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  • 1
    Electronic Resource
    Electronic Resource
    Anomalous dissolution behavior of the diazepam — γ-cyclodextrin complex in polymer solutions (1984)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 1 (1984), S. 309-312 
    Details
    ISSN: 1573-1111
    Keywords: Diazepam — γ-cyclodextrin complex ; dissociation of inclusion complexes ; water soluble polymers as additives ; supersaturated behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The dissolution process of the diazepam — γ-cyclodextrin complex in aqueous polymer solutions has been studied. Hydroxypropyl cellulose and polyvinylpyrrolidone stabilize the supersaturated state of the complex, maintaining the higher drug level for a longer period. Polyethyleneglycol and dextran accelerated the dissociation of the complex, and caused a rapid decrease in drug concentration. These anomalous dissolution behaviors are discussed on the basis of viscosity changes of the polymer solutions along with the competitive interaction of polymers for the inclusion complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00656765
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  • 2
    Electronic Resource
    Electronic Resource
    Alleviation of the chlorpromazine-induced muscular tissue damage by β-cyclodextrin complexation (1984)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 2 (1984), S. 637-644 
    Details
    ISSN: 1573-1111
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract From the gross and histological examinations, β-cyclodextrin (β-CyD) was found to reduce the muscular tissue damage produced by chlorpromazine hydrochloride (CPZ) onM. vastus lateralis in rabbits. The protective effect of β-CyD may be attributable to the decrease in affinity of CPZ to the tissue membrane through inclusion complexation. There was no appreciable difference in the pharmacokinetic and pharmacodynamic behaviors between CPZ and its β-CyD complex in rabbits. These results suggest that β-CyD is useful to reduce the local tissue toxicity of CPZ without altering the pharmacological efficacy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00662230
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  • 3
    Electronic Resource
    Electronic Resource
    Comparative study on inclusion complexations of antiinflammatory drug flurbiprofen with β-cyclodextrin and methylated β-cyclodextrins (1984)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 2 (1984), S. 597-604 
    Details
    ISSN: 1573-1111
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstruct Some physicochemical properties of methylated β-cyclodextrins, i.e., heptakis(2,6-di-O-methyl)-β-cyclodextrin (DM-β-CyD) and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TM-β-CyD) were compared with those of natural β-cyclodextrin (β-CyD). Inclusion behaviors of β-CyD and methylated β-CyDs in water and in solid state were studied by solubility analysis, spectroscopies (UV, CD,13C-NMR and IR), X-ray diffractometry and thermal analysis, using an antiinflammatory drug flurbiprofen (FP) as a guest molecule. The spectral data suggest that the inclusion mode of FP-TM-β-CyD is somewhat different from those of FP-β-CyD and FP-DM-β-CyD. The solid complexes of FP with β- and methylated β-CyDs were obtained in molar ratio of 1∶1, and their dissolution behavior and release from suppository base were examined. The data are presented suggesting that DM-β-CyD is particularly useful for improving the pharmaceutical properties of FP in various dosage forms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00662225
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  • 4
    Electronic Resource
    Electronic Resource
    Differential Effects of Sulfate and Sulfobutyl Ether of β-Cyclodextrin on Erythrocyte Membranes in Vitro (1995)
    Springer
    Pharmaceutical research 12 (1995), S. 78-84 
    Details
    ISSN: 1573-904X
