Determination of Lorazepam in Drug Formulation and Biofluids Using a Spectrophotometric Method and Response Surface Meth
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Journal of Applied Spectroscopy, Vol. 87, No. 5, November, 2020 (Russian Original Vol. 87, No. 5, September–October, 2020)
DETERMINATION OF LORAZEPAM IN DRUG FORMULATION AND BIOFLUIDS USING A SPECTROPHOTOMETRIC METHOD AND RESPONSE SURFACE METHODOLOGY Sara Ghorbanpoor, M. Reza Shishehbor,* Ali Sheibani, Mohadeseh Safaei, and Ali Nazari
UDC 543.42.062:615.45
A novel, simple, sensitive, and selective kinetic spectrophotometric method has been developed for the determination of lorazepam in pharmaceutical and bioloical samples. The procedure is based on the catalytic effect of lorazepam on the Janus Green–bromate reaction system. The change in absorbance was followed spectrophotometrically at 618 nm. To obtain the maximum sensitivity, the reagents concentration, temperature, and time were optimized by one at the time method. Under optimum experimental conditions, the calibration curve was linear over the range 0.3–19.5 μg/mL of lorazepam, including two linear segments. The relative standard deviations (n = 5) for 1.0, 5.0, and 15.0 μmol/L of lorazepam were 1.09, 1.03, and 0.97%, respectively. The limit of detection was 0.08 μg/mL of lorazepam. An experimental check under these optimal conditions confirmed good agreement in the RSM results. The developed method was successfully applied for the determination of lorazepam in real samples, and the obtained results are in a good agreement with those using HPLC. Keywords: lorazepam, kinetic spectrophotometry, response surface methodology, drug formulation, biofluids. Introduction. Kinetic methods have certain advantages in pharmaceutical analysis regarding selectivity and elimination of additive interferences, which affect direct spectrophotometric methods [1, 2]. The literature is still poor in analytical assay methods based on kinetics for the determination of lorazepam in dosage forms. Some specific advantages that the kinetic methods possess are as follows: simple and fast because some experimental steps such as filtration, extraction, etc., are avoided prior to absorbance measurements; high selectivity since they involve the measurement of the absorbance as a function of reaction time instead of measuring the concrete absorbance value; other active compounds present in the commercial dosage forms may not interfere if they resist the chemical reaction conditions established for the proposed kinetic method; and colored and/or turbid sample background may not interfere with the determination process [3–6]. Lorazepam (7-chloro-5-(2-chlorophenyl)-3-hydroxy-2,3-dihydro-1H-1, 4-benzo-diazepin-2-one) is sold under the trademark Ativan; it was introduced in 1977 by D. J. Richards [7–9].
Molecular structure of lorazepam It is a kind of benzodiazepines that is often used as a sedative. Lorazepam has all intrinsic benzodiazepine effects such as anterograde antiemesis, amnesia, anticonvulsion, and muscle relaxation. Lorazepam is used for the short-term treatment _____________________ *
To whom correspondence should be addressed.
Department of Chemistry, Yazd Branch, Islamic Az
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