Foam sclerosants are more stable at lower temperatures.
OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
Foam sclerosants are more stable at cooler temperatures.
School of Aerospace, Mechanical & Mechatronic Engineering, University of Sydney, Sydney, Australia.
G C
GC
Valenzuela
K
K
Wong
D E
DE
Connor
M
M
Behnia
K
K
Parsi
D003080:Cold Temperature; D004304:Dosage Forms; D004355:Drug Stability; D006207:Half-Life; D006358:Hot Temperature; D000077423:Polidocanol; D011092:Polyethylene Glycols / Q000737:chemistry*; D012597:Sclerosing Solutions / Q000737:chemistry*; D012981:Sodium Tetradecyl Sulfate / Q000737:chemistry*; D013500:Surface Tension; D013696:Temperature; D013997:Time Factors
D004304:Dosage Forms; D012597:Sclerosing Solutions; D000077423:Polidocanol; D011092:Polyethylene Glycols; D012981:Sodium Tetradecyl Sulfate
Foam; Liquid drainage; Polidocanol; Sclerosants; Sodium tetradecyl sulphate; Surface tension; Temperature