, Department of Chemical Engineering and Applied Chemistry, 200 College Street, Room 131, Toronto, Ontario M5S 3E5, Canada.
authors.forename: Jacquelene
authors.initials: J
authors.lastname: Chu
authors.affiliation: University of Toronto, Department of Chemical Engineering and Applied Chemistry, 200 College Street, Room 131, Toronto, Ontario M5S 3E5, Canada.
authors.forename: Yu-Ling
authors.initials: YL
authors.lastname: Cheng
authors.affiliation: University of Toronto, Department of Nutritional Sciences, 150 College Street, Room 315, Toronto, Ontario M5S 3E2, Canada.
authors.forename: A Venketeshwer
authors.initials: AV
authors.lastname: Rao
authors.affiliation: University of Toronto, Department of Chemical Engineering and Applied Chemistry, 200 College Street, Room 131, Toronto, Ontario M5S 3E5, Canada.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Nouraei
authors.affiliation: University of Toronto, Department of Chemical Engineering and Applied Chemistry, 200 College Street, Room 131, Toronto, Ontario M5S 3E5, Canada.
authors.forename: Silvia
authors.initials: S
authors.lastname: Zarate-Muñoz
authors.affiliation: University of Toronto, Department of Chemical Engineering and Applied Chemistry, 200 College Street, Room 131, Toronto, Ontario M5S 3E5, Canada. Electronic address: edgar.acosta@utoronto.ca.
authors.forename: Edgar J
authors.initials: EJ
authors.lastname: Acosta
mesh_terms: D000818:Animals; D002626:Chemistry, Pharmaceutical; D019587:Dietary Supplements; D004337:Drug Carriers / Q000737:chemistry*; D004655:Emulsions; D057927:Hydrophobic and Hydrophilic Interactions; D066298:In Vitro Techniques; D007583:Jejunum / Q000378:metabolism; D054709:Lecithins / Q000737:chemistry*; D015394:Molecular Structure; D010539:Permeability; D044367:Phase Transition; D012756:Sheep; D012855:Sitosterols / Q000008:administration & dosage* / Q000493:pharmacokinetics; D013025:Glycine max / Q000737:chemistry; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry*; D019207:beta Carotene / Q000008:administration & dosage* / Q000493:pharmacokinetics
chemical_list: D004337:Drug Carriers; D004655:Emulsions; D054709:Lecithins; D012855:Sitosterols; D013501:Surface-Active Agents; D019207:beta Carotene; C025473:gamma-sitosterol
keywords: Lecithin; Linkers; Microemulsion; Oral delivery; SEDS; SMEDS