Carbohydrate carbamate coated onto microporous silica: Application to chiral analysis of commercial pharmaceutical drugs

Cass, Quézia B.; Bassi, Ana Karolina Zamprônio; Calafatti, Silvana A.; Matlin, Stephen A.; Tiritan, Maria Elizabeth; Campos, Lígia Maria Moreira de

doi:10.1002/(sici)1520-636x(1996)8:1<143::aid-chir21>3.0.co;2-m

Cited by 16 publications

(14 citation statements)

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“…Zhang et al, also evaluated the enantioresolution of fourteen derivatives (21-26, 28-35) ( Table 2) and concluded that like chitin phenylcarbamates [55], the nature of substituents and their position in the phenyl moiety, played a great role in the enantiorecognition of the derivative [59]. In fact, the 3,5-disubstituted phenylcarbamates of chitosan (22)(23) CSPs have the highest chiral recognition abilities while 2-substituted phenylcarbamate (24)(25)(26)(28)(29)(30)(31)(32)(33)(34)(35) CSPs showed the lowest enantiorecognition. Additionally, mobile phases containing ethyl acetate and chloroform were studied and, once again, revealed to improve the enantiorecognition performance of the CSPs [59].…”

Section: Chitosan Tris-carbamate Cspsmentioning

confidence: 99%

“…Phenylcarbamates, esters, alkylcarbamates and benzylcarbamates derivatives of cellulose and amylose derivatives were developed as selectors for CSPs. Since then, other research groups have demonstrated interest in the development of amylose [8][9][10][11][12][13][14][15] and cellulose [10,14,[16][17][18][19][20][21] derivatives as CSPs, including coating onto microporous silica [9,22,23]. Several reviews focusing the preparation and evaluation of this type of CSPs can be found [24][25][26][27][28][29][30][31][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

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Chiral Stationary Phases for Liquid Chromatography Based on Chitin- and Chitosan-Derived Marine Polysaccharides

et al. 2017

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The development of chiral stationary phases (CSPs) for liquid chromatography (LC) revolutionized the enantioseparation and, nowadays, different types of CSPs are commercially available. Polysaccharide-based CSPs are one of the most versatile and widely used for both analytical and preparative applications and they are able to resolve several classes of racemates. Phenylcarbamates of amylose and cellulose derivatives are the most successful; however, polysaccharide-based CSPs comprising marine-derived polysaccharides are also described revealing high chiral recognition abilities and wider range of mobile phases. A literature survey covering the report on chitin and chitosan based CSPs is presented. The chemical structure of the chiral selectors, their development and applications in chiral LC are emphasized.

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Section: Chitosan Tris-carbamate Cspsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chiral Stationary Phases for Liquid Chromatography Based on Chitin- and Chitosan-Derived Marine Polysaccharides

et al. 2017

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“…The column was evaluated in the normal phase mode as described elsewhere 29 before it was passed into the reverse mode. This was achieved by successive elution with ∼ 20 mL each of 2-propanol and then methanol, followed by the mobile phase of acetonitrile: 0.01 M phosphate buffer (pH = 3.0) (60:40 v/v).…”

Section: Preparation Of Stationary Phasesmentioning

confidence: 99%

First direct resolution of gossypol enantiomers on a chiral high‐performance liquid chromatography phase

