1351
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Groom CA, Halasz A, Paquet L, D'Cruz P, Hawari J. Cyclodextrin-assisted capillary electrophoresis for determination of the cyclic nitramine explosives RDX, HMX and CL-20 comparison with high-performance liquid chromatography. J Chromatogr A 2003; 999:17-22. [PMID: 12885047 DOI: 10.1016/s0021-9673(03)00389-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A sulfobutyl ether-beta-cyclodextrin-assisted electrokinetic chromatographic method was developed to rapidly resolve and detect the cyclic nitramine explosives 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaaza-isowurtzitane (CL-20), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and their related degradation intermediates in environmental samples. Development of the electrophoretic method required the measurement of the aqueous solubility of CL-20 which was determined to be 3.59 +/- 0.74 mg/l at 25 degrees C (95% confidence interval, n=3). The performance of the method was then compared to results obtained from existing high-performance liquid chromatography methods including US Environmental Protection Agency method 8330.
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Affiliation(s)
- Carl A Groom
- Biotechnology Research Institute, National Research Council Canada, 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada
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1352
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Yockot D, Moreau V, Demailly G, Djedaïni-Pilard F. Synthesis and characterization of mannosyl mimetic derivatives based on a beta-cyclodextrin core. Org Biomol Chem 2003; 1:1810-8. [PMID: 12926374 DOI: 10.1039/b301670f] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of branched beta-cyclodextrins substituted with mannosyl mimetic derivatives at one primary hydroxy group is described. It was shown that the self-inclusion phenomenon observed for the target compounds in water did not preclude the inclusion properties of the cyclodextrin moiety.
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Affiliation(s)
- Duplex Yockot
- Laboratoire des glucides, Université Picardie Jules Verne, 33 rue St-Leu, 80039 Amiens, France
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1353
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Hishiya T, Asanuma H, Komiyama M. Molecularly Imprinted Cyclodextrin Polymers as Stationary Phases of High Performance Liquid Chromatography. Polym J 2003. [DOI: 10.1295/polymj.35.440] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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1354
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Funasaki N, Yamaguchi H, Ishikawa S, Neya S. Coexistence of Two 1:1 Complexes of Oxyphenonium Bromide and α-Cyclodextrin. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2003. [DOI: 10.1246/bcsj.76.903] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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1355
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1356
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Abstract
Inclusion complexes of several steroid derivatives with beta-cyclodextrin (7) were studied in dimethylsulfoxide solution. The investigated molecules were ketosteroids with different functional groups on the skeleton: 3beta-acetoxypregn-5-en-20-one (1), 3beta-acetoxypregna-5,16-dien-20-one (2), 3beta-acetoxyandrost-5-en-17-one (3), 3beta-hydroxyandrost-5-en-17-one (4), 5alpha-androstane-3,17-dione (5) and 17beta-hydroxyandrost-4-en-3-one (6). Complex formation was monitored by two-dimensional ROESY experiments through the detection of intermolecular dipolar interactions. In case of inclusion complex formation, the steroid molecule penetrates the cavity of the cyclodextrin and dipole-dipole interactions (ROEs) can be detected between the glucose H-3 and H-5 protons inside the cyclodextrin cavity and the steroid skeletal protons. Intermolecular interactions were detected in all six cases. However, ROESY experiments provided data indicating only partial immersion (A and B ring of the steroid skeleton) in case of 1, 2 and 6. On the contrary, compounds 3 and 5, showing the most correlation rich spectra, seem to fully immerse in the beta-cyclodextrin cavity.
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Affiliation(s)
- Peter Forgo
- Department of Organic Chemistry, University of Szeged, Dóm tér 8, Szeged H-6720, Hungary.
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1357
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Fernandes CM, Carvalho RA, Pereira da Costa S, Veiga FJB. Multimodal molecular encapsulation of nicardipine hydrochloride by beta-cyclodextrin, hydroxypropyl-beta-cyclodextrin and triacetyl-beta-cyclodextrin in solution. Structural studies by 1H NMR and ROESY experiments. Eur J Pharm Sci 2003; 18:285-96. [PMID: 12694880 DOI: 10.1016/s0928-0987(03)00025-3] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Proton nuclear magnetic resonance spectroscopy (1H NMR), which has become an important tool for in vitro study of cyclodextrin (CD) complexes, was used to study and structurally characterize the inclusion compounds formed in solution between nicardipine hydrochloride (NC) and beta-cyclodextrin (betaCD), hydroxypropyl-beta-cyclodextrin (HPbetaCD) and triacetyl-beta-cyclodextrin (TAbetaCD). The large variation of chemical shifts from protons located around the interior of the hydrophobic cavity (i.e. H-3, H-5 and H-6) coupled with minimal variation of shifts from protons located on the outer sphere of the betaCD (i.e. H-1, H-2 and H-4) provided clear evidence of inclusion complexation. In the presence of the different CDs, the aromatic protons of NC were the most affected, suggesting a strong involvement of the phenyl groups in the inclusion mechanism. The application of continuous variation method indicated the presence of complexes with a 1:1 host/guest stoichiometry for all the studied CDs. Two-dimensional rotating frame nuclear Overhauser effect spectroscopy (ROESY) experiments were carried out to further support the proposed inclusion mode. Inspection of the ROESY spectra allowed the establishment of spatial proximities between several aromatic hydrogens of the guest and the CD protons, indicating that the inclusion occurs by accommodation of the two aromatic groups of NC. All the experimental data were further rationalized to elaborate possible three-dimensional geometric models of inclusion complexes. From the aforementioned observations, we concluded there is no preference for inclusion of a particular aromatic ring. Instead, two types of 1:1 complexes with different inclusion structures may exist simultaneously in solution, being alternatively included through the wider side of the cavity, i.e. the so-called multimodal inclusion occurs in the interaction of NC with the different CDs.
