RESUMO
Rotigotine (RTG) is a dopamine agonist used in the treatment of Parkinson's disease. As it is susceptible to oxidation, stability studies must be carefully designed for the identification and characterization of all possible degradation products. Here, RTG degradation was evaluated according to the International Conference on Harmonization guidelines under various stress conditions, including acidic and basic hydrolysis, oxidative, metallic, photolytic, and thermal conditions. Additionally, more severe stress conditions were applied to induce RTG degradation. Significant degradation was only observed under oxidative and photolytic conditions. The samples were analyzed by high performance liquid chromatography coupled to photodiode array detectors, charged aerosol, and high-resolution mass spectrometry. Chromatographic analyses revealed the presence of eight substances related to RTG, four of which were already described and were qualified impurities (impurities B, C, K and E) and four new degradation products (DP-1 - DP-4), whose structures were characterized by high-resolution mass spectrometry through Q-Orbitrap and electrospray ionization. In the stress testing of the active pharmaceutical ingredient in solid form, significant RTG degradation was observed in the presence of the oxidative matrix. The results corroborate the literature that confirm the high susceptibility of RTG to oxidation and the importance of using different detectors to detect degradation products in forced degradation studies.
Assuntos
Estabilidade de Medicamentos , Espectrometria de Massas por Ionização por Electrospray , Tetra-Hidronaftalenos , Tiofenos , Cromatografia Líquida de Alta Pressão/métodos , Tiofenos/química , Tiofenos/análise , Espectrometria de Massas por Ionização por Electrospray/métodos , Tetra-Hidronaftalenos/química , Tetra-Hidronaftalenos/análise , Oxirredução , Agonistas de Dopamina/análise , Agonistas de Dopamina/química , Hidrólise , Contaminação de Medicamentos/prevenção & controle , FotóliseRESUMO
Bexarotene is a specific retinoid X receptor agonist that has been used for the treatment of cutaneous T-cell lymphoma (CTCL). Because bexarotene causes hypothyroidism, it requires the administration of levothyroxine. However, levothyroxine, in addition to its ubiquitous nuclear receptors, can activate the αVß3 integrin that is overexpressed in CTCL, potentially interfering the antineoplastic effect of bexarotene. We thus investigated the biological effect of levothyroxine in relation to bexarotene treatment. Although in isolated CTCL cells levothyroxine decreased, in an αVß3-dependent manner, the antineoplastic effect of bexarotene, levothyroxine supplementation in preclinical models was necessary to avoid suppression of lymphoma immunity. Accordingly, selective genetic and pharmacologic inhibition of integrin αVß3 improved the antineoplastic effect of bexarotene plus levothyroxine replacement while maintaining lymphoma immunity. Our results provide a mechanistic rationale for clinical testing of integrin αVß3 inhibitors as part of CTCL regimens based on bexarotene administration. TEASER: Inhibiting αVß3 integrin improves the antineoplastic effect of bexarotene while maintaining lymphoma immunity.
Assuntos
Anticarcinógenos , Antineoplásicos , Linfoma Cutâneo de Células T , Neoplasias Cutâneas , Anticarcinógenos/farmacologia , Anticarcinógenos/uso terapêutico , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Bexaroteno/farmacologia , Bexaroteno/uso terapêutico , Humanos , Integrina alfaVbeta3 , Linfoma Cutâneo de Células T/tratamento farmacológico , Linfoma Cutâneo de Células T/patologia , Neoplasias Cutâneas/patologia , Tetra-Hidronaftalenos/farmacologia , Tetra-Hidronaftalenos/uso terapêutico , Tiroxina/uso terapêuticoRESUMO
Antimicrobial resistance is among the most serious public health threats of the 21st century, with great impact in terms of One Health. Among antimicrobial resistant bacteria (ARB), extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) represent major challenges to human healthcare. Wild birds have been commonly used as environmental bioindicators of ESBL-EC. Remote locations represent a unique opportunity to evaluate the occurrence, dissemination and epidemiology of ARB in the environment. Herein we surveyed ESBL-EC in 204 cloacal swabs from six nonsynanthropic seabird species at the pristine Rocas Atoll, Brazil. We identified ESBL-EC isolates in 2.4% (5/204) of the tested seabirds, all in magnificent frigatebirds (Fregata magnificens). We isolated strains of O25b-ST131-fimH22 harboring gene blaCTX-M-8 (3 clones), ST117 harboring gene blaSHV-12, and a novel ST11350 (clonal complex 349) harboring genes blaCTX-M-55 and fosA3. All the isolates presented Extraintestinal pathogenic E. coli (ExPEC) virulence profiles. We suggest that magnificent frigatebirds may act as "flying bridges", transporting ESBL-EC and ARGs from an anthropogenically-impacted archipelago geographically close to our pristine and remote study site. The characteristics of our isolates suggest zoonotic potential and, despite the apparent good health of all the evaluated birds, may represent a hypothetical potential threat to the avian population using the atoll. To our knowledge, this is the first description of: (1) the pandemic and public health relevant ST131-O25b harboring blaCTX-M-8 worldwide; (2) ST131-fimH22 in wild birds; and (3); fosA3 in wildlife. Our findings expand the current epidemiological knowledge regarding host and geographical distribution of ESBL-EC and ARGs in wild birds, and emphasize the disseminating characteristics and adaptability of ST131 and ST117 strains within the human-animal-interface. Herein we discuss the involvement of nonsynanthropic wild birds in the epidemiology of antimicrobial resistance and their potential as sentinels of ESBL E. coli in insular environments.
