Gerhard Wenz

Publications (10)81.57 Total impact

• Article: Inclusion of chemotherapeutic agents in substituted β-cyclodextrin derivatives

  Carolin Thiele, Dagmar Auerbach, Gregor Jung, Gerhard Wenz
  [show abstract] [hide abstract]
  ABSTRACT: The stabilities of the inclusion compounds of three chemotherapeutic agents, camptothecin (CPT), docetaxel (DOC) and idarubicin (IDA), plus a model compound 1,4-dihydroxyanthraquinone (DHA) with several β-cyclodextrin (β-CD) derivatives were investigated by solubility measurements, isothermal titration microcalorimetry and fluorescence anisotropy measurements. Ionic heptakis-(6-deoxy-6-thioethers) of β-CD were found to exhibit very high binding potentials for these drugs making them to good candidates for advanced drug delivery. KeywordsCamptothecin–Docetaxel–Idarubicin–Cyclodextrin–Solubility–Isothermal titration calorimetry–Binding constant–Fluorescence anisotropy
  Journal of Inclusion Phenomena 04/2012; 69(3):303-307. · 1.89 Impact Factor
• Article: A comparison investigation on the solubilization of betulin and betulinic acid in cyclodextrin derivatives.

  Hai Ming Wang, Codruta M Soica, Gerhard Wenz
  [show abstract] [hide abstract]
  ABSTRACT: Betulin (BET) and betulinic acid (BA) are naturally occurring pentacyclic lupane triterpenes, exhibit great promise as bioactive agents for the treatment of many diseases. The poor solubilities of BET and BA in water have limited their applications. In the present work, BET and BA were selected as guest molecules, three hydrophilic gamma-cyclodextrin (CD) thioethers were synthesized and selected as host molecules. beta-, Hydroxypropyl-beta-CD, (HP-beta-CD), gamma-CD and HP-gamma-CD were also investigated as hosts in order to compare the solubilization abilities of these host molecules. The solubilities of BET and BA were estimated from 1H NMR measurements by comparing the relative integral areas of the proton signals between CDs and guests. gamma-CD thioethers 5-7solubilized BET and BA to much higher extends than other host molecules. The obtained maximal solubilities of BET and BA were 5.2 and 4.5 mM, respectively. The topographies of the inclusion compounds were determined by ROESY NMR spectroscopy.
  Natural product communications 03/2012; 7(3):289-91. · 1.24 Impact Factor
• Article: Molecular solubilization of fullerene C(60) in water by γ-cyclodextrin thioethers.

  Hai Ming Wang, Gerhard Wenz
  [show abstract] [hide abstract]
  ABSTRACT: Various hydrophilic γ-cyclodextrin (CD) thioethers, containing neutral or ionic side arms were found to form molecular disperse solutions of C(60) in water reaching concentrations of 15 mg/L. Equilibrium state was approached after seven days without the use of organic cosolvents. The 1:2 stoichiometry of the C(60)/γ-CD thioether complexes was demonstrated by a parabolic phase-solubility diagram. In contrast, native γ-CD forms nanoparticles with C(60). Particle sizes of C(60) were determined by dynamic light scattering.
  Beilstein Journal of Organic Chemistry 01/2012; 8:1644-51. · 2.52 Impact Factor
• Article: Solubilization of polycyclic aromatics in water by γ-cyclodextrin derivatives.

  Hai Ming Wang, Gerhard Wenz
  [show abstract] [hide abstract]
  ABSTRACT: A series of hydrophilic per-6-thio-6-deoxy-γ-cyclodextrins (CDs) were synthesized from per-6-iodo-6-deoxy-γ-CD. These new hosts are able to solubilize polycyclic aromatic guests in aqueous solution to much higher extents than native CDs. Phase-solubility diagrams were mostly linear in accordance with both 1:1 and 1:2 CD-guest complexes in aqueous solution. The stoichiometry of the inclusion complexes was further investigated by fluorescence spectroscopy, which revealed very pronounced Stokes shifts typical for 1:2 complexes. This finding was further consolidated by quantum mechanical calculations of dimer formation of the guests and space-filling considerations by using the cross-sectional areas of the CDs and guests. The calculated dimerization energies correlated well with the binding free energies measured for the 1:2 complexes, and provided the main contribution to the driving force of complexation in the γ-CD cavity.
  Chemistry - An Asian Journal 09/2011; 6(9):2390-9. · 4.50 Impact Factor
• Article: Recognition of ionic guests by ionic beta-cyclodextrin derivatives.

