Abstract
Spectrophotometric procedures are presented for the determination of the antiparkinsonism drug entacapone. The first method based on the formation of a coloured complex of entacapone with ferric chloride in ethanolic solutions. The coloured product is quantified spectrophotometrically at 665nm. The other Spectrophotometric method determine entacapone in presence of levodopa and carbidopa (which formulated with entacapone in stalevo tablets) by measuring the UV absorbance of entacapone either in zero order at 391nm or in the first order by measuring the amplitude between 360nm and 402nm without any interference from levodopa and carbidopa. HPLC method is described forthe separation and determination of entacapone, levodopa and carbidopa on Luna CN 150 x 4.6 column with UV detection at 390nm for entacapone and at 280nm for both levodopa and carbidopa.