title: Percutaneous absorption of chemicals: developing an understanding for the treatment of disease in frogs.
abstract: The permeable nature of frog skin presents an alternative route for the delivery of therapeutic chemicals to treat disease in frogs. However, although therapeutic chemicals are often topically applied to the skin of frogs, their pharmacokinetics have rarely been reported. To provide evidence to guide both candidate drug and formulation selection, we highlight factors expected to influence percutaneous absorption through frog skin, including the anatomy and physiology of the skin and the physicochemical properties of applied therapeutic chemicals. Importantly, we also highlight the effects of the formulation on percutaneous absorption, especially the inclusion of potential penetration enhancers as excipients. Finally, we collate empirical data on the topical application of various therapeutic chemicals in postmetamorphic frogs and show that, in contrast to mammalian species, even large chemicals (i.e. >500 Da) and those with a wide range of log P values (-4 through +6) are likely to be absorbed percutaneously. Topical application in frogs thus promises a convenient and effective method for delivering systemic treatments of a diverse range of chemicals; however, further experimental quantification is required to ensure optimal outcomes.
authors.affiliation: Pharmacy, College of Medicine and Dentistry, James Cook University, Townsville, Qld, Australia.
authors.forename: V K
authors.initials: VK
authors.lastname: Llewelyn
authors.affiliation: One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Qld, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Berger
authors.affiliation: Pharmacy, College of Medicine and Dentistry, James Cook University, Townsville, Qld, Australia.
authors.forename: B D
authors.initials: BD
authors.lastname: Glass
mesh_terms: D000287:Administration, Topical; D000820:Animal Diseases / Q000188:drug therapy*; D000818:Animals; D001001:Anura; D004364:Pharmaceutical Preparations / Q000008:administration & dosage*; D012867:Skin / Q000187:drug effects*; D012879:Skin Physiological Phenomena
chemical_list: D004364:Pharmaceutical Preparations