A stability indicating simultaneous dual wavelength UV-HPLC method for the determination of potential impurities in fampridine active pharmaceutical ingredient.

A novel, sensitive, stability indicating simultaneous dual wavelength reverse phase UV-HPLC method has been developed for the quantitative determination of potential impurities of fampridine active pharmaceutical ingredient. Efficient chromatographic separation was achieved on a C18 stationary phase in gradient mode and quantitation by ultraviolet dual wavelength detection. The method was validated according to ICH guidelines with respect to specificity, precision, linearity and accuracy. Regression analysis showed correlation coefficient value greater than 0.999 for fampridine and its seven impurities. Detection limit as low as 0.003% was achieved for fampridine N-oxide and 0.01% for other impurities. Accuracy of the method was established based on the recovery obtained between 93.3% and 110.0% for all impurities. The method was found to be specific, selective to the degradation products and robust. Peak purity analysis by PDA detector confirmed the specificity of the method. Major degradation of the drug substance was found to occur under oxidative stress conditions to form fampridine N-oxide.

Highly efficient, selective, sensitive and stability indicating RP-HPLC-UV method for the quantitative determination of potential impurities and characterization of four novel impurities in eslicarbazepine acetate active pharmaceutical ingredient by LC/ESI-IT/MS/MS.

A novel, sensitive, selective and stability indicating LC-UV method was developed for the determination of potential impurities of eslicarbazepine acetate. High performance liquid chromatographic investigation of eslicarbazepine acetate laboratory sample revealed the presence of several impurities. Three impurities were characterized rapidly and four impurities were found to be unknown. The unknown impurities were identified by liquid chromatography coupled with electrospray ionization, ion trap mass spectrometry (LC/ESI-IT/MS/MS). Structural confirmation of these impurities was unambiguously carried out by synthesis followed by characterization using nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (FT-IR) and mass spectrometry (MS). Based on the spectroscopic, spectrometric and elemental analysis data unknown impurities were characterized as 5-acetyl-5,11-dihydro-10H-dibenzo [b,f]azepin-10-one, N-acetyl-5H-dibenzo[b,f]azepine-5-carboxamide, 5-acetyl-10,11-dihydro-5H-dibenzo[b,f]azepin-10-yl acetate and 5-acetyl-5H-dibenzo[b,f]azepin-10-yl acetate. The newly developed LC-UV method was validated according to ICH guidelines considering eleven potential impurities and four new impurities to demonstrate specificity, precision, linearity, accuracy and stability indicating nature of the method. The newly developed method was found to be highly efficient, selective, sensitive and stability indicating. A plausible pathway for the formation of four new impurities is proposed.

Quantification of potential impurities by a stability indicating UV-HPLC method in niacinamide active pharmaceutical ingredient.

A sensitive, stability indicating reverse phase UV-HPLC method has been developed for the quantitative determination of potential impurities of niacinamide active pharmaceutical ingredient. Efficient chromatographic separation was achieved on C18 stationary phase in isocratic mode using simple mobile phase. Forced degradation study confirmed that the newly developed method was specific and selective to the degradation products. Major degradation of the drug substance was found to occur under oxidative stress conditions to form niacinamide N-oxide. The method was validated according to ICH guidelines with respect to specificity, precision, linearity and accuracy. Regression analysis showed correlation coefficient value greater than 0.999 for niacinamide and its six impurities. Detection limit of impurities was in the range of 0.003-0.005% indicating the high sensitivity of the newly developed method. Accuracy of the method was established based on the recovery obtained between 93.3% and 113.3% for all impurities.