(S,<i>S</i>)-2,2′-(Ethane-1,2-diyldiiminio)dibutan-1-ol dinitrate

Bai, Guoyi; Ning, Huisen; Zhang, Yue-Cheng; Zeng, Tao; Li, Jiang-Sheng

doi:10.1107/s1600536806026778

Cited by 3 publications

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“…In solid state two conformations for quiral ETB cationic molecule (SS and RS) with some counter-ion were observed: nitrate, 23,25 oxalate 24 and sulfate. 26 These species are stabilized by O-H … O and N-H … O hydrogen bond forming two 23,25 and three-dimensional network. 26 The observation of compound (I) in solid state indicates that the ETB residue is in SS conformation.…”

Section: Cuetb X-ray Diffractionmentioning

confidence: 98%

Section: Cuetb X-ray Diffractionmentioning

confidence: 99%

“…[23][24][25][26] In these compounds the positive charge is obtained by protonation of NH groups of ETB. In solid state two conformations for quiral ETB cationic molecule (SS and RS) with some counter-ion were observed: nitrate, 23,25 oxalate 24 and sulfate. 26 These species are stabilized by O-H … O and N-H … O hydrogen bond forming two 23,25 and three-dimensional network.…”

Section: Cuetb X-ray Diffractionmentioning

confidence: 99%

“…Some cationic species of ETB unit are described in the literature. [23][24][25][26] In these compounds the positive charge is obtained by protonation of NH groups of ETB. In solid state two conformations for quiral ETB cationic molecule (SS and RS) with some counter-ion were observed: nitrate, The CuETB and ETB forms I and II crystallize in the same crystal system (orthorhombic) and the most relevant difference among of CuETB and ETB (forms I and II) is in N-C-C-O torsion angles.…”

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confidence: 99%

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Ethambutol analysis by copper complexation in pharmaceutical formulations: spectrophotometry and crystal structure

Faria¹,

Vasconcelos²,

Souza³

et al. 2011

J. Braz. Chem. Soc.

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Um método alternativo para determinação de etambutol (ETB) por espectrofotometria UV em formulações farmacêuticas por complexação com Cu(II) foi otimizado usando um planejamento fatorial completo 3 2 , tendo como variáveis Cu(II) e tampão aquoso de acetato de sódio em pH 4,6. A estequiometria predominante do complexo em solução aquosa tamponada nesse pH e a constante de formação do complexo foram obtidas usando o método de Job e o diagrama de Scatchard, respectivamente. A estrutura cristalina do complexo de monocristal foi obtida por difração de raios X. O método espectrofotométrico foi aplicado na análise de formulação farmacêutica sendo encontrado: 408,0 ± 11,9 mg de ETB•2HCl, faixa de recuperação de 100,9-104,0% e limites de detecção e quantificação de 0,8 e 2,8 mg L -1 , respectivamente. O método espectrofotométrico ao ser comparado com o método por eletroforese capilar de zona não evidenciou diferenças significativas no intervalo de 95% de confiança.An alternative method for ethambutol (ETB) determination by UV spectrophotometry in pharmaceutical formulations using ETB complexation with Cu(II) was optimized employing a 3 2 full experimental design having Cu(II) and aqueous acetic acid/sodium acetate buffer at pH 4.6 as variables. The predominant complex stoichiometry in aqueous buffer solution at this pH and formation constant were obtained by using Job's method and Scatchard diagram, respectively. The complex crystalline structure of monocrystal was obtained by X-ray diffraction. The developed method was applied to the pharmaceutical formulation analysis being found: 408.0 ± 11.9 mg of ETB•2HCl, recovery range of 100.9-104.0% and detection and quantification limits of 0.8 and 2.8 mg L -1 , respectively. The spectrophotometric method was compared to zone capillary electrophoresis and no significant difference was found within the 95% confidence interval.Keywords: ethambutol, complexation, spectrophotometry, crystal structure IntroductionNowadays, tuberculosis (TB) is becoming a worldwide problem. This contagious disease is transmitted through the air and it is caused by the bacterium Mycobacterium tuberculosis, which can attack different organs of the human body. However, it most commonly affects the lungs, accounting for more than 75% of the cases.1 According to the World Health Organization (WHO), more than two billion people are infected with TB bacilli and a total of 1.77 million people died from TB in 2007.2 Nowadays, the first line TB treatment is based on four drugs: isoniazid, rifampicin, pyrazinamide and ethambutol (ETB), which are available in cheap generic forms and are effective if taken as prescribed. 3 These drugs complement each other and are used in various combinations, which are very important to prevent the emergence of multiple drugresistant organisms, resulting in ineffective treatment. 3In this context, ETB is an important component in TB treatment (Figure 1). This drug is an aminoalcohol, which affects the biosynthesis of mycolic acids, an important class of compounds frequently found...

