SWELLING OF HYDROCOLLOID DRESSINGS

Wound healing is promoted by dressings that maintain a moist environme nt. Specifically, hydrocolloid dressings allow excess fluid to escape without permitting wound desiccation. However, the fluid handling capa city of hydrocolloid dressings depends on many factors such as the phy sicochemical properties of the gel formulation, and the design of the dressing. We measured the moisture uptake kinetics of different hydroc olloid dressings by placing the gel side of a sample in contact with w ater. The time evolution of the thickness was measured by means of a v ideo camera linked to a computer. The theory of Tanaka and Fillmore (1 979) was used to predict the kinetics of uniaxial swelling of a cylind rical gel sample. The model allows to associate to an experimental cur ve a total thickness increase h(f)-h(o) (where h(f) and h(o) are respe ctively the final and initial thickness) and a characteristic time tau . The model also relates h(f) - h(o) and tau to the physicochemical co mposition of the dressing, and to the initial thickness h(o). The infl uence of h(o) is discussed by means of experiments performed on dressi ngs with different initial thickness. (C) 1997 Elsevier Science Ltd.