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PubMedDate not supplied

Tramadol and beta-cyclodextrin piroxicam: effective multimodal balanced analgesia for the intra- and postoperative period.

BACKGROUND AND OBJECTIVES: This study was conducted to evaluate the analgesic efficacy of tramadol, an analgesic with both opioid and nonopioid actions (norepinephrine and serotonin pathways), with beta-cyclodextrin piroxicam, a nonsteroidal antiinflammatory drug, in the perioperative setting. METHODS: The study population consisted of 48 patients scheduled for minor abdominal procedures, who were assigned to one of four groups of 12 patients each. The premedication was either a placebo tablet or a 192.1-mg beta-cyclodextrin piroxicam tablet, administered orally 30-40 minutes before anesthesia induction. After intravenous administration of tramadol 1.5 mg/kg, anesthesia was induced with an intravenous loading dose of propofol. Anesthesia was maintained an intravenous infusion of propofol at 6-12 mg/kg/h plus either saline or tramadol at 1.2 mg/kg/h, atracurium, and a 2:1 nitrous oxide-oxygen mixture. The control group received a placebo tablet and an infusion of saline with propofol for anesthesia maintenance; the tramadol group received a placebo tablet and a continuous tramadol-propofol infusion; the beta-cyclodextrin piroxicam (BCP) group received a BCP tablet and a continuous saline-propofol infusion; and the beta-cyclodextrin piroxicam-tramadol (BCPT) group received beta-cyclodextrin piroxicam and a continuous tramadol-propofol infusion. RESULTS: The relative propofol consumption by the four groups was control = BCP (P > .05) >tramadol (P < .001) > B-CPT (P < .0002). The time for analgesic rescue decreased in the order BCPT > BCP (P < .0002) = tramadol > control (P < .001). The degree of sedation and the visual analog scores 10-cm scale at the time patients requested rescue analgesics were similar among the groups (P > .05). CONCLUSIONS: The combination of tramadol and beta-cyclodextrin piroxicam provided better perioperative analgesia than tramadol alone.

Abdomen↗
PubMed2003

Rayleigh light scattering study on the supramolecular interactions of beta-cyclodextrin derivatives with tetrakis(4-methoxylphenyl)porphyrin.

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.

Cyclodextrins↗
PubMed1998

Comparison of the effects of potential parenteral vehicles for poorly water soluble anticancer drugs (organic cosolvents and cyclodextrin solutions) on cultured endothelial cells (HUV-EC).

The effect of dilution of parenteral vehicles (organic cosolvent and 0.1 M cyclodextrin solutions) on cultured endothelial cells (HUV-EC) were compared in vitro. Cell morphology was observed by phase contrast light microscopy and cell viability by measuring 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) reduction or intracellular lactate dehydrogenase (LDH) activity and total protein. Disruption of the HUV-EC monolayer was observed at dilutions of 1 in 20 for the melphalan and PEP cosolvents, 1 in 100 for an investigational drug cosolvent, and 1 in 10 for 0.1 M dimethyl-beta-cyclodextrin. In comparison, 0.1 M SBE7M- and HP-beta-cyclodextrin caused only minor disruption at a 1 in 5 dilution. MTT reduction, intracellular LDH, and total protein were decreased following exposure to 1 in 10 dilution of the melphalan cosolvent. For other test solutions, intracellular LDH activity and total protein were measured, and reductions were observed following exposure to 1 in 10, 20, and 50 dilutions of the investigational drug cosolvent and 1 in 5 dilution of DM-beta-cyclodextrin (0.1 M). At a dilution of 1 in 10, no delayed toxicity was observed for cosolvents or cyclodextrin solutions. Hence, 0.1 M SBE7M- or HP-beta-cyclodextrin formulations may be less damaging to the venous endothelium at the site of injection than organic cosolvent formulations.

Antineoplastic Agents↗
PubMed1995

Crystallographic studies of the interaction of cyclodextrin glycosyltransferase from Bacillus circulans strain 251 with natural substrates and products.

