Chromatographic separation of tiropramide hydrochloride and its degradation products along with their structural characterization using liquid chromatography quadrupole time-of-flight tandem mass spectrometry and nuclear magnetic resonance

Tiropramide HCl, a widely used antispasmodic drug, was subjected to various stress conditions (hydrolytic, oxidative, photolytic and thermal) per International Council for Harmonization guidelines in the present work. However, there were no comprehensive degradation studies reported on the drug. Therefore, forced degradation studies of tiropramide HCl were carried out to establish the degradation profile and the storage conditions to maintain its quality attributes during the shelf life and usage. A selective HPLC method was developed to separate the drug and its degradation products (DPs) using Agilent C18 column (250 x 4.6 mm; 5 mu m). The mobile phase of 10 mM ammonium formate at pH 3.6 (solvent A) and methanol (solvent B) with gradient elution at a flow rate of 1.00 ml/min was used. Tiropramide was found to be susceptible to acidic and basic hydrolytic exposures as well as oxidative stress conditions in the solution state. This drug was found to be stable under neutral, thermal and photolytic conditions in both solutions and the solid state. Five DPs were detected under different stress conditions. The mass spectrometric fragmentation pattern of tiropramide and its DPs was extensively studied using liquid chromatography quadrupole time-of-flight tandem mass spectrometry for their structural characterization. The position of the oxygen atom in the N-oxide DP was confirmed by NMR studies. The knowledge gained by these studies was used to predict drug degradation profiles, which help analyse any impurities in the dosage form.