Assuntos
Escherichia coli , beta-Lactamases , Antagonistas de Receptores de Angiotensina , Inibidores da Enzima Conversora de Angiotensina , Animais , Antibacterianos , Brasil , Células Clonais , Humanos , Testes de Sensibilidade Microbiana , Tetra-HidronaftalenosRESUMO
Propolis comprises a complex resinous product composed of plant's parts or exudates, pollen, bee wax, and enzymes. Brazilian brown propolis from Araucaria sp displays several biological activities. Considering the lack of validated analytical methods for its analysis, we are reporting the development of a validated high-performance liquid chromatography with photodiode array detector method to analyze Araucaria brown propolis. The crude propolis were extracted and chromatographed, furnishing six main diterpenes. The isolated standards were used to draw the analytical curves, allowing the studies of selectivity, precision, accuracy, recovery, robustness, the determination of limits of detection and limits of quantification. The mobile phase consisted of 0.1% acetic acid in water and acetonitrile, using an octadecylsilane column, 1 mL/min flow rate and detection at 200 or 241 nm. Relative standard deviation values obtained for intra-day and inter-day precision were lower than 4% for all diterpenes. From the five parameters for robustness, wavelength detection and flow rate were the critical ones. Limits of detection and quantification ranged from 0.808 to 10.359 µg/mL and from 2.448 to 31.392 µg/mL, respectively. The recoveries were between 105.03 and 108.13%, with relative standard deviation values around 5.0%. The developed method is precise, sensitive, and reliable for analyzing Araucaria brown propolis.
Assuntos
Araucaria/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Diterpenos/análise , Própole/análise , Abietanos/análise , Brasil , Ácidos Carboxílicos/análise , Técnicas de Química Analítica , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , Tetra-Hidronaftalenos/análiseRESUMO
PKC and PKA phosphorylation inhibit TREK-1 channels downstream of Gs protein-coupled receptor activation in vitro. However, the role of phosphorylation of TREK-1 in neuropathic pain is unknown. The purpose of this study was to investigate whether altered TREK-1 channel function by PKA and PKC modulators contributes to antiallodynia in neuropathic rats. Furthermore, we investigated if the in vitro described sites for PKC and PKA phosphorylation (S300 and S333, respectively) participate in the modulation of TREK-1 in naïve and neuropathic rats. L5/L6 spinal nerve ligation (SNL) induced tactile allodynia. Intrathecal injection of BL-1249 (TREK-1 activator) reversed nerve injury-induced tactile allodynia, whereas spadin (TREK-1 blocker) produced tactile allodynia in naïve rats and reversed the antiallodynic effect induced by BL-1249 in neuropathic rats. Intrathecal administration of rottlerin or Rp-cAMPs (PKC and PKA inhibitors, respectively) enhanced the antiallodynia observed with BL-1249 in neuropathic rats. In contrast, pretreatment with PdBu or forskolin (PKC and PKA activators, respectively) reduced the BL-1249-induced antiallodynia. Intrathecal injection of two high-activity TREK-1 recombinant channels, using a in vivo transfection method with lipofectamine, with mutations at PKC/PKA phosphosites (S300A and S333A) reversed tactile allodynia in neuropathic rats, with no effect in naïve rats. In contrast, transfection of two low-activity TREK-1 recombinant channels with phosphomimetic mutations at those sites (S300D and S333D) produced tactile allodynia in naïve rats and interfered with antiallodynic effects of rottlerin/BL-1249 or Rp-cAMPs/BL-1249. Data suggest that TREK-1 channel activity can be dynamically tuned in vivo by PKC/PKA to provoke allodynia and modulate its antiallodynic role in neuropathic pain.
Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Neuralgia/metabolismo , Canais de Potássio de Domínios Poros em Tandem/metabolismo , Proteína Quinase C/metabolismo , Animais , Feminino , Injeções Espinhais , Camundongos , Neuralgia/tratamento farmacológico , Medição da Dor/métodos , Peptídeos/administração & dosagem , Fosforilação/efeitos dos fármacos , Fosforilação/fisiologia , Canais de Potássio de Domínios Poros em Tandem/agonistas , Canais de Potássio de Domínios Poros em Tandem/antagonistas & inibidores , Ratos , Ratos Wistar , Tetra-Hidronaftalenos/administração & dosagem , Tetrazóis/administração & dosagemRESUMO
BACKGROUND: Rotigotine is a dopaminergic agonist developed for the treatment of Parkinson's disease and restless leg syndrome. The pure levorotatory enantiomer is marketed in several countries as a transdermal patch. Reports of oxidation and instability in a previous formulation indicate the need to evaluate impurities in both the raw material and pharmaceutical dosage forms of rotigotine to ensure product quality. OBJECTIVE: This review examines the main analytical methods for analyzing rotigotine in raw material and its transdermal patches with the aim of assisting the development of new pharmaceutical formulations and stability studies. METHODS: Analytical methods based on high-performance liquid chromatography for rotigotine from pharmacopoeias and literature were evaluated. A comparison was made between the methods found in the literature and official rotigotine monographs described by the United States, European, and British Pharmacopoeias, including a discussion of their acceptance limits for impurities related to the drug. The different impurities from the synthesis processes and degradation studies of rotigotine were also evaluated, as well as the main articles that describe methods for assessing their chiral purity. RESULTS: Qualified and unofficial official impurities found in forced degradation studies were verified. The methods presented show adequate specificity and selectivity in determining the drug in the presence of its impurities. CONCLUSIONS: The approached methods are promising, but more detailed studies on the stability of rotigotine are still lacking, mainly in the pharmacokinetic and toxicological characterization of its impurities.
Assuntos
Tetra-Hidronaftalenos , Tiofenos , Administração Cutânea , Composição de Medicamentos , HumanosRESUMO
Melatonin MT1 and MT2 receptors are expressed in the glomerular layer of the olfactory bulb (OB); however, the role of these receptors has not been evaluated until now. Considering the association of the OB with olfactory and depressive disorders in Parkinson's disease (PD), we sought to investigate the involvement of melatonin receptors in these non-motor disturbances in an intranigral 6-hydroxydopamine (6-OHDA)-lesioned rat model of PD. We demonstrate the presence of functional melatonin receptors in dopaminergic neurons of the glomerular layer. Local administration of melatonin (MLT, 1 µg/µl), luzindole (LUZ, 5 µg/µl) or the MT2-selective receptor drug 4-P-PDOT (5 µg/µl) reversed the depressive-like behavior elicited by 6-OHDA. Sequential administration of 4-P-PDOT and MLT (5 µg/µl, 1 µg/µl) promoted additive antidepressant-like effects. In the evaluation of olfactory discrimination, LUZ induced an olfactory impairment when associated with the nigral lesion-induced impairment. Thus, our results suggest that melatonin MT2 receptors expressed in the glomerular layer are involved in depressive-like behaviors and in olfactory function associated with PD.
