Study on the thermal decomposition of capecitabine

Wang, Xuejie; You, Jingsong

doi:10.1007/s10973-015-4857-9

Cited by 10 publications

(2 citation statements)

References 18 publications

(20 reference statements)

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“…Various mass samples were used, usually 10 mg [ 22 , 23 , 24 , 25 , 26 , 27 ], 12–15 mg [ 28 , 29 , 30 , 31 , 32 ] or 15–20 mg [ 24 , 33 ]. Samples in open α-alumina sample holders [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] or ceramic crucibles [ 34 ] were heated from ambient temperature to 400 °C [ 26 , 27 ], 500 °C [ 34 ], 700 °C [ 35 ] or 800 °C [ 22 , 23 ]; at heating rates of 5 °C/min [ 34 ], 10 °C/min [ 28 , 29 , 30 , 31 , 32 ] or 20 °C/min [ 22 , 23 , 24 , 25 , 26 , 27 , 35 ]; in dry nitrogen [ 22 , 23 , 26 , 27 , 28 , 29 ,...…”

Section: Coupled Tg Measurementsmentioning

confidence: 99%

Coupled and Simultaneous Thermal Analysis Techniques in the Study of Pharmaceuticals

Wesołowski

Leyk

2023

Pharmaceutics

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Reliable interpretation of the changes occurring in the samples during their heating is ensured by using more than one measurement technique. This is related to the necessity of eliminating the uncertainty resulting from the interpretation of data obtained by two or more single techniques based on the study of several samples analyzed at different times. Accordingly, the purpose of this paper is to briefly characterize thermal analysis techniques coupled to non-thermal techniques, most often spectroscopic or chromatographic. The design of coupled thermogravimetry (TG) with Fourier transform infrared spectroscopy (FTIR), TG with mass spectrometry (MS) and TG with gas chromatography/mass spectrometry (GC/MS) systems and the principles of measurement are discussed. Using medicinal substances as examples, the key importance of coupled techniques in pharmaceutical technology is pointed out. They make it possible not only to know precisely the behavior of medicinal substances during heating and to identify volatile degradation products, but also to determine the mechanism of thermal decomposition. The data obtained make it possible to predict the behavior of medicinal substances during the manufacture of pharmaceutical preparations and determine their shelf life and storage conditions. Additionally, characterized are design solutions that support the interpretation of differential scanning calorimetry (DSC) curves based on observation of the samples during heating or based on simultaneous registration of FTIR spectra and X-ray diffractograms (XRD). This is important because DSC is an inherently non-specific technique. For this reason, individual phase transitions cannot be distinguished from each other based on DSC curves, and supporting techniques are required to interpret them correctly.

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Section: Coupled Tg Measurementsmentioning

confidence: 99%

Coupled and Simultaneous Thermal Analysis Techniques in the Study of Pharmaceuticals

Wesołowski

Leyk

2023

Pharmaceutics

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“…In our studies, we have applied the simultaneous TG/DTG/DSC coupled with spectroscopic methods (i.e., FTIR and QMS), because these reliable techniques are preferred in the thermal analyses of medicines and therapeutic agent candidates in the preclinical phase of drug development. They enable the determination of thermal stability, heat of fusion, the identification of volatile degradation products, as well as checking the purity (including a content of water and solvents used in the crystallisation process) and possible solid-solid transitions [14,15,[18][19][20][21][22][23]. This entire research is aimed at understanding the beneficial thermal properties of these compounds, which may increase their usefulness as potential candidates for pharmaceutical applications.…”

Section: Introductionmentioning

confidence: 99%

Studies on the Thermal Decomposition Course of Nitrogen-Rich Heterocyclic Esters as Potential Drug Candidates and Evaluation of Their Thermal Stability and Properties

Worzakowska,

Sztanke,

Sztanke

2024

IJMS

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Drug candidates must undergo thermal evaluation as early as possible in the preclinical phase of drug development because undesirable changes in their structure and physicochemical properties may result in decreased pharmacological activity or enhanced toxicity. Hence, the detailed evaluation of nitrogen-rich heterocyclic esters as potential drug candidates, i.e., imidazolidinoannelated triazinylformic acid ethyl esters 1–3 (where R1 = 4–CH3 or 4–OCH3 or 4–Cl, and R2 = –COOC2H5) and imidazolidinoannelated triazinylacetic acid methyl esters 4–6 (where R1 = 4–CH3 or 4–OCH3 or 4–Cl, and R2 = –CH2COOCH3)—in terms of their melting points, melting enthalpy values, thermal stabilities, pyrolysis, and oxidative decomposition course—has been carried out, using the simultaneous thermal analysis methods (TG/DTG/DSC) coupled with spectroscopic techniques (FTIR and QMS). It was found that the melting process (documented as one sharp peak related to the solid–liquid phase transition) of the investigated esters proceeded without their thermal decomposition. It was confirmed that the melting points of the tested compounds increased in relation to R1 and R2 as follows: 2 (R1 = 4–OCH3; R2 = –COOC2H5) < 6 (R1 = 4–Cl; R2 = –CH2COOCH3) < 5 (R1 = 4–OCH3; R2 = –CH2COOCH3) < 3 (R1 = 4–Cl; R2 = –COOC2H5) < 1 (R1 = 4–CH3; R2 = –COOC2H5) < 4 (R1 = 4–CH3; R2 = –CH2COOCH3). All polynitrogenated heterocyclic esters proved to be thermally stable up to 250 °C in inert and oxidising conditions, although 1–3 were characterised by higher thermal stability compared to 4–6. The results confirmed that both the pyrolysis and the oxidative decomposition of heterocyclic ethyl formates/methyl acetates with para-substitutions at the phenyl moiety proceed according to the radical mechanism. In inert conditions, the pyrolysis process of the studied molecules occurred with the homolytic breaking of the C–C, C–N, and C–O bonds. This led to the emission of alcohol (ethanol in the case of 1–3 or methanol in the case of 4–6), NH3, HCN, HNCO, aldehydes, CO2, CH4, HCl, aromatics, and H2O. In turn, in the presence of air, cleavage of the C–C, C–N, and C–O bonds connected with some oxidation and combustion processes took place. This led to the emission of the corresponding alcohol depending on the analysed class of heterocyclic esters, NH3, HCN, HNCO, aldehydes, N2, NO/NO2, CO, CO2, HCl, aromatics, and H2O. Additionally, after some biological tests, it was proven that all nitrogen-rich heterocyclic esters—as potential drug candidates—are safe for erythrocytes, and some of them are able to protect red blood cells from oxidative stress-induced damage.

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Study on the thermal decomposition of famciclovir

You

Wang

2017

J Therm Anal Calorim

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Study on the thermal decomposition of capecitabine

Cited by 10 publications

References 18 publications

Coupled and Simultaneous Thermal Analysis Techniques in the Study of Pharmaceuticals

Coupled and Simultaneous Thermal Analysis Techniques in the Study of Pharmaceuticals

Studies on the Thermal Decomposition Course of Nitrogen-Rich Heterocyclic Esters as Potential Drug Candidates and Evaluation of Their Thermal Stability and Properties

Study on the thermal decomposition of famciclovir

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