Rheology and NMR self-diffusion experiments as well as skin permeation of diclofenac-sodium and cyproterone acetate of new gel preparations.

The viscoelastic properties of two transparent semisolid preparations, one consisting of surfactant, paraffin oil, and water (BAS), and the other consisting of surfactant, cetylstearyl-2-ethylhexanoate, and water (CUBO), were characterized by oscillatory measurements. In (1)H-NMR diffusion experiments it was confirmed that the formulations are O/W systems, and the three-dimensional packing of the closed globular aggregates form a cubic structure. Moreover, standard diffusion experiments with porcine skin using Franz cells were performed with incorporated diclofenac-sodium and cyproterone acetate, respectively. The cumulative amount released after 48 h of diclofenac-sodium were excellent with 665.28 microg/cm(2) and with 36.7 microg/cm(2) for cyproterone acetate. The new drug-containing formulations were also prepared as transdermal patches by using carrageenan as a matrix. In diffusion studies zero-order kinetics was found for both drugs, but with a higher lag time for cyproterone acetate. The total work of adhesion was analyzed by tensile studies on porcine skin and found to be very good. The presented cubic gels as well as mixtures with carrageenan are promising alternative drug carrier systems for topical pharmaceutical as well as cosmetics. Copyright 2004 Wiley-Liss, Inc.