title: In situ film forming fibroin gel intended for cutaneous administration.
abstract: The possible use of regenerated silk fibroin gels as in situ film forming formulations for cutaneous administration of drugs was studied. Ethanol was selected as volatile and skin tolerant solvent to favor the sol-gel transition of silk fibroin solutions. Glycerin was chosen to ameliorate the gel texture profile. Eighteen placebo formulations were prepared to individuate the optimal component ratios as a function of the texture analysis, spreadability and drying time. The in vitro biopharmaceutical performance was investigated by in vitro permeation test through human epidermis on formulations loading caffeine as a model drug. The data evidenced that the optimal technological performances were achieved using gels containing 70% ethanol and silk fibroin/glycerin ratio from 0.18 to 0.36. The caffeine flux (J) through the skin was significantly improved due to an increase of the drug thermodynamic activity (hydro-alcoholic solution: J∼0.8μg/cm(2)/h; in situ formed film: J∼1.4-1.7μg/cm(2)/h). In conclusion, silk fibroin can be advantageously proposed as a novel film forming material to develop dosage forms to be topically applied.
authors.affiliation: Department of Pharmaceutical Sciences, Università Degli Studi di Milano, Via G. Colombo, 71, 20133 Milan, Italy.
authors.forename: Chiara G M
authors.initials: CGM
authors.lastname: Gennari
authors.affiliation: Department of Pharmaceutical Sciences, Università Degli Studi di Milano, Via G. Colombo, 71, 20133 Milan, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Selmin
authors.affiliation: Department of Chemistry, CRC Materiali Polimerici (LaMPo), Università Degli Studi di Milano, Via Golgi, 19, 20133 Milan, Italy.
authors.forename: Marco A
authors.initials: MA
authors.lastname: Ortenzi
authors.affiliation: Department of Pharmaceutical Sciences, Università Degli Studi di Milano, Via G. Colombo, 71, 20133 Milan, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Franzé
authors.affiliation: Department of Pharmaceutical Sciences, Università Degli Studi di Milano, Via G. Colombo, 71, 20133 Milan, Italy.
authors.forename: Umberto M
authors.initials: UM
authors.lastname: Musazzi
authors.affiliation: Department of Pharmaceutical Sciences, Università Degli Studi di Milano, Via G. Colombo, 71, 20133 Milan, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Casiraghi
authors.affiliation: Department of Pharmaceutical Sciences, Università Degli Studi di Milano, Via G. Colombo, 71, 20133 Milan, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Minghetti
authors.affiliation: Department of Pharmaceutical Sciences, Università Degli Studi di Milano, Via G. Colombo, 71, 20133 Milan, Italy. Electronic address: francesco.cilurzo@unimi.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Cilurzo
mesh_terms: D000279:Administration, Cutaneous; D004817:Epidermis / Q000187:drug effects* / Q000378:metabolism; D005349:Fibroins / Q000008:administration & dosage* / Q000378:metabolism; D005782:Gels; D006801:Humans; D009924:Organ Culture Techniques; D047011:Silk / Q000008:administration & dosage* / Q000378:metabolism; D012869:Skin Absorption / Q000187:drug effects* / Q000502:physiology
chemical_list: D005782:Gels; D047011:Silk; D005349:Fibroins
keywords: Caffeine; In situ film forming; Silk fibroin; Skin penetration enhancement; Texture analyses; Thixotropic gel