Archives of Pharmacal Research

, 24:572

Effect of vehicles and enhancers on thein vitro skin penetration of aspalatone and its enzymatic degradation across rat skins

Research Article Pharmacology, Toxicology & Pharmaceutics

DOI: 10.1007/BF02975168

Cite this article as:
Gwak, H.S. & Chun, I.K. Arch Pharm Res (2001) 24: 572. doi:10.1007/BF02975168


The feasibility of skin penetration was studied for aspalatone (AM, acetylsalicylic acid maltol ester), a novel antithrombotic agent. In this study, hairless mouse dorsal skins were used as a model to select composition of vehicle and AM. Based on measurements of solubility and partition coefficient, the concentration of PG that showed the highest flux for AM across the hairless mouse skin was found to be 40%. The cumulative amount permeated at 48 h, however, appear inadequate, even when the PG concentration was employed. To identify a suitable absorption enhancer and its optimal concentration for AM, a number of absorption enhancers and a variety of concentration were screened for the increase in transdermal flux of AM. Amongst these, linoleic acid (LOA) at the concentration of 5% was found to have the largest enhancement factor (i.e., 132). However, a further increase in AM flux was not found in the fatty acid concentration greater than 5%, indicating the enhancement effect is in a bell-shaped curve. In a study of the effect of AM concentration on the permeation, there was no difference in the permeation rate between 0.5 and 1% for AM, below its saturated concentration. At the donor concentration of 2%, over the saturated condition, the flux of AM was markedly increased. A considerable degradation of AM was found during permeation studies, and the extent was correlated with protein concentrations in the epidermal and serosal extracts, and skin homogenates. In rat dorsal skins, the protein concentration decreased in the rank order of skin homogenate > serosal extract > epidermal extract. Estimated first order degradation rate constants were 6.15±0.14, 0.57 ±0.02 and 0.011 ±0.004 h-1 for skin homogenate, serosal extract and epidermal extract, respectively. Therefore, it appeared that AM was hydrolyzed to some extent into salicylmaltol by esterases in the dermal and subcutaneous tissues of skin. Taken together, our data indicated that transdermal delivery of AM is feasible when the combination of PG and LOA is used as a vehicle. However, since AM is not metabolically stable, acceptable degradation inhibitors may be necessary to fully realize the transdermal delivery of the drug.

Key words

Aspalatone Percutaneous absorption Vehicles Penetration enhancers Degradation 

Copyright information

© The Pharmaceutical Society of Korea 2001

Authors and Affiliations

  1. 1.Laboratory of Pharmaceutics, College of PharmacyDongduk Women’s UniversitySeoulKorea

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