title: Development of a thermogelling ophthalmic formulation of cysteine.
abstract: Preliminary studies carried out with cysteine 2% solution showed that pH adjusted to isoelectrical pH (i.e., 4.9) led to enhance stability during autoclaving and ensured no significant degradation during at least 14 days if stored at 2-8 degrees C protected from light. Optimized formulations combined either cysteine(2%)/Poloxamer407(16.5%) or cysteine(2%)/Poloxamer407(20%)/Poloxamer188(5%) and were characterized by an adequate temperature of gelification (TG) (25.9 degrees C and 26.9 degrees C, respectively), an important gel strength (5.1daN and 5.3daN, respectively) and a drastic increase in the apparent viscosity between 24 degrees C and 32 degrees C (multiplication factor of 78 and 77-fold, respectively). Cysteine addition produced only slight but significant decrease in temperature of gelification and increase in gel strength.
authors.affiliation: Laboratoire de Galénique, UPRES EA 2498, Faculté des Sciences Pharmaceutiques et Biologiques (Université Descartes Paris 5), 4, Avenue de l'Observatoire, Paris Cedex 06, 75270, France. gilles.dumortier@univ-paris5.fr
authors.forename: G
authors.initials: G
authors.lastname: Dumortier
authors.forename: N
authors.initials: N
authors.lastname: El Kateb
authors.forename: M
authors.initials: M
authors.lastname: Sahli
authors.forename: S
authors.initials: S
authors.lastname: Kedjar
authors.forename: A
authors.initials: A
authors.lastname: Boulliat
authors.forename: J C
authors.initials: JC
authors.lastname: Chaumeil
mesh_terms: D002626:Chemistry, Pharmaceutical; D003545:Cysteine / Q000008:administration & dosage* / Q000737:chemistry; D004355:Drug Stability; D005782:Gels; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D020442:Poloxamer / Q000008:administration & dosage; D014783:Viscosity
chemical_list: D005782:Gels; D020442:Poloxamer; D003545:Cysteine