The influence of hydrocolloid patch composition on the bioavailability of triamcinolone acetonide in humans

Triamcinolone acetonide (TACA) is a corticosteroid; it is used in the systemic and topical treatment of a variety of inflammatory conditions, including eczema and psoriasis. Conventionally, for topical use, the drug is formulated in a cream or ointment. However, it has been observed in vitro that percutaneous penetration of corticosteroids can be influenced by hydrocolloid patches. Corticosteroids produce a pallor or blanching when applied to the skin that correlates with anti-inflammatory activity; this property has been used extensively as a bioassay. The aim of this study therefore was to evaluate the occlusive properties of a range of hydrocolloid patches containing TACA on the drug's penetration in vivo using visual assessment and a graded multiple measurement. The in vivo hydration of these dermatological patches was also investigated. Statistical analysis of the weight gains of patches containing either NaCMC 39% or pectin 39% showed that there was a significant difference in the rates of hydration of the two types of patch (p < .005). An increase in application time of the hydrocolloid patches allowed more TACA to be released, which was illustrated by an increase in both the maximum percentage total possible score (%TPS) values and AUC, although changes in the hydrocolloid composition did not significantly alter the blanching response. All of the patches adhered well, were unobtrusive to the normal activity of the wearers, and showed great potential for the convenient, localized, prolonged delivery of drugs to the skin.