Dinâmica molecular e particionamento do marcador de spin di-terc-butil nitróxido em membranas de estrato córneo. Efeito de Terpenos
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Data
2009-03-31
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Universidade Federal de Goiás
Resumo
Terpenes are a very promising class of skin penetration enhancers especially due
to their low potential of irritation in the skin. In this work, we have used the electron
paramagnetic resonance (EPR) spectroscopy of the small spin label di-tert-butyl nitroxide
(DTBN), which partitions the aqueous and hydrocarbon phases, to study the interaction
of the terpenes ®-terpineol, 1,8-cineole, L(-)-carvone and (+)-limonene with the uppermost
skin layer, the stratum corneum, and the membrane models of 1,2-dipalmitoyl-sn-glycero-
3-phosphatidylcholine (DPPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC).
The EPR spectra indicated that the terpenes increase both the partition coe±cient and
the rotational di®usion rate of the spin labels in the stratum corneum membranes whereas
for DMPC and DPPC bilayers were observed similar e®ects only at temperatures below
the liquid-crystalline phase. The EPR parameter associated to probe polarity inside the
membranes showed thermotropic induced changes, suggesting relocations of spin probe,
which were dependent of the membrane phases. While DMPC and DPPC bilayers showed
abrupt changes in the partitioning and rotational correlation time parameters at the phase
transitions, the SC membranes were characterized by slights changes in whole interval of
measured temperatures, presenting the greatest changes or membranes reorganizations in
the temperature range of v50 to v74±C. The results suggest that the terpenes act as spacers
that weaken the hydrogen-bonded network at the polar interface thus °uidizing the stratum
corneum lipids and, in consequence, increase the permeation of small polar molecules across
the membranes.
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Citação
CAMARGOS, Heverton Silva de. Molecular dynamics and partitioning Bookmark
spin di-tert-butyl nitroxide in membrane of stratum
corneum. Effect of Terpenes. 2009. 89 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de Goiás, Goiânia, 2009.