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 × 4.6 mm; 5 µm). 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.

Comprehensive degradation profiling and influence of different oxidizing reagents on tinoridine hydrochloride: Structural characterization of its degradation products using HPLC and HRMS.

RATIONALE: Stress testing on tinoridine hydrochloride was carried out using a multidimensional approach. This included different conditions: hydrolytic (acidic, alkaline, and neutral conditions), different oxidative reagents, thermal, photolytic conditions, HPLC method development, and structural elucidation using high-resolution mass spectrometry (HRMS). It provides the basis for quality control of tinoridine hydrochloride and its derivatives during storage conditions. METHODS: The tinoridine hydrochloride was subjected to a variety of stress conditions. A gradient reversed-phase HPLC method was developed on a X-Bridge C18 column (250 × 4.6 mm, 5 µm) to separate all the degradation products (DPs). HRMS studies have been performed to elucidate the structure of DPs. RESULTS: HPLC-PDA study revealed that significant degradation products were formed in hydrolytic, AIBN (radical initiator at 40°C), thermal, and solid-state photolight stress conditions, but the drug was stable under oxidative conditions (H2 O2, Fenton's reagent at room temperature and ferric chloride at 40°C). The structure of degradation products was elucidated, and mechanism of their formation was explained. CONCLUSION: Stress study was successfully carried out as per ICH Q1A (R2) guideline on tinoridine hydrochloride. A total of six new degradation products were characterized, DP 2 and DP 6 formed by the effect of co-solvent. This study provides the scientifically sound basis for quality monitoring and storage conditions of tinoridine hydrochloride.

Characterization of stress degradation products of nintedanib by UPLC, UHPLC-Q-TOF/MS/MS and NMR: Evidence of a degradation product with a structure alert for mutagenicity.

Nintedanib is an anti-cancer drug used for the treatment of idiopathic pulmonary fibrosis and non-small cell lung cancer. The purpose of this study was to explore its degradation chemistry under various stress conditions recommended in ICH guidelines Q1A R(2). The drug was subjected to hydrolytic, photolytic, thermal and oxidative (H2O2, AIBN, FeCl3 and FeSO4) stress conditions. The degradation products formed in stressed solutions were successfully separated on an ACQUITY UPLC CSH C18 (2.1 × 100 mm, 1.7 µm) column, using a gradient UPLC-PDA method, developed with acetonitrile:methanol (90:10) and 0.1 % formic acid (pH 3.0) as the mobile phase. The drug proved to be labile to acidic, neutral and alkaline hydrolytic, and H2O2/AIBN oxidative conditions. It was stable to photolytic and thermal stress conditions, and even in oxidative reaction solutions containing FeCl3 or FeSO4. Additionally, the drug exhibited instability when its powder with added sodium bicarbonate was stored at 40 °C/75 % RH for 3 months. In total, nine degradation products (DPs 1-9) were formed. To characterize them, a comprehensive mass fragmentation pathway of the drug was first established using UHPLC-Q-TOF/MS/MS data. Similarly, the mass studies were then carried out on the stressed samples using the developed UPLC method. All the degradation products were primarily characterized through comparison of their mass fragmentation profiles with that of the drug. To confirm the structure in one case (DP 3), additional nuclear magnetic resonance (NMR) studies were carried out on the isolated product. Subsequently, mechanisms for their formation were laid down. A significant finding was the formation of a degradation product upon acid hydrolysis having a free aromatic amine moiety, which is considered as a structural alert for mutagenicity. Furthermore, the physicochemical and ADMET properties of the drug and its degradation products were predicted using ADMET predictor™ software.