Foam sclerosants are more stable at lower temperatures.

Abstract

Sclerosant foams are aqueous and break down under the influence of gravity, pressure, and temperature. The aim of this study was to investigate the effects of temperature on foam stability. Sodium tetradecyl sulphate (STS) and polidocanol (POL) liquid and foam (1 + 4, liquid-plus-air fraction) were investigated in a range of concentrations (0.5%, 1.5%, 3.0%) and temperatures. Surface tension was measured by the Du Nuoy ring method. Liquid drainage from foam was measured and documented by serial photography. Both pre- and post-cooling variations were investigated. Surface tension decreased at higher temperatures. Surface tension of POL was higher than STS at concentrations tested. POL foam half-time increased significantly at higher concentrations while the half-time of STS foam was not affected by concentration. Heating the sclerosant foam above the ambient temperature reduced its half-time while cooling below the ambient temperature prolonged the half-time. Both pre- and post-cooling of the foams resulted in significant prolongation of half-times when compared to no cooling. Maximum stability of the two sclerosant foams tested was achieved at 10 °C. Foam sclerosants are more stable at cooler temperatures.