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Affiliation(s)
- Catarina M Fernandes
- Laboratory of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra, 3000 Coimbra, Portugal
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1358
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Chen J. Molecular Recognition in Terms of a Dimensionless Index. 1. A Theoretical Model of the Orientation-Based Fit and Its Applicability to Ligand−Macromolecule Systems. J Phys Chem B 2003. [DOI: 10.1021/jp026570y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jian Chen
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China
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1359
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Durán N, Justo GZ, Melo PS, De Azevedo MBM, Brito ARMS, Almeida ABA, Haun M. Evaluation of the antiulcerogenic activity of violacein and its modulation by the inclusion complexation with beta-cyclodextrin. Can J Physiol Pharmacol 2003; 81:387-96. [PMID: 12769230 DOI: 10.1139/y03-033] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of beta-cyclodextrin (betaCD) inclusion complexation on the ability of violacein to prevent gastric ulceration in mice were studied. Violacein-betaCD inclusion complexes were prepared in 1:1 and 1:2 molar ratios and analysed by differential scanning calorimetry and powder X-ray diffractometry. Violacein previously administered orally at 10 mg/kg significantly reduced indomethacin-induced gastric lesions, as well as 100 mg/kg of cimetidine (positive control). However, betaCD complexation in both molar ratios significantly potentiated the protective action of violacein. In the HCl--ethanol-induced gastric ulcer model, violacein and the 1:2 inclusion complex (10 mg/kg, p.o.) inhibited gastric damage by almost 85%, whereas a 63% reduction was observed for the positive control, lansoprazole, at 30 mg/kg. In contrast, treatment with the 1:1 inclusion complex resulted in almost total disappearance of the antiulcer activity in this model. No significant changes in stress-induced gastric injury were found. In addition, the 1:2 inclusion complex improved the antilipoperoxidant activity of violacein in rat liver cells exposed to t-butyl hydroperoxide, whereas the 1:1 complex was less active than violacein. In summary, the 1:2 betaCD inclusion complex has gastroprotective properties similar to or higher than that of violacein. An increase in mucosal defensive mechanisms and protection against peroxidative damage might be involved.
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Affiliation(s)
- Nelson Durán
- Biological Chemistry Laboratory, Instituto de Química, Universidade Estadual de Campinas (UNICAMP), C.P. 6184, CEP 13083-970, Campinas, SP, Brazil
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1360
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Bravo-Díaz C, González-Romero E. Monitoring dediazoniation product formation by high-performance liquid chromatography after derivatization. J Chromatogr A 2003; 989:221-9. [PMID: 12650254 DOI: 10.1016/s0021-9673(03)00170-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A derivatization protocol that exploits the rapid reaction between arenediazonium ions and a suitable coupling agent followed by high-performance liquid chromatography analyses of the reaction mixture was employed to determine the product distribution, the rate constants for product formation and the association constant of 4-nitrobenzenediazonium, PNBD, ion with beta-cyclodextrin, beta-CD. The derivatization of PNBD with the coupling agent leads to the formation of a stable azo dye that prevents by-side reactions of PNBD with the solvents of the mobile phase, including water, or the metallic parts of the chromatographic system that would eventually lead to erroneous identification and quantification of dediazoniation products. The results show that in the presence of beta-CD, nitrobenzene is formed at the expense of 4-nitrophenol, which is the major product in its absence. The observed rate constants for the interaction between PNBD and beta-CD increase upon increasing [beta-CD] showing a saturation profile indicative of the formation of an inclusion complex between PNBD and beta-CD. By fitting the experimental data to a simplified Lineaweaver-Burk equation, the corresponding association constant and the maximum acceleration rate of beta-CD towards PNBD were estimated. The protocol is applicable under a variety of experimental conditions provided that the rate of the coupling reaction is much faster than that of dediazoniation.
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Affiliation(s)
- Carlos Bravo-Díaz
- Dpto. Química Física, Facultad de Ciencias, Universidad de Vigo, 36200 Vigo, Pontevedra, Spain.
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1361
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Valero M, Pérez-Revuelta BI, Rodríguez LJ. Effect of PVP K-25 on the formation of the naproxen:beta-ciclodextrin complex. Int J Pharm 2003; 253:97-110. [PMID: 12593941 DOI: 10.1016/s0378-5173(02)00664-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The aim of this study was to investigate the effects of the presence of the water-soluble polymer polyvinylpyrrolidone K-25 (MW=24000g/mol) on the complexation of the AINE naproxen, in its sodium salt form, with the beta-cyclodextrin. The data revealed that the polyvinylpyrrolidone K-25 interacts with the drug as well as with the drug:beta-cyclodextrin inclusion complex. The polymer shows more affinity for the inclusion complex, K=(6.67+/-0.292) x 10(-5)M(-1) than for the free drug, (2.08+/-0.208) x 10(-5)M(-1). The presence of different proportions of polymer, in a range 0-1% (w/w) of polyvinylpyrrolidone, does not increase the ability of drug-cyclodextrin complexation but important changes in the driving force of complex formation were detected, depending on the percentage of polyvinylpyrrolidone K-25 present. At low polymer concentrations, the complexation process is driven entropically, while at higher PVP proportions it is enthalpically favored. In the ternary system, polyvinylpyrrolidone K-25 partially or totally coats the drug:beta-cyclodextrin inclusion complex interacting with the beta-cyclodextrin (through hydrogen bonds), and with the naproxen.
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Affiliation(s)
- Margarita Valero
- Departamento de Química Física, Facultad de Farmacia, Universidad de Salamanca, Salamanca, Spain
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1362
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Nostro PL, Fratoni L, Ridi F, Baglioni P. Surface treatments on Tencel fabric: Grafting with ?-cyclodextrin. J Appl Polym Sci 2003. [DOI: 10.1002/app.11676] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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1363
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Law H, Baussanne I, García Fernández JM, Defaye J. Regioselective sulfonylation at O-2 of cyclomaltoheptaose with 1-(p-tolylsulfonyl)-(1H)-1,2,4-triazole. Carbohydr Res 2003; 338:451-3. [PMID: 12559748 DOI: 10.1016/s0008-6215(02)00482-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
2(I)-O-p-Tolylsulfonylcyclomaltoheptaose was obtained in 42% yield by reaction of 1-(p-tolylsulfonyl)-(1H)-1,2,4-triazole on NaH-deprotonated cyclomaltoheptaose in DMF and further converted into the corresponding mono-2(I),3(I)-manno-epoxide.
