Summary

Background: Sulfur mustard and VX are potent chemical warfare agents that penetrate rapidly through the skin, causing severe prolonged injuries and sometimes death.

Objectives: To develop a topically applied pretreatment that will act as a barrier and prevent the absorption of these agents through the skin, reducing morbidity and saving life.

Methods: Several formulations were developed and tested in preclinical animal studies in pigs. The protecting cream was applied as a single application (0.5–1 ml/100 cm²) prior to exposure (10 minutes to 12 hours) to sulfur mustard or VX. Assessment of sulfur mustard-induced skin damage was based on clinical and histologic evaluations. When tested against VX, clinical signs and blood cholinesterase activity were monitored. At the final stage of development, safety studies were conducted in animals and in human volunteers.

Results: The formulation that gave the best results, coded IB1 (under patent application), provided significant protection against a 1 hour exposure to sulfur mustard (droplets or vapor). All the pigs pretreated with IB1 cream survived a 1–4 hour challenge of 2xLD₅₀ VX and did not exhibit any overt clinical signs. Protection was exhibited even when the cream was applied 12 hours (single application) prior to exposure. IB1 was found to be non-irritating in animals and humans. No adverse effects were found in a Phase I clinical study in young healthy volunteers when the cream was applied to around 20% of the skin surface (results presented elsewhere).

Conclusions: IB1 cream has been shown to be a safe and effective topical skin protectant against the chemical warfare agents sulfur mustard and VX.