A comparison of different surfactants on foam stability in foam sclerotherapy in vitro

Objective: This article compares the effect of different surfactants on foam stability and determines the foam decay relationship, so that the suitability of surfactants in a clinical setting can be evaluated. Methods: Five different surfactants were used to prepare sclerosing foam at room temperature using a liquid: gas ratio of 1: 4 in vitro. Foam decay experiments were performed for each sample using a laboratory-made foaming apparatus, and the process was recorded using a video camera. The stability indices used included the drainage time, drainage rate, halflife, foam half-life volume, surfactant stability index, and foaming index. Results: The sodium morrhuate foam was relatively more stable than the polidocanol foam, but exhibited weak foaming. After the addition of the surfactants, the foam half-life was less than 300 seconds. The effect of the surfactants on the stability of the sodium morrhuate foam was more pronounced. The surfactant stability indices could be arranged as follows: poloxamer 188 > Tween 80 > macrogol 4000 > propanediol > lecithin. However, the differences in the foaming indices were small. Conclusions: Of the five surfactants tested, poloxamer 188 has best performance to enhance sclerosing foam stability. The addition of the surfactants improved the stability of the sclerosing foams. It was observed that the relationships between the foam half-life and the surfactant stability index and the surfactant concentration follow the power law. (J Vasc Surg 2019; 69: 581-91.) Clinical Relevance: Improving foam stability would not only improve the efficacy of foam sclerotherapy, but would also increase patient safety. Therefore, we investigated the effects of five commonly used surfactants on the stability of foams of two drugs used widely for treating varicose diseases. A new test scheme for evaluating the foaming characteristics and stability of two commonly used drugs was proposed. The results of this study should aid the preparation and use of sclerosing foams in clinical applications as well as further our understanding of the nature of the foams themselves and, thus, provide a more grounded theoretical and experimental basis for their use in the treatment of varicose diseases.