title: The Localization of Phenolic Compounds in Liposomal Bilayers and Their Effects on Surface Characteristics and Colloidal Stability.
abstract: The interactions with and effects of five chemically distinct, bioactive phenolic compounds on the lipid bilayers of model dipalmitoylphosphatidylcholine (DPPC) liposomes were investigated. Complementary analytical techniques, including differential scanning calorimetry (DSC) and phosphorus and proton nuclear magnetic resonance spectroscopy (NMR), were employed in order to determine the location of the compounds within the bilayer and to correlate location with their effects on bilayer characteristics and liposomal stability. As compared to the phenolic compounds localized in the glycerol region of the DPPC head group within the bilayer, which enhanced the colloidal stability of the liposomes, compounds located closer to the center of the bilayer reduced vesicle stability as a function of time. Molecules present in the upper region of liposomal DPPC acyl chains (C1-C10) inhibited liposomal aggregation and size increase, perhaps due to tighter packing of adjoining DPPC molecules and increased surface exposure of DPPC phosphate head groups. These data may be useful for designing liposomal systems containing hydrophobic phenols and other small molecules, selecting appropriate analytical methods for determining their location within liposomal bilayers, and predicting their effects on liposome characteristics early in the liposome formulation development process.
authors: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 495M Pharmacy Building, 7 Greenhouse Drive, Kingston, Rhode Island, 02881, USA.
authors: Swapnil A
authors: SA
authors: Malekar
authors: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 495M Pharmacy Building, 7 Greenhouse Drive, Kingston, Rhode Island, 02881, USA.|Department of Chemical Engineering, College of Engineering, University of Rhode Island, Kingston, Rhode Island, 02881, USA.
authors: Ashish L
authors: AL
authors: Sarode
authors: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 495M Pharmacy Building, 7 Greenhouse Drive, Kingston, Rhode Island, 02881, USA.
authors: Alvin C
authors: AC
authors: Bach
authors: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 495M Pharmacy Building, 7 Greenhouse Drive, Kingston, Rhode Island, 02881, USA. drworthen@uri.edu.|Department of Chemical Engineering, College of Engineering, University of Rhode Island, Kingston, Rhode Island, 02881, USA. drworthen@uri.edu.
authors: David R
authors: DR
authors: Worthen
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D002152:Calorimetry, Differential Scanning / Q000379:methods; D003102:Colloids / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D019800:Phenol / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
chemical_list: D003102:Colloids; D008051:Lipid Bilayers; D008081:Liposomes; D015060:1,2-Dipalmitoylphosphatidylcholine; D019800:Phenol
keywords: bilayer; liposome; phenolic; stability; surface characterization; vesicle