The Effect of Gamma Irradiation on the Toxicity of the Lightly Crosslinked Polyacrylic Acid “Carbomer 940”

The impact of gamma irradiation in the range of 500 to 2000 kGy on the toxicological profile of Carbomer 940 was evaluated. Irradiation at a dose of 500 kGy increased the toxicity of aqueous dispersions of the carbomer by 20% compared to its unirradiated sample, whereas increasing the dose to 1000–2000 kGy led to a subsequent decrease in toxicity by 7%. It was also found that gamma irradiation affected the dynamics of animal body weight. When the unirradiated carbomer was administered to animals, the maximum body weight loss reached 3.5 g over a 3 day period. In the case of irradiated carbomer, the weight loss was as low as 0.5–2.2 g and recovery occurred faster due to a reduction in dispersion viscosity and the loss of carbomer gelling properties. Structural degradation caused by irradiation allowed for single dose administration above 1400 mg per kg, unlike the unirradiated material, which required repeated dosing. Absence of residual abdominal fluid in animals treated with the carbomer irradiated at 1000 to 2000 kGy confirmed the loss of gelling capacity. Carbomer 940 retained moderate toxicity corresponding to hazard class 3 according to GOST 12.1.007 76 after intraperitoneal administration.