Development of controlled delivery drug system for glyphosate used in weed control of agricultural manage

Development of Controlled Delivery Drug System for Glyphosate Used in Weed Control of Agrıcultural Manage In this work, controlled release systems of glyphosate, an effective non-selective herbicide widely used in agricultural manage worldwide, have been developed. The ability of the clay samples to adsorb of glyphosate active ingredient was investigated with crude and thermally activated calcine forms. Remaining glyphosate in the liquid solution has been identified using UV spectrophotometer. The adsorption capacities of glyphosate material for crude kaolin, calcined kaolin, crude bauxite and calcined bauxite (KB) were 0.12, 2.72, 2.70 and 13.6 mg / g, respectively. Adsorption equilibrium data were analyzed using Langmuir and Freundlich isotherms and it was determined that the glyphosate adsorption was compatible with the Langmuir isotherm. Adsorption enthalpy was determined to be 9.79 kