title: Importance of a suitable working protocol for tape stripping experiments on porcine ear skin: Influence of lipophilic formulations and strip adhesion impairment.
abstract: The tape stripping method is a very important tool for dermopharmacokinetic experiments in vitro and the accurate measurement of the removed corneocytes is key for a reliable calculation of a drug's skin penetration behavior. Therefore, various methods to quantify the amount of corneocytes removed with each tape strip have been employed, ranging from gravimetric approaches to protein assays and recently near infrared densitometry (NIR) has become very widely used. As this method is based on a reduction of light intensity, interference of formulation components seems conceivable, as they could scatter light and change the results. In this study, NIR measurements were compared to a protein assay and in addition, the influence of highly lipophilic formulations on the results of tape stripping experiments was investigated as impairment of the adherence of strips has been reported. To this end, different tape stripping protocols were employed. The obtained results ensure suitability of the NIR method and moreover suggest a more pronounced influence on adherence with increasing lipophilicity in applied formulations. The results show that adaptation of the tape stripping protocol to the specifications of envisioned experiments is important for reliable results. Two protocols were found favorable and are presented in this work.
authors.affiliation: University of Vienna, Department of Pharmaceutical Technology and Biopharmaceutics, Althanstraße 14, 1090 Vienna, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Nagelreiter
authors.affiliation: University of Vienna, Department of Pharmaceutical Technology and Biopharmaceutics, Althanstraße 14, 1090 Vienna, Austria.
authors.forename: D
authors.initials: D
authors.lastname: Mahrhauser
authors.affiliation: University of Vienna, Department of Pharmaceutical Technology and Biopharmaceutics, Althanstraße 14, 1090 Vienna, Austria.
authors.forename: K
authors.initials: K
authors.lastname: Wiatschka
authors.affiliation: University of Vienna, Department of Pharmaceutical Technology and Biopharmaceutics, Althanstraße 14, 1090 Vienna, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Skipiol
authors.affiliation: University of Vienna, Department of Pharmaceutical Technology and Biopharmaceutics, Althanstraße 14, 1090 Vienna, Austria; University of Vienna, Research Platform 'Characterisation of Drug Delivery Systems on Skin and Investigation of Involved Mechanisms', Vienna, Austria. Electronic address: claudia.valenta@univie.ac.at.
authors.forename: C
authors.initials: C
authors.lastname: Valenta
mesh_terms: D000269:Adhesives; D000818:Animals; D002626:Chemistry, Pharmaceutical; D003720:Densitometry; D003879:Dermatologic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D004431:Ear, External / Q000166:cytology / Q000378:metabolism; D004655:Emulsions; D066298:In Vitro Techniques; D009824:Ointments; D011506:Proteins / Q000737:chemistry; D012869:Skin Absorption; D019265:Spectroscopy, Near-Infrared; D013552:Swine
chemical_list: D000269:Adhesives; D003879:Dermatologic Agents; D004655:Emulsions; D009824:Ointments; D011506:Proteins
keywords: Dermal formulations; Protein quantification; Tape stripping