Development and Validation of Four Spectrophotometric Methods for Assay of Rebamipide and its Impurity: Application to Tablet Dosage Form.

Background: Rebamipide (REB) is quinolinone derivative compound, which is used for the treatment of stomach ulcers.
Objective: The development of four spectrophotometric methods for quantification of REB and its impurity and degradation product: the debenzoylated isomer of REB (DER).
Methods: Method A is ratio difference spectrophotometry where 254 and 291 nm were selected for REB and 320 and 355 nm were selected for DER, allowing spectral discrimination for both. Method B is derivative ratio spectrophotometry, where the peak amplitudes of the first derivative of ratio spectra at 261 and 350.2 nm for REB and DER, respectively, are determined. Method C is a second derivative approach, which allows quantification of both REB and DER at 337 and 340 nm, respectively. Method D is mean centering of ratio spectra, where electronic absorption spectra of REB and DER were recorded and divided by a suitable divisor from DER and REB, respectively, and then the mean center is represented by the ratio spectrum so obtained.
Results: The proposed methods are simple, selective, and sensitive in the quantification of REB and DER. These methods were validated according to International Conference on Harmonization guidelines. Statistical analyses performed on the findings from the suggested methods and those obtained from reported methods revealed high accuracy and good precision.
Conclusion: The developed and validated methods are useful for quality control assay in routine analyses.
Highlights: First derivative, second derivative, derivative ratio, and mean centering methods for quantification of REM and DER. These methods are useful for analysis of REB in pharmaceutical dosage form.
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