    Keywords: β-cyclodextrin sulfate ; sulfobutyl-β-cyclodextrin ; rabbit erythrocytes ; hemolysis ; morphological changes ; lipid solubilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The hemolytic activity of β-cyclodextrin (β-CyD) on rabbit erythrocytes was reduced by the introduction of negatively-charged groups onto the hydroxyls of β-CyD; the membrane disrupting abilities decreased in the order of β-CyD 〉 2-hydroxypropyl-β-CyD (HP-β-CyD) 〉 sulfobutyl-β-CyD (SB-β-CyD) 〉〉 β-CyD sulfate (S-β-CyD). Under pre-hemolytic concentrations, both β-CyD and SB-β-CyD induced shape changes of membrane invagination on the erythrocytes. In sharp contrast, S-β-CyD showed biphasic effect on the shape of the erythrocytes; i.e. the crenation at relatively low concentrations and the invagination at higher concentrations. The S-β-CyD-induced membrane crenation arose from a direct action on the membranes rather than cell metabolism-mediated effects. Unlike β-CyD, S-β-CyD was found to bind to the erythrocytes and may be confined to the outer surface of the membrane bilayer, which may expand the exterior layer relative to the cytoplasmic half, thereby inducing the cells to crenate. On the other hand, the membrane invagination mediated by the three β- CyDs was initiated by extracting specific membrane lipids from the cells, depending upon their inclusion abilities, subsequently leading to the lysis of the cells. These results indicate that SB-β-CyD and S-β-CyD interact with the erythrocyte membranes in a differential manner and possess lower membrane disrupting abilities than the parent β-CyD and HP-β-CyD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016238720701
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  • 5
    Electronic Resource
    Electronic Resource
    Design and Evaluation of an Osmotic Pump Tablet (OPT) for Chlorpromazine Using (SBE)7m-β-CD (1999)
    Springer
    Pharmaceutical research 16 (1999), S. 549-554 
    Details
    ISSN: 1573-904X
    Keywords: osmotic pump ; controlled-porosity osmotic pump tablet ; (SBE)7m-β-CD ; cyclodextrins ; HP-β-CD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. The purpose of this study was to develop a controlled-porosity osmotic pump tablet (OPT) which exhibits pH-independent release profiles for a basic drug using a sulfobutyl ether-β-cyclodextrin, (SBE)7m-β-CD, which acts as both a solubilizer and as an osmotic agent. Methods. Chlorpromazine free base (CLP) was chosen as a model drug for this study. The release of CLP from osmotic pump tablets was studied in vitro. In vivo absorption of CLP from the OPT was evaluated in male beagle dogs. Results. The CLP release profile from an OPT prepared from a core tablet composed of a 1:10 molar ratio of CLP to (SBE)7m-β-CD was pH-independent, and was controlled by modulating the membrane thickness of the OPT. Another cyclodextrin, hydroxypropyl-β-cyclodextrin (HP-β-CD), and a sugar mixture of lactose and fructose resulted in pH-dependent release at the same molar ratio. An in vivo absorption study in dogs with an OPT containing (SBE)7m-β-CD correlated very well with the in vitro release profiles using the Japanese Pharmacopoeia dissolution method. Conclusions. In addition to serving as a solubilizer and osmotic agent, (SBE)7m-β-CD can also serve as the controlling agent for pH independent release of CLP from OPTs. This system successfully modified the in vivo input rate of CLP without compromising oral bioavailability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018827214223
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  • 6
    Electronic Resource
    Electronic Resource
    Protection Afforded by Maltosyl-β-cyclodextrin Against α-Chymotrypsin-Catalyzed Hydrolysis of a Luteinizing Hormone-Releasing Hormone Agonist, Buserelin Acetate (1997)
    Springer
    Pharmaceutical research 14 (1997), S. 1401-1405 
    Details
    ISSN: 1573-904X