Cass¹,

Bassi²,

Matlin³

1999

Chirality

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The first direct resolution of gossypol enantiomers has been achieved by HPLC on a chiral stationary phase consisting of cellulose tris-(3,5-dimethylphenyl carbamate) coated onto microporous aminopropyl-silica eluted in the reverse phase mode. Chirality 11: 46-49, 1999. © 1999 KEY WORDS: enantiomers of gossypol; direct resolution; chiral HPLC phase; carbohydrate carbamate coating; cellulose tris-(3,5-dimethylphenyl carbamate)Gossypol (Fig. 1), a binaphthyl pigment isolated from the cotton plant and also present in a number of other members of the Malvaceae, is chiral due to steric hindrance to rotation about the internaphthyl bond.1 The standard isolation procedure developed for the extraction of gossypol from the cotton plant 1 affords racemic gossypol as a 1:1 complex with acetic acid. However, investigations have shown that there are wide variations in the ratio of gossypol enantiomers present in different species of cotton plant (Gossypium species) and even within different tissues in the same plant. 2-5There has been considerable interest in the pharmacological properties of gossypol and it has been shown to be potent as an anti-spermatogenic agent 1,6,7 and anti-tumor agent, 8,9 and to possess activity against the HIV-1 virus 10 and the Entamoeba histolytica organism responsible for amoebiasis. 11,12 In all these cases, the (−)-enantiomer of gossypol has been shown to be substantially more active than the (+)-isomer. [13][14][15][16][17][18][19][20][21] Interest in studies of the varied biological activities of the enantiomers of gossypol [13][14][15][16][17][18][19][20][21] and of its unequal enantiomeric distribution in different Malvaceae species [2][3][4][5] has resulted in a need for simple and rapid methods for the analysis of the enantiomeric composition of gossypol samples, as well as for large-scale methods for the resolution of the racemic compound. Previous efforts to resolve gossypol enantiomers directly by HPLC on chiral stationary phases have been unsuccessful, and as a result it was necessary to develop indirect methods, in which gossypol was converted into Schiff's base derivatives that could be separated on either chiral or achiral phases. [22][23][24][25] For the first time, we have now identified conditions suitable for the direct resolution of gossypol enantiomers, using a chiral carbohydrate carbamate phase under reverse phase conditions. MATERIAL AND METHODS ChemicalsAminopropyl-silica (Hypersil-APS, Shandon, UK) had the following properties: particle size, 5 µm; pore size, 120 Å.Isocyanates were purchased from Aldrich (Milwaukee, WI). Solvents were either HPLC grade from Carlo Erba (Milan, Italy) or were purified as usual. 26 Cellulose used was Avicel from Merck. HPLC dead times (t 0 ) were estimated using acetonitrile. (±)-Gossypol acetic acid was isolated from cotton seeds and its separated (−) and (+) enantiomers obtained as described previously. 22-24 EquipmentThe HPLC system consisted of a Shimadzu LC-10AD pump (Kyoto, Japan), a Rheodyne 7125 injector fitted with a 20-µl ...

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“…A influência na discriminação quiral da proporção carbamato/suporte g/g na cobertura foi examinada para sílica microporosa. Com sílica macroporosa 20,37 como suporte, a proporção usada tem sido 20-25%g/g, enquanto com sílica microporosa (120 Å) foi evidenciado que o percentual ótimo de cobertura depende do polissacarídeo usado [41][42][43][44] . Com celulose Sigma Cell [41][42] , a proporção ótima encontrada foi de 15%g/g, enquanto com celulose dos tipos Sigma Fibrosa e Avicel Merck, a proporção ideal de cobertura foi de 20%g/g 43 .…”

Section: Desenvolvimentounclassified

“…A importância das propriedades físico-químicas do polissacarídeo para a discriminação quiral foi claramente observada quando se compararam as resoluções obtidas com o tris(3,5dimetilfenilcarbamato) de celulose partindo-se de celulose dos tipos Sigma Fibrosa e Avicel Merck 43 . A influência da natureza do polissacarídeo e a importância da determinação da proporção carbamato/suporte (g/g) na discriminação quiral foram também observadas, quando se investigou o uso de bis(arilcarbamato)s de quitina 44 .…”

Section: Desenvolvimentounclassified

Discriminação quiral por CLAE em carbamatos de polissacarídeos: desenvolvimento, aplicações e perspectivas

Cass¹,

Tiritan²,

Bassi³

et al. 1997

Quím. Nova

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Carbohydrate carbamate coated onto microporous silica: Application to chiral analysis of commercial pharmaceutical drugs

Cited by 16 publications

References 10 publications

Chiral Stationary Phases for Liquid Chromatography Based on Chitin- and Chitosan-Derived Marine Polysaccharides

Chiral Stationary Phases for Liquid Chromatography Based on Chitin- and Chitosan-Derived Marine Polysaccharides

First direct resolution of gossypol enantiomers on a chiral high‐performance liquid chromatography phase

Discriminação quiral por CLAE em carbamatos de polissacarídeos: desenvolvimento, aplicações e perspectivas

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