Spectrophotometric Quantification of Atomoxetine Hydrochloride Based on Nucleophilic Substitution Reaction with 1,2-Naphthoquinone-4-Sulfonic Acid Sodium Salt (NQS).

Objectives: A simple, sensitive, selective, and cost-effective colorimetric method has been established for the quantitative estimation of atomoxetine hydrochloride in bulk and formulation.A simple, sensitive, selective and cost effective colorimetric method has been entrenched for the quantitative estimation of Atomoxetine hydrochloride in bulk and formulation. Materials and Methods: It was established based on the visible reaction between atomoxetine hydrochloride and 1,2-naphthoquinone-4-sulfonic acid sodium salt in a basic medium (potassium hydroxide). The resulting orange colored chromogen exhibited an absorption maximum at 474 nm. Results: Based on the optimization studies, distilled water as the solvent, 1% w/v potassium hydroxide (2 mL), and 0.3% w/v 1,2-naphthoquinone-4-sulfonic acid sodium salt (2 mL) were used in the method. The developed method was validated per the International Council for Harmonization (ICH) guidelines. The linearity was found at a concentration of 10-50 µg/mL. The method showed a good correlation between the concentration of atomoxetine hydrochloride and its absorbance. The correlation coefficient (r2) of 0.999 evidenced the same. The limits of detection and quantification were 0.20 and 0.606 µg/mL, respectively, for atomoxetine hydrochloride. The accuracy and precision of the method were also evaluated and the results obtained were within the acceptance criteria (relative standard deviation % < 2.00). The percentage assay of atomoxetine hydrochloride proved to be 101.52, which is in accordance with its label claim. Conclusion: The developed method is non-complex and can be effectively employed in the analytical practices of atomoxetine hydrochloride in pharmaceutical dosage forms.

Development and Validation of a Spectrofluorimetric Method for the Quantification of Capecitabine in Bulk and Tablets.

Objectives: A new, simple, and affordable spectrofluorimetric method was established for quantification of capecitabine in bulk and in marketed formulations. Materials and Methods: Native fluorescence of capecitabine in 0.1% (w/v) cetrimide was measured at 386 nm after excitation at 313 nm. Results: A linear relationship between fluorescence intensity and capecitabine concentration was noticed in 0.2-1.0 µg/mL range. The method was supported by checking several validation parameters as stated using International Conference on Harmonization (ICH) guidelines. The limit of detection (LOD) and quantification (LOQ) values (0.032 and 0.096 µg/mL, respectively) and results of validation parameters demonstrated that the method procedure were sensitive, accurate, precise, and reproducible (% relative standard deviation <2.0). The percentage assay in commercial formulation was found to be 99.2, which agrees with ICH guidelines. Conclusion: Due to the above findings, developed method can be successfully adopted for routine analysis of capecitabine in pharmaceutical dosage forms.

Response Surface Methodology in Spectrophotometric Estimation of Saxagliptin, Derivatization with MBTH and Ninhydrin

Objectives: Design of experiments assisted spectrophotometric methods have been established for the quantification of saxagliptin in pharmaceutical formulation via charge transfer complexation and Schiff's base formation. Materials and Methods: Box-Behnken design was exploited in method-1, involved the measurement of absorbance of green/blue-colored complex (at 600 nm), formed by the reaction of saxagliptin with 3-methyl-2-benzothiazolinone hydrazone in the presence of ferric chloride. The central composite design was employed in method-2, involved the determination of absorbance of Ruhemann's purple (at 585 nm), formed by the reaction of the primary amine group of saxagliptin with ninhydrin reagent in presence of sodium hydroxide. Optimization of reaction variables namely, reagent concentration (A), oxidizing agent/alkalinity (B) and reaction/heat time (C) was performed through response surface methodology for the response (Y) i.e. absorbance of colored compound. The reliability of both methods was investigated through validation as per International Council for Harmonisation guidelines. Results: Saxagliptin executed linearity in the concentration range of 0.01-0.25 µg/mL and 1-10 µg/mL by method-1 and 2. A high value of molar absorptivity, low values of Sandell's sensitivity and limit of detection/limit of quantification divulges the good sensitivity methods. The % assay of saxagliptin in the marketed formulation was found to be 100.27 and 99.86 by method-1 and method-2, respectively. Conclusion: The proposed eco-friendly and economical methods can be routinely employed in quality control for the analysis of saxagliptin in the pharmaceutical dosage forms.