    Keywords: buserelin acetate ; maltosyl-β-cyclodextrin ; complexation ; α-chymotrypsin-catalyzed hydrolysis ; thermal unfolding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. The present study addresses how maltosyl-β-cyclodextrin (G2-β-CyD) impacts upon the α-chymotrypsin-catalyzed hydrolysis of buserelin acetate, an agonist of luteinizing hormone-releasing hormone with emphasis upon the direct effect of G2-β-CyD on the activity of the protease. Methods. Kinetic and solubility studies were performed in isotonic phosphate buffer (pH 7.4) at 25°C and 37°C. The interaction of α-chymotrypsin with G2-β-CyD in the buffer solution was examined by differential scanning calorimetry. Results. G2-β-CyD decelerated the α-chymotrypsin-catalyzed hydrolysis of buserelin acetate to give the 1−3 tripeptide and the 4−9 hexapeptide fragments. This deceleration can be explained solely by a nonproductive encounter between a complex of the substrate with G2-β-CyD and the protease at relatively low CyD concentrations, while the direct inhibitory effect of G2-β-CyD on the proteolytic activity made a considerable contribution to the overall deceleration of the hydrolysis at higher CyD concentrations. Calorimetric studies indicate the presence of intermediate states in the thermal unfolding of α-chymotrypsin, simultaneously accompanied by the autolysis. By contrast, a two-state thermal unfolding of α-chymotrypsin was observed in the presence of G2-β-CyD, suggesting reduced proteolytic activity upon binding to G2-β-CyD. Conclusions. These results suggest that G2-β-CyD at higher concentrations inhibits the proteolytic action of α-chymotrypsin through direct interaction with the protease, as well as through the formation of a non-productive complex with the substrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1012120705408
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  • 7
    Electronic Resource
    Electronic Resource
    Design and Evaluation of an Osmotic Pump Tablet (OPT) for Prednisolone, a Poorly Water Soluble Drug, Using (SBE)7m-β-CD (1998)
    Springer
    Pharmaceutical research 15 (1998), S. 1562-1568 
    Details
    ISSN: 1573-904X
    Keywords: osmotic pump ; controlled-porosity osmotic pump tablet ; (SBE)7m-β-CD ; cyclodextrins, HP-β-CD ; poorly water soluble drug ; prednisolone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. The purpose of this study was to develop a controlled-porosity osmotic pump tablet (OPT) for poorly water soluble drugs using a sulfobutyl ether-β-cyclodextrin, (SBE)7m-β-CD or Captisol™, which acted as both a solubilizer and as an osmotic agent. Methods. Prednisolone (PDL) was chosen as a model drug for this study. The release of PDL from osmotic pump devices and tablets was studied. In vivo absorption of PDL from OPT was evaluated in male beagle dogs. Results. PDL release from the osmotic pump tablet with (SBE)7m-β-CD was complete. Another cyclodextrin, hydroxypropyl-β-cyclodextrin (HP-β-CD), and a sugar mixture of lactose and fructose resulted in incomplete release. Although PDL release from the OPT with (SBE)7m-β-CD and the sugar formulation displayed mainly zero-order release characteristics, the tablet utilizing HP-β-CD showed apparent first-order release characteristics. An in vivo absorption study in dogs correlated very well with the in vitro release profiles using the Japanese Pharmacopoeia dissolution method. Conclusions. The present results confirm that (SBE)7m-β-CD can serve as both the solubilizer and the osmotic agent for OPT of PDL, and modify the input rate of PDL without compromising oral bioavailability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011955117026
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  • 8
    Electronic Resource
    Electronic Resource
    Reduction of photohemolytic activity of benoxaprofen byβ-cyclodextrin complexations (1988)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 6 (1988), S. 415-423 
    Details
    ISSN: 1573-1111
    Keywords: Benoxaprofen ; β-cyclodextrin ; di-O-methyl-β-cyclodextrin ; inclusion complex ; photolysis ; photohemolysis ; lipid peroxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Inclusion complexations of benoxaprofen (BXP) withβ-cyclodextrin (β-CyD) and heptakis (2,6-di-O-methyl)-β-CyD (DM-β-CyD) were studied by the solubility method and CD and1H-NMR spectroscopy. Both β-CyDs decelerated the photodecarboxylation of BXP, and suppressed the BXP-photosensitized hemolysis, where the inhibitory effect of DM-β-CyD was larger than that of β-CyD. This order was well correlated with the magnitude of the stability constants of BXP-β-CyD complexes. The peroxidation of lipid components in erythrocyte ghosts induced by BXP was also suppressed particularly by DM-β-CyD. The protective effect of β-CyDs on the BXP-induced photohemolysis seems to be due to the suppression in the photochemical reactions of BXP yielding toxic transient species, together with the inhibition in attacks of the transient species to the membrane, through inclusion complexation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00658983
