Influence of micro gel particles of sodium alginate on gel structure of calcium alginate gels used for controlled release of active substances

The properties of gel particles of calcium alginate with a chitosan membrane for controlled release of active substances, beside the conformation properties of the macromolecules of sodium alginate and chitosan in solution, depend on the internal structure of the gel which can be controlled or be modified by inducing micro gel structures in the pregel solution with addition of calcium ions. The quantity, dimension and the form of the micro gel structures are in direct relation with the molecular mass, dimension, flexibility, electrical properties, concentration and the mannuronic-to-guluronic ratio from the primary chain of sodium alginate macromolecules as well as temperature. Also, the final properties of controlled release are predetermined from the conditions of gel particle preparation (rate of dropping of sodium alginate solution in the gelling bath, speed of steering of the gelling bath and the time of setting of the gel particles). The research is realised by working with the methods of- gel-permeation chromatography, viscosimetry, static and dynamic light scattering, electric birefringence, spectrophotometry of the kinetics of release of the active substance and scanning electron microscopy.(Author)