Interaction of clonixin with EPC liposomes used as membrane models

• Type: Article in International Scientific Journal
• Date: 2005

Authors

Ferreira, H (Author) Other; Lucio, M (Author) Other; Lima, JLFC (Author) FFUP; Matos, C (Author) Other; Reis, S (Author) FFUP

Journal

Title: Journal of Pharmaceutical Sciences

Vol. 94 No. 6

Pages: 1277-1287

ISSN: 0022-3549

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 29 Citations

ISI Web of Science

Scopus - 30 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

CORDIS: Health sciences

Other information

Authenticus ID: P-000-34H

DOI: 10.1002/jps.20351

Resumo (PT): In this work, an overall analysis of clonixin interaction with liposomes was achieved using different techniques, which allowed the evaluation of the change in different membrane's characteristics as well as the possible location of the drug in the membrane. Clonixin acidity constants were obtained and the values are 5.5 ± 0.08 and 2.2 ± 0.04. Clonixin partition coefficient (Kp) between liposomes and water was also determined using derivative spectrophotometry, fluorescence quenching, and zeta-potential (-potential). These three techniques yielded similar results. -potential measurements were performed and an increase of the membrane negative charge with an increase of drug concentration was observed. Drug location within the bilayer was performed by fluorescence quenching using a set of n-(9-anthroyloxy) fatty acid probes (n = 2, 6, 9, and 12). The fluorescence intensity of all probes was quenched by the drug. This effect is more noticeable for the outer located probe, indicating that the drug is positioning in the external part of the membrane. These same probes were used for steady-state anisotropy measurements to determine the perturbation in membrane structure induced by clonixin. Clonixin increased membrane fluidity in a concentration dependent manner, with the highest perturbation occurring nearby the 2-AS probe, closely located to the bilayer surface. <br> <br> Keywords clonixin • liposomes • drug interaction • light scattering • UV/Vis spectroscopy • fluorescence spectroscopy • partition coefficient • drug location • membrane fluidity <br> <a target="_blank" href="http://www3.interscience.wiley.com/journal/110478183/abstract"> Texto integral</a> <br> <br>

Abstract (EN): In this work, an overall analysis of clonixin interaction with liposomes was achieved using different techniques, which allowed the evaluation of the change in different membrane's characteristics as well as the possible location of the drug in the membrane. Clonixin acidity constants were obtained and the values are 5.5 +/- 0.08 and 2.2 +/- 0.04. Clonixin partition coefficient (K-p) between liposomes and water was also determined using derivative spectrophotometry, fluorescence quenching, and zeta-potential (zeta-potential). These three techniques yielded similar results. zeta-potential measurements were performed and an increase of the membrane negative charge with an increase of drug concentration was observed. Drug location within the bilayer was performed by fluorescence quenching using a set of n-(9-anthroyloxy) fatty acid probes (n = 2, 6, 9, and 12). The fluorescence intensity of all probes was quenched by the drug. This effect is more noticeable for the outer located probe, indicating that the drug is positioning in the external part of the membrane. These same probes were used for steady-state anisotropy measurements to determine the perturbation in membrane structure induced by clonixin. Clonixin increased membrane fluidity in a concentration dependent manner, with the highest perturbation occurring nearby the 2-AS probe, closely located to the bilayer surface. (C) 2005 Wiley-Liss, Inc. and the American Pharmacists Association.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11