Journal: Journal of Pharmaceutical Sciences

Abbreviation

J. Pharm. Sci.

Publisher

Wiley

Journal Volumes

ISSN

1520-6017
0022-3549

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Publications 1 - 4 of 4
  • Cholesterol-Mediated Activation of P-Glycoprotein: Distinct Effects on Basal and Drug-Induced ATPase Activities
    Item type: Journal Article
    Belli, Sara; Elsener, Priska M.; Wunderli-Allenspach, Heidi; et al. (2009)
    Journal of Pharmaceutical Sciences
    Cholesterol promotes basal and verapamil-induced ATPase activity of P-glycoprotein (P-gp). We investigated whether these effects are related to each other and to the impact of the sterol on bilayer fluidity and verapamil membrane affinity. P-gp was reconstituted in egg-phosphatidylcholine (PhC) liposomes with or without cholesterol, 1,2-dipalmitoyl-phosphatidylcholine (DPPC), α-tocopherol (α-Toc) or 2,2,5,7,8-pentamethyl-6-chromanol (PMC). Basal and verapamil-induced ATPase activities were studied with an enzymatic assay. Membrane fluidity was characterized with diphenyl-hexatriene anisotropy measurements and membrane affinity by equilibrium dialysis. DPPC (70% mol/mol) decreased the fluidity of PhC bilayers to the same level as 20% cholesterol. PMC (20%) and α-Toc (20%) decreased the fluidity to lesser extents. α-Toc and PMC, but not DPPC increased the verapamil membrane affinity. While 20% cholesterol strikingly enhanced the basal ATPase activity, none of the other constituents had a similar effect. In contrast, verapamil stimulation of P-gp ATPase activity was not only enabled by cholesterol but also by α-Toc and DPPC. PMC had no effect. In conclusion, cholesterol exerts distinct effects on basal and verapamil-induced ATPase activity. The influence on basal ATPase activity is sterol-specific while its effect on verapamil-induced ATPase activity is unspecific and not related to its influence on membrane fluidity and on verapamil membrane affinity.
  • Lecithin Organogel as Matrix for Transdermal Transport of Drugs
    Item type: Journal Article
    Willimann, Haus; Walde, Peter; Luisi, Pier L.; et al. (1992)
    Journal of Pharmaceutical Sciences
  • Fabrication of Paclitaxel Nanocrystals by Femtosecond Laser Ablation and Fragmentation
    Item type: Journal Article
    Kenth, Sukhdeep; Sylvestre, Jean-Philippe; Fuhrmann, Kathrin; et al. (2011)
    Journal of Pharmaceutical Sciences
  • An experimental divalent vaccine based on biodegradable microspheres induces protective immunity against tetanus and diphtheria
    Item type: Journal Article
    Peyre, Marisa; Sesardic, Dorothea; Merkle, Hans P.; et al. (2003)
    Journal of Pharmaceutical Sciences
Publications 1 - 4 of 4