Surfactant to dye binding degree method for the determination of fluvoxamine maleate and citalopram hydrobromide in pharmaceuticals

The surfactant to dye binding degree (SBDB) methodology was used to determine fluvoxamine maleate and citalopram hydrobromide. Neutral red and sodium dodecyl sulfate (SDS) were used as the dye and surfactant, respectively, to form dye-surfactant aggregates. When a cationic drug is added to dye-surfactant mixture, it interacts with the surfactant and decreases the dye-surfactant binding degree. This decrease is proportional to the drug concentration. This was measured by monitoring the absorbance changes of the dye at 532 nm. Under the optimum conditions, the calibration graphs were linear over the range of 1.2 - 15 mu g mL(-1) and 1.1 - 15 mu g mL(-1) for fluvoxamine maleate and citalopram hydrobromide, respectively. The detection limits (signal to noise ratio = 3) were found to be 0.37 and 0.35 mu g mL(-1), for fluvoxamine maleate and citalopram hydrobromide, respectively.