الفهرس | Only 14 pages are availabe for public view |
Abstract Pesticides in relation to various biological system is a two edged issue.Most,if not all,pesticides are toxic but the degree to which they are toxic well known only in a few species of animals Some authors extrapolate from findings on mice,rats,rabbits,toads and variety of other test animals and use their extrapolations as a guide to human toxicity. Synthetic pyrethroids are widely used in compacting ectoparasites affecting farm animals and pests of agricultural crops. The frist synthetic pyrethroids in which characteristically high activity against insect and low mammalian toxicity was combined with greatly increased stability.All pyrethroids are lipophilic compounds almost insoluble in water, are relatively high boiling viscous liquid with low vapour pressure the insecticidal activity of these compounds depends upon the intact molecules,for the components alone are essentially non-toxics. The synthetic pyrothroids insecticides have been developed from the natural pyrethin by structural modification aimed at retaining bioactiviy and increased photostability. The maculated toad Bufo regularis so extensively used nowadays in the laboratory in the different physiological,pharmacological and biochemical experiments. |