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PubMed2004

Characterization of aqueous and solid inclusion complexes of diuron and isoproturon with beta-cyclodextrin.

The interaction of diuron and isoproturon herbicides with beta-cyclodextrin is conducive to the formation of inclusion compounds in aqueous solution as well as in the solid state. The physico-chemical study of these complexes was carried out by various analytical techniques such as ultraviolet (UV), Fourier transform infrared (FT-IR), Raman, X-ray diffraction, and 1H-NMR (nuclear magnetic resonance) spectroscopies. The existence of inclusion complexes in water solution between the beta-cyclodextrin and each of the herbicides was revealed by electronic absorption and 1H-NMR spectroscopies. A 1:1 stoichiometry was determined for both complexes in aqueous medium from UV absorption spectra by using the Benesi-Hildebrand method; the relative stability constants at room temperature were calculated at 2700 +/- 300 L mol(-1) and 750 +/- 50 L mol(-1) for isoproturon and diuron, respectively. In the solid state, inclusion processes with beta-cyclodextrin were characterized by means of infrared and Raman techniques and confirmed by X-ray diffraction spectra.

Cyclodextrins↗
PubMed2000

Unexpected activity of beta-cyclodextrin against experimental infection by Cryptosporidium parvum.

An unexpected activity of beta-cyclodextrin, an excipient used in pharmaceutical technology, was observed against Cryptosporidium parvum. The viability and infectivity of purified oocysts, exposed for 24 hr to beta-cyclodextrin (2.5% suspension), were evaluated by inclusion/exclusion of 2 fluorogenic vital dyes and a suckling murine model, respectively. Results of the viability assay showed a high proportion of nonviable oocysts (81.5%). The intensity of experimental infection, determined 7 days postinoculation by examination of intestinal homogenates, was significantly lower (P < 0.05) than in the control litters. The preventive and curative efficacies of beta-cyclodextrin suspension were also evaluated in experimentally infected neonatal mice. Infection was prevented when the suspension was administered 2 hr before inoculated oocysts and on days 1 and 2 postinoculation.

Animals↗
PubMed2004

Evaluation of hydroxypropyl-beta-cyclodextrin in the treatment of aldicarb poisoning in rats.

Cyclodextrins are ring-shaped oligosaccharides with a hydrophilic exterior and a hydrophobic interior. The interior cavity is capable of complexing fat-soluble molecules small enough to fit inside. Sprague-Dawley rats were used to evaluate the efficacy of hydroxypropyl-beta-cyclodextrin as treatment of aldicarb poisoning in rats. Survival times in the majority of rats dosed with aldicarb and receiving intravenous cyclodextrin were longer compared with the control rats only dosed with aldicarb per os.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMedDate not supplied

Inclusion of piroxicam into beta-cyclodextrin by means of supercritical carbon dioxide: thermal, spectroscopic and physicochemical studies.

The preparation of a piroxicam-beta-cyclodextrin inclusion compound using supercritical CO2 was investigated. The solubility piroxicam in supercritical CO2 was determined. The influence of the temperature, the pressure and the time of exposure on the inclusion rate were studied and a complete inclusion was achieved by keeping a physical mixture of piroxicam and beta-cyclodextrin (1:2.5 mol/mol) for 6 hours at 150 degrees C and 150 bar of CO2. This complex was characterised by Differential Scanning Calorimetry and Fourier Transform Infrared Spectrometry. Supercritical carbon dioxide may prove to be a novel useful complexation method of non-polar drugs into beta-cyclodextrin.

Carbon Dioxide↗
PubMed2000

Enhancement of selectivity for producing gamma-cyclodextrin.

The production of cyclodextrins (CDs) by cyclodextrin-glycosyl-transferase (CGTase) from Bacillus firmus was studied, with respect to the effect of the source of starch upon CD yield and on the selectivity for producing gamma-CD. Cyclodextrin production tests were run for 24 h at 50 degrees C, pH 8.0, and 1 mg/L of CGTase, and substrates were maltodextrin or the starches of rice, potato, cassava, and corn hydrolyzed up to D.E. 10. Cornstarch was the best substrate for producing gamma-CD. Later, glycyrrhizin (2.5% [w/v]), which forms a stable complex with gamma-CD, was added to the cornstarch reaction medium and increased the yield of gamma-CD to about four times that produced with only maltodextrin, but the total yield of CDs remained practically unchanged. Therefore, the results showed that the studied CGTase is capable of giving relatively high yield of gamma-CD in the presence of glycyrrhizin as complexant and cornstarch as substrate.

