title: Nanosuspension improves tretinoin photostability and delivery to the skin.
abstract: The aims of this work were to improve cutaneous targeting and photostability of tretinoin by using nanosuspension formulation. Tretinoin is a drug widely used in the topical treatment of various dermatological diseases. The tretinoin nanosuspension was prepared by precipitation method and then characterized by photo correlation spectroscopy for mean size and size distribution, and by transmission electron microscopy for morphological studies. An oil in water tretinoin nanoemulsion was also prepared and used as a control. Dermal and transdermal delivery of both tretinoin nanosuspension and nanoemulsion were tested in vitro by using Franz diffusion cells and newborn pig skin. Photodegradation studies were carried out by UV irradiation (1h, λ=366 nm) of the tretinoin nanosuspension in comparison with the nanoemulsion and a methanolic solution of the drug. During 8h percutaneous experiments, the nanosuspesion was able to localize the drug into the pig skin with a very low transdermal drug delivery, whereas the nanoemulsion greatly improved drug permeation. UV irradiation of the nanosuspension showed a great improvement of tretinoin stability in comparison with both controls. Overall results show that nanosuspension might be a useful formulation for improving tretinoin dermal delivery and stability.
authors.affiliation: Dept. Scienze della Vita e dell'Ambiente, Sezione di Scienze del Farmaco, CNBS, University of Cagliari, Cagliari 09124, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Lai
authors.forename: Rosa
authors.initials: R
authors.lastname: Pireddu
authors.forename: Francesco
authors.initials: F
authors.lastname: Corrias
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Fadda
authors.forename: Donatella
authors.initials: D
authors.lastname: Valenti
authors.forename: Elena
authors.initials: E
authors.lastname: Pini
authors.forename: Chiara
authors.initials: C
authors.lastname: Sinico
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D002626:Chemistry, Pharmaceutical / Q000379:methods; D004058:Diffusion; D016503:Drug Delivery Systems / Q000379:methods; D004355:Drug Stability; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry*; D010316:Particle Size; D012867:Skin / Q000378:metabolism*; D013535:Suspensions / Q000008:administration & dosage* / Q000737:chemistry*; D013552:Swine; D014212:Tretinoin / Q000008:administration & dosage* / Q000737:chemistry*
chemical_list: D013535:Suspensions; D014212:Tretinoin
keywords: Dermal delivery; Nanoemulsion; Nanosuspension; Photostability; Tretinoin