Assuntos
Anosmia/metabolismo , Comportamento Animal , Transtorno Depressivo/metabolismo , Neurônios Dopaminérgicos/metabolismo , Bulbo Olfatório/metabolismo , Transtornos Parkinsonianos/metabolismo , Receptor MT2 de Melatonina/metabolismo , Animais , Anosmia/etiologia , Anosmia/fisiopatologia , Anosmia/psicologia , Comportamento Animal/efeitos dos fármacos , Transtorno Depressivo/etiologia , Transtorno Depressivo/fisiopatologia , Transtorno Depressivo/psicologia , Modelos Animais de Doenças , Neurônios Dopaminérgicos/efeitos dos fármacos , Locomoção/efeitos dos fármacos , Masculino , Melatonina/farmacologia , Bulbo Olfatório/efeitos dos fármacos , Bulbo Olfatório/fisiopatologia , Percepção Olfatória/efeitos dos fármacos , Oxidopamina , Transtornos Parkinsonianos/induzido quimicamente , Transtornos Parkinsonianos/fisiopatologia , Transtornos Parkinsonianos/psicologia , Ratos Wistar , Receptor MT2 de Melatonina/efeitos dos fármacos , Transdução de Sinais , Olfato/efeitos dos fármacos , Natação , Tetra-Hidronaftalenos/farmacologia , Triptaminas/farmacologiaRESUMO
RATIONALE: The nuclear receptor retinoid X receptor (RXR) belongs to a nuclear receptor superfamily that modulates diverse functions via homodimerization with itself or several other nuclear receptors, including PPARα. While the activation of PPARα by natural or synthetic agonists regulates the sleep-wake cycle, the role of RXR in the sleep modulation is unknown. OBJECTIVES: We investigated the effects of bexarotene (Bexa, a RXR agonist) or UVI 3003 (UVI, a RXR antagonist) on sleep, sleep homeostasis, levels of neurochemical related to sleep modulation, and c-Fos and NeuN expression. METHODS: The sleep-wake cycle and sleep homeostasis were analyzed after application of Bexa or UVI. Moreover, we also evaluated whether Bexa or UVI could induce effects on dopamine, serotonin, norepinephrine epinephrine, adenosine, and acetylcholine contents, collected from either the nucleus accumbens or basal forebrain. In addition, c-Fos and NeuN expression in the hypothalamus was determined after Bexa or UVI treatments. RESULTS: Systemic application of Bexa (1 mM, i.p.) attenuated slow-wave sleep and rapid eye movement sleep. In addition, Bexa increased the levels of dopamine, serotonin, norepinephrine epinephrine, adenosine, and acetylcholine sampled from either the nucleus accumbens or basal forebrain. Moreover, Bexa blocked the sleep rebound period after total sleep deprivation, increased in the hypothalamus the expression of c-Fos, and decreased NeuN activity. Remarkably, UVI 3003 (1 mM, i.p.) induced opposite effects in sleep, sleep homeostasis, neurochemicals levels, and c-Fos and NeuN activity. CONCLUSIONS: The administration of RXR agonist or antagonist significantly impaired the sleep-wake cycle and exerted effects on the levels of neurochemicals related to sleep modulation. Moreover, Bexa or UVI administration significantly affected c-Fos and NeuN expression in the hypothalamus. Our findings highlight the neurobiological role of RXR on sleep modulation.
Assuntos
Bexaroteno/farmacologia , Ácidos Cumáricos/farmacologia , Receptores X de Retinoides/metabolismo , Fases do Sono/efeitos dos fármacos , Fases do Sono/fisiologia , Tetra-Hidronaftalenos/farmacologia , Animais , Masculino , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/metabolismo , Ratos , Ratos Wistar , Receptores Citoplasmáticos e Nucleares/agonistas , Receptores Citoplasmáticos e Nucleares/antagonistas & inibidores , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores X de Retinoides/agonistas , Receptores X de Retinoides/antagonistas & inibidoresRESUMO
OBJECTIVES: Klebsiella pneumoniae has emerged as one of the major pathogens of humans and companion animals. Moreover, polymyxin resistance in K. pneumoniae is increasingly reported worldwide, mainly among extended-spectrum ß-lactamase (ESBL)- and/or carbapenemase-producing isolates. The aim of this study was to report the draft genome sequence of a polymyxin-resistant, ESBL-producing K. pneumoniae isolate (14CSI) from a hospitalised domestic cat in Brazil. METHODS: Whole-genome sequencing of strain 14CSI was performed on an Illumina NextSeq platform and the genome was de novo assembled using Velvet v.1.2.10. Data analysis was performed using bioinformatics tools available from the Center for Genomic Epidemiology and the Institut Pasteur database. RESULTS: The genome size of strain 14CSI was calculated at 5 260 459 bp, with a GC content of 57.3% and comprising 5294 total genes, 28 tRNAs, 7 rRNAs, 8 ncRNAs and 237 pseudogenes. Klebsiella pneumoniae strain 14CSI belongs to sequence type 491 (ST491), presents a mutation (A14S) in the mgrB gene and co-harbours blaCTX-M-8 and qnrE1 genes. Genes conferring resistance to heavy metals were further identified. CONCLUSION: This draft genome could be used as a reference sequence for comparative analysis of polymyxin-resistant and/or CTX-M-8-producing K. pneumoniae strains circulating at the human-animal interface.