Bacillus↗
PubMed2000

[Preparation of gas chromatographic capillary columns with beta-cyclodextrin polymer stationary phase modified with methyl phenyl silicone(OV-17)].

An insoluble beta-cyclodextrin polymer cross-linked with epichlorohydrin was prepared. beta-Cyclodextrin polymer (0.26 g) was treated for 0.5 h by a ultrasonator in the mixed solvent (10 mL) of isopropyl ether, methylene dichloride and benzene with a volume ratio 2:1:2, and a 26 g/L colloidal stationary liquid was prepared. It was coated on a fused silica capillary by superdynamic coating method. The capillary column was of high column efficiency of above 3,000/m with good thermal stability and moderate polarity. Enantiomers of xylene, dichlorobenzene, alpha-pinene, beta-pinene, ethyl lactate, alpha-phenyl ethanol, 1, 2-propanediol, alpha-lonone, methyl alpha-chloropropionate and gamma-valerolactone were separated on the capillary column. The experimental results showed that beta-cyclodextrin polymer treated by a ultrasonator is a capillary chromatographic stationary phase with good performance and high selectivity.

Chromatography, Gas↗
PubMed2000

[Preparation and evaluation of glycine derivatized beta-cyclodextrin bonded silica for high performance liquid chromatography].

Glycine derivatized beta-cyclodextrin bonded silica (GCDS) has been prepared for high performance liquid chromatography through the reactions of beta-cyclodextrin bonded silica with tosyl chloride and glycine in sequence. The separation performance of GCDS for positional isomers, dansyl amino acids and phenylpropionic acids was investigated. It was found that nitrophenols could not be eluted with methanol as mobile phase, but could be eluted with methanol-phosphate buffer solution within appropriate time, which was much different from the behavior observed on native beta-cyclodextrin bonded silica. The effect of column temperature on the enantio-separation of dansyl D,L-Phe with GCDS was examined. The results show that the enantio-separation ability of the GCDS decreases with the increase of the column temperature. Other factors such as methanol concentration and pH of the mobile phase influencing the retention behavior of solutes on the GCDS are also discussed.

Amino Acids↗
PubMed2000

[The UV-Vis spectrographic and electrochemical study on the beta-cyclodextrin inclusion compound of 3,3',5,5'-tetramethylbenzidine].

This paper reports the results of UV-Vis spectrographic and electrochemical studying on the beta-cyclodextrin inclusion compound of 3,3',5,5'-tetramethylbenzidine (TMB). The molecules of TMB show better redox performance after they were included in the cavities of beta-cyclodextrin, especially while there were the redox enzyme. The composition of oxidization product in the inclusion compound is more single. The results were also revealed by the obviously increasing of voltammetrical current when this inclusion compound was modified on the electrode surface. It is reasonable to conclude that the formation of TMB-beta-cyclodextrin inclusion compound would enhance the sensitivity of those analytical methods based on the redox reaction of TMB.

Benzidines↗
PubMed2003

[Study on stability of beta-cyclodextrin to chlorogenic acid].

To investigate the stabilizing effect of chlorogenic acid against beta-cyclodextrin, beta-cyclodextrin inclusion compound of chlorogenic acid was prepared by liquid phase method, and affirmed by UV and different thermal analysis. Stability in solution was contrasted between chlorogenic acid and its inclusion complex with beta-cyclodextrin, and the stability of the latter was increased.

Chlorogenic Acid↗
PubMed2004

Evaluation of apparent formation constants of pentacyclic triterpene acids complexes with derivatized beta- and gamma-cyclodextrins by reversed phase liquid chromatography.