Asp-229, Glu-257, and Asp-328 constitute the catalytic residues in cyclodextrin glycosyl transferase from Bacillus circulans strain 251. Via site-directed mutagenesis constructed D229N, E257Q, and D328N mutant proteins showed a 4,000-60,000-fold reduction of cyclization activity. A D229N/E257Q double mutant showed a 700,000-fold reduction and was crystallized for use in soaking experiments with alpha-cyclodextrin. Crystal structures were determined of wild type CGTase soaked at elevated pH with alpha-cyclodextrin (resolution, 2.1 A) and maltoheptaose (2.4 A). In addition, structures at cryogenic temperature were solved of the unliganded enzyme (2.2 A) and of the D229N/E257Q mutant after soaking with alpha-cyclodextrin (2.6 A). In the crystals soaked in alpha-cyclodextrin and maltoheptaose, a maltotetraose molecule is observed to bind in the active site. Residue 229 is at hydrogen bonding distance from the C-6 hydroxyl group of the sugar, which after cleavage will contain the new reducing end. In the D229N/E257Q double mutant structure, two alpha-cyclodextrins are observed to replace two maltoses at the E-domain, thus providing structural information on product inhibition via binding to the enzyme's raw starch binding domain.

Bacillus↗
PubMed1998

Enhancement of bioavailability of griseofulvin by its complexation with beta-cyclodextrin.

Griseofulvin is a poorly soluble antifungal antibiotic drug, the solubility of which can be enhanced by complexation with beta-cyclodextrin. The inclusion complex was prepared by coprecipitation method in various molar ratios of 1:1, 2:1, 3:1, and 1:2 of the drug and beta-cyclodextrin, respectively. The inclusion complex was characterized and evaluated by UV-VIS spectral studies and FTIR. The in vitro drug release studies indicated that the 1:2 molar ratio complex form of the drug significantly increased the dissolution rate when compared to the free form. The acute toxicity studies clearly indicated that the beta-cyclodextrin complex was nontoxic and the safety range was close to other Griseofulvin formulations. The in vivo study of the beta-cyclodextrin was carried out in both animals and human beings by administering in four different rabbits and volunteers, respectively. Pellets made with Griseofulvin-beta-cyclodextrin complex also showed a significant increase in the dissolution of the drug, revealing that beta-cyclodextrin plays an important role in the solubilization of Griseofulvin.

Animals↗
PubMed1999

Comparison of the capacity of beta-cyclodextrin derivatives and cyclophanes to shuttle cholesterol between cells and serum lipoproteins.

Previous studies from this laboratory have demonstrated that low concentrations of cyclodextrins (<1.0 mm), when added to serum, act catalytically as cholesterol shuttles to accelerate the exchange of free cholesterol between cells and serum lipoproteins. As cholesterol shuttles, cyclodextrins have the potential to serve as pharmacological agents for modifying cholesterol metabolism. In the present study, we have quantitated the cholesterol-shuttling capacity of a series of newly synthesized beta-cyclodextrin derivatives (betaCDs), with varying structure, and two double-decker cyclophanes. The general protocol is as follows. [(3)H]cholesterol-labeled CHOK1 cells are incubated for 2 h with the test compounds alone or together with 5% human serum, and efflux of the cellular [(3)H]cholesterol is measured. As methyl beta-cyclodextrin (MbetaCD) served as the basis for comparison, initial experiments were conducted that demonstrated there was a dose-dependent stimulation of cell cholesterol efflux as the concentration of MbetaCD increased, with an EC(50) that was calculated to be 0.05 mm. To determine the cholesterol-shuttling capacity of the newly synthesized compounds, cell cholesterol efflux is measured when the compounds are present alone, at a concentration of 0.05 mm, or together with 5% human serum. Our results demonstrate that the double-decker cyclophanes are the most efficient cholesterol shuttles. Under our experimental conditions, methyl beta-cyclodextrin (MbetaCD) approximately doubles the efflux of cell cholesterol to serum, whereas one of the double-decker cyclophanes produces a 4-fold stimulation in efflux. Four of the beta-cyclodextrin derivatives (betaCDs) display shuttling ability similar to that of MbetaCD. Furthermore, there does not appear to be a structural pattern among the other betaCDs which could explain their shuttling capacity.

Animals↗
PubMed2001

Treatment of Raynaud's phenomenon with intravenous prostaglandin E1alpha-cyclodextrin improves endothelial cell injury in systemic sclerosis.

