Isolation and Characterization of Cetirizine Degradation Product: Mechanism of Cetirizine Oxidation

Potential degradation products of abemaciclib: Identification and structural characterization employing LC-Q/TOF-MS and NMR including mechanistic explanation

Degradation products are the potential drug impurities that can be generated during transport and storage of pharmaceuticals. Before this study, degradation chemistry and potential degradation products of abemaciclib (ABM) were unknown. Moreover, no stability-indicating analytical method was available that can be used to analyse ABM in presence of its degradation products. In this study, stress testing on ABM was carried out under oxidative, thermal, photolytic (UV & visible), and hydrolytic (acid, alkaline, and neutral) degradation conditions. The study revealed that ABM is susceptible to photolytic, oxidative, and thermal stress leading to the formation of five degradation products (DPs). ABM and its degradation products were chromatographically separated employing a developed RP-HPLC-based stability-indicating analytical method. The method was transferred to an LC-Q-TOF system for further analysis. To elucidate the structure of degradation products, fragmentation pathway of ABM was initially established through high-resolution mass spectrometry (HRMS). Subsequently, mass fragmentation pathways of all the DPs have been established through HRMS and MSn based analysis. The major degradation product was isolated and fully characterized using atmospheric chemical ionization-mass spectrometry and nuclear magnetic resonance techniques. ABM showed extensive degradation under oxidative and photolytic systems. Therefore, special care may be sought during storage and transport of ABM or its formulations to avoid photolytic and oxidative stress exposure to the drug. Lastly, in silico toxicity of the characterized degradation products was assessed employing ProTox ІІ online web predictor freeware in which some of them were found to have the potential of hepatotoxicity, immunogenicity and mutagenicity.

Analysis of degradation and pathways of three common antihistamine drugs by NaClO, UV, and UV-NaClO methods

Antihistamines (ANTs) are medicines to treat allergic diseases. They have been frequently detected in the natural water environment, posing potential threats to the ecological environment and human health. In this study, the degradation of three common antihistamines, loratadine, fexofenadine, and cetirizine, was estimated under different oxidation methods (NaClO, UV, and UV-NaClO). The results showed that UV-NaClO had the highest degree of degradation on the drugs under most conditions: 100% degradation for fexofenadine within 20 s at pH 7 and 10. Under UV irradiation, the degradation efficiencies of the three drugs during 150 s were all above 77% at a pH of 7. The drugs' removal by NaClO was much lower than that of the previous two methods. In addition, this study explored the contribution rates of active oxygen species in the photolysis process. Among them, the contribution of ¹O₂ to the fexofenadine and cetirizine removal rate reached 70%. Different aqueous matrices (HCO₃^-, NO₃^-, and humic acid) had varying degrees of influence on the degradation. Acute toxicity tests and ultraviolet scans of the degradation products showed that the drugs were not completely mineralized, and the toxicities of the intermediates were even higher than those of the parent drugs. There were 9, 8, and 10 chloride oxidation products of loratadine, fexofenadine, and cetirizine, respectively, and 8 photolysis products of cetirizine were identified. For cetirizine, it was found that there were three identical intermediates produced by photodegradation and NaClO oxidation.

Rapid transformation of H1-antihistamines cetirizine (CET) and diphenhydramine (DPH) by direct peroxymonosulfate (PMS) oxidation

With growing interest in advanced oxidation processes (AOPs), the number of research studies on peroxymonosulfate (PMS) mediated pollutant degradation has increased significantly due to its high radical generation potential upon activation. However, rare studies have focused on the non-radical based PMS reactions. In this study, degradation of model H₁-antihistamines cetirizine (CET) and diphenhydramine (DPH) by unactivated PMS was investigated. Addition of scavengers to the reaction mixture ruled out the involvement of hydroxyl radical (OH), sulfate radical (SO₄^-), singlet oxygen (¹O₂) and superoxide anion radical (O₂^-), indicating direct PMS oxidation as the predominant reaction path. Such a mechanism was further supported by the N-oxide products identified by mass spectrometry and nuclear magnetic resonance (NMR) analyses. Solution pH had a pronounced influence on the degradation kinetics regardless the presence or absence of transition metal Fe(II). The highest species dependent second order rate constants were k_HSO5-/DPH0 of 175 ± 15.9 M^-1 s^-1 and k_HSO5-/CET- of 36.6 ± 0.16 M^-1 s^-1. The addition of 100 μM Fe(II) promoted OH mediated degradation of H₁-antihistamines and their N-oxide products. This study demonstrated selective transformation with the potential for extensive degradation employing both the direct and catalytic PMS oxidative processes.