A reversed phase HPLC method has been investigated in order to resolve three main pentacyclic triterpene acids (oleanolic-, betulinic- and ursolic acid) found in a lot of plants. Some of them (oleanolic and ursolic acids) are position isomers and their resolution is highly improved by the addition of derivatized cyclodextrins in mobile phase. The formation of 1:1 inclusion complexes was assumed. Apparent formation constants of triterpene acids with DM-beta-CD and HP-gamma-CD were determined by HPLC method. Experimental results confirmed the complexation model and explained the modification of elution order according to the type of cyclodextrin added to the mobile phase. The influence of mobile phase organic modifier on apparent formation constants was also investigated. Results proved the competition between cyclodextrins hydrophobic cavity and organic solvent towards triterpene acids affinity.

Chromatography, High Pressure Liquid↗
PubMed2005

[Preparation, identification and inclusion actions of irisquinone hydroxypropyl-beta-cyclodextrin inclusion complex].

AIM: To perpare and identify irisquinone hydroxypropyl-beta-cyclodextrin inclusion complex (irisquinone-HP-beta-CD), as well as to study the inclusion mechanism and molecule stoichiometry between irisquinone and hydroxypropyl-beta-cyclodextrin. METHODS: Irisquinone-HP-beta-CD was prepared by freeze-drying technique. The ratio of host and guest was also studied in inclusion process by mol gradient and continuing variational methods. At the same time, the inclusion complex was identified by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). RESULTS: It was demonstrated that the solubility of irisquinone was enhanced markedly by inclusion with HP-beta-CD when stoichiometry was 2:1 of host and guest at 25 degrees C, 35 degrees C and 45 degrees C. CONCLUSION: The solubility and stability of irisquinone could be increased by preparing the inclusion complex with hydroxypropyl-beta-cyclodextrin.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed2005

[Solubilization on cryptotanshinone by hydroxypropyl-beta-cyclodextrin and preparation of their inclusion compound].

OBJECTIVE: To prepare cryptotanshinone (CT)-cyclodextrin inclusion compound and improve dissolution of CT. METHOD: Inclusion ratio was determined by plotting the phase solubility curve of CT versus hydroxypropyl-beta-cyclodextrin (HPCD). CT-cyclodextrin inclusion compound was made by wet grinding method. Properties of the inclusion compound was investigated by in vitro dissolution test, DTA and IR spectrum. RESULT: Inclusion ratio of CT versus HPCD was 1:1. Dissolution of CT-HPCD inclusion compound at 45 min was 21.6 times of material drug. CONCLUSION: Dissolution of CT was improved remarkably in CT-HPCD inclusion compound. The complexation force of the inclusion compound was hydrogen bond formed by carbonyl group of CT and hydroxyl group of HPCD.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1990

Effect of diethyl-beta-cyclodextrin on the release of nitroglycerin from formulations.

The complex-forming abilities of 2,6-di-O-ethyl-beta-cyclodextrin (DE-beta-CD), and its effect on the release of nitroglycerin (TNG) from formulations of the compound, were studied and compared with corresponding properties of beta-cyclodextrin (beta-CD) and 2,6-di-O-methyl-beta-cyclodextrin (DM-beta-CD). Complex formation was confirmed by differential scanning calorimetry and infrared absorption spectroscopy. In an accelerator test involving temperature and reduced pressure, marked depression of the volatility of TNG was observed as a result of CD complex formation. Dissolution rates of TNG from powdery TNG/DE-beta-CD complex and its tablets were retarded in comparison with the rates from other CD complexes. The release rate of TNG from ointments was accelerated by complexation with DE-beta-CD, and retarded by complexation with beta-CD. To evaluate their in vivo percutaneous absorption, samples were applied to the inside tip of the cheek pouch of male golden hamsters. The amount of TNG remaining in the cheek pouch was lowest in the case of the TNG/DE-beta-CD complex ointment, and relatively high in the case of the TNG/beta-CD complex ointment, in agreement with the in vitro results. We suggest that the combination of DE-beta-CD complex and beta-CD complex might be applicable to sustained-release preparations for percutaneous administration.