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Affiliation(s)
- Ho Law
- Département de Pharmacochimie Moléculaire, CNRS and Université Joseph Fourier-Grenoble 1 (UMR 5063), BP 138, F-38243, Meylan, France
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1364
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Wang T, Feng H, Li SFY. Indirect capillary electrophoresis with 8-anilino-1-naphthalenesulfonic acid as a fluorescence probe for determining the apparent stability constant of an inclusion complex formed between a cyclodextrin and a solute. J Chromatogr A 2003; 987:485-92. [PMID: 12613845 DOI: 10.1016/s0021-9673(02)01823-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An indirect capillary electrophoresis (CE) method was developed based on two competitive chemical equilibria for determining the stability constant of an inclusion complex formed between a cyclodextrin and a solute. 8-Anilino-1-naphthalenesulfonic acid was employed as a fluorescence probe. A linear relationship between mobility difference and concentration of uncomplexed ligand was theoretically established and experimentally verified. The principle of the method was explained using an example of determining stability constant of an inclusion complex formed between a ligand of hydroxypropyl-beta-cyclodextrin and a solute of amantadine. The stability constant was determined to be approximately 2 x 10(2) M(-1). It was calculated without knowledge of the mobility of the complex measured at saturating ligand concentrations. This indirect method can be applied to solutes and ligands lacking signal response on the selected detector in the CE. In addition, the indirect method is valid for both charged and neutral solutes and ligands.
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Affiliation(s)
- Tianlin Wang
- Department of Chemistry, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore
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1365
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Wang YH, Zhu MZ, Liu T, Guo QX. Inclusion complexation of N-substituted phenothiazines and their radical cations generated electrochemically with β-cyclodextrin. RESEARCH ON CHEMICAL INTERMEDIATES 2003. [DOI: 10.1163/156856703321505085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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1366
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Jaimez J, Fente CA, Franco CM, Cepeda A, Vázquez BI. Application of a modified culture medium for the simultaneous counting of molds and yeasts and detection of aflatoxigenic strains of Aspergillus flavus and Aspergillus parasiticus. J Food Prot 2003; 66:311-8. [PMID: 12597494 DOI: 10.4315/0362-028x-66.2.311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Molds and yeasts from 91 samples of feed and raw materials used in feed formulation were enumerated on a new culture medium to which a beta cyclodextrin (beta-W7M 1.8-cyclodextrin) had been added. This medium was compared with other media normally used in laboratories for the routine analysis of fungi, such as Sabouraud agar, malt agar supplemented with 2% dextrose, and potato dextrose agar. When a t test for paired data (0.05 significance level, 95% confidence interval) was applied, no statistically significant differences between the results obtained with the new culture medium and those obtained with the other media used to enumerate molds and yeasts were found. For the evaluation of contamination due to aflatoxin for all of the samples, Sabouraud agar and yeast extract agar, both supplemented with 0.3% beta-W7M 1.8-cyclodextrin, and APA (aflatoxin-producing ability) medium were used. Aflatoxin was detected in 21% of the feed samples and in 23% of the raw-material samples analyzed, with maximal amounts of 2.8 and 6.0 microg of aflatoxin B1 per kg, respectively, being detected. In any case, the aflatoxin contents found exceeded the legally stipulated limits. The t test for paired data (0.05 significance level, 95% confidence interval) did not show statistically significant differences between the results obtained with the different culture media used for the detection of aflatoxins. The advantage of the new medium developed (Sabouraud agar with 0.3% beta-W7M 1.8-cyclodextrin) is that it allows simultaneous fungal enumeration and determination (under UV light) of the presence of aflatoxin-producing strains without prior isolation and culture procedures involving expensive and/or complex specific media and thus saves work, time, and money.
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Affiliation(s)
- J Jaimez
- Laboratorio de Higiene, Inspección y Control de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Veterinaria, Campus universitario, s/n, pabellón 4, planta baja, Universidad de Santiago de Compostela, 27002, Lugo, Spain
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1367
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He P, Lu H, Guo Y. The Determination of Non-covalent Complexes of Diclofenac Sodium and Cyclodextrins by Electrospray Ionization/Time-of-Flight Mass Spectrometry. ANAL LETT 2003. [DOI: 10.1081/al-120017705] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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1368
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De Lisi R, Lazzara G, Milioto S, Muratore N. Volumes and heat capacities of the aqueous sodium dodecanoate/sodium perfluorooctanoate mixtures in the presence of β-cyclodextrin. Phys Chem Chem Phys 2003. [DOI: 10.1039/b308354c] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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1369
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Yang R, Li K, Wang K, Liu F, Li N, Zhao F. Rayleigh light scattering study on the supramolecular interactions of beta-cyclodextrin derivatives with tetrakis(4-methoxylphenyl)porphyrin. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2003; 59:153-161. [PMID: 12509156 DOI: 10.1016/s1386-1425(02)00147-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The supramolecular interactions of beta-cyclodextrin(beta-CD) and four kinds of alkylated beta-cyclodextrin (beta-CDs), i.e. heptakis (2,6-di-O-isobutyl)-beta-cyclodextrin (Ob-beta-CD), heptakis (2,6-di-O-n-octyl)-beta-cyclodextrin (Oc-beta-CD), heptakis (2,6-di-O-n-dodecyl)-beta-cyclodextrin (Od-beta-CD) and heptakis (2,6-di-O-n-hexadecyl)-beta-cyclodextrin (Oh-beta-CD) with tetrakis(4-methoxylphenyl)porphyrin (TMOPP) have been investigated by Rayleigh light scattering (RLS) technique. Beta-CDs form 2:1 inclusion complex with TMOPP following an obvious RLS enhancement of TMOPP. The inclusion abilities of different beta-CDs were compared. The results show that the inclusion ability of beta-CDs is related to the size of the alkylated substituent. Thus, a new mechanism of inclusion interaction has been proposed. The exact stoichiometric ratios and the association constants of the inclusion complexes have been examined by application of curve fitting method.