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  • 9
    Electronic Resource
    Electronic Resource
    Amorphous Water-Soluble Cyclodextrin Derivatives: 2-Hydroxyethyl, 3-Hydroxypropyl, 2-Hydroxyisobutyl, and Carboxamidomethyl Derivatives of β-Cyclodextrin (1988)
    Springer
    Pharmaceutical research 5 (1988), S. 713-717 
    Details
    ISSN: 1573-904X
    Keywords: amorphous water-soluble cyclodextrin derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The pharmaceutical usefulness of natural, crystalline cyclodextrins can be improved by chemical conversions into water-soluble, amorphous mixtures of their derivatives. Reaction of β-cyclodextrin with 2-chloroethanol, 3-chloropropanol, isobutylene oxide, or iodoacetamide yielded the title compounds. Distributions of the substitution degree were close to symmetrical and relatively narrow. The average substitution degrees increased with the amount of alkylating reagent used in the preparation. The number of components (half-width of distribution) increased with increasing average substitution degree. Further, distributions of the substitution degree were measured in glucose derivatives after hydrolysis of 2-hydroxyethyl, 2-hydroxypropyl, and 2-hydroxyisobutyl-β-cyclodextrin. The results show an uneven distribution of substitutents around the cyclodextrins, suggesting that growth of oligoglycol side chains and/or clustering of substituents on one glucose residue occurs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1015907927950
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  • 10
    Electronic Resource
    Electronic Resource
    Enhancement of the Antiinflammatory Effect of Ethyl 4-Biphenylyl Acetate in Ointment by β-Cyclodextrin Derivatives: Increased Absorption and Localized Activation of the Prodrug in Rats (1990)
    Springer
    Pharmaceutical research 7 (1990), S. 1152-1156 
    Details
    ISSN: 1573-904X
    Keywords: antiinflammatory ointments ; 4-biphenylyl acetic acid ; ethyl 4-biphenylyl acetate ; β-cyclodextrin derivatives ; percutaneous absorption ; prodrug activation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Ethyl 4-biphenylyl acetate (EBA) is a prodrug of the antiinflammatory 4-biphenylyl acetic acid (BPAA). The inclusion complexes of EBA with β-cyclodextrin (β-CyD), heptakis(2,6-di-O-methyl)-β-cyclodextrin (DM-β-CyD), and 2-hydroxypropyl-β-cyclodextrin (HP-β-CyD) at a molar ratio of 1:2 (EBA:cyclodextrin) were prepared and used to make hydrophilic antiinflammatory ointments. The in vitro release of EBA from the ointments was enhanced by complexation in the order of β-CyD 〈 DM-β-CyD ≤ HP-β-CyD. The improvement correlated with the improved solubility and not with the decreased diffusibility observed to occur upon the complexation of EBA. In vivo the complexation with cyclodextrin derivatives increased both the release of EBA from the vehicle and its conversion in the underlying tissue to BPAA, but the total of EBA and BPAA in the tissue was decreased. In vitro studies confirmed that the effects of cyclodextrin derivatives on the conversion were exerted indirectly. The combination of the enhanced release and of the enhanced prodrug hydrolysis by esterases in the site where the antiinflammatory action is required resulted in increased therapeutic effects. In the model of carrageenan-induced acute edema in rat paw, the complexation improved the therapeutic effects over those of EBA alone in the order of β-CyD 〈 DM-β-CyD 〈 HP-β-CyD. HP-β-CyD may be a particularly useful cyclodextrin derivative since it improves the topical availability and does not irritate tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1015932325998
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