Structure Elucidation Of Degradation Products Research Articles

Analytical Lifecycle Management (ALM) and Analytical Quality by Design (AQbD) based Analytical Method Development for Separation of Related Substances in Amodiaquine Hydrochloride along with its Degradation Products and Structural Elucidation by LC-Quadrupole-Time of Flight-Tandem Mass Spectrometry

The current study aimed to develop a robust, regulatory-flexible, stability-indicating ultra high performance liquid chromatography (UHPLC) analytical procedure compatible with mass spectrometry for the determination of impurities in amodiaquine hydrochloride using analytical lifecycle management (ALM) and analytical quality by design (AQbD) principles. The analytical target profile (ATP) and critical method attributes (CMAs) for the analytical method were identified. The pH of the mobile phase, flow rate and column oven temperature were identified as critical method parameters (CMPs) through risk assessment studies and they were screened and optimized using the design of experiments (DoE) to generate the design space (DS). Finally, all the impurities were well separated in a 15 min run time by using an Acquity UPLC BEH-C18 column with 20 mM ammonium acetate pH 8.0 as mobile phase A and acetonitrile as mobile phase B with a gradient program of time (min), % of B: 0/15, 1.0/15, 9/55, 12/55, 12.1/15 and 15/15. The flow rate was 0.3 mL min-1 and the column oven temperature were 30 ºC. Evaluated the robustness of the developed analytical method. Degradation products obtained from the forced degradation studies are well separated from process impurities and main compound. Based on the stress studies, impurity-3 was identified as a key degradation product in base degradation, while DP-1, impurity-3, DP-2, DP-3 and DP-4 were in the oxidative degradation. Total 9 impurities out of 4 process related and 5 degradation impurities were well separated in the developed method. Used the same method to LC coupled tandem mass spectrometer for separation and structure elucidation of degradation products. The method validation was carried out in accordance with ICH Q2 (R1) and USP <1225> guidelines.

Application of Gas Chromatography Hyphenated to Atmospheric Pressure Chemical Ionization-Quadrupole-Time-of-Flight-Mass Spectrometry (GC-APCI-Q-TOF-MS) for Structure Elucidation of Degradation Products Based on the Cation in Pyr14TFSI

In this study, the hyphenation of gas chromatography to atmospheric pressure chemical ionization-quadrupole-time-of-flight-mass spectrometry (GC-APCI-Q-TOF-MS) is applied for the investigation of degradation products of ionic liquid (IL) based electrolytes. The advantage of APCI compared to electron ionization (EI) for amine-based analytes due to a higher sensitivity of the molecular ion was demonstrated and the results obtained in this work contribute to a better understanding of the IL aging behavior in regard to their application as green electrolyte for lithium metal batteries (LMBs). Pristine N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI) and Pyr14TFSI-based electrolytes with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as conducting Li salt were investigated. For this purpose, ion source optimization was performed for amine-based analytes using N-butyl-N-methylbutan-1-amine (BMBA) as standard compound. Furthermore, a customized water flow was directed into the ion source to inhibit in-source reactions, such as fragmentation or oxidation processes, and therefore to promote the [M+H]+-ion formation. The respective headspace (HS) above the ionic liquids (ILs) and electrolytes was sampled at first for the detection of highly volatile analytes. Structure proposals were provided by matching mass spectra obtained from GC-APCI-Q-TOF-MS/MS and GC-EI-MS measurements. Aliphatic amine-, pyrrolidine- and pyrrole-based aging products were identified as decomposition species of the Pyr14 +-cation, e.g. N-butylpyrrole and N-butyl-N-methylpent-4-en-1-amine. Furthermore, the presence of lithium metal on a copper substrate in the pristine IL led to significantly stronger aging effects. Galvanic corrosion processes at the redox-couple Li and Cu were suggested as possible causes. This phenomenon questions the practicability of using copper current collectors with lithium anodes for IL-based battery cell systems. Additionally, the LiTFSI concentration in the electrolyte showed an impact on aging caused by corrosion.

Structure Characterization of Degradation Products of Drug Candidate HM30571 by UPLC‐QTOF‐MS and In Silico Toxicity Prediction

Procedure of forced degradation study, structure elucidation of degradation products by UPLC-QTOF-MS and in silico toxicity prediction.

