title: Effect of D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) on surfactant monolayers.
abstract: In the present study, the effects of an amphiphilic polymer, d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) on model surfactant monolayers dipalmitoylphosphatidylcholine (DPPC), a binary mixture of DPPC with palmitoyloleoyl phosphatidylglycerol (DPPC-POPG) 9:1 (w/w) and binary mixture of DPPC and oleic acid (DPPC-OA) were evaluated. The ability of TPGS to act as an antioxidant adjuvant for pulmonary surfactants was also evaluated. Compression isotherms of surfactant monolayers at 37 °C in a Langmuir-Blodgett trough showed that DPPC and DPPC:TPGS mixed monolayers (1:0.25-1:1, w/w) exhibited low minimum surface tensions (MST) of 1-2 mN/m. Similarly [DPPC:POPG (9:1, w/w)]:TPGS mixed films of 1:0.25-1:1 weight ratios reached 1-2 mN/m MST. DPPC:POPG:TPGS liposomes adsorbed to surface tensions of 29-31 mN/m within 1s. While monolayers of DPPC:OA (1:1, w/w) reached high MST of ∼11 mN/m, DPPC:OA:TPGS (1:1:0.25, w/w) film reached near zero MST suggesting that low concentrations of TPGS reverses the effect of OA on DPPC monolayer. Capillary surfactometer studies showed DPPC:TPGS and [DPPC:POPG (9:1, w/w)]:TPGS liposomes maintained 84-95% airway patency. Fluorescence spectroscopy of Laurdan loaded DPPC:TPGS and DPPC:POPG:TPGS liposomes revealed no segregation of lipid domains in the lipid bilayer. Addition of TPGS to soybean liposome significantly reduced thiobarbituric acid reactive substance (TBARS) by 29-39% confirming its antioxidant nature. The results suggest a potential use of TPGS as an adjuvant to improve the surfactant activity as well as act as an antioxidant by scavenging free radicals.
authors.affiliation: Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, Maharashtra, India.
authors.forename: Apurva R
authors.initials: AR
authors.lastname: Shah
authors.forename: R
authors.initials: R
authors.lastname: Banerjee
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry; D015394:Molecular Structure; D019301:Oleic Acid / Q000737:chemistry; D010084:Oxidation-Reduction / Q000187:drug effects; D010715:Phosphatidylglycerols / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D013499:Surface Properties / Q000187:drug effects; D013501:Surface-Active Agents / Q000737:chemistry*; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology
chemical_list: D008051:Lipid Bilayers; D008081:Liposomes; D010715:Phosphatidylglycerols; D013501:Surface-Active Agents; D014810:Vitamin E; D015060:1,2-Dipalmitoylphosphatidylcholine; D019301:Oleic Acid; D011092:Polyethylene Glycols; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol; C014225:tocophersolan