Two green spectrofluorimetric methods for the assay of atomoxetine hydrochloride in pure form and commercial capsules with application to content uniformity testing

Atomoxetine hydrochloride (ATX) is a potent and non-stimulant drug which was approved for the treatment of attention-deficit hyperactivity disorder. Owing to its importance, two green, simple and validated spectrofluorimetric methods were developed for its sensitive assay in pure and capsule forms. The first method (Method I) relied on measuring the enhanced fluorescence of ATX by the use of sodium dodecyl sulfate in alkaline medium at λ(ex) 227 nm/λ(em) 298 nm. The second method (Method II) involved complex formation of ATX with Erythrosine B (EB) in aqueous acidic solution resulting in quantitative quenching of the EB naive fluorescence. This complex was formed in the presence of Britton–Robinson buffer (pH 4.0). The difference in fluorescence intensity was measured at λ(ex) 527/λ(em)550 nm. The calibration curves were linear through the ranges of 0.2–2.0 µg ml(−1) for Method I, 0.2–4.0 µg ml(−1) for Method II with good correlation coefficient (r = 0.9998) for both methods. The suggested methods were perfectly applied for determination of ATX in its commercial capsules and content uniformity test. The greenness of the proposed methods was confirmed by three different assessment tools and it was found that both methods were green, eco-friendly and environmentally safe.