An experimental ninhydrin design approach for the sensitive spectrofluorimetric assay of milnacipran in human urine and plasma.

Women are the most ones who susceptible to a common syndrome called fibromyalgia syndrome, up to 90% of all people with fibromyalgia are women. It affects mainly muscles and soft tissue and cause for them muscle pain, sleep problems and painful tender points. Milnacipran is acting as a serotonin-norepinephrine reuptake inhibitor (SNRI) therefore, it is recommended for the treatment of this syndrome. The widespread use of this compound in our market requires the development and validation of a simple, sensitive, cheap, fast and reproducible spectrofluorimetric method for the assay of milnacipran hydrochloride in its pure state, pharmaceutical tablets and spiked human urine and plasma. In the current work ninhydrin and phenylacetaldehyde in Teorell and Stenhagen buffer (pH 7) reacts with the amino moiety of milnacipran through a sensitive condensation reaction resulting in formation of a fluorescent product, which exhibits its fluorescence emission intensity at 465 nm after excitation at 390 nm. It is observed that, in the concentration range 0.5 to 3.0 μgmL-1, the constructed calibration curve was linear with a good correlation coefficient (0.9998). The condensation reaction was successfully applied for the assay of the studied drug in Avermilan® tablets, spiked human urine and plasma without interference from the components of the sample matrix with average percentage recoveries of 101.73 ± 0.56 and 100.55 ± 0.64 for urine and plasma, respectively.