Abstract
Atopic dermatitis is a major public health problem worldwide. It has a wide clinical spectrum ranging from minor forms such as dry, depigmented patches (pityraisis alba), to major forms with erythrodermic rash, with the rash being slightly more common in boys (Beiber and Prolss, 2008). The age of onset is generally 2-6 months.
Several treatments are available for atopic dermatitis including: oral corticosteroids, topical corticosteroids, calcineurin inhibitors and antibiotics. Given orally, corticosteroids can have permanent and severe side effects (e.g. Cushing’s syndrome). Topical or transdermal drug delivery is preferred over oral treatments because it allows prolonged continuous and consistent release of the drug into the systemic circulation, direct drug release to the target area, and the ability to avoid first-pass gastrointestinal and hepatic metabolism to minimise adverse effects. At the time of this study, at least two textiles had been developed for the treatment of atopic dermatitis: DermaSilk® and Padycare®. Both these fabrics have antimicrobial finishes which treat the secondary bacterial infection generally present on the erythrodermic rash. Previous studies have shown that both fabrics are effective in treating the rash present in atopic dermatitis. However, at the time of the current study DermaSilk® was not commonly available in New Zealand and was expensive, therefore it was not a viable option for wide use. The other fabric available, Padycare®, was made from silver filaments. Silver had been shown to have potential side effects to humans and the environment. Thus, there was a need for an inexpensive, safe, readily available dermal treatment for atopic dermatitis.
The purpose of the current study was to design a cotton and silk transdermal patch for the treatment of atopic dermatitis and to study the relevant physical properties of these fabrics. The mass, thickness, air permeability, water vapour permeability and LAC of the fabrics were measured. The fabric specimens were then immersed in one of the two different concentrations (5mg/ml and 10mg/ml) of hydrocortisone and ethanol solutions for two minutes. The specimens were then dried and physical properties re-measured. FTIR, XRPD and SEM were performed to determine whether the hydrocortisone adhered to the fabric and if so in what solid state form (amphorous or crystalline). The physical properties of the fabrics differed from each other but both would be suitable for a transdermal patch in the treatment of atopic dermatitis. The physical properties of the fabrics did not differ after immersion compared to before. FTIR and XRPD did not show any difference between the non-treated, 5mg/ml and 10mg/ml specimens. Neither FTIR nor XRPD showed any difference between the non-treated and the pipetted samples; therefore both instruments may not have been able to detect small amounts of hydrocortisone on the fabrics. SEM confirmed that there was no visible evidence of hydrocortisone on specimens immersed in either of the two concentrations tested, although hydrocortisone was evident on the pipetted specimens. Further studies are needed to determine a successful method to impart hydrocortisone on to fabrics for the treatment of atopic dermatitis.