Animals↗
PubMedDate not supplied

Beta-cyclodextrin post-column fluorescence enhancement of aflatoxins for reverse-phase liquid chromatographic determination in corn.

beta-Cyclodextrin enhances the fluorescence of aflatoxins B1 and G1 in aqueous systems. This effect was utilized in developing a unique reverse-phase liquid chromatographic (LC) method for determination of aflatoxins B1, B2, G1, and G2 (B1 detection limit 1 ppb), without preparing derivatives of B1 and G1. The aflatoxins are dissolved in methanol or the mobile phase for injection onto the LC system. Using a mobile phase of methanol-beta-cyclodextrin (1 + 1), the aflatoxins are resolved on a C18 column. Fluorescence of the aflatoxins is enhanced by post-column introduction of an aqueous concentrated beta-cyclodextrin solution. All 4 aflatoxins elute within 10 min in the order G2, G1, B2, B1. Fluorescence responses for B1 and G1 standards were linear over the concentration range 0.5-10 ng, yielding correlation coefficients (r) of 0.9989 and 1.000, respectively. The average peak response ratio for G1:B1 for the mobile phase-enhancement solution described was 0.765 with a coefficient of variation (CV) of 0.98%. CVs were 6.2, 9.0, and 7.5% for multiple assays of aflatoxin B1 in 3 samples of naturally contaminated corn. For samples of corn spiked to a total B1 content of 8.3 ng/g, average B1 recovery was 90% (CV 11.7%).

Aflatoxin B1↗
PubMed1983

Preparation, properties and biological activity of beta-cyclodextrin inclusion complex of menadione.

The molar ratio of menadione (vitamin K3) to beta-cyclodextrin in the microcrystalline inclusion complex showed this to be 1:3 with a menadione content of approximately 4.1-4.3%. Complexes with higher vitamin content could not be prepared. Bound and free vitamin can be readily separated by sublimation in vacuum. The menadione is highly stable in complexed form; in dry state it is released only when cyclodextrin is destroyed by heating to about 300 degrees C. Complexed menadione does not react with amino acids. Solubility and dissolution rate are strongly increased. Treating hypovitaminotic chickens with equivalent doses of menadione or menadione-beta-cyclodextrin complex and monitoring blood clotting times, recalcification times and prothrombin times the complex proved to be at least as effective as--or even somewhat more potent than--free vitamin. 1.5-2.0 micrograms/animal/d free or complexed menadione was sufficient to cover the daily vitamin K needs of chickens.

Animals↗
PubMed1983

Effect of cyclodextrins on the solubilization of lignoceric acid, ceramide, and cerebroside, and on the enzymatic reactions involving these compounds.

alpha-Cyclodextrin at concentrations of 1-8 mM helps dissolve, in aqueous solution, fatty acids such as lignoceric, stearic, and palmitic, and complex lipids such as ceramide and cerebroside that contain these acids. Formation of an inclusion complex was indicated on examination of the solution by gel filtration. alpha-Cyclodextrin strikingly increased synthesis of ceramide from sphingosine and either free lignoceric or stearic acid by rat brain preparations. These results suggest the further use of alpha-cyclodextrin in lipid enzymology, especially in relation to sphingolipid metabolism.

Animals↗
PubMed1994

Evaluation of piroxicam-beta-cyclodextrin, piroxicam, paracetamol and placebo in post-operative oral surgery pain.

Two hundred ninety-eight patients with post-operative pain after the surgical removal of an impacted third molar were randomly assigned, on a double-blind basis, to receive a single oral dose of piroxicam 20 mg, or piroxicam-beta-cyclodextrin equivalent to 20 mg piroxicam, or paracetamol 500 mg, or placebo. Using a semi-quantitative self-rating scale, patients rated their pain and its relief at 30-min intervals for the first 2 h, and then hourly for 4 h after treatment administration. All active medications were reported to be significantly superior to placebo. The three active drugs were comparable for the degree of analgesia up to the third hour, after which the effect of paracetamol decreased significantly as compared to piroxicam-beta-cyclodextrin and piroxicam. Piroxicam-beta-cyclodextrin and paracetamol were more rapid than piroxicam in inducing analgesia. The tolerability for the active drugs was comparable to that for placebo.

Acetaminophen↗