CONICET | Buscador de Institutos y Recursos Humanos

Molecular aggregation and instability of small molecules are common problems of next generation of pharmaceuticals and foods under physiological conditions. It requires the develop an appropriate technology. Stimuli responsive hydrobiogels for control release of molecule are becoming increasingly attractive for industry. Two anionic biopolymers Alginate (Alg) and Pectin (P) have been studied as a matrix system to release molecules, oral or transdermal. The polymers can control the release of molecules through mechanisms dependent on pH and temperature. However these polymers are commonly unstable under physiological conditions present in biology fluids and usually are requires to be combined with others polymers. To stabilize the matrix two gums were chosen: Guar (GG) and Arabic (AG) and as model molecules to release was used Congo Red (CR) and crystal violet (CV). The mixtures of different polymers with gums were made with different ratios to determinate the best formulation Alg/GG and P/GA. The microspheres of Alg-GG containing Congo Red (CR) and P-AG containing Crystal Violet (CV) were formed in presence of calcium ions. Kinetics of dyes release in Alg/GG (7/1) and P/AG (2/1) microspheres were studied at 37ºC and 150 rpm. Loading efficiency was approximately 90%. All microspheres were very stable in simulated gastric fluid (pH 1.2) for at least 3 hours. Physiological conditions were simulated to evaluated the behavior of systems using phosphate buffer pH 7.4 and 6.8 without or plus 154 mM NaCl. Encapsulation of the dyes, in all cases, showed a decrease of the biopolymer solution viscosity indicating and interaction between probes and the matrixes. The interactions were confirmed by FTIR and Raman spectroscopy by the shift of functional dyes groups.