title: Film-forming formulations containing porous silica for the sustained delivery of actives to the skin.
abstract: The purpose of this study was to develop film-forming formulations facilitating long-term treatment of chronic pruritus with capsaicinoids. To this end, an oily solution of nonivamide was loaded into porous silica particles which were then suspended in the dispersion of a sustained release polymer. Such formulations form a film when applied to the skin and encapsulate the drug loaded silica particles in a dry polymeric matrix. Dermal delivery and permeation of the antipruritic drug nonivamide (NVA) are controlled by the matrix. The film-forming formulations were examined regarding homogeneity, storage stability, substantivity and ex vivo skin permeation. Confocal Raman spectral imaging proved the stability of silica-based film-forming formulations over a period of 6 months. Substantivity was found to be enhanced substantially compared to a conventional semisolid formulation. Permeation rates of nonivamide from film-forming formulations through the skin are much lower compared to those achieved with a conventional immediate release formulation with the same drug amount. Due to the drug reservoir in the polymer matrix, a sustained permeation is enabled. Film-forming formulations may therefore improve the treatment of chronic pruritus with capsaicinoids by enhancing patient compliance through a sustained release regime.
authors.affiliation: Department of Pharmaceutical Technology, Eberhard Karls University, Auf der Morgenstelle 8, 72076 Tuebingen, Germany.
authors.forename: Rouven
authors.initials: R
authors.lastname: Heck
authors.affiliation: Department of Pharmaceutical Technology, Eberhard Karls University, Auf der Morgenstelle 8, 72076 Tuebingen, Germany.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Hermann
authors.affiliation: Department of Pharmaceutical Technology, Eberhard Karls University, Auf der Morgenstelle 8, 72076 Tuebingen, Germany. Electronic address: dominique.lunter@uni-tuebingen.de.
authors.forename: Dominique J
authors.initials: DJ
authors.lastname: Lunter
authors.affiliation: Department of Pharmaceutical Technology, Eberhard Karls University, Auf der Morgenstelle 8, 72076 Tuebingen, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Daniels
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D000982:Antipruritics / Q000737:chemistry; D002211:Capsaicin / Q000031:analogs & derivatives / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry; D016503:Drug Delivery Systems / Q000379:methods*; D065546:Drug Liberation; D006801:Humans; D018613:Microscopy, Confocal; D023421:Models, Animal; D009821:Oils; D010539:Permeability; D011108:Polymers / Q000737:chemistry; D016062:Porosity; D011537:Pruritus / Q000188:drug therapy; D012822:Silicon Dioxide / Q000737:chemistry*; D012867:Skin / Q000187:drug effects*; D012869:Skin Absorption; D013059:Spectrum Analysis, Raman; D013552:Swine
chemical_list: D000982:Antipruritics; D004337:Drug Carriers; D009821:Oils; D011108:Polymers; D012822:Silicon Dioxide; D002211:Capsaicin; C040937:nonivamide
keywords: Confocal Raman Microscopy; Dermal drug delivery; Eudragit® RS (Pub Chem CID: 104931); Film adhesion; Nonivamide; Nonivamide (PubChem CID: 2998); Porous silica; Silica (PubChem CID: 24261); Skin permeation