Effects of inclusion of cetirizine hydrochloride in β-cyclodextrin

Following the preparation of inclusion complex of cetirizine (CTZ) and β-cyclodextrin (β-CD), the compound was investigated to assess the possibility of modifying the physicochemical properties (solubility, release, stability, permeability) of CTZ after complexation that are vital for subsequent formulation studies involving the said complex. Changes in FT-IR/Raman spectra, DSC thermograms and XRD diffractograms confirmed the formation of a CTZ-β-CD system. Hydrophilic interaction chromatography with a DAD detector was employed to determine alterations of the CTZ concentration during studies following complexation. An analysis of a phase-solubility diagram of c_CTZ = fc_β-CD indicated a linear rise in the solubility of CTZ as the concentration of β-CD increased. The inclusion of CTZ in a system with β-CD significantly reduced the instability of CTZ in the presence of oxidizing factors. It was also found that regardless of the pH of the acceptor fluids used in the release studies an increase was observed in the concentration of CTZ in CD system compared to its free form. The ability to permeate artificial biological membranes manifested by CTZ after complexation was enhanced as well. In summary, CD has significant potential to mask the bitter taste of CTZ and to counter the instability induced by oxidizing factors.

Cellular Uptake of Levocetirizine by Organic Anion Transporter 4

The pharmacokinetics of cetirizine, a nonsedating antihistamine, is profoundly affected by transporter-mediated membrane transport in the kidney. In this study, we aimed to investigate the transport mechanism of levocetirizine, the pharmacologically active enantiomer of cetirizine, via human organic anion transporter 4 (OAT4) expressed in the apical membrane of renal proximal tubules and the basal plasma membrane of placental syncytiotrophoblasts. In cells expressing human OAT4 under the control of tetracycline, levocetirizine uptake was increased by tetracycline treatment. On the other hand, OAT4 expression did not facilitate efflux of preloaded levocetirizine from the cells, either in the presence or absence of extracellular Cl^-. The OAT4-mediated levocetirizine uptake was concentration-dependent with a K_m of 38 μM. The uptake rate of levocetirizine via OAT4 was approximately twice that of racemic cetirizine, indicating stereoselective uptake of levocetirizine. On the other hand, OAT4-mediated [³H]dehydroepiandrosterone sulfate uptake was inhibited by dextrocetirizine and levocetirizine. Overall, our findings indicate that OAT4 mediates levocetirizine uptake but is unlikely to mediate the efflux.

Non-target impurity profiling of marketplace Cetirizine using high-resolution mass spectrometry and multivariate data analysis

RATIONALE

As always, drug impurity is the first concern of medication safety. The quality of pre- and post-marketed drugs is estimated through systematic analysis of potential hazardous substances by impurity profiling. Impurity profile is the general name of all unwanted materials which may affect the purity of an active pharmaceutical ingredient (API). The safety of original drugs is guaranteed by an enormous amount of animal experiments and clinical research while the safety of generic drugs should also be ensured by comparative analysis for consistency evaluation. The significantly differential impurities between them should be focused on and the toxicity should be further estimated if necessary. Herein, we take a marketplace drug named Cetirizine as an example to investigate if there was a method which could effectively discover the potential markers among Cetirizine tablets with different brands and describe specific impurity profiling which makes the unknown brand of Cetirizine tablets predictable.

METHODS

Liquid chromatography coupled with high-resolution mass spectrometry (LC/HRMS) was applied to capture the characteristic features of the impurity profile for three brands of marketplace Cetirizine tablets using full scan data-dependent MS/MS scan mode (FS-ddMS(2) ).

RESULTS

Unsupervised learning: principal component analysis (PCA) and supervised learning: consensus orthogonal partial least squares discriminant analysis (OPLS-DA) were utilized to reveal the essential character of Cetirizine impurity profile; 16 differential impurities were finally found, their structures were speculated by HRMS(2) data.

CONCLUSIONS

The cause of formation was further elucidated which gave a suggestion for production process optimization. Copyright © 2016 John Wiley & Sons, Ltd.

