Thermal behavior of some antihistamines

Thermogravimetry (TG), differential scanning calorimetry (DSC), polarized light thermal microscopy (PLTM), as well as X-ray powder diffraction (XRD) and Fourier transformed infrared spectroscopy (FTIR) were used to study the thermal behavior and the chemical structure of cimetidine, famotidine, ranitidine-HCl, and nizatidine. The TG-DSC curves show that the famotidine and ranitidine-HCl suffer decomposition during melting and they are thermally less stable in comparison with cimetidine and nizatidine, the latter being the most stable of all the drugs studied in this study. The DSC curves of famotidine and ranitidine-HCl show exothermic peaks immediately after the melting, confirming the occurrence of thermal decomposition. The DSC curves also show that the cimetidine and nizatidine have some thermal stability after melting. The thermal events shown in the PLTM images are consistent with the results shown in the TG-DSC and DSC curves. The XRD patterns show that the cimetidine and famotidine are less crystalline compared with ranitidine-HCl and nizatidine. The theoretical FTIR bands are in agreement with those obtained experimentally, and in some cases, no difference is observed between the theoretical and experimental values, even being identical in one of the cases. © 2012 Akadémiai Kiadó, Budapest, Hungary.

A role for histamine in cardiovascular regulation in late stage embryos of the red-footed tortoise, Chelonoidis carbonaria Spix, 1824

A chorioallantoic membrane artery in embryos of the red-footed tortoise, Chelonoidis carbonaria was occlusively cannulated for measurement of blood pressure and injection of drugs. Two age groups of embryos in the final 10 % of incubation were categorized by the ratio of embryonic body to yolk mass. All embryos first received cholinergic and β-adrenergic blockade. This revealed that β-adrenergic control was established in both groups whereas cholinergic control was only established in the older group immediately prior to hatching. The study then progressed as two series. Series one was conducted in a subset of embryos treated with histamine before or after injection of ranitidine, the antagonist of H2 receptors. Injection of histamine caused an initial phasic hypertension which recovered, followed by a longer lasting hypertensive response accompanied by a tachycardia. Injection of the H2 receptor antagonist ranitidine itself caused a hypotensive tachycardia with subsequent recovery of heart rate. Ranitidine also abolished the cardiac effects of histamine injection while leaving the initial hypertensive response intact. In series, two embryos were injected with histamine after injection of diphenhydramine, the antagonist to H1 receptors. This abolished the whole of the pressor response to histamine injection but left the tachycardic response intact. These data indicate that histamine acts as a non-adrenergic, non-cholinergic factor, regulating the cardiovascular system of developing reptilian embryos and that its overall effects are mediated via both H1 and H2 receptor types. © 2013 Springer-Verlag Berlin Heidelberg.

Efeitos da rifampicina na farmacocinética e hepatotoxicidade da isoniazida

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influência da pirazinamida na farmacocinética da isoniazida associada ou não à rifampicina

Pós-graduação em Ciências Farmacêuticas - FCFAR

Contenção química com dexmedetomidina associada à cetamina em quatis (Nasua nasua) e a reversão dos efeitos sedativos pela iombina e o atipamezol

Pós-graduação em Medicina Veterinária - FMVZ

Efeito do cloridrato de dorzolamida a 2%, maleato de timol a 0,5% e associação de ambos na pressão intra-ocular: estudo experimental em cães

Pós-graduação em Medicina Veterinária - FMVZ

Formadores de filmes híbridos orgânicos inorgânicos do tipo ureasil-poliéter para liberação controlada de fármacos

Pós-graduação em Ciências Farmacêuticas - FCFAR

Ciprofloxacino encapsulado em lipossomas revestidos com ácido poli láctico co-glicólico ou veiculado em gel de copolímero de bloco Pluronic R F127

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação de distribuição de doxorrubicina incorporada em microemulsão lipídica em tecido tumoral e cardíaco em Camundongos

Pós-graduação em Ciências Farmacêuticas - FCFAR

Análise químico-farmacêutica de cloridrato de ciprofloxacino em solução oftálmica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento e controle de qualidade de formulação cosmética contendo digluconato de clorexidina

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determinação do potencial antimicrobiano, antioxidante e da motibilidade intestinal de extrato de Paepalanthus geniculatus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência do treinamento resistido e do raloxifeno no metabolismo ósseo de ratas Wistar

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Filmes nanoestruturados para a detecção de glicose e sacarose em bebidas comerciais

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeitos do extrato aquoso de Ottonia martiana Miq. (Piperaceae), como anestésico local, para o exame oftálmico, em cães

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)