Validated spectrophotometric and spectrofluorimetric methods for determination of dapoxetine hydrochloride and dosulepin hydrochloride in their dosage forms using mercurochrome

Abstract

Validated, simple, rapid and sensitive spectrophotometric and spectrofluorimetric methods were developed for the determination of dapoxetine HCl and dosulepin HCl. The spectrophotometric method (I) was based on a binary complex formation between each drug and mercurochrome (MER) in acetate buffer (pH 3.5) with maximum absorbance at 557 nm. Calibration graphs were linear over the range 2.0–20.0 and 2.0–24.0 μg/ml, detection limits were 0.23 and 0.41 μg/ml and quantitation limits were 0.71 and 1.26 μg/ml for dapoxetine HCl and dosulepin HCl, respectively. Spectrofluorimetric method (II) was based on the measurement of the quantitative quenching effect of each drug on the native fluorescence of MER at the same pH. Fluorescence quenching of MER was measured at 538 nm after excitation at 470 nm. Calibration graphs were linear over the range 0.5–10.0 and 0.4–10.0 μg/ml, detection limits were 0.17 and 0.12 μg/ml and quantitation limits were 0.5 and 0.36 μg/ml for dapoxetine HCl and dosulepin HCl, respectively. Statistical comparison of results with those obtained by reported methods provided good agreement and revealed that there were no significant differences in accuracy and precision between methods. The proposed methods were applied successfully to analyse commercial tablets and capsules containing the studied drugs.

Applying different spectroscopic techniques for the selective determination of daclatasvir using merbromin as a probe: Applications on pharmaceutical analysis

“…It is well known that some lipophilic basic drugs produce a quenching effect in the fluorescence strength of xanthene dyes. [ 9,17,23,27–29 ] Therefore, daclatasvir dihydrochloride (log P = 4.57 [ 30 ] ) can suppress the fluorescence strength of merbromin at 545 nm and can be quantitatively estimated through spectrofluorometric methodology (Figure 5).…”

“…[ 12–16 ] Generally, chromatographic methodologies require a large volume of hazardous organic solvents, tedious procedures, long time periods, and expensive detectors. Merbromin or sodium mercurescein is a stable low‐cost fluorescent reagent [ 17 ] and has been applied spectrophotometrically and fluorometrically for the quantification of some antibiotics, fluoroquinolones, thio‐compounds, dapoxetine hydrochloride, and allopurinol in their pharmaceutical dosage forms. [ 17–20 ] To date, there has been no resonance Rayleigh scattering (RRS) methodology reported for the quantification of daclatasvir dihydrochloride, and merbromin has not been studied previously using this technique.…”

“…Merbromin or sodium mercurescein is a stable low‐cost fluorescent reagent [ 17 ] and has been applied spectrophotometrically and fluorometrically for the quantification of some antibiotics, fluoroquinolones, thio‐compounds, dapoxetine hydrochloride, and allopurinol in their pharmaceutical dosage forms. [ 17–20 ] To date, there has been no resonance Rayleigh scattering (RRS) methodology reported for the quantification of daclatasvir dihydrochloride, and merbromin has not been studied previously using this technique. Therefore, this study aimed to apply the RRS technique for quantification of daclatasvir dihydrochloride in pharmaceutical samples.…”

Investigation of the association complex formed between dapoxetine and erythrosine‐B for facile dapoxetine assay in pharmaceutical formulation using resonance Rayleigh scattering and spectrofluorimetric techniques

“…The estimated percentage values of recovery were 99.62 ± 1.34 and 101.18 ± 1.11 for fluorimetric and RRS approaches. Additionally, the same product was evaluated using a previously published [ 10 ] method, and outcomes of the published [ 10 ] and proposed methods were statistically compared by F‐test and Student's t ‐test to calculate precision and accuracy. No discrepancy appeared between the proposed and published methods (Table 6) as F‐test and Student's t ‐test values were smaller than tabulated at a confidence limit of 95%.…”

“…The published analytical methods for DPX involve spectrophotometric, [ 3–7 ] and spectrofluorimetric approaches based on native fluorescence properties, [ 8 ] synchronous spectrofluorimetry, [ 9 ] or association complex with mercurochrome, [ 10 ] HPTLC, [ 11 ] high‐performance liquid chromatography (HPLC) using ultraviolet (UV) or fluorescence detectors [ 12–14 ] , and electrochemical methods. [ 15,16 ]…”