Spectrophotometric Method for the Determination of Trace Level Formaldehyde in Rivastigmine Tartrate Drug Substance

To develop a fast and sensitive  UV spectrophotometric method for the quantitative estimation of Formaldehyde in Rivastigmine tartrate drug substances and validate as per ICH guidelines. The method was based upon the observation, that a characteristic colourresults upon addition of  solution of Pentane-2,4-dione , also known as acetylacetone . In acetic acid and ammonium acetate buffer condition, acetylacetone and formaldehyde react to form dimethyl pyridine. Dimethyl pyridine is slightly yellow and its absorption maximum in aqueous solution is λ 420 nmin Rivastigmine tartrate drug substance.The developed method resulted in Formaldehyde exhibiting linearity in the range 0.975 to 234 µg/g. The Intraday and interday precision is exemplified by relative standard deviation of 0.562 % and 0.757%. Percentage Mean recovery was found to be in the range of 98‐101%, during accuracy studies. The limit of detection (LOD) and limit of quantitiation (LOQ) were found to be 1.3 µg/g and 3.9 µg/g respectively.The present work was aimed to develop a visible spectrophotometric method, which is simple, sensitive, accurate and cost effective to evaluate the quality of the bulk drugs.