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Affiliation(s)
- Ronghua Yang
- College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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1370
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Ikeda T, Lee WK, Ooya T, Yui N. Thermodynamic Analysis of Inclusion Complexation between α-Cyclodextrin-Based Molecular Tube and Poly(ethylene oxide)-block-poly(tetrahydrofuran)-block-poly(ethylene oxide) Triblock Copolymer. J Phys Chem B 2003. [DOI: 10.1021/jp020817+] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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1371
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Competitive complexation and SPE techniques combined with liquid chromatography for the separation and determination of cyclodextrin encapsulated drug substances. Chromatographia 2003. [DOI: 10.1007/bf02492088] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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1372
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Fan L, Hindsgaul O. Synthesis of novel cyclic oligosaccharides: beta-1,6-thio-linked cycloglucopyranosides. Org Lett 2002; 4:4503-6. [PMID: 12465923 DOI: 10.1021/ol0270430] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[structure: see text] A protocol for the synthesis of novel cyclic beta-1,6-S-linked glucopyranosides is developed. The key intermediate is a linear thiooligosaccharide bearing an iodo group at C-6 of the nonreducing sugar and a thioacetyl group at the anomeric center of the reducing end sugar. The crucial macrocyclization step was achieved through base-promoted intramolecular S(N)2 glycosylation in remarkably high yields (92-95%) and with well-controlled stereochemistry.
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Affiliation(s)
- Linfeng Fan
- Department of Chemistry, University of Alberta, Edmonton, Canada
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1373
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Rossi LI, de Rossi RH. Synthesis of FeBr3-cyclodextrin complexes in non-aqueous solution. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1472-7862(02)00076-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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1374
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da Silva AMM, Empis JMA, Teixeira-Dias JJC. Inclusion of carvone enantiomers in cyclomaltoheptaose (beta-cyclodextrin): thermal behaviour and H-->D and D-->H exchange. Carbohydr Res 2002; 337:2501-4. [PMID: 12493236 DOI: 10.1016/s0008-6215(02)00314-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The inclusion compounds of carvone enantiomers in cylcomaltoheptaose (beta-cyclodextrin, betaCD) are studied at defined temperatures above room temperature and in relation to H-->D and D-->H exchanges. Loss of water molecules and release of carvone molecules from the betaCD cavity are caused by increase of temperature above room temperature and are measured by the integrated intensities of the O-H and C-H Raman stretching bands, respectively. In turn, H-->D and D-->H exchanges are monitored by the integrated intensities of the O-H and O-D Raman stretching bands, respectively. All of these processes were followed in real time with a Raman spectrometer equipped with CCD detection. The results indicate that distinct carvone enantiomers lead to the formation of different betaCD inclusion hydrates that have different water content and hydration structures. In particular, the results suggest that SCarv-betaCD has a greater water content, dehydrates strongly for temperatures above room temperature, and exchanges protons faster than the RCarv-betaCD complex.
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1375
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Conformational features and coordination properties of functionalized β-cyclodextrins. Formation, stability and structure of proton and copper(II) complexes of 3A-[1-(2-amino)ethylamino]-3A-deoxy-2A(S),3A(R)-β-cyclodextrin. Inorganica Chim Acta 2002. [DOI: 10.1016/s0020-1693(02)01048-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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1376
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Influence of methanol and cyclodextrin cavity size on stoichiometry and binding constant of 3-[2-(9-anthryl)benzoxazol-5-yl]-alanine. J Photochem Photobiol A Chem 2002. [DOI: 10.1016/s1010-6030(02)00269-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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1377
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Loftsson T, Magnúsdóttir A, Másson M, Sigurjónsdóttir JF. Self-association and cyclodextrin solubilization of drugs. J Pharm Sci 2002; 91:2307-16. [PMID: 12379916 DOI: 10.1002/jps.10226] [Citation(s) in RCA: 204] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Phase-solubility diagrams are frequently used to calculate stoichiometry of drug/cyclodextrin complexes. Linear diagrams (A(L)-type systems) are thought to indicate that the complexes are first order with respect to cyclodextrin and first or higher order with respect to the drug. Positive deviation from linearity (A(P)-type systems) are thought to indicate formation of complexes that are first order with respect to the drug but second or higher order with respect to cyclodextrin. The phase solubility of several different compounds, i.e., cholesterol, ibuprofen, diflunisal, alprazolam, 17beta-estradiol and diethylstilbestrol, and various charged and uncharged cyclodextrins was investigated. Phase-solubility diagrams of cholesterol in aqueous cyclodextrin solutions were all of A(P) type. However, the phase-solubility diagrams obtained with charged cyclodextrins could not be fitted to complexes of second or higher order with respect to cyclodextrin. The phase-solubility diagrams of ibuprofen and diflunisal were of A(L) type with slope greater than unity indicating formation of 2:1 drug/cyclodextrin complexes. However, Job's plots and space filling docking studies indicated that 1:1 complexes were formed. These and other observations show that stoichiometry of drug/cyclodextrin complexes cannot be derived from simple phase-solubility studies. Furthermore, the results indicate that drug/cyclodextrin complexes can self-associate to form water-soluble aggregates, which then can further solubilize the drug through non-inclusion complexation.
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Affiliation(s)
- Thorsteinn Loftsson
- Faculty of Pharmacy, University of Iceland, Hofsvallagata 53, IS-107 Reykjavik, Iceland.
