Navegando por Autor "Ribeiro, Thiago Soares Silva"

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    Crystal structure analysis and fragmentation profile of lorcaserin hydrochloride hemihydrate
    (2021) Ribeiro, Thiago Soares Silva; Silva, Alisson Moraes e; Alvarenga, Meiry Edivirges; Kato, Lucilia; Oliveira, Cecilia Maria Alves de; Martins, Felipe Terra
    Lorcaserin, a 2,3,4,5-tetrahydro-3-benzazepine possessing a methyl and chloro groups in C-4 and C-9, respectively, is a drug currently used to treat obesity. Considering the role of the crystalline state to the understanding of the drug properties, allied to inexistence of solid state structural data in the worldwide accessible literature and database such as Crystallographic Cambridge Data Centre (CCDC), here we report the crystal structure of lorcaserin hydrochloride hemihydrate, inspecting in full detail its intra and intermolecular features for the first time, together with NMR data and fragmentation profile by ESI(+)-MS/MS.
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    Nb2O5 supported catalysts for cross-coupling reactions
    (2020) Souza, Guilherme Botelho Meireles de; Ribeiro, Thiago Soares Silva; Mourão, Lucas Clementino; Pereira, Mariana Bisinotto; Leles, Maria Inês Goncalves; Liao, Luciano Morais; Oliveira, Guilherme Roberto de; Alonso, Christian Gonçalves
    Palladium and nickel supported on Nb2O5 were synthesized via wet impregnation method and tested for the Suzuki-Miyaura reaction. The catalysts were characterized by X-ray fluorescence, textural analysis, scanning and transmission electron microscopy, thermogravimetry/differential thermal analysis and X-ray diffraction. Palladium catalyst resulted in high isolated yields (91%). Satisfactory yields (48%) were achieved employing the nickel catalyst. Hot filtration experiments were performed to evaluate the reaction heterogeneity. The catalysts were submitted to consecutive reactions runs to assess recyclability. Deactivation was attributed to catalyst loss by filtration between cycles, minor leaching of the active phase and poisoning by inorganic species.
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    New multicomponent crystal forms of adiphenine with low hygroscopicity
    (2022) Ribeiro, Thiago Soares Silva; Silva, Alisson Moraes e; Araujo Neto, João Honorato de; Viana, André Luiz Machado; Faria, Henrique Dipe de; Ruela, André Luís Morais; Doriguetto, Antonio Carlos; Oliveira, Cecilia Maria Alves de; Martins, Felipe Terra
    Adiphenine is an acetylcholine receptor inhibitor used as an antispasmodic drug due to its strong smooth muscle relaxant action. Adiphenine hydrochloride is largely marketed in drug associations to treat muscle spasms and relieve pain in colic and cramps. However, it presents serious problems with hygroscopicity and chemical stability under high humidity conditions, which have limited its use as an active pharmaceutical ingredient (API). Here, we have solved the adiphenine solid-state hygroscopicity problem through the preparation of stable, nonhygroscopic multicomponent crystal forms thereof. Two new salts of adiphenine were designed by recognition of intermolecular interaction patterns in the Cambridge Structural Database (CSD) and ΔpKa rules. Two generically recognized as safe (GRAS) coformers, namely, citric acid and oxalic acid, were chosen and formed monobasic salts with adiphenine. Crystal structure elucidation reveals that adiphenine adopts different conformations in our salts, while in the literature, hydrochloride adopts one, which is related to different intermolecular arrays. In the dynamic vapor sorption (DVS) analysis, it was verified that adiphenine citrate and adiphenine oxalate starts to incorporate water slowly from 50 to 70% of relative humidity (RH), increasing up to 3.2 and 2.6% of their initial masses in 90% of RH, respectively. At the end of the desorption cycle (RH = 0%), the samples retained only 0.12 and 0.08% of water relative to their initial masses. On the other hand, adiphenine hydrochloride exhibits a classical high hygroscopicity behavior, which retains water fast from 50% of relative humidity (RH), increasing up to 22% of its initial mass in 90% of RH and a net mass gain of 5% at the end of the desorption cycle (RH = 0%). Notably, both carboxylic acid salts had similar solubility as a function of medium pH, while the hydrochloride one was more soluble than them by factors ranging from 6.7 (relative to citrate in pH 1.2) to 28.2 (relative to oxalate in pH 4.5). Nevertheless, the pharmacokinetic parameters of adiphenine after oral administration of the capsules containing the salt forms did not reflect these solubility differences, since all adiphenine salt forms can be considered highly soluble drugs according to the Biopharmaceutics Classification System (dose/solubility ratio < 250 mL). It was observed that the rats treated with capsules containing adiphenine hydrochloride had an increase in AUC0–∞ (1537 vs 914 vs 991 min μg mL–1) compared with rats treated with adiphenine citrate and oxalate capsules, respectively, even though the same tmax (48 min) was observed. However, dosage tuning can bring the bioavailability of our salts into that of the hydrochloride salt, with the advantage of nonhygroscopicity and higher chemical stability.