title: L-cysteine encapsulation in liposomes: effect of phospholipids nature on entrapment efficiency and stability.
abstract: Liposomal entrapment of L-cysteine (L-CySH) could be a solution to enhance its oxidative stability and its intracellular bioavailability for glutathione (GSH) synthesis. This study addresses the influence of different factors (i.e. pH value (6.3 vs 7.4), antioxidant agents (EDTA or tocopherol (TO and nature of phosphatidylcholine (PC) (Soybean PC (SPC) vs hydrogenated SPC (HSPC)) to formulate and optimize Large Unilamellar Vesicles (LUVs) of L-CySH composed of PC/Cholesterol/ Phosphatidylglycerol (6:3:1). pH decrease (p = 0.0002) and substitution of SPC by HSPC (p < 0.001) reduced L-CySH oxidation. EE% (entrapment efficiency) varied from 0.98% +/- 0.54 (SPC, pH 7.4) to 6.46% +/- 1.37 (HSPC, pH 6.3) and was improved by decreasing pH (p = 0.011) and using HSPC (p < 0.0001). An immediate release of L-CySH was observed with SPC. On the contrary, with HSPC at pH 6.3, 42.0% +/- 1.2 and 73.0% +/- 1.7 remained encapsulated after 24h at 25 degrees C and 4 degrees C, respectively. In conclusion, HSPC offering both stronger rigidity and lesser propensity for peroxidation led to optimize L-CySH liposomal stability.
authors.affiliation: Faculté des Sciences Pharmaceutiques et Biologiques, Laboratoire de Pharmacie Galénique, Paris, France. nabil.el-kateb@etu.univ-paris5.fr
authors.forename: Nabil
authors.initials: N
authors.lastname: El Kateb
authors.forename: Luc
authors.initials: L
authors.lastname: Cynober
authors.forename: Jean Claude
authors.initials: JC
authors.lastname: Chaumeil
authors.forename: Gilles
authors.initials: G
authors.lastname: Dumortier
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D003545:Cysteine / Q000008:administration & dosage*; D004337:Drug Carriers; D016503:Drug Delivery Systems; D015195:Drug Design; D004492:Edetic Acid / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008081:Liposomes / Q000737:chemistry*; D008956:Models, Chemical; D010100:Oxygen / Q000737:chemistry; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D013025:Glycine max; D013696:Temperature
chemical_list: D000975:Antioxidants; D004337:Drug Carriers; D008081:Liposomes; D010713:Phosphatidylcholines; D010743:Phospholipids; D006859:Hydrogen; D004492:Edetic Acid; D003545:Cysteine; D010100:Oxygen