title: Biodegradable derivatives of tranexamic acid as transdermal permeation enhancers.
abstract: The purpose of this work was to develop a novel approach to transdermal permeation enhancer design, based on utilizing some favorable properties of their metabolites. As an example of this concept, a series of carbamic acid salts of tranexamic acid (TXA) esters was synthesized, because TXA was previously shown to improve skin barrier homeostasis. Enhancement activities of 1% TXA derivatives dispersed in both hydrophilic and lipophilic vehicles were evaluated in vitro using human skin and theophylline as a model drug. Dispersed in an aqueous donor vehicle, the dodecyl ester showed the enhancement ratio (ER) of 4.3+/-0.9, which is almost 2 times higher than that of 1-dodecylazepan-2-one (Azone; 2.2+/-0.7). From an isopropyl-myristate suspension, the decyl ester was the most effective enhancer (4.9+/-1.4), while Azone was inactive. Decomposition of the carbamate in a slightly acidic environment was shown by FTIR; hydrolysis of the pertinent ester by porcine esterase was monitored by TLC and HPLC. Biodegradable enhancers of this type could mediate easier and faster recovery of the skin barrier after transdermal delivery through the action of the released TXA.
authors.affiliation: Department of Inorganic and Organic Chemistry, Charles University, Faculty of Pharmacy, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic. vavrovak@faf.cuni.cz
authors.forename: Katerina
authors.initials: K
authors.lastname: Vávrová
authors.forename: Alexandr
authors.initials: A
authors.lastname: Hrabálek
authors.forename: Pavel
authors.initials: P
authors.lastname: Dolezal
authors.forename: Tomás
authors.initials: T
authors.lastname: Holas
authors.forename: Jana
authors.initials: J
authors.lastname: Klimentová
mesh_terms: D000279:Administration, Cutaneous; D001673:Biodegradation, Environmental; D002219:Carbamates / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004337:Drug Carriers / Q000737:chemistry / Q000494:pharmacology*; D004952:Esters / Q000737:chemistry; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D010539:Permeability / Q000187:drug effects; D012867:Skin / Q000187:drug effects / Q000378:metabolism*; D012869:Skin Absorption / Q000187:drug effects*; D017550:Spectroscopy, Fourier Transform Infrared; D013806:Theophylline / Q000493:pharmacokinetics; D014148:Tranexamic Acid / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000494:pharmacology*
chemical_list: D002219:Carbamates; D004337:Drug Carriers; D004952:Esters; D014148:Tranexamic Acid; D013806:Theophylline