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1378
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Karlson L, Thuresson K, Lindman B. A rheological investigation of the complex formation between hydrophobically modified ethyl (hydroxy ethyl) cellulose and cyclodextrin. Carbohydr Polym 2002. [DOI: 10.1016/s0144-8617(02)00036-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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1379
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Setnicka V, Urbanová M, Král V, Volka K. Interactions of cyclodextrins with aromatic compounds studied by vibrational circular dichroism spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2002; 58:2983-2989. [PMID: 12477043 DOI: 10.1016/s1386-1425(02)00050-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The host/guest complexation between cyclodextrins (CDs) and aromatic compounds was studied by vibrational circular dichroism (VCD) spectroscopy in mid-IR region. Benzoic acid, 4-aminobenzoic acid, and 2,6-naphthalene-dicarboxylic acid acting as the guests with aromatic skeleton, cause the significant changes in VCD patterns of CD, which indicate that the secondary hydroxyl groups of the CDs are involved in the host/guest complexation. In addition, the intensities and dissymmetry factors (deltaA/A) of the VCD bands, which belong to skeletal CD vibrations, depend on the sizes of the guest molecules. Our results indicate that the formation of the CD inclusion complexes can be followed by VCD spectroscopy.
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Affiliation(s)
- Vladimir Setnicka
- Department of Analytical Chemistry, Institute of Chemical Technology, Technická 5, 166 28 Praha 6, Czech Republic.
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1380
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Li NB, Liu SP, Luo HQ. Frequency doubling scattering and second-order scattering technology as novel methods for the determination of the inclusion constant of procaine hydrochloride to β-cyclodextrin. Anal Chim Acta 2002. [DOI: 10.1016/s0003-2670(02)00999-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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1381
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Norkus E, Grinciene G, Vaitkus R. Interaction of lead(II) with beta-cyclodextrin in alkaline solutions. Carbohydr Res 2002; 337:1657-61. [PMID: 12423967 DOI: 10.1016/s0008-6215(02)00044-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Polarographic and UV-spectrophotometric investigations of Pb(II) complex formation with beta-cyclodextrin have showed that the complexation of Pb(II) ions begins at pH >10. The formation of lead(II) 1:1 complex with the beta-cyclodextrin anion was observed at pH 10-11.5. The logarithm of the stability constant of this complex compound is 15.9+/-0.3 (20 degrees C, ionic strength 1.0), and the molar extinction coefficient value is ca. 5500 (lambda(max)=260 nm). With further increase in solution pH the Pb-beta-cyclodextrin complex decomposes and converts to Pb(OH)(2) or Pb(OH)(3)(-) hydroxy-complexes. This process occurs with a decrease in Pb(II) complexation degree. The latter result could be explained by a decrease in the beta-cyclodextrin anion activity. Neither Pb(OH)(2) nor Pb(OH)(3)(-) encapsulation into beta-CD cavity was observed.
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Affiliation(s)
- Eugenijus Norkus
- Institute of Chemistry, A Gostauto 9, LT-2600, Vilnius, Lithuania.
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1382
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Wang Z, Wang AY, Luo G. A selective voltammetric method for uric acid detection at beta-cyclodextrin modified electrode incorporating carbon nanotubes. Analyst 2002; 127:1353-8. [PMID: 12430609 DOI: 10.1039/b204357b] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A beta-cyclodextrin-coated electrode incorporating carbon nanotubes was constructed and applied to the detection of uric acid in the presence of high concentration of ascorbic acid. The major obstacle of the overlapped oxidation potential of ascorbic acid was overcome owing to the distinct ability of the carbon nanotubes-modified electrode to yield a large anodic peak difference ca. 400 mV. The sensitive detection of uric acid has been further improved by the formation of a supramolecular complex between beta-cyclodextrin and uric acid. A linear calibration curve was obtained for 5 x 10(-7) to 5 x 10(-5) M in 0.2 M HAc-NaAc buffer (pH 4.5) with correlation coefficient of 0.998 and detection limit of 0.2 microM. The practical analytical application was illustrated by a selective measurement of uric acid in human urine without any preliminary treatment.
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Affiliation(s)
- Zonghua Wang
- Department of Chemistry, Tsinghua University, Beijing, People's Republic of China
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1383
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Tønnesen HH, Másson M, Loftsson T. Studies of curcumin and curcuminoids. XXVII. Cyclodextrin complexation: solubility, chemical and photochemical stability. Int J Pharm 2002; 244:127-35. [PMID: 12204572 DOI: 10.1016/s0378-5173(02)00323-x] [Citation(s) in RCA: 513] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cyclodextrin complexes of the natural compound curcumin were prepared in order to improve the water solubility and the hydrolytic and photochemical stability of the compound. Complex formation resulted in an increase in water solubility at pH 5 by a factor of at least 10(4). The hydrolytic stability of curcumin under alkaline conditions was strongly improved by complex formation, while the photodecomposition rate was increased compared to a curcumin solution in organic solvents. The cavity size and the charge and bulkiness of the cyclodextrin side-chains influenced the stability constant for complexation and the degradation rate of the curcumin molecule.
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Affiliation(s)
- Hanne Hjorth Tønnesen
- Institute of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, 0316 Oslo, Norway.
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1384
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Phan TN, Bacquet M, Morcellet M. The removal of organic pollutants from water using new silica-supported β-cyclodextrin derivatives. REACT FUNCT POLYM 2002. [DOI: 10.1016/s1381-5148(02)00079-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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1385
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1386
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De Lisi R, Milioto S, Muratore N. Thermodynamic Evidence of Cyclodextrin−Micelle Interactions. J Phys Chem B 2002. [DOI: 10.1021/jp013648m] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- R. De Lisi
- Dipartimento di Chimica Fisica, Università di Palermo, Viale delle Scienze, Parco D'Orleans II, 90128 Palermo, Italy
| | - S. Milioto
- Dipartimento di Chimica Fisica, Università di Palermo, Viale delle Scienze, Parco D'Orleans II, 90128 Palermo, Italy
| | - N. Muratore
- Dipartimento di Chimica Fisica, Università di Palermo, Viale delle Scienze, Parco D'Orleans II, 90128 Palermo, Italy
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1387
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Gabelica V, Galic N, De Pauw E. On the specificity of cyclodextrin complexes detected by electrospray mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2002; 13:946-953. [PMID: 12216735 DOI: 10.1016/s1044-0305(02)00416-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Alpha-cyclodextrin complexes with linear alpha,omega-dicarboxylic acids were investigated by electrospray mass spectrometry. These hydrophobic complexes are known to have an equilibrium binding constant that increases with the diacid chain length. However, the electrospray mass spectrometry (ES-MS) spectra showed that the relative intensity of the complex did not vary significantly with chain length. This contradiction is caused by a contribution of nonspecific adducts to the signal of the complex in ES-MS. In order to estimate the contribution of nonspecific adducts to the total intensity of the complexes with alpha-cyclodextrin, the comparison was made between alpha-cyclodextrin and maltohexaose, the latter being incapable of making inclusion complexes in solution. The signal observed for complexes between diacids and maltohexaose can only result from nonspecific electrostatic aggregation, and is found to be more favorable with the shorter diacids. This is also supported by MS/MS experiments. A procedure is described which allows estimation of the contribution of the nonspecific complex in the spectra of the complexes with alpha-cyclodextrin by using the relative intensity of the complex with maltohexaose. The contribution of the specific complex to the total signal intensity is found to increase with the diacid chain length, which is in agreement with solution behavior.
