Preventive immunization against snake envenomation.I.Immunogenicity of formol detoxified snake venom

Dessicated viper venom in a concentration of 1 mg/ml dissolved in 1 percent phosphate buffered peptone solution at pH 7.2 was formolised by adding 0.5 percent formalin and incubating at 37C for 4 weeks. The toxicity of the detoxified venom in rabbits was reduced to 69 times over that of the initial venom. Rabbits inoculated intraperitoneally with 5 ml of detoxified viper venom at 3 days intervals for 4 times were found to be able to withstand 2-3 times the minimum lethal doseof venom when challenged 7 days after last immunizing dose. The immunodiffusion studies of the detoxified venoms however showed loss of some of the components of the original venom.

Freezedrying of anti-snake venom sera

Freezedrying of antisnake venom was carried out using Edwards Centrifugal Freezedrier. The process consisted of 36 hours of primary drying followed by 24 hours of secondary drying. No differences in the chemical and biological characteristics of antivenom were observed before and after drying. Stability studies indicated that when dried to moisture content of 0.5 per cent it was stable for 2 years at 37C, 5 years at room temperature and could withstand heating at 100C for at least 4 hours.