OBJECTIVE: To evaluate the efficacy and safety of prostaglandin (PG) E1alpha-cyclodextrin for Raynaud's phenomenon (RP) secondary to systemic sclerosis (SSc) and its effect on variables of immune activation and endothelial injury in SSc such as tumor necrosis factor-alpha (TNF-alpha), soluble interleukin 2 receptor (sIL-2R), circulating intercellular adhesion molecule-1 (cICAM-1), von Willebrand factor (vWF), and tissue-type plasminogen activator (t-PA). METHODS: We studied 36 women with SSc, 24 of them given three 60 microg intravenous PGE1alpha-cyclodextrin infusions on 5 consecutive days at 6 week intervals during the winter. RP symptoms and healing of digital lesions were evaluated. Twenty age matched healthy women were the controls. TNF-alpha, sIL-2R, cICAM-1, vWF, and t-PA were measured after the first and last infusion of PGEE1alpha-cyclodextrin and correlated with clinical features. RESULTS: RP symptoms improved in 87% of the patients. The benefit of each 5 day cycle lasted 4 or more weeks in 75%. PGE1alpha-cyclodextrin reduced the daily frequency of RP symptoms by 20% (p < 0.05), 41% (p < 0.005), and 53% (p < 0.0005) from baseline after the 1st, 2nd, and 3rd infusions, respectively. The severity of the attacks was reduced to a limited degree. In 12 of the 14 patients with digital lesions, these healed completely. Ten patients had mild side effects during treatment (headache, increased intestinal motility, flushing). TNF-alpha, sIL-2R, cICAM-1, vWF, and t-PA plasma concentrations were significantly higher in patients with SSc than controls (p < 0.05, p < 0.001). TNF-alpha, sIL-2R, and cICAM-1 were higher in diffuse SSc and patients with lung involvement. The plasma levels of cICAM-1 and t-PA were significantly reduced after the 1st infusion of PGE1alpha-cyclodextrin (both p < 0.005) and further reduced after the last (p < 0.0005 and p < 0.005). CONCLUSION: PGE1alpha-cyclodextrin reduces RP symptoms and plasma levels of the markers of endothelial injury in SSc, suggesting that an improvement of endothelial dysfunction contributes to its prolonged therapeutic effect.

Adult↗
PubMed1992

The angiogenesis inhibitor beta-cyclodextrin tetradecasulfate inhibits ecto-protein kinase activity.

The growth of new blood vessels plays an important role in the pathogenesis of several diseases including cancer, diabetes, and arthritis. Beta-cyclodextrin tetradecasulfate, when administered with an appropriate steroid inhibits angiogenesis, and can stimulate angiogenesis when given alone. The regulation of angiogenesis is not well understood, and the mechanism of action of beta-cyclodextrin tetradecasulfate is similarly not well defined. Ecto-protein kinase activity that utilizes extracellular ATP has recently been reported on several types of cells. Human neutrophils appear to possess two distinct ecto-protein kinase activities; one that phosphorylates exogenous substrates including vitronectin and basic fibroblast growth factor, and one that phosphorylates endogenous cell-surface proteins. This report shows that beta-cyclodextrin tetradecasulfate inhibits the phosphorylation of the exogenous substrates casein, vitronectin (the major ecto-protein kinase substrate in serum), and basic fibroblast growth factor by human neutrophil ecto-protein kinase activity. In contrast, beta-cyclodextrin tetradecasulfate had no effect on the phosphorylation of endogenous cell-surface proteins by the neutrophil ecto-protein kinase activity. Ecto-protein kinase activity that was inhibited by beta-cyclodextrin tetradecasulfate was also detected on porcine aortic and human umbilical vein endothelial cells. The effects of beta-cyclodextrin tetradecasulfate on ecto-protein kinase activities may play a role in its effects on angiogenesis.

Caseins↗
PubMed2004

Cyclodextrines as functional agents for decontamination of the skin contaminated by nerve agents.

Three decontamination solutions of beta-cyclodextrines were prepared. Their abilities to decontamine rat skin contamined with nerve agent soman were tested. Decontamination efficacy of the tested cyclodextrine solutions was compared with the same decontamination means but without the cyclodextrines. The efficacy of tested decontaminants was evaluated by the assessment of the ID50 values. Two decontamination prescriptions with cyclodextrines (tetraborate buffer and tetraborate buffer with acetone) do not show significantly better decontamination efficacies in comparison with prescriptions without cyclodextrines. Only in case of aqueous solution of 2-aminoethanol the addition of beta-cyclodextrine resulted in significant increase (32%) in decontamination efficacy.