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1388
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Lecourt T, Mallet JM, Sinaÿ P. Symmetrical doubly connected head-to-head α-cyclodextrin dimers: a high yield synthesis of a novel type of neoglycolipid. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)01125-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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1389
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Engeldinger E, Armspach D, Matt D, Jones PG, Welter R. A cyclodextrin diphosphane as a first and second coordination sphere cavitand: evidence for weak C-H...Cl-M hydrogen bonds within metal-capped cavities. Angew Chem Int Ed Engl 2002; 41:2593-6. [PMID: 12203545 DOI: 10.1002/1521-3773(20020715)41:14<2593::aid-anie2593>3.0.co;2-m] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Eric Engeldinger
- Laboratoire de Chimie Inorganique Moléculaire, Université Louis Pasteur, UMR 7513 CNRS, 1 rue Blaise Pascal, 67008 Strasbourg Cedex, France
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1390
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Otzen DE, Knudsen BR, Aachmann F, Larsen KL, Wimmer R. Structural basis for cyclodextrins' suppression of human growth hormone aggregation. Protein Sci 2002; 11:1779-87. [PMID: 12070330 PMCID: PMC2373647 DOI: 10.1110/ps.0202702] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2002] [Revised: 04/04/2002] [Accepted: 04/15/2002] [Indexed: 10/14/2022]
Abstract
Many therapeutic proteins require storage at room temperature for extended periods of time. This can lead to aggregation and loss of function. Cyclodextrins (CDs) have been shown to function as aggregation suppressors for a wide range of proteins. Their potency is often ascribed to their affinity for aromatic amino acids, whose surface exposure would otherwise lead to protein association. However, no detailed structural studies are available. Here we investigate the interactions between human growth hormone (hGH) and different CDs at low pH. Although hGH aggregates readily at pH 2.5 in 1 M NaCl to form amorphous aggregates, the presence of 25 to 50 mM of various beta-CD derivatives is sufficient to completely avoid this. alpha- and gamma-CD are considerably less effective. Stopped-flow data on the aggregation reaction in the presence of beta-CD are analyzed according to a minimalist association model to yield an apparent hGH-beta-CD dissociation constant of approximately 6 mM. This value is very similar to that obtained by simple fluorescence-based titration of hGH with beta-CD. Nuclear magnetic resonance studies indicate that beta-CD leads to a more unfolded conformation of hGH at low pH and predominantly binds to the aromatic side-chains. This indicates that aromatic amino acids are important components of regions of residual structure that may form nuclei for aggregation.
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Affiliation(s)
- Daniel Erik Otzen
- Department of Life Sciences, Aalborg University, Sohngaardsholmsvej 49, DK-9000 Aalborg, Denmark.
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1391
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Lo Meo P, D'Anna F, Riela S, Gruttadauria M, Noto R. Spectrophotometric determination of binding constants between some aminocyclodextrins and nitrobenzene derivatives at various pH values. Tetrahedron 2002. [DOI: 10.1016/s0040-4020(02)00579-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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1392
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Faucci MT, Melani F, Mura P. Computer-aided molecular modeling techniques for predicting the stability of drug–cyclodextrin inclusion complexes in aqueous solutions. Chem Phys Lett 2002. [DOI: 10.1016/s0009-2614(02)00410-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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1393
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González-Gaitano G, Guerrero-Martínez A, Núñez-Barriocanal JL, Montoro T, Tardajos G. Spectroscopic Characterization of the System β-Cyclodextrin + Propafenone Hydrochloride + Water. J Phys Chem B 2002. [DOI: 10.1021/jp013695e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- G. González-Gaitano
- Departamento de Química y Edafología (Sección de Química-Física), Universidad de Navarra, 31080, Pamplona, Navarra, Spain, Departamento de Química-Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain, and Cetedra de Føsica, EUIT Forestal, UPM Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - A. Guerrero-Martínez
- Departamento de Química y Edafología (Sección de Química-Física), Universidad de Navarra, 31080, Pamplona, Navarra, Spain, Departamento de Química-Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain, and Cetedra de Føsica, EUIT Forestal, UPM Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - J. L. Núñez-Barriocanal
- Departamento de Química y Edafología (Sección de Química-Física), Universidad de Navarra, 31080, Pamplona, Navarra, Spain, Departamento de Química-Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain, and Cetedra de Føsica, EUIT Forestal, UPM Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - T. Montoro
- Departamento de Química y Edafología (Sección de Química-Física), Universidad de Navarra, 31080, Pamplona, Navarra, Spain, Departamento de Química-Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain, and Cetedra de Føsica, EUIT Forestal, UPM Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - G. Tardajos
- Departamento de Química y Edafología (Sección de Química-Física), Universidad de Navarra, 31080, Pamplona, Navarra, Spain, Departamento de Química-Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain, and Cetedra de Føsica, EUIT Forestal, UPM Ciudad Universitaria s/n, 28040, Madrid, Spain
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1394
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Wimmer R, Aachmann FL, Larsen KL, Petersen SB. NMR diffusion as a novel tool for measuring the association constant between cyclodextrin and guest molecules. Carbohydr Res 2002; 337:841-9. [PMID: 11996838 DOI: 10.1016/s0008-6215(02)00066-6] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In this paper we introduce the use of diffusion measurements by nuclear magnetic resonance (NMR) spectroscopy for determining association constants of weak and very weak interactions between cyclodextrin and guest molecules, as long as both the free and complexed guest molecules are soluble to an extent that allows good sensitivity in the NMR experiment. The experimental setup and data analysis is discussed for three different guest molecules: L-phenylalanine, L-leucine and L-valine, representing different strengths of interaction. The underlying assumptions are discussed and the scope of the method (range of K(a) values, requirements to the guest molecule) are discussed. The method's main advantage is its general applicability independent of chromogenic or electrochemical properties of the guest molecule. Whereas calorimetric methods that exhibit a similar generality, are applicable mainly to strong interactions, NMR diffusion measurements are applicable to weaker interactions down to the theoretical limit of 1 M(-1), the upper limit for K(a) values to be determined by it is approximately 200. A further advantage of the method is the low amount of sample needed. The method is in principle applicable to any case of molecular recognition between a host and guest molecule leading to weak interactions.
