الفهرس 
INTRODUCTION.Only 14 pages are availabe for public view
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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.