Identification and characterization of stressed degradation products of metoprolol using LC/Q‐TOF‐ESI‐MS/MS and MSn experiments

A rapid, specific and reliable isocratic high-performance liquid chromatography combined with quadrupole time-of-flight electrospray ionization tandem mass spectrometry (LC/Q-TOF-ESI-MS/MS) method has been developed and validated for the identification and characterization of stressed degradation products of metoprolol. Metoprolol, an anti-hypertensive drug, was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress, as per ICH-specified conditions. The drug showed extensive degradation under oxidative and hydrolysis (acid and base) stress conditions. However, it was stable to thermal, neutral and photolysis stress conditions. A total of 14 degradation products were observed and the chromatographic separation of the drug and its degradation products was achieved on a C(18) column (4.6 × 250 mm, 5 µm). To characterize degradation products, initially the mass spectral fragmentation pathway of the drug was established with the help of MS/MS, MS(n) and accurate mass measurements. Similarly, fragmentation pattern and accurate masses of the degradation products were established by subjecting them to LC-MS/QTOF analysis. Structure elucidation of degradation products was achieved by comparing their fragmentation pattern with that of the drug. The degradation products DP(2) (m/z 153) and DP(14) (m/z 236) were matched with impurity B, listed in European Pharmacopoeia and British Pharmacopoeia, and impurity I, respectively. The LC-MS method was validated with respect to specificity, linearity, accuracy and precision.

Fast in vitro hydrolytic degradation of polyester urethane acrylate biomaterials: Structure elucidation, separation and quantification of degradation products

Synthetic biomaterials have evoked extensive interest for applications in the field of health care. Prior to administration to the body a quantitative study is necessary to evaluate their composition. An in vitro method was developed for the quick hydrolytic degradation of poly-2-hydroxyethyl methacrylate (pHEMA), poly(lactide-co-glycolide50/50)1550-diol (PLGA(50:50)1550-diol), PLGA(50:50)1550-diol(HEMA)2 and PLGA(50:50)1550-diol(etLDI-HEMA)2 containing ethyl ester lysine diisocyanate (etLDI) linkers using a microwave instrument. Hydrolysis time and temperature were optimized while monitoring the degree of hydrolysis by 1H NMR spectroscopy. Complete hydrolytic degradation was achieved at 120°C and 3bar pressure after 24h. Chemical structure elucidations of the degradation products were carried out using 1H and 13C NMR spectroscopy. The molecular weight (MW) of the polymethacrylic backbone was estimated via size-exclusion chromatography coupled to refractive index detection (SEC-dRI). A bimodal MW distribution was found experimentally, also in the pHEMA starting material. The number average molecular weights (Mn) of the PLGA-links (PLGA(50:50)1550-diol) were calculated by high pressure liquid chromatography–time-of-flight mass spectrometry (HPLC–TOF-MS) and 1H NMR. The amounts of the high and low MW degradation products were determined by SEC-dRI and, HPLC–TOF-MS, respectively. The main hydrolysis products poly (methacrylic acid) (PMAA), ethylene glycol (EG), diethylene glycol (DEG), lactic acid (LA), glycolic acid (GA) and lysine were recovered almost quantitatively. The current method leads to the complete hydrolytic degradation of these materials and will be helpful to study the degradation behavior of these novel cross-linked polymeric biomaterials.

Isolation and structure elucidation of degradation products in the potential anticancer drug PAC-1

PAC-1 was subjected to acid degradation conditions at 80 °C for 10 h. Four unknown degradation products were isolated from PAC-1 by semi-preparative high performance liquid chromatography using isocratic elution conditions. Based on the ESI-MS and NMR spectral data the structures of these four degradation products were characterized as 2-allyl-6-((E)-((E)-(2-hydroxy-3-(2-hydroxypropyl)benzylidene)hydrazono)methyl)phenol, 2-hydroxy-3-(2-propenyl)-[[2-hydroxy-3-(2-propenyl)phenyl]methylene]hydrazone, 6,6′-(1E,1′E)-hydrazine-1,2-diylidenebis(methan-1-yl-1-ylidene)bis(2-(2-hydroxypropyl)phenol) and 2-hydroxy-3-(2-hydroxypropyl)benzaldehyde.

Structure Elucidation of Degradation Products of the Antibiotic Amoxicillin with Ion Trap MS n and Accurate Mass Determination by ESI TOF

Today, it is necessary to identify relevant compounds appearing in discovery and development of new drug substances in the pharmaceutical industry. For that purpose, the measurement of accurate molecular mass and empirical formula calculation is very important for structure elucidation in addition to other available analytical methods. In this work, the identification and confirmation of degradation products in a finished dosage form of the antibiotic drug amoxicillin obtained under stress conditions will be demonstrated. Structure elucidation is performed utilizing liquid chromatography (LC) ion trap MS/MS and MS3 together with accurate mass measurement of the molecular ions and of the collision induced dissociation (CID) fragments by liquid chromatography electro spray ionization time-of-flight mass spectrometry (LC/ESI-TOF).