title: Phospholipid-based nonlamellar mesophases for delivery systems: bridging the gap between empirical and rational design.
abstract: Phospholipids are ubiquitous cell membrane components and relatively well-accepted ingredients due to their natural origin. Phosphatidylcholine (PC) in particular offers a promising alternative to monoglycerides for lyotropic liquid crystalline (LLC) delivery system applications in the food, cosmetics and pharmaceutical industries, provided its strong tendency to form zero-mean curvature lamellar mesophases in water can be overcome. Higher negative curvatures are usually reached through the addition of a third lipid component, forming a ternary diagram phospholipid/water/oil. The initial part of this work summarizes the potential advantages and the challenges of phospholipid-based delivery system applications. In the next part, various ternary PC/water/oil systems are discussed, with a special emphasis on the PC/water/cyclohexane and PC/water/α-tocopherol systems. We report that R-(+)-limonene has a quantitatively similar effect as cyclohexane. The last part is devoted to the theoretical interpretation of the observed phase behaviors. A fruitful parallel is drawn with PC polymer-like reverse micelles, leading to a thermodynamic description in terms of interfacial bending energy. Investigations at the molecular level are reviewed to help in bridging the empirical and theoretical approaches. Predictive rules are finally derived from this wide-ranging overview, thereby opening the way to a future rational design of PC-based LLC delivery systems.
authors.affiliation: Food and Soft Materials Science, Institute of Food, Nutrition & Health, ETH Zurich, Schmelzbergstrasse 9, CH-8092 Zurich, Switzerland.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Martiel
authors.affiliation: Nestlé Research Center, Vers-Chez-Les-Blanc, CH-1000 Lausanne 26, Switzerland.
authors.forename: Laurent
authors.initials: L
authors.lastname: Sagalowicz
authors.affiliation: Food and Soft Materials Science, Institute of Food, Nutrition & Health, ETH Zurich, Schmelzbergstrasse 9, CH-8092 Zurich, Switzerland. Electronic address: raffaele.mezzenga@hest.ethz.ch.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Mezzenga
mesh_terms: D002784:Cholesterol / Q000737:chemistry; D016503:Drug Delivery Systems; D006017:Glycolipids / Q000737:chemistry; D008055:Lipids / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry; D050866:Liquid Crystals; D008823:Micelles; D044085:Microfluidics; D016011:Normal Distribution; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D012542:Scattering, Radiation; D017550:Spectroscopy, Fourier Transform Infrared; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry; D014965:X-Rays
chemical_list: D006017:Glycolipids; D008055:Lipids; D008081:Liposomes; D008823:Micelles; D010713:Phosphatidylcholines; D010743:Phospholipids; D013501:Surface-Active Agents; D014867:Water; D002784:Cholesterol
keywords: Delivery system; Interface curvature; Lyotropic liquid crystal; Nonlamellar; Phase diagram; Phospholipid