Enantioseparation of phenothiazines in capillary zone electrophoresis using cyclodextrins as chiral selectors

Lin, Chin‐Feng; Chen, Kuo-Hsing

doi:10.1016/s0021-9673(01)01188-8

Cited by 34 publications

(30 citation statements)

References 15 publications

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“…As shown (Table 2), during the microencapsulation procedure both alkannin and shikonin commercial samples (A/S microcapsules), the proportion of A:S is almost the same as the initial proportion in the commercial samples in powder form. The same occurs during the inclusion of shikonin in β-hydroxypropylcyclodextrin; this proves that, during encapsulation of shikonin in β-hydroxypropyl-cyclodextrin, selective inclusion of one of the two antipodes (A/S) does not occur, even though cyclodextrins have been reported as chiral selectors (Lin and Chen, 2001) for several enantiomers and comprise the packing material for chiral columns. Thus, both microencapsulation of alkannin and shikonin samples and molecular inclusion of shikonin in cyclodextrins do not alter the enantiomeric ratio of A/S in alkannin and shikonin commercial samples.…”

Section: Resultsmentioning

confidence: 56%

Study on the enantiomeric ratio of the pharmaceutical substances alkannin and shikonin

Assimopoulou

Papageorgiou

2004

Biomedical Chromatography

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The chiral pair alkannin and shikonin (A/S) are potent pharmaceutical substances with a wide spectrum of biological activity; their enantiomeric ratio does not influence the major biological activity studied hitherto. Nevertheless, in pharmaceutical development and approval of chiral drugs from the Health and Regulatory Authorities, full documentation of methods of analysis of enantiomeric drugs, is required in order to evaluate the enantiomeric purity of starting materials and final products and to control the stability of enantiomers in pharmaceutical formulations under several experimental conditions. In the present study, the enantiomeric ratio of A/S was determined in several commercial samples of alkannin and shikonin and also the proportion of A/S derivatives in several Alkanna root samples, which are all used as active ingredients in pharmaceuticals. Light and air proved not to influence the enantiomeric ratio of A/S on a shikonin commercial sample, and temperature also did not alter the A/S ratio on shikonin and alkannin commercial samples. Microencapsulation of alkannin and shikonin commercial samples in ethylcellulose microspheres and also molecular inclusion of a shikonin commercial sample in beta-hydroxypropyl-cyclodextrin, which are used as drug delivery systems, did not alter the A/S enantiomeric ratio.

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Section: Resultsmentioning

confidence: 56%

Study on the enantiomeric ratio of the pharmaceutical substances alkannin and shikonin

Assimopoulou

Papageorgiou

2004

Biomedical Chromatography

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“…Phenothiazines, and the enantiomers as well, have previously been separated by CE [35,[44][45][46][47][48][49][50][51][52][53][54][55], mostly by CZE [44-52, 54, 55]. Several articles have appeared in the literature regarding the applications of the CE technique to the enantioseparation of phenothiazines using CDs as chiral selectors [35,44,49,50,[52][53][54][55]. Enantioseparations of seven chiral phenothiazines in CZE using various native CDs and some of neutral and charged CD derivatives as chiral selectors in 100 mM triethanolamine phosphate buffer at pH 3.0 were investigated [44].…”

Section: Introductionmentioning

confidence: 99%

Enantioseparation of phenothiazines in cyclodextrin-modified capillary zone electrophoresis using sulfated cyclodextrins as chiral selectors

et al. 2005

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In this study, enantioseparations of five phenothiazines, including promethazine, ethopropazine, trimeprazine, methotrimeprazine, and thioridazine, in CD-modified CZE using dual CD systems consisting of randomly sulfate-substituted CD (MI-S-beta-CD) and a neutral CD as chiral selectors in a citrate buffer (100 mM) at pH 3.0 were investigated. The results indicate that MI-S-beta-CD is an excellent chiral selector for enantioseparation of ethopropazine. The enantiomers of promethazine can also be baseline-resolved with MI-S-beta-CD at concentrations in the range of 0.5-1.0% w/v. On the other hand, thioridazine and trimeprazine interact strongly with neutral CDs. As a result, the enantioselectivity of these two phenothiazines is remarkably and synergistically enhanced with increasing the concentration of neutral CDs in the presence of MI-S-beta-CD and simultaneous enantioseparations of these phenothiazines, except for methotrimeprazine, could favorably be achieved with the use of dual CD systems. Moreover, by varying the concentration of beta-CD or gamma-CD at a fixed concentration of MI-S-beta-CD (0.75% w/v) reversal of the enantiomer migration order of promethazine occurred. This may be attributable to the opposite effects of charged and neutral CDs on the mobility of the enantiomers of promethazine.

