Simultaneous HPLC determination of thiocolchicoside and glafenine as well as thiocolchicoside and floctafenine in their combined dosage forms

Sensitive and accurate high-performance liquid chromatographic methods have been developed for the simultaneous determination of thiocolchicoside (TC)-glafenine (GF) (Mix I) and thiocolchicoside-floctafenine (FN) (Mix II) in their pharmaceutical formulations. The analysis for both mixtures was performed using 250 mm × 4.6 mm i.d., 5 μm particle size C18 Waters Symmetry column. The mobile phase consisted of methanol-0.035 M phosphate buffer (50:50, v/v) of pH 4.5 for Mix I and methanol-0.03 M phosphate buffer (70:30, v/v) of pH 4 for Mix II with flow rate of 1 mL/min and UV detection at 400 nm in both cases. The calibration plots were rectilinear over the concentration range of 0.2-2 μg/mL for TC in both mixtures and 20-200 μg/mL for each of GF and FN.The limits of detection for TC and GF were 0.05 μg/mL and 0.62 μg/mL, respectively, and for TC and FN were 0.02 μg/mL and 0.70 μg/mL, respectively. Additionally, the proposed methods were successfully applied to their combined tablets with average percentage recoveries of 100.35 ± 0.61 and 100.57 ± 0.72% for TC and GF respectively and for TC and FN the percentage recoveries were 101.2 ± 0.72 and 100.36 ± 0.67%, respectively. The results obtained were favorably compared with those given using the comparison methods.