Animals↗
PubMed1990

Effect of beta-cyclodextrin on the in vitro permeation rate and in vivo rectal absorption of acetaminophen hydrogel preparations.

The amounts of beta-cyclodextrin and hydroxyl propyl methyl cellulose (HPMC) affecting the in vitro permeation rate of acetaminophen containing in both aqueous solutions and HPMC hydrogel preparations through the dialyzer tubing and isolated rat rectum were investigated. The partition coefficient of acetaminophen with or without beta-cyclodextrin in water/n-octanol system was also studied. In vivo absorption experiments of these test formulations were carried out by rectal administration in rats. The results indicate that the concentrations of beta-cyclodextrin and HPMC used decreased the amount permeated of acetaminophen from both test formulations. The more the amount of beta-cyclodextrin or HPMC the slower the permeation rate of acetaminophen. The permeation rate of acetaminophen through the dialyzer tubing was higher than that of acetaminophen through the isolated rat rectum. The result also shows beta-cyclodextrin and HPMC markedly reduced the in vivo bioavailability of acetaminophen from both test formulations. The lower partition coefficient and the higher hydrophilic properties of beta-cyclodextrin inclusion complex, and the higher viscosity of HPMC hydrogel matrix might be responsible for decreasing the in vitro permeation rate and depression of in vivo rectal absorption of acetaminophen. The in vitro permeation data was well correlated with in vivo absorption results, suggesting that the in vitro permeation study regardless of the dialyzer tubing method or the isolated rat rectum method might be used to estimate the in vivo rectal absorption of acetaminophen.

Acetaminophen↗
PubMedDate not supplied

The effect of beta-cyclodextrins as buffer additives on the (capillary) electrophoretic separation of peptides and proteins.

Electrophoretic and chromatographic experiments performed under straightforward conditions do not always provide satisfactory resolution. An obvious approach, then, is to manipulate the magnitude of relevant separation parameters, such as charge (zeta potential), size, and hydrophobicity, all of which can be accomplished by complex formation. This alternative has been studied with both a neutral, an anionic, and a cationic derivative of beta-cyclodextrin in an attempt to increase the resolution of peptides and proteins in free-zone electrophoresis utilizing the capillary format. The investigation showed that charged beta-cyclodextrins are suitable for this purpose. As expected, the effect seems to be most significant for substances with a small net surface charge, i.e., low mobility. Consequently, it may be advantageous to choose a pH of the buffer that is not far from the isoelectric point of the solutes. It should be emphasized that changes in the electropherograms observed upon addition of any complexing agent to the buffer may involve improvement or worsening of the resolution. Only by experimentation can one determine whether complexation with cyclodextrins favors resolution, since our knowledge about the interactions taking place is limited. However, if a positively (negatively) charged beta-cyclodextrin decreases the resolution of an acidic (basic) protein, one can expect theoretically, a negatively (positively) charged beta-cyclodextrin to increase the resolution, as was verified experimentally. The difference in mobility between two peaks caused by the complexation with cyclodextrins need not be larger than 2-3% for satisfactory resolution because the peaks are sharp. We have introduced a new definition for the resolution of two very adjacent peaks--the most common and interesting case in real-world analyses--that does not require measurement of peak widths.

Amino Acids↗
PubMed2004

Comparative study on the inclusion behaviour of cyclodextrin derivatives with venoruton and rutin by thin layer chromatography.

The interaction of rutin and venoruton (troxerutin), with alpha-, beta- and gamma-cyclodextrin (CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and methyl-beta-cyclodextrin (M-beta-CD) was investigated by reversed-phase thin layer chromatography on polyamide plates. A mobile phase consisted of NH(4)OH; NH(4)Cl buffer solution containing various CD concentrations (pH = 9.7, 20 degrees C) was used as mobile phase. The equilibrium constants (K(f)) and the retention factor (R(f)) were determined and used to study the inclusion process. The in fluence of CDs on the solubility of rutin and venoruton was characterized by R(M) values and the increasing hydrophilicity of drugs. The results show that the inclusion capacity of cyclodextrins follows the order HP-beta-CD > M-beta-CD > beta-CD > gamma-CD, and rutin is more easily included by the studied cyclodextrins than venoruton. In addition, the thermodynamic parameters (Delta H, Delta S) for the formation of complexes were obtained from the van't Hoff equation, displaying the enthalpy-entropy compensation effect.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed2000

Statistical properties of thermodynamic quantities for cyclodextrin complex formation.

