First Spectrofluorimetric Determination of Mirogabalin in Biological Fluids: A Validated Hantzsch Derivatization Strategy With Full NMR Structural Confirmation.

Mirogabalin (MGB) is a new gabapentinoid drug and is designated for peripheral neuropathic pain, involving peripheral neuropathic pain related to diabetes and postherpetic neuralgia. Despite its critical therapeutic importance, reported methods for its determination remain scarce and mainly dependent on LC-MS/MS methods. These published methods demand costly equipment and lengthy sample preparation. Herein, we describe the development and validation of the first spectrofluorimetric report for the sensitive assay of MGB in bulk drug, pharmaceutical tablets, and spiked human urine and plasma. The quantification strategy relies on the Hantzsch condensation reaction between amino group of MGB with acetylacetone and formaldehyde under mildly acidic conditions to produce a strongly fluorescent product. The reaction product was confirmed using 1H NMR and 13C NMR analysis. Calibration was linear across 0.1-2.0 μg/mL in the pure drug standard, with a detection limit of 0.029 μg/mL and a quantification limit of 0.089 μg/mL. The linear ranges for spiked human urine and plasma are 0.2-2.0 and 0.1-1.5, respectively. Application to spiked human urine and plasma yielded mean recoveries of 98.28 ± 1.14-98.74 ± 0.91%. Moreover, the introduced was method used for investigating the content uniformity testing of the drug tablets.