Fulvic acid transdermal patch: Its properties, optimization and release

There is a high demand for the design of fulvic acids (FA) transdermal patches being natural biologically active substances with a wide action. The difficulties in FA transdermal patches creating are due to the peculiarities of FA obtaining with high purity and solubility, the existence of many several polymorphic forms, as well as the problems of their insertion into dosage forms. In this work, we modified the FA isolation as water-soluble polymorph. This operation allowed us to reduce the impurities in the product, to optimize the formulation of the emulsion-based transdermal patches, to provide a quantitative assessment of FA release. Data of IR, 13C NMR, AAS, ICP-AES-spectra, direct and reverse titration of carboxyl groups and phenolic hydroxyls, potentiometry, molecular weight determination by cryoscopy (M.m=740 g/mol), fluorescent analysis, solubility (3.3 mL of water per gram) confirmed the receipt of the desired polymorph. Optimization of the transdermal patches formulations by Response Surface Methodology and release evaluation and kinetics mathematical modeling using a Franz cell showed the preferences of Pluronic Kolliphor p237 as a transcutant. The obtained water-soluble FA can be used as a potential component of transdermal patches with controlled release parameters. Keywords: fulvic acid, transdermal patches, pluronics, release