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Affiliation(s)
- Reinhard Wimmer
- Department of Biotechnology, Institute of Life Sciences, Aalborg University, Sohngaardsholmsvej 49, Denmark.
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1395
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Avram L, Cohen Y. Complexation in pseudorotaxanes based on alpha-cyclodextrin and different alpha,omega-diaminoalkanes by NMR diffusion measurements. J Org Chem 2002; 67:2639-44. [PMID: 11950310 DOI: 10.1021/jo016321q] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The interactions of 1,4-diaminobutane (1), 1,6-diaminohexane (2), 1,8-diaminooctane (3), 1,10-diaminodecane (4), and 1,12-diaminododecane (5) with alpha-cyclodextrin (alpha-CD) were studied in aqueous solutions by NMR diffusion measurements before and after protonation. The correlation between the association constant and the length of the alkyl chain of the diamine unit was studied. The assumption that protonation on the amino groups can be used as a stopper and, as a result, to convert the pseudorotaxanes into rotaxanes was tested. In addition, other factors that can affect the pseudorotaxane stability, such as the effects of temperature, were tested. On the basis of these measurements, the following conclusions could be reached: (1) The association constant increases with the increase in the alkyl chain length. (2) For the salts (2b-5b), both in neutral and in acidic solutions, the binding constants increase as the number of CH(2) units increases. (3) The association constants of the complexes of the diaminoalkane salts and alpha-CD are lower than those of the corresponding neutral diaminoalkanes. (4) This difference between the binding constants of the diaminoalkanes and their respective salts decreases as the chain length increases. (5) By examining the effects of temperature on the (1)H NMR spectra, it was found that after addition of DCl the energy barrier for the threading-dethreading process of the salt of 5a is larger than that for the salt of 4a.
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Affiliation(s)
- Liat Avram
- School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv 69978, Tel Aviv, Israel
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1396
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Liu Y, Han BH, Chen YT. Molecular Recognition and Complexation Thermodynamics of Dye Guest Molecules by Modified Cyclodextrins and Calixarenesulfonates. J Phys Chem B 2002. [DOI: 10.1021/jp015603r] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yu Liu
- Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Bao-Hang Han
- Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Yun-Ti Chen
- Department of Chemistry, Nankai University, Tianjin 300071, China
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1397
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Carofiglio T, Fornasier R, Jicsinszky L, Saielli G, Tonellato U, Vetta R. Capillary Electrophoresis, ROESY NMR and Molecular Modelling Study of the Inclusion Complex β-Cyclodextrin/Lipoic Acid. European J Org Chem 2002. [DOI: 10.1002/1099-0690(200204)2002:7<1191::aid-ejoc1191>3.0.co;2-i] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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1398
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Buchanan CM, Alderson SR, Cleven CD, Dixon DW, Ivanyi R, Lambert JL, Lowman DW, Offerman RJ, Szejtli J, Szente L. Synthesis and characterization of water-soluble hydroxybutenyl cyclomaltooligosaccharides (cyclodextrins). Carbohydr Res 2002; 337:493-507. [PMID: 11890887 DOI: 10.1016/s0008-6215(01)00328-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We have examined the synthesis of hydroxybutenyl cyclomaltooligosaccharides (cyclodextrins) and the ability of these cyclodextrin ethers to form guest-host complexes with guest molecules. The hydroxybutenyl cyclodextrin ethers were prepared by a base-catalyzed reaction of 3,4-epoxy-1-butene with the parent cyclodextrins in an aqueous medium. Reaction byproducts were removed by nanofiltration before the hydroxybutenyl cyclodextrins were isolated by co-evaporation of water-EtOH. Hydroxybutenyl cyclodextrins containing no unsubstituted parent cyclodextrin typically have a degree of substitution of 2-4 and a molar substitution of 4-7. These hydroxybutenyl cyclodextrins are randomly substituted, amorphous solids. The hydroxybutenyl cyclodextrin ethers were found to be highly water soluble. Complexes of HBen-beta-CD with glibenclamide and ibuprofen were prepared and isolated. In both cases, the guest content of the complexes was large, and a significant increase in the solubility of the free drug was observed. Dissolution of the complexes in pH 1.4 water was very rapid, and significant increases in the solubility of the free drugs were observed. Significantly, after reaching equilibrium concentration, a decrease in the drug concentration over time was not observed.
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Affiliation(s)
- Charles M Buchanan
- Eastman Chemical Company, Research Laboratories, Kingsport, TN 37662, USA.