Theoretical studies to investigate the effect of different cores and two different topologies on the optical and charge transfer properties of donor materials for organic solar cells

Three dimensional conjugated three- and four-armed molecules with core-D–π–A and core-A–π–D topologies were designed and studied by DFT, revealing that molecules with the core-A–π–D topology and N or C cores would result low reorganization energies and broad absorption bands for organic solar cells.

Photodegradation of the antihistamine cetirizine in natural waters

The photodegradation rate of the anti-histamine cetirizine (Zyrtec®) was investigated in various water matrices. The average observed first-order photodegradation rate coefficient (kobs ), obtained by linear regression of the logarithmic-transformed cetirizine concentrations versus irradiation time in simulated sunlight, was 0.024 h(-1) (n = 6; standard deviation ± 0.004) in deionized water corresponding to a half-life of approximately 30 h. There was no statistical difference in the kobs of cetirizine photodegradation in coastal seawater compared with deionized water or deionized water amended with dissolved chromophoric organic matter. The quantum yield of cetirizine photodegradation decreased dramatically with increasing wavelength and decreasing energy of incoming radiation, with the average value ranging from 5.28 × 10(-4) to 6.40 × 10(-3) in the ultraviolet wavelength range (280-366 nm). The activation energy of cetirizine photodegradation was 10.3 kJ mol(-1) with an observed increase in cetirizine photodegradation as temperature increased. This is a significant environmental factor influencing half-life and an important consideration, given that cetirizine has been detected in wastewater and receiving waters from different locations globally.

Pharmaceutical impurities and degradation products: uses and applications of NMR techniques

Current standards and regulations demand the pharmaceutical industry not only to produce highly pure drug substances, but to achieve a thorough understanding of the impurities accompanying their manufactured drug substances and products. These challenges have become important goals of process chemistry and have steadily stimulated the search of impurities after accelerated or forced degradation procedures. As a result, impurity profiling is one of the most attractive, active and relevant fields of modern pharmaceutical analysis. This activity includes the identification, structural elucidation and quantitative determination of impurities and degradation products in bulk drugs and their pharmaceutical formulations. Nuclear magnetic resonance (NMR) spectroscopy has evolved into an irreplaceable approach for pharmaceutical quality assessment, currently playing a critical role in unequivocal structure identification as well as structural confirmation (qualitative detection), enabling the understanding of the underlying mechanisms of the formation of process and/or degradation impurities. NMR is able to provide qualitative information without the need of standards of the unknown compounds and multiple components can be quantified in a complex sample without previous separation. When coupled to separative techniques, the resulting hyphenated methodologies enhance the analytical power of this spectroscopy to previously unknown levels. As a result, and by enabling the implementation of rational decisions regarding the identity and level of impurities, NMR contributes to the goal of making better and safer medicines. Herein are discussed the applications of NMR spectroscopy and its hyphenated derivate techniques to the study of a wide range pharmaceutical impurities. Details on the advantages and disadvantages of the methodology and well as specific challenges with regards to the different analytical problems are also presented.

Realistic prediction of solid pharmaceutical oxidation products by using a novel forced oxidation system

This study investigated a novel solid-state-based forced oxidation system to enable a realistic prediction of pharmaceutical product oxidation, a key consideration in drug development and manufacture. Polysorbate 80 and ferric(III) acetylacetonate were used as an organic hydroperoxide source and a transition metal catalyst, respectively. Homogeneous solutions of target compounds and these reagents were prepared in a mixed organic solvent. The organic solvent was removed rapidly under reduced pressure, and the oxidation of the resulting dried solid was investigated. Analysis of the oxidation products generated in test compounds by this proposed forced oxidation system using HPLC showed a high similarity with those generated during more prolonged naturalistic drug oxidation. The proposed system provided a better predictive performance in prediction of realistic oxidative degradants of the drugs tested than did other established methods. Another advantage of this system was that the generation of undesired products of hydrolysis, solvolysis, and thermolysis was prevented because efficient oxidation was achieved under mild conditions. The results of this study suggest that this system is suitable for a realistic prediction of oxidative degradation of solid pharmaceuticals.

Identification of major degradation products of ketoconazole

Analytical methods were developed for the identification of major degradation products of Ketoconazole, an antifungal agent. The stressed degradation of Ketoconazole drug substance was performed under acid, base, thermal, photo and oxidative stress conditions. The major degradation was observed under acid, base and oxidative stress conditions. The degradation study was performed on Inertsil ODS-3V, length 100 X diameter 4.6 mm, particle size 3 μm column using gradient method. These degradants were identified by LC-MS technique.