Thermal behavior and decomposition of oxytetracycline hydrochloride

Cervini, Priscila; Ambrozini, Beatriz; Machado, Luis Carlos M.; Ferreira, Ana Paula Garcia; Cavalheiro, Éder Tadeu Gomes

doi:10.1007/s10973-015-4447-x

Cited by 21 publications

(9 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thermogravimetry also showed no event from 30–190 °C; however, approximately 12% of weight reduction was noted closer to the melting point, corresponding to an approximately half molar ratio of succinic acid. Further heating caused over 20% of weight reduction, reflecting the thermal degradation of API Figure b shows the 1 H NMR spectrum of form VII.…”

Section: Resultsmentioning

confidence: 99%

Microelectron Diffraction Reveals Contamination of Polymorphs by Structure Analysis of Microscale Crystals in a Novel Pharmaceutical Cocrystal

Miyano,

Hirakawa,

Yamano

et al. 2023

Crystal Growth & Design

View full text Add to dashboard Cite

A P2X7 receptor antagonist (basic nature) with possible amino/imino tautomeric forms was used as an active pharmaceutical ingredient (API). After the amorphous form was confirmed by powder X-ray diffraction (PXRD), crystallization was performed using various organic solvents. Crystal forms I−VI were obtained, and thermal and NMR analyses suggested the presence of solvate forms. A multicomponent crystal of form VII, containing succinic acid, was successfully obtained. Form VII was predicted to be a cocrystal based on the ΔpK a between the API and succinic acid. The stoichiometry of API and succinic acid was 2:1, as determined by TG−DTA and nuclear magnetic resonance analyses. Single-crystal XRD analysis was performed to determine the crystal tautomerism of form VII. However, no diffraction peaks were observed, owing to the streaky morphology. Hence, microelectron diffraction (MED) analysis was performed, and electron diffraction patterns were obtained, revealing unexpected polymorphic forms VII-A and VII−B. Similar dimer formation between the triazine and hydroxyl groups of the APIs was confirmed for both polymorphs, suggesting a tautomeric imino form. Intermolecular interactions were observed between the API imidazole group and the carboxylic acid group of succinic acid; however, these modes differed between forms VII-A and VII-B. Taken together, the MED analysis accurately revealed the crystal structures, particularly for isomeric and/or multicomponent crystals with poor growth.

show abstract

Section: Resultsmentioning

confidence: 99%

Microelectron Diffraction Reveals Contamination of Polymorphs by Structure Analysis of Microscale Crystals in a Novel Pharmaceutical Cocrystal

Miyano,

Hirakawa,

Yamano

et al. 2023

Crystal Growth & Design

View full text Add to dashboard Cite

show abstract

“…The second event occurred in two steps (first between 126 °C and 200 °C with 20% mass loss, and second between 200 °C and 280 °C with 50% mass loss, also observed on the DTG curve), and the third event occurred between 500 °C and 600 °C, with 94% mass loss. These events can be attributed to the oxidative decomposition of TMX and the remaining carbonaceous matter ( Dos Santos Ferreira da Silva et al, 2015 ; Cervini et al, 2015 ). The PCL-TMX nanofiber patterns (red line) were similar to the reported PCL weight loss pattern (black line), which comprises three events of mass loss, the most critical thermal decomposition event starting at about 340 °C and ending at 470 °C ( Mohamed et al, 2008 ) with 70% mass loss for PCL-TMX and with total weight loss for PCL-P at 600 °C.…”

Section: Resultsmentioning

confidence: 99%

Polycaprolactone nanofibers as an adjuvant strategy for Tamoxifen release and their cytotoxicity on breast cancer cells

Pinzón-García

Sinisterra

Cortés

et al. 2021

PeerJ

View full text Add to dashboard Cite

Breast cancer is the second leading cause of death in women, and tamoxifen citrate (TMX) is accepted widely for the treatment of hormone receptor–positive breast cancers. Several local drug-delivery systems, including nanofibers, have been developed for antitumor treatment. Nanofibers are biomaterials that mimic the natural extracellular matrix, and they have been used as controlled release devices because they enable highly efficient drug loading. The purpose of the present study was to develop polycaprolactone (PCL) nanofibers incorporating TMX for use in the treatment of breast tumors. Pristine PCL and PCL-TMX nanofibers were produced by electrospinning and characterized physiochemically using different techniques. In addition, an in vitro study of TMX release from the nanofibers was performed. The PCL-TMX nanofibers showed sustained TMX release up to 14 h, releasing 100% of the TMX. The Resazurin reduction assay was used to evaluate the TMX cytotoxicity on MCF-7 breast cancer cell line and PBMCs human. The PCL-TMX nanofiber was cytotoxic toPBMCs and MCF-7. Based on these results, the PCL-TMX nanofibers developed have potential as an alternative for local chronic TMX use for breast cancer treatment, however tissue tests must be done.

show abstract

“…The second event occurred in two steps (first between 126°C and 200ºC with 20% mass loss, and second between 200ºC and 280°C with 50% mass loss, also observed on the DTG curve), and the third event occurred between 500°C and 600°C, with 94% mass loss. These events can be attributed to the oxidative decomposition of TMX and the remaining carbonaceous matter (dos Santos Ferreira da Silva et al, 2015;Cervini et al, 2015). The PCL-TMX nanofiber patterns (red line) were similar to the reported PCL weight loss pattern (black line), which comprises three events of mass loss, the most critical thermal decomposition event starting at about 340°C and ending at 470°C (Mohamed et al, 2008) with 70% mass loss for PCL-TMX and with total weight loss for PCL-P at 600°C.…”

Section: Physicochemical Characterizationmentioning

confidence: 99%

Peer Review #1 of "Polycaprolactone nanofibers as an adjuvant strategy for Tamoxifen release and their cytotoxicity on breast cancer cells (v0.1)"

Jarai¹

2021

View full text Add to dashboard Cite

Thermal behavior and decomposition of oxytetracycline hydrochloride

Cited by 21 publications

References 27 publications

Microelectron Diffraction Reveals Contamination of Polymorphs by Structure Analysis of Microscale Crystals in a Novel Pharmaceutical Cocrystal

Microelectron Diffraction Reveals Contamination of Polymorphs by Structure Analysis of Microscale Crystals in a Novel Pharmaceutical Cocrystal

Polycaprolactone nanofibers as an adjuvant strategy for Tamoxifen release and their cytotoxicity on breast cancer cells

Peer Review #1 of "Polycaprolactone nanofibers as an adjuvant strategy for Tamoxifen release and their cytotoxicity on breast cancer cells (v0.1)"

Contact Info

Product

Resources

About