Effects of surfactants and thermodynamic activity of model active ingredient on transport over plant leaf cuticle.
Colloids Surf B Biointerfaces
; 103: 572-9, 2013 Mar 01.
Article
en En
| MEDLINE
| ID: mdl-23261582
The main objective of this study was to investigate the mechanism of molecular transport across the cuticle of Clivia leaves. In vitro diffusion methodology was used to investigate the transport of a systemic fungicide, tebuconazole, over a model silicone membrane, enzymatically isolated cuticle membranes, and dermatomed leaves. It was shown that dermatomed leaves may replace enzymatically isolated cuticles. Furthermore, the effects of two surfactants, C(10)EO(7) and C(8)G(1.6), on the fungicide transport were investigated. Tebuconazole cuticle permeation was described using Fick's first law of diffusion, expressed by the thermodynamic activity of the solute in the membrane. A new method for calculation of diffusion coefficients in the membrane is proposed. To access the thermodynamic activity of the fungicide in the membranes, sorption isotherms of tebuconazole in the membrane materials studied were recorded. The thermodynamic activity of the fungicide in aqueous solutions was calculated from solubility data. For that purpose, the effect of surfactants on tebuconazole solubility was studied. The results show that addition of surfactants allows for higher concentrations of tebuconazole available for penetration. Nonetheless, at a fixed fungicide thermodynamic activity, all formulations produced the same flux over the silicone membrane independently on the fungicide concentration. This shows that the driving force across non-responding membranes is the gradient of thermodynamic activity, rather than the gradient of the fungicide concentration. In case of leaves, surfactants induced the same quantitative increase in both flux and diffusion coefficient of solute in the cuticle, while the cuticle-water partition coefficient was unaffected.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Tensoactivos
/
Triazoles
/
Hojas de la Planta
/
Epidermis de la Planta
/
Liliaceae
Idioma:
En
Revista:
Colloids Surf B Biointerfaces
Asunto de la revista:
QUIMICA
Año:
2013
Tipo del documento:
Article
País de afiliación:
Suecia
Pais de publicación:
Países Bajos