Application of HPTLC and LC-MS Methods for Determination of Topiramate in Pharmaceutical Formulations

Methods for determination of topiramate in pharmaceutical formulation by high-performance thin-layer chromatography (HPTLC) UV-densitometry and liquid chromatography-mass spectrometry (LC-MS) have been developed. HPTLC method as recommended by United States Pharmacopeia was performed using the silica plates, mobile phase composed of benzene:ethanol (5:2, v/v) and densitometric detection at 340 nm after topiramate visualization with the use of chemical reagent. Moreover, quantification was achieved in the concentration range of 0.25-4.0 μg/spot and with adequate precision (RSD=4.16%) and recovery (104.47%) using non-linear calibration curve by fitting to y=a+blnx. LC-MS method was performed using Zorbax SB-C18 column and isocratic elution mode with a mobile phase composed of acetonitrile:water (85:15, v/v) with 0.1% (v/v) formic acid at a flow rate 0.5 ml/min. Moreover, the single quadrupole mass spectrometer employing ESI interface operated in the negative ion mode was used to quantify the topiramate at m/z=338.1. Proposed LC-MS method provided good results of precision (RSD=2.05%) and recovery (99.53%) in the concentration range of 0.25-10.0 μg/ml using linear y=a+bx regression analysis. Additionally, no interferences were found from tablet excipients at the selected wavelength, mass-to-charge ratio and assay procedures. The developed methods found to be sufficiently precise and reproducible for established conditions and after validation may be used for routine quality control of topiramate in pharmaceutical formulations.