Stability and rheology of emulsified systems for cutaneous delivery of isoflavones present in soyextract (Glycine max (L). Merr.)

摘要

The symptoms of menopause have been treated byhormonal reposition therapy (HRT) but the use of fitohormoneshas been growing as an alternative to HRT anddermal administration has been evidenced due to itsbiopharmaceutical advantages. Soy (Glycine max (L.)Merr.) interests the pharmaceutical industry as a source ofisoflavones, which have estrogenic as well as antioxidant,antifungal e antineoplastic activities. Only few drugs arestill available as dermal formulations despite theadvantages this route presents over others. The mainchallenge for topical formulations is to provide enoughdrug penetration and release into the skin withoutinducing irreversible alterations on dermis, as well as tokeep constant the technical product's characteristics.Rheology has been theme of crescent importance for thepharmaceutical and cosmetic industries, since each and allcharges of a product may maintain the same good qualityrepresented by its consistency and sprayability. This workevaluated the effect of soy extract, C12-20 ácid Peg-8 Ester(Xalifin(R)) non ionic auto-emulsifying wax, cetostearyland etoxylated cetostearyl (Cosmowax(R)) alcohols andcarboxyvinyl polymer with xantan gum on the rheologicalproperties of emulsified systems (8). These systems wereprepared by pharmacopoeial methods and analyzed by aHaake cone & plate rheometer at room temperature. Theaddition of both polymer and xantan gum promotedgreater structuration of the systems, increasing theirviscosity and the storage modulus. Such formulationspresented higher degrees of plasticity and tixotropy, thiseffect being more pronounced with the use of C12-20 ácidPeg-8 Ester. Soy extract considerably diminished theviscosity and provoqued system destructuration, withreduced values for the storage modulus.