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  • 1
    Electronic Resource
    Electronic Resource
    Development of Anti-Influenza Virus Drugs I: Improvement of Oral Absorption and In Vivo Anti-Influenza Activity of Stachyflin and Its Derivatives (1999)
    Springer
    Pharmaceutical research 16 (1999), S. 1041-1046 
    Details
    ISSN: 1573-904X
    Keywords: influenza ; oral absorption ; PEG ; phosphate ester prodrug ; anti-influenza virus drug
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. Stachyflin and its derivatives which are active against the influenza virus in vitro, were studied to improve their reduced in vivo activity after oral administration by chemical modification and some vehicles. Methods. The solubility was examined for different vehicles. The improvement of gastrointestinal absorption was evaluated by the plasma concentration after oral administration to mice or the in situ loop method with rats. The in vivo anti-influenza activity was examined using mice infected with the influenza virus and evaluated based on the virus titer in the lung by TCID50. Results. PEG 400 showed the highest solubility of Stachyflin and its derivative among the vehicles studied. While no viral inhibition was found in the lung after oral administration of 0.5% HPMC suspension of Stachyflin, in vivo anti-influenza virus activity was found with the PEG 400 solution. The absorption of Stachyflin by PEG 400 showed about a fifty-fold increase in AUC compared with that of 0.5% HPMC suspension. Improving the oral absorption of Stachyflin led to an increase in the in vivo anti-influenza virus activity. When the Stachyflin derivative in PEG 4000 was administered orally, there was more enhancement of the oral absorption than with PEG 400. When the aqueous solution of the phosphate ester prodrugs of Stachyflin and its derivative was administered orally, the absorption of the parent compound was improved and in vivo anti-influenza virus activity was found. Conclusions. When Stachyflin and its derivatives were administered orally to mice with a solution in PEG and an aqueous solution of their phosphate ester, their oral absorption was improved and in vivo anti-influenza virus activity was observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018983715982
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Transport Characteristics of S-1090, A New Oral Cephem, in Rat Intestinal Brush-Border Membrane Vesicles (1995)
    Springer
    Pharmaceutical research 12 (1995), S. 1488-1492 
    Details
    ISSN: 1573-904X
    Keywords: S-1090 ; transport ; brush-border membrane ; oligopeptide ; histidine ; oral cephem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. Elucidating the transport characteristics of S-1090, a new orally active cephalosporin in rat small intestinal brush-border membranes. Methods. A rapid filtration technique. Results. The uptake of S-1090 was stimulated by an inwardly directed H+-gradient, but did not show overshooting uptake. To investigate the transport system, the inhibitory and countertransport effects of various compounds on S-1090 uptake were examined. Although the dipeptides and tripeptides composed of amino acids with aliphatic side chains did not inhibit the uptake of S-1090, those having histidine, proline or tryptophan as the N-terminal amino acid showed an inhibitory effect. Among the oral cephems tested, ceftibuten showed marked inhibition, while cefaclor and cephalexin had no inhibitory effect. Countertransport effects on S-1090 uptake were observed only when the vesicles were preloaded with histidyl peptides such as His-Gly or His-Ala, while other compounds which exhibited inhibition had no countertransport effect. Conclusions. Based on the above results, there seems to be heterogeneity (multiplicity) in the oligopeptide transport system which may depend on the structure of the N-terminal amino acid. S-1090 may be dominantly transported via a system that recognizes peptides having histidine as the N-terminal amino acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016287421436
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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