Deactivation of sodium tetradecyl sulphate injection by blood proteins.

OBJECTIVES: The aim of this work was to quantify the volume of blood required to deactivate 1 ml of 3% sodium tetradecyl sulphate (STS).
DESIGN: A series of experiments were performed where the concentration of STS remaining in a stock solution was measured after adding increasing volumes of blood protein solutions.
MATERIALS AND METHODS: Increasing volumes of bovine serum albumin, bovine erythrocytes and a mixture of both was added to a stock solution of STS. The BP manual titration method was used to measure the assay of the remaining STS.
RESULTS: The method was reproducible and increasing volumes of blood protein lowered the STS concentration in a linear fashion. Approximately 2 ml of a 4% blood protein solution deactivates 1 ml of 3% STS, which means approximately 0.5 ml of whole blood will deactivate 1 ml of 3% STS.
CONCLUSIONS: Sodium tetradecyl sulphate injection is deactivated by a relatively small volume of blood. The practical implication is that changes in technique to reduce the blood volume in larger veins and to introduce fresh aliquots of sclerosant along the length of the vein could improve the efficacy of sclerotherapy.