The Addition of Lipid-Based Contrast Medium does not Inactivate the Detergent Sclerosant Sodium Tetradecyl Sulfate in-vitro.

PURPOSE: To investigate if the detergent sclerosant sodium tetradecyl sulfate (STS) is deactivated by the lipid-based contrast agent ethiodised oil.

METHOD: 3% STS was mixed with ethiodised oil and room air in a 2:1:4 ratio in two luer lock syringes and a three way connector and agitated to make foam (the Tessari technique) to replicate the clinical use of the products. The assay of STS in the mixture was assessed using the British Pharmacopoeia method. Briefly this is a manual titration method where the solution of STS is mixed with an indicator solution and titrated with hyamine solution of known concentration; the concentration of the STS can then be calculated with the titration results. To further mimic the clinical environment with the presence of blood, the effect of adding increasing amounts of albumin to the STS-ethiodised oil mixture was assessed.

RESULTS: The assay of STS in the solution after mixing with ethiodised oil was 3% indicating that the ethiodised oil did not deactivate the STS. The addition of albumin to the STS-contrast mixture resulted in near linear neutralisation of the STS with increasing concentrations in the same quantities as with STS alone.

CONCLUSIONS: The mixture of the lipid-based contrast agent ethiodised oil with the detergent sclerosant STS did not affect the availability of the sclerosant. The continued use of STS-ethiodised oil in the management of vascular malformations can be supported.