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Section: Cuetb X-ray Diffractionmentioning

confidence: 98%

Section: Cuetb X-ray Diffractionmentioning

confidence: 99%

Section: Cuetb X-ray Diffractionmentioning

confidence: 99%

mentioning

confidence: 99%

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Ethambutol analysis by copper complexation in pharmaceutical formulations: spectrophotometry and crystal structure

Faria¹,

Vasconcelos²,

Souza³

et al. 2011

J. Braz. Chem. Soc.

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“…The hygroscopicity of ethambutol dihydrochloride catalyzes the degradation of rifampicin and isoniazid in the FDC formulation, resulting in the loss of drug potency upon storage. , As a consequence, individual drugs of the FDC formulation must be separately coated with polymers to avoid mutual interactions and water uptake and then blended to make up the final product formulation . Several salts of ethambutol base (dinitrate, dihydrobromide, oxalate pentahydrate, and metal salts), including a drug–drug methanesulfonic acid salt with isoniazid, are reported but without any discussion of their physicochemical properties. The dihydrochloride salt of ethambutol is tetramorphic, but neither the X-ray crystal structure nor any polymorphs of the S , S -ethambutol base are reported.…”

Section: Introductionmentioning

confidence: 99%

Salts and Ionic Liquid of The Antituberculosis Drug S,S-Ethambutol

Cherukuvada

Nangia

2013

Crystal Growth & Design

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A salt screen of the antituberculosis chiral basic drug Ethambutol with protic acids resulted in the formation of several salts and an ionic liquid. The protic salt/ionic liquid product was characterized by spectroscopic (ATR-IR and ss-NMR), thermal (DSC and TGA), and X-ray diffraction. Similar to the marketed Ethambutol dihydrochloride salt of the drug, all the new salts were found to be hygroscopic. Moisturefree conditions of the desiccator and rotavapor gave nonhygroscopic materials in a few cases. X-ray crystal structures of two new salts were determined and that of the Ethambutol base and Ethambutol dihydrochloride salt were redetermined in this work.

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Eutectics as improved pharmaceutical materials: design, properties and characterization

2014

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Eutectics are a long known class of multi-component solids with important and useful applications in daily life. In comparison to other multi-component crystalline solids, such as salts, solid solutions, molecular complexes and cocrystals, eutectics are less studied in terms of molecular structure organization and bonding interactions. Classically, a eutectic is defined based on its low melting point compared to the individual components. In this article, we attempt to define eutectics not just based on thermal methods but from a structural organization view point, and discuss their microstructures and properties as organic materials vis-a-vis solid solutions and cocrystals. The X-ray crystal structure of a cocrystal is different from that of the individual components whereas the unit cell of a solid solution is similar to that of one of the components. Eutectics are closer to the latter species in that their crystalline arrangement is similar to the parent components but they are different with respect to the structural integrity. A solid solution possesses structural homogeneity throughout the structure (single phase) but a eutectic is a heterogeneous ensemble of individual components whose crystal structures are like discontinuous solid solutions (phase separated). Thus, a eutectic may be better defined as a conglomerate of solid solutions. A structural analysis of cocrystals, solid solutions and eutectics has led to an understanding that materials with strong adhesive (hetero) interactions between the unlike components will lead to cocrystals whereas those having stronger cohesive (homo/self) interactions will more often give rise to solid solutions (for similar structures of components) and eutectics (for different structures of components). We demonstrate that the same crystal engineering principles which have been profitably utilized for cocrystal design in the past decade can now be applied to make eutectics as novel composite materials, illustrated by stable eutectics of the hygroscopic salt of the anti-tuberculosis drug ethambutol as a case study. A current gap in the characterization of eutectic microstructure may be fulfilled through pair distribution function (PDF) analysis of X-ray diffraction data, which could be a rapid signature technique to differentiate eutectics from their components.

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(S,S)-2,2′-(Ethane-1,2-diyldiiminio)dibutan-1-ol dinitrate

Cited by 3 publications

References 3 publications

Ethambutol analysis by copper complexation in pharmaceutical formulations: spectrophotometry and crystal structure

Ethambutol analysis by copper complexation in pharmaceutical formulations: spectrophotometry and crystal structure

Salts and Ionic Liquid of The Antituberculosis Drug S,S-Ethambutol

Eutectics as improved pharmaceutical materials: design, properties and characterization

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