  Gerhard Wenz, Christian Strassnig, Carolin Thiele, Annegret Engelke, Bernd Morgenstern, Kaspar Hegetschweiler
  [show abstract] [hide abstract]
  ABSTRACT: Inclusion compounds of cationic, anionic, and neutral p-substituted derivatives of tert-butylbenzene complexed in beta-cyclodextrin and its ionic 6-mono and 6-hepta derivatives were systematically investigated by isothermal titration calorimetry (ITC). All inclusion compounds showed 1:1 stoichiometry with binding constants ranging from 10 to 3 x 10(6) M(-1). The binding free energies could be subdivided into apolar and electrostatic contributions. The electrostatic interactions could be quantitatively described by Coulomb's law by taking into account the degree of protonation of hosts and guests, the orientations of the guests within the hosts, and ion shielding as described by the Debye-Hückel-Onsager theory. The orientations of the guests within the cyclodextrin cavities were determined by ROESY NMR spectroscopy.
  Chemistry 08/2008; 14(24):7202-11. · 5.93 Impact Factor
• Article: Thickness recognition of bolaamphiphiles by alpha-cyclodextrin.

  Axel Müller, Gerhard Wenz
  [show abstract] [hide abstract]
  ABSTRACT: The minimum internal diameters of alpha-, beta-, and gamma-cyclodextrin were calculated by a space filling algorithm, MolShape, from the electron density maps created by semiempirical AM1 and PM3 calculations using Gaussian03. In addition, the minimum diameters of a series of dicationic bolaamphiphiles were calculated by MolShape as well. The calculated diameters of these hosts and guests allowed prognosis about the stabilities of the corresponding inclusion compounds. The experimental binding data, obtained by isothermal titration calorimetry (ITC), revealed indeed a very pronounced thickness recognition and correlate well with the calculated diameters.
  Chemistry 02/2007; 13(8):2218-23. · 5.93 Impact Factor
• Article: Improved cyclodextrin-based receptors for camptothecin by inverse virtual screening.

  Andreas Steffen, Carolin Thiele, Simon Tietze, Christian Strassnig, Andreas Kämper, Thomas Lengauer, Gerhard Wenz, Joannis Apostolakis
  [show abstract] [hide abstract]
  ABSTRACT: We report the computer-aided optimization of a synthetic receptor for a given guest molecule, based on inverse virtual screening of receptor libraries. As an example, a virtual set of beta-cyclodextrin (beta-CD) derivatives was generated as receptor candidates for the anticancer drug camptothecin. We applied the two docking tools AutoDock and GlamDock to generate camptothecin complexes of every candidate receptor. Scoring functions were used to rank all generated complexes. From the 10 % top-ranking candidates nine were selected for experimental validation. They were synthesized by reaction of heptakis-[6-deoxy-6-iodo]-beta-CD with a thiol compound to form the hepta-substituted beta-CDs. The stabilities of the camptothecin complexes obtained from solubility measurements of five of the nine CD derivatives were significantly higher than for any other CD derivative known from literature. The remaining four CD derivatives were insoluble in water. In addition, corresponding mono-substituted CD derivatives were synthesized that also showed improved binding constants. Among them the 9-H-purine derivative was the best, being comparable to the investigated hepta-substituted beta-CDs. Since the measured binding free energies correlated satisfactorily with the calculated scores, the applied scoring functions appeared to be appropriate for the selection of promising candidates for receptor synthesis.
  Chemistry 02/2007; 13(24):6801-9. · 5.93 Impact Factor
• Article: Cyclodextrin rotaxanes and polyrotaxanes.

  Gerhard Wenz, Bao-Hang Han, Axel Müller
  Chemical Reviews 04/2006; 106(3):782-817. · 40.20 Impact Factor
• Article: Molecular recognition of polymers by cyclodextrin vesicles.

  Bart Jan Ravoo, Jean-Christophe Jacquier, Gerhard Wenz
  Angewandte Chemie International Edition 06/2003; 42(18):2066-70. · 13.45 Impact Factor
• Article: Combined similarity and QSPR virtual screening for guest molecules of ß-cyclodextrin

  Andreas Steffen, Maximilian Karasz, Carolin Thiele, Thomas Lengauer, Andreas Kämper, Gerhard Wenz, Joannis Apostolakis
  New Journal of Chemistry, v.31, 1941-1949 (2007).