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1399
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Vargas-Berenguel A, Ortega-Caballero F, Santoyo-González F, García-López JJ, Giménez-Martínez JJ, García-Fuentes L, Ortiz-Salmerón E. Dendritic galactosides based on a beta-cyclodextrin core for the construction of site-specific molecular delivery systems: synthesis and molecular recognition studies. Chemistry 2002; 8:812-27. [PMID: 11857696 DOI: 10.1002/1521-3765(20020215)8:4<812::aid-chem812>3.0.co;2-p] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In order to evaluate the ability of multivalent glycosides based on a beta-cyclodextrin core as site-specific molecular carriers, a study on both the inclusion complexation behaviour and lectin binding affinity of branched and hyperbranched beta-cyclodextrins is presented. A series of cluster galactosides constructed on beta-cyclodextrin scaffolds containing seven 1-thio-beta-lactose or beta-lactosylamine bound to the macrocyclic core through different spacer arms were synthesised. In addition, the first synthesis of three first-order dendrimers based on a beta-cyclodextrin core containing fourteen 1-thio-beta-D-galactose, 1-thio-beta-lactose and 1-thio-beta-melibiose residues was performed. Calorimetric titrations performed at 25 degrees C in buffered aqueous solution (pH 7.4) gave the affinity constants and the thermodynamic parameters for the complex formation of these beta-cyclodextrin derivatives with guests sodium 8-anilino-1-naphthalenesulfonate (ANS) and 2-naphthalenesulfonate, and lectin from peanut (Arachis hypogaea) (PNA). The persubstitution of the primary face of the beta-cyclodextrin with saccharides led to a slight increase of the binding constant values for the inclusion complexation with ANS relative to the native beta-cyclodextrin. However, the increase of the steric congestion due to the presence of the saccharide residues on the narrow rim of the beta-cyclodextrin may cause a decrease of the binding ability as shown for sodium 2-naphthalenesulfonate. The spacer arms are not passive elements and influence the host binding ability according to their chemical nature. PNA forms soluble cross-linked complexes with cluster galactosides and lactosides scaffolded on beta-cyclodextrin but not with cluster galactopyranosylamines or melibiose. Both, perbranched and hyperbranched beta-cyclodextrins, form stronger complexes with PNA than the monomeric analogues. However, the use of hyperbranched CDs does not contribute to the improvement of the complex stability relative to heptakis-glycocyclodextrin derivatives. Finally, a titration experiment with PNA and a complex formed by a heptakis lactose beta-cyclodextrin derivative with sodium 2-naphthalenesulfonate showed the formation of a soluble cross-linked complex with stronger affinity constant and higher stoichiometry than those observed for the complex formation of PNA with the same heptakis-lactose beta-cyclodextrin derivative, suggesting the formation of a three component complex.
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Aoki S, Shiro M, Kimura E. A cuboctahedral supramolecular capsule by 4:4 self-assembly of Tris(Zn(II)-cyclen) and trianionic trithiocyanurate in aqueous solution at neutral pH (cyclen=1,4,7,10-tetraazacyclododecane). Chemistry 2002; 8:929-939. [PMID: 11857707 DOI: 10.1002/1521-3765(20020215)8:4%3c929::aid-chem929%3e3.0.co;2-q] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A 1:1 mixture of a tris(Zn(II)-cyclen) (1: [Zn(3)L(1)], L(1)=1,3,5-tris(1,4,7,10-tetraazacyclododecan-1-ylmethyl)benzene) and trithiocyanuric acid (TCA) yielded a 4:4 self-assembly complex [(Zn(3)L(1))(4)-(TCA(3-))(4)] (6) through the formation of Zn(II)-S(-) coordination bonds and hydrogen bonds between 1,3,5-triazine N and cyclen NH (cyclen=1,4,7,10-tetraazacyclododecane); the supramolecular capsule structure was revealed by X-ray crystal structure analysis. The capsule exterior represents a twisted cuboctahedral framework containing a nanoscale truncated tetrahedral cavity. The crystal data: formula C(144)H(308)N(72)O(58)S(12)Zn(12) (6[NO(3)](12) x 22 H(2)O), M(r)=5145.75, cubic, space group F432 (No. 209), a=39.182(1) A, V=60153(3) A (3), Z=8, R=0.100, R(w)=0.259. Lipophilic organic molecules with the matching sizes, for example, ([D(4)]-2,2,3,3)-3-(trimethylsilyl)propionic acid (TSP), 1-adamantanecarboxylic acid, 2,4-dinitrophenol (2,4-DNP), adamantane (ADM), or the tetra-n-propylammonium (TPA) cation, are encapsulated in the inner cavity, as revealed by remarkable upfield shifts of the (1)H NMR signals of these guest molecules. The encapsulation of ADM was confirmed by X-ray crystal structure analysis. Crystal data of the ADM-encapsulating complex: formula C(154)H(334)N(72)O(63)S(12)Zn(12) (6-ADM[NO(3)](12) x 27 H(2)O), M(r)=5372.06, cubic, space group F432 (No. 209), a=39.061(1) A, V=59599(3) A(3), Z=8, R=0.103, R(w)=0.263. The 4:4 self-assembly was stabilized by incorporation of one of these guest molecules. The apparent 4:4 self-assembly constants for 6 in the presence of an excess amount of a guest TPA, log K(app) (K(app)=[6-TPA]/[1](4)[TCA](4)) (M(-7))), were determined to be 34.0+/-2.0 and 35.5+/-3.0 by potentiometric pH and UV spectrophotometric titrations, respectively. An apparent encapsulation constant for 2,4-DNP, log K(enc) (K(enc)=[6-2,4-DNP]/[6][2,4-DNP] (M(-1))), was 6.0+/-0.1 at pH 7.0 (50 mM HEPES with I=0.1 (NaNO(3))), as determined by UV titrations. The lipophilicity of the inner cavity was close to that of 2-propanol, as a quantum yield (phi) of 0.24+/-0.1 for the fluorescent emission of 7-diethylaminocoumarin-1-carboxylic acid (20 microM) in the capsule was close to the phi of 0.22 found for 2-propanol. Encapsulation properties of the present Zn(II)-containing cage have been compared with those of cyclodextrins and Fujita's Pd(II)-containing supramolecular cage. The exterior chirality of the 4:4 complex was controlled from within by an encapsulated chiral guest molecule, 2,10-camphorsultam, as indicated by Cotton effects in the circular dichroism spectra.
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Affiliation(s)
- Shin Aoki
- Department of Medicinal Chemistry Faculty of Medicine, Hiroshima University Kasumi 1-2-3, Minami-ku, Hiroshima, 734-8551, Japan
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