ABSTRACT:
Two simple and sensitive visible spectrophotometric methods (M1 and M2) have been developed for the estimation of Donepezil hydrochloride (DH) in bulk and dosage forms. Method M1 involves Internal salt formation of aconitic anhydride, dehydration product of citric acid [CIA] with acetic anhydride [Ac2O] to form colored chromogen with an absorption maximum of 580 nm and the method M2 is based on the formation of green colored coordination complex by the drug with cobalt thiocyanate which is quantitatively extractable into nitro benzene with an absorption maximum of 620 nm. Beer’s law obeyed in the concentration range of 8-24µg/ml for method M1and 16-48 µg/ml for method M2. Commercially available tablets were analyzed and the results are statistically compared with those obtained by the reference method and validated by recovery studies. The results are found satisfactory and reproducible. These methods are applied successfully for the estimation of the Donepezil hydrochloride in the presence of other ingredients that are usually present in dosage forms. These methods offer the advantages of rapidity, simplicity and sensitivity and normal cost and can be easily applied to resource-poor settings without the need for expensive instrumentation and reagents.