Literature values of DeltaG degrees (change in Gibbs free energy), DeltaH degrees (change in enthalpy), and TDeltaS degrees (temperature times change in entropy) for 1:1 complex formation by alpha-, beta-, and gamma-cyclodextrins constitute normally distributed populations with the following statistical parameters (all energy quantities in kcal mol(-1); n is the number of data points; mu is the population mean; sigma is the standard deviation): for alpha-cyclodextrin, n = 512, micro(DeltaG) = -2.85, sigma(DeltaG) = 1.23, micro(DeltaH) = -4.77, sigma(DeltaH) = 2.98, micro(TDeltaS) = -1.96, and sigma(TDeltaS) = 2.72; for beta-cyclodextrin, n = 415, micro(DeltaG) = -3.67, sigma(DeltaG) = 1. 37, micro(DeltaH) = -4.24, sigma(DeltaH) = 2.89, micro(DeltaS) = -0. 56, and sigma(TDeltaS) = 2.63; for gamma-cyclodextrin, n = 42, micro(DeltaG) = -3.71, sigma(DeltaG) = 1.19, micro(DeltaH) = -3.10, sigma(DeltaH) = 3.39, micro(TDeltaS) = +0.69, and sigma(TDeltaS) = 3. 29. The temperature is 298.15 K. The mean DeltaG degrees values correspond to binding constants of 123, 490, and 525 M(-1) for alpha-, beta-, and gamma-cyclodextrins, respectively.

Cyclodextrins↗
PubMed1987

The binding of fluorescent 4,6,8(14)-triene-3-one steroids to cyclodextrins as a model for steroid-protein interactions.

The 4,6,8(14)-triene-3-one steroids, highly fluorescent in aqueous solutions, lose their fluorescence power when binding occurs to hydrophobic regions of other molecules, such as the hydrophobic cavity in the ring system of cyclodextrins. The fluorescence intensity decreases almost completely when beta- and gamma-cyclodextrins are present in the solution. Scatchard plots derived from fluorescence titrations show that one or two molecules of steroid bind to one cyclodextrin molecule with KD,F-values of about 10(-4)-10(-5) mol/liter. Temperature-jump experiments show a single relaxation process, with rate constants for the decay of the beta-cyclodextrin-steroid complexes of about 10(4)-10(5) per s. For alpha- and gamma-cyclodextrins such relaxation processes are not observed.

17-alpha-Hydroxyprogesterone↗
PubMed2000

Simultaneous determination of alpha, beta and gamma cyclodextrins by LC.

Cyclodextrins (CDs) can be synthesized from starch by cyclodextrin glycosyltransferase (CGTase). This enzyme produces alpha-, beta- and gamma-CDs in varying proportions. In the production of cyclodextrins, purity as well as yield are important factors. A precise and reproducible method was developed and validated for the simultaneous determination of alpha-, beta-, and gamma-CDs. Optimum separation between the three CDs was achieved using a Finepak amino column with a mobile phase consisting of acetonitrile-water (70:30, v/v) at a flow rate of 1 ml/min. Detection was carried out using a differential refractive index detector. The developed method gave good chromatographic resolution of the three components with retention times of 13.16, 16.83 and 21.74 min for alpha-, beta- and gamma-CDs, respectively. The polynomial regression data for the calibration plots exhibited good linear relationship (coefficient of correlation r = 0.9987 for alpha, r = 0.9986 for beta and r = 0.9998 for gamma-CDs) over a concentration range of 2-10 mg/ml. Statistical analysis proves that the proposed LC method is precise, reproducible and accurate for the estimation of alpha-, beta- and gamma-cyclodextrins. The method can be employed for determination of percent purity as well as estimation of process yields of the cyclodextrins during the enzymatic production.

