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Titolo:
Electrorepulsion versus electroosmosis: Effect of pH on the iontophoretic flux of 5-fluorouracil
Autore:
Merino, V; Lopez, A; Kalia, YN; Guy, RH;
Indirizzi:
Ctr Interuniv Rech & Enseignement Pharmapeptides, Archamps, France Ctr Interuniv Rech & Enseignement Pharmapeptides Archamps France France Univ Geneva, Fac Sci, Pharm Sect, Geneva, Switzerland Univ Geneva GenevaSwitzerland Fac Sci, Pharm Sect, Geneva, Switzerland Univ Valencia, Dept Farm & Tecnol Farmaceut, Valencia, Spain Univ Valencia Valencia Spain t Farm & Tecnol Farmaceut, Valencia, Spain
Titolo Testata:
PHARMACEUTICAL RESEARCH
fascicolo: 5, volume: 16, anno: 1999,
pagine: 758 - 761
SICI:
0724-8741(199905)16:5<758:EVEEOP>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
HAIRLESS MOUSE; SKIN; INVITRO; FLOW;
Keywords:
percutaneous absorption; 5-fluorouracil; iontophoresis; electroosmosis; isoelectric point;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
9
Recensione:
Indirizzi per estratti:
Indirizzo: Guy, RH Ctr Interuniv Rech & Enseignement Pharmapeptides, Archamps, FranceCtr Interuniv Rech & Enseignement Pharmapeptides Archamps France
Citazione:
V. Merino et al., "Electrorepulsion versus electroosmosis: Effect of pH on the iontophoretic flux of 5-fluorouracil", PHARM RES, 16(5), 1999, pp. 758-761

Abstract

Purpose. To delineate the contributions of electrorepulsion and electroosmosis to the iontophoretic flux of 5-FU across porcine skin in vitro. Also, the isoelectric point (pI) of the skin model was determined. Methods. The electrotransport of 5-FU, anode-to-cathode ("anodal") and cathode-to-anode ("cathodal") was determined as a function of the pH of the electrolyte bathing the skin. Results. At pH 8.5, the drug (pK(a) similar to 8) is negatively charged and "cathodal", viz electrorepulsive, transport is much greater than that in the opposite direction. At pH 7.4, where similar to 25% of 5-FU is charged,electrorepulsive and electroosmotic ("anodal") fluxes are balanced. Decreasing the pH to 6, and then 5, reduces the percentage of ionized 5-FU such that "anodal" electroosmosis dominates across the negatively-charged membrane. But at pH 4, "anodal" and "cathodal" fluxes are again equal suggesting neutralization of the skin (i.e., pI similar to 4). This is confirmed at pH 3, where "cathodal" electroosmosis dominates across the now net-positively charged barrier. Conclusions. Electrotransport is sensitive, mechanistically, to the properties of the permeant and of the skin; interactions of, for example, the drug or constituents of a formulation, that alter the barrier's net charge, can affect iontophoretic delivery. The pI of porcine ear skin is similar to 4.

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Documento generato il 11/07/20 alle ore 17:34:18