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“…Phenothiazines and the enantiomers as well have previously been separated by CE [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58], mostly by CZE [41,[43][44][45][46][47][48][49][50][52][53][54][55][56][57]. The applications of the CE technique to the enantioseparations of phenothiazines using CDs as chiral selectors have been reported [41,42,47,48,[50][51][52][53][54]. (1)-Promethazine was found to have a greater binding strength than (2)-promethazine with b-CD [42].…”

Section: Introductionmentioning

confidence: 99%

“…The enantiomers of trimeprazine were completely separated with addition of hydroxypropyl-b-CD (HP-b-CD) in a phosphate buffer at low pH [47]. The enantiomers of promethazine, ethopropazine, trimeprazine, and thioridazine were effectively separated by CZE using HP-b-CD, b-CD, and g-CD at relatively low concentrations (,8 mM) in a phosphate buffer at pH 3.5 [50]. The interaction of phenothiazines with CDs was found to increase in the order g-CD, HP-b-CD, b-CD [50].…”

Section: Introductionmentioning

confidence: 99%

“…The enantiomers of promethazine, ethopropazine, trimeprazine, and thioridazine were effectively separated by CZE using HP-b-CD, b-CD, and g-CD at relatively low concentrations (,8 mM) in a phosphate buffer at pH 3.5 [50]. The interaction of phenothiazines with CDs was found to increase in the order g-CD, HP-b-CD, b-CD [50]. Enantioseparations of phenothiazines with g-CD as a chiral selector using citrate and phosphate buffer electrolytes at pH 3.0 were reported [53].…”

Section: Introductionmentioning

confidence: 99%

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Enantioseparation of phenothiazines in CD‐modified CZE using single isomer sulfated CD as a chiral selector

et al. 2007

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Enantioseparations of five chiral phenothiazines in CD-modified CZE using the single isomer sulfate-substituted beta-CD (heptakis(2,3-dihydroxy-6-O-sulfo)-beta-CD, SI-S-beta-CD) and dual CD systems consisting of SI-S-beta-CD and a neutral CD as chiral selectors in a citrate buffer at pH 3.0 were investigated. The results indicate that SI-S-beta-CD is an excellent chiral selector for enantioseparation of promethazine. The enantiomers of trimeprazine were well separated, while those of ethopropazine could also be baseline-resolved with SI-S-beta-CD. With dual CD systems, especially with hydroxypropyl-beta-CD (HP-beta-CD) as neutral CD, the enantioselectivity of thioridazine and ethopropazine was considerably enhanced. Effective enantioseparation of phenothiazines, except for methotrimeprazine, could thus be favorably and simultaneously achieved. Moreover, reversal of the enantiomer migration order of ethopropazine and thioridazine occurred by varying the concentration of gamma-CD in the presence of SI-S-beta-CD. These phenomena may be attributable to the opposite effects of sulfated beta-CD and gamma-CD on the mobility of the enantiomers of ethopropazine and of thioridazine. Comparative studies on the enantioseparations of phenothiazines with single CD and dual CD systems containing SI-S-beta-CD and randomly sulfate-substituted beta-CD (MI-S-beta-CD) were made.

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Enantioseparation of phenothiazines in capillary zone electrophoresis using cyclodextrins as chiral selectors

Cited by 34 publications

References 15 publications

Study on the enantiomeric ratio of the pharmaceutical substances alkannin and shikonin

Study on the enantiomeric ratio of the pharmaceutical substances alkannin and shikonin

Enantioseparation of phenothiazines in cyclodextrin-modified capillary zone electrophoresis using sulfated cyclodextrins as chiral selectors

Enantioseparation of phenothiazines in CD‐modified CZE using single isomer sulfated CD as a chiral selector

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