Development and validation of LC methods with visible detection using pre-column derivatization and mass detection for the assay of voglibose

Two sensitive and selective liquid chromatographic methods were developed for the assay of voglibose (VB) and validated as per International Conference on Harmonization (ICH) guidelines. First method is based on the pre-column derivatization of VB followed by visible detection (LC–VD) and second method involves mass spectrometric detection (LC–MS). In LC–VD method, VB was derivatized with sodium metaperiodate and 3-methyl-2-benzothiazolinone hydrazone hydrochloride monohydrate (MBTH). The derivatized color product of VB (DCPVB) was run through Novapak C18 (300 × 3.9 mm, 4 μm) column using the mobile phase containing buffer (0.01 M mixture of sodium di hydrogen orthophosphate and disodium hydrogen orthophosphate, pH 6.0) and acetonitrile in 35:65 v/v ratio. The eluted DCPVB was monitored at 667 nm. The fixation of optimum conditions in LC–VD method is described. DCPVB structure was confirmed by mass spectral analysis. In LC–MS method, VB was passed through Venusil XBPPH (150 × 4.6 mm, 5 μm) column using a 95:5 v/v mixture of 0.01% formic acid and methanol as mobile phase. The assay concentrations of VB in pure form and in tablets for LC–VD and LC–MS methods are 25 and 5 ng ml−1, respectively.