Effect of Induced Acute Diabetes and Insulin Therapy on Stratum Corneum Barrier Function in Rat Skin

Abstract

Background: A wide variety of cutaneous manifestations are associated with diabetes. However, there is a paucity of information on stratum corneum barrier function in diabetics, with and without insulin therapy. Methods: To assess for alteration of the stratum corneum, its barrier function was tested by evaluating the percutaneous absorption of water, ethanol, lidocaine and hydrocortisone, in vitro, on normal control, 4-week diabetic and 8-day insulin-treated diabetic Sprague-Dawley CD rats. Results: Total water penetration was not different between the 3 groups though flux profiles were different. Both total penetration and peak flux of lidocaine and hydrocortisone increased slightly in the diabetic rats over the control group. However, total penetration and peak flux (including ethanol) were significantly increased in the insulin-treated rats. Conclusion: The data indicate that diabetes modestly alters stratum corneum physiology but less so than that seen following insulin therapy.

A Simplified Approach for Estimating Skin Permeation Parameters from In Vitro Finite Dose Absorption Studies

“…Example 1 is a subset of the study data in which the percutaneous absorption of 5% tetracaine in a vehicle containing ethanol and water (curve B) was compared with a vehicle consisting of 50:50 ethanol–dimethyl sulfoxide (curve A) in human skin (poster presentation: AAPS 2002 Annual Meeting; data on file). Example 2 is a subset of the study data in which percutaneous absorption of 5% lidocaine was evaluated in ex vivo skin from control Fischer rats (curve A) and diabetic rats (curve B) . Example 3 is a subset of the study data in which the percutaneous absorption of 15% Azelaic acid from a gel formulation, with a moisturizer lotion pretreatment (curve A), compared with no pretreatment (curve B) in human skin .…”

“…Example 2 is a subset of the study data in which percutaneous absorption of 5% lidocaine was evaluated in ex vivo skin from control Fischer rats (curve A) and diabetic rats (curve B). 17 Example 3 is a subset of the study data in which the percutaneous absorption of 15% Azelaic acid from a gel formulation, with a moisturizer lotion pretreatment (curve A), compared with no pretreatment (curve B) in human skin. 18 Example 4 is a subset of the study data in which the percutaneous absorption of caffeine and testosterone were each evaluated separately in a neat petrolatum vehicle in human skin.…”