Asian Journal of Research in Chemistry

P. Nagaraju ¹, V. D. N. Srinivas ¹, S. V. N. Padma ¹, P. N. V. Gopal ¹, D. Mallikarjuna Rao ¹

Affiliations
1 Department of Pharmaceutical Analysis, Hindu College of Pharmacy, Amaravathi Road, Guntur, IN

Abstract

Over the past decade, cavity ring down spectroscopy has emerged as a powerful technique for performing direct absorption measurements using pulsed lasers. Cavity ring down spectroscopy has since been used from the ultraviolet to the mid-infrared. It is a direct absorption technique, which can be performed with pulsed or continuous light sources and has a significantly higher sensitivity than obtainable in conventional absorption spectroscopy. It can be used to measure the concentration of some light-absorbing substances. Typically, the substances to be measured are in gaseous form. This technique is most widely known as cavity ring-down spectroscopy, although the alternative, but more cumbersome, cavity ring-down laser absorption spectroscopy is preferred by some authors. Here we discuss about the experimental implementation of Cavity ring down spectroscopy and its application to a number of areas of research including laser diagnostics of hostile environments, reaction kinetics and spectroscopy, with particular emphasis on our ongoing studies of the fast (sub-nanosecond) pre dissociation of electronically excited states of small molecules and radicals.

Keywords

Cavity Ring Down Spectroscopy, Absorption Spectroscopy.

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P. Nagaraju ¹, D. Narendra ¹, P. Jitendra Kumar ¹, V. D. N. Srinivas ¹, S. V. N. Padma ¹

Affiliations
1 Hindu College of Pharmacy, Amaravathi Road, Guntur-522002, IN

Abstract

A reverse phase high performance liquid chromatographic method (HPLC) has been developed for the estimation of entacapone in its dosage forms using C₁₈ column. The mobile phase (acetonitrile and 20 mM potassium dihydrogen phosphate, P^H 3.5) was pumped at a flow rate of 1 ml/min in the ratio of 80:20 and the eluents were monitored at 320 nm. The intra- and inter- day variation was found to be less than 2% showing high precision of the assay method. The mean recovery of the drug from the solution containing 200 or 300 μg/ml was 99.66±1.20% indicating high accuracy. The proposed HPLC method may be used for determining entacapone in bulk drug samples or in pharmaceutical dosage forms.

Keywords

Estimation, Entacapone, Tablets and HPLC.

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