Chromatography, Liquid↗
PubMed2005

Inclusion complexation of lorazepam with different cyclodextrins suitable for parenteral use.

The development of a parenteral lorazepam formulation, using cyclodextrins (CDs) as inclusion complexation agents, was investigated. CDs suitable for parenteral injection, i.e., hydroxypropyl-beta-cyclodextrin (HP-beta-CD), hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD), sulfobutylether-7-beta-cyclodextrin (SBE-7-beta-CD), and maltosyl-beta-cyclodextrin (malt-beta-CD) were studied for the possibility to increase the solubility of lorazepam. Lorazepam interacted with all tested CD derivatives and 1:1 complexes are formed. HP-beta-CD exerts the highest solubility improvement, reaching about 6 mg/ml lorazepam in 30% (w/v) CD solution. When using SBE-7-beta-CD or malt-beta-CD only half of that concentration can be dissolved. HP-gamma-CD interacts much less with lorazepam. Parenteral solutions with 4 mg/ml in 30% (w/v) HP-beta-CD solution, with 2 mg/ml in 30% (w/v) SBE-7-beta-CD, and with 2 mg/ml lorazepam in 15% (w/v) HP-beta-CD, were prepared. Sterile filtration of the formulation needs to be applied because of massive degradation of lorazepam during autoclaving. No precipitation is observed after dilution of the different formulations with (physiological) water or with 5% dextrose in water, which proves their suitability for administration with perfusions. The stability of the preparations was investigated in aqueous medium. During the first month, in all solutions more than 90% of lorazepam remained; after 3 months, less than 60% of lorazepam remained in the solutions with 15% (w/v) HP-beta-CD and around 65-70% in the solutions with 30% (w/v) of CDs. Because of this short stability time, the preparations need to be lyophilized.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed2003

The binding of beta- and gamma-cyclodextrins to glycogen phosphorylase b: kinetic and crystallographic studies.

A number of regulatory binding sites of glycogen phosphorylase (GP), such as the catalytic, the inhibitor, and the new allosteric sites are currently under investigation as targets for inhibition of hepatic glycogenolysis under high glucose concentrations; in some cases specific inhibitors are under evaluation in human clinical trials for therapeutic intervention in type 2 diabetes. In an attempt to investigate whether the storage site can be exploited as target for modulating hepatic glucose production, alpha-, beta-, and gamma-cyclodextrins were identified as moderate mixed-type competitive inhibitors of GPb (with respect to glycogen) with K(i) values of 47.1, 14.1, and 7.4 mM, respectively. To elucidate the structural basis of inhibition, we determined the structure of GPb complexed with beta- and gamma-cyclodextrins at 1.94 A and 2.3 A resolution, respectively. The structures of the two complexes reveal that the inhibitors can be accommodated in the glycogen storage site of T-state GPb with very little change of the tertiary structure and provide a basis for understanding their potency and subsite specificity. Structural comparisons of the two complexes with GPb in complex with either maltopentaose (G5) or maltoheptaose (G7) show that beta- and gamma-cyclodextrins bind in a mode analogous to the G5 and G7 binding with only some differences imposed by their cyclic conformations. It appears that the binding energy for stabilization of enzyme complexes derives from hydrogen bonding and van der Waals contacts to protein residues. The binding of alpha-cyclodextrin and octakis (2,3,6-tri-O-methyl)-gamma-cyclodextrin was also investigated, but none of them was bound in the crystal; moreover, the latter did not inhibit the phosphorylase reaction.

Animals↗
PubMed2000

Cyclodextrin encapsulation to prevent the loss of l-menthol and its retention during drying.

The taste and flavor of spray-dried powdered products are the most important quality factors. In the present study, molecular encapsulation in cyclodextrin was applied to prevent the loss of a hydrophobic flavor compound (l-menthol) during the drying of a droplet. beta-Cyclodextrin appeared to be a better encapsulant for menthol than alpha- and gamma-cyclodextrin. The retention of menthol increased with increasing concentration of both cyclodextrin and maltodextrin. A simple mathematical model is proposed for estimating the flavor retention. The theoretical results by this model estimated well the final retention of menthol encapsulated in a blend of beta-cyclodextrin and maltodextrin.

Cyclodextrins↗