The precise, systematic, definite, particular, linear, exact and robust scientific method was developed validated for the assay of Cypermethrin in 25% EC Insecticide Injection, USP 500 mg/vial. Presently utilized 25 % as a working standard having limit 95% development validation. quantitative determination bring to accomplished by HPLC- Waters - Alliance 510 system equipped with UV/PDA detector...