Identification and characterization of stress degradation products of febuxostat employing ultra-performance liquid chromatography-ultraviolet/photodiode array and liquid chromatography-mass spectrometry/time-of-flight studies.

Febuxostat (FEB) is a xanthine oxidase inhibitor approved by the U.S. Food and Drug Administration for long-term treatment of gout and hyperuricemia. There were no reports on identification and characterization of stress degradation products of the drug. FEB was subjected to forced decomposition conditions such as hydrolysis (neutral, acidic, and alkaline), oxidation, photolysis, and thermal stress, per the ICH guideline Q1A(R2). The degradation products formed were subjected to ultra-performance liquid chromatography (UPLC) on a C18 Kinetex column (100 × 4.6 mm, 2.6 μm) using isocratic elution method. Detection wavelength was 317 nm. The developed method was extended to UPLC-mass spectrometry/time of flight (MS/TOF) studies to identify and characterize the degradation products. The drug exhibited significant degradation under alkaline/neutral hydrolytic, alkaline/acidic photolytic, and oxidative conditions, whereas it remained stable under acid hydrolytic, neutral photolytic, and thermal conditions. In total, eight degradation products (I-VIII) were formed, which could be adequately determined from the drug using the developed UPLC method. Of the eight degradation products identified from the liquid chromatography-ultraviolet (LC-UV) chromatogram, five (III and IV and VI-VIII) could be characterized using their MS/TOF spectral data. The degradation pathway leading to the formation of the products was postulated, and this is not reported so far. Forced degradation studies were conducted on FEB, and the degradation products produced were identified by their mass spectral data obtained using LC-MS studies.

Saha M ，Bali A ，Patra SR ，Singh J ... -  《-》

Method validation and characterization of stress degradation products of azelastine hydrochloride using LC-UV/PDA and LC-Q/TOF-MS studies.

Azelastine HCl is a second-generation H1 -receptor antagonist approved by the US Food and Drug Administration (US FDA) for treating seasonal allergic rhinitis and non-allergic vasomotor rhinitis. This study encompasses the validation of a liquid chromatography-ultra violet photo diode array (LC-UV/PDA) method for the drug and its extension to liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-Q/TOF-MS) studies for identification and characterization of various stress degradation products of the drug. Stress degradation of azelastine HCl was undertaken under the International Council for Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) prescribed conditions of hydrolytic, photolytic, oxidative, and thermal stress. The degraded drug solutions were analyzed using Ultra Performance Liquid Chromatography (UPLC) employing a C18 (100 × 4.6 mm; 2.6 μ, Kinetex) column by isocratic elution. Detection wavelength was 241 nm. The degradation products were identified and characterized using UPLC-MS/TOF studies, and an attempt was made to isolate one of the degradation products by solvent extraction. The drug was found to significantly degrade under acidic/alkaline/neutral photolytic, oxidative, and alkaline hydrolytic conditions. Six degradation products (I-VI) were identified through LC-Q/TOF-MS studies that were adequately resolved from the drug with the developed UPLC method. All degradation products (I-VI) were ionized in the total ion chromatogram (TIC) in the LC-MS studies, and these were identified and characterized, and the degradation pathway of the drug was postulated. One of the oxidation products isolated from the degraded drug solution was characterized through differential scanning calorimetry, Fourier-transform infrared spectroscopy, and nuclear magnetic resonance spectral data. Six degradation products generated from stress degradation studies on azelastine HCl were adequately resolved through LC-UV/PDA studies followed by method validation. These were successfully identified and characterized through LC-Q/TOF-MS studies, and the degradation pathways for the generation of these products from the drug have been postulated.

Shekhar S ，Bali A 《-》

Analytical method development, identification, and characterization of stress degradation products of idelalisib by ultrahigh-performance liquid chromatography with photodiode array and ultrahigh-performance liquid chromatography with electrospray ionizat

As per International Council for Harmonization (ICH) drug stability test guideline Q1A(R2), inherent stability characteristics of a drug should be studied. This work was designed to investigate inherent degradation characteristics of the drug idelalisib under ICH prescribed stress conditions, identify its degradation products, and postulate their corresponding degradation pathways. Idelalisib was subjected to the ICH prescribed conditions of hydrolytic (neutral, acidic, and alkaline), photolytic, oxidative, and thermal stress according to ICH guideline Q1A(R2). An ultrahigh-performance liquid chromatography with photodiode array (UHPLC-PDA) method was developed to adequately resolve the drug from its degradation products, validated as per the ICH guidelines, and subsequently extended to UHPLC with electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOFMS) studies to identify the degradation products. Significant degradation was noted under conditions of acidic/alkaline hydrolysis, acid photolysis, and oxidative stress. The UHPLC/ESI-QTOFMS studies revealed the generation of four degradation products (I-IV), which were satisfactorily resolved from the drug by UHPLC on a Kinetex® C18 (100 × 4.6 mm; 2.6 μm) column by the developed isocratic elution method. Detection wavelength was selected as 270 nm. All the degradation products (I-IV) could be identified and characterized from their mass spectral data. The degradation pathways for the generation of various products from the drug were postulated. A UHPLC-PDA method was developed and validated for idelalisib. Four degradation products of idelalisib were revealed through UHPLC/ESI-QTOFMS studies, and corresponding degradation pathways were postulated for the same.

Mahesh M ，Bali A ，Gupta T 《-》

Characterization of stress degradation products of duloxetine hydrochloride employing LC-UV/PDA and LC-MS/TOF studies.

Duloxetine HCl was subjected to forced degradation under conditions of hydrolysis (neutral, acidic and alkaline), oxidation, photolysis and thermal stress, as suggested in the ICH guideline Q1A(R2). The drug showed significant degradation under acidic, alkaline and aqueous hydrolytic as well as photolytic conditions. The drug remained stable under thermal and oxidative stress conditions. In total, seventeen degradation products (I-XVII) were formed under varied conditions, which could be separated by chromatography of respective degraded solutions on C18 (250 mm×4.6 mm; 5 μ, Nulceodur) column using isocratic elution method. Detection wavelength was selected as 290 nm. MS/TOF accurate mass studies were carried out to establish the complete fragmentation pathway of the drug and degradation products, which, in turn, was utilized in characterization of the products. The degradation pathway of the drug leading to generation of fifteen products I-X, XII-XIII, XV-XVII was postulated and this has not been reported so far.

Chadha R ，Bali A ，Bansal G 《-》

LC/Q-TOF-MS-based structural characterization of enasidenib degradation products and establishment of a stability-indicating assay method: Insights into chemical stability.

Enasidenib (EDB) is an orally active selective mutant isocitrate dehydrogenase-2 enzyme inhibitor approved by the U.S. Food and Drug Administration to treat acute myeloid leukemia. It lacks a reported forced degradation study and a stability-indicating assay method (SIAM). This study addresses this gap by establishing a degradation profile in accordance with the International Council for Harmonisation Q1A and Q1B (R2) guidelines and developing a validated SIAM for EDB. EDB was exposed to forced degradation under various conditions (hydrolytic, photolytic, oxidative, and thermal stress). Degradation samples were analyzed using high-performance liquid chromatography on an Agilent ZORBAX Eclipse Plus C18 column with a mobile phase consisting of 0.1% formic acid in Milli-Q water and acetonitrile at a flow rate of 1 mL/min and detection at 270 nm. Liquid chromatography-quadrupole time-of-flight-high-resolution mass spectrometry (LC/Q-TOF HRMS) was used for the identification and characterization of degradation products. Nitrosamine risk assessment was conducted using a modified nitrosation assay procedure (NAP) test due to the presence of a secondary amine group in the drug, which is liable to forming nitrosamine drug substance-related impurities (NDSRI). The drug exhibited significant degradation under acidic, basic, photolytic, and oxidative conditions in the solution state. A total of nine degradation products (DP) were formed (DP-I, DP-III, and DP-IV: acidic conditions; DP-I and DP-III: basic conditions; DP-II, DP-V, DP-VI, and DP-VII: oxidative stress; and DP-VII, DP-VIII, and DP-IX: photolytic conditions), which were separated and identified using reversed-phase high-performance liquid chromatography and characterized using liquid chromatography-tandem mass spectrometry. The mechanism behind the formation of EDB degradation products has been discussed, and this study was the first to develop a degradation pathway for EDB. In addition, the possibilities of NDSRI formation for EDB were studied using a modified NAP test, which can contribute to the risk assessment of the drug. Forced degradation studies were conducted by establishing a SIAM for EDB. All the degradation products were characterized by mass spectral data obtained using LC/Q-TOF-HRMS.

Chakkar A ，Chaturvedi S ，Rajput N ，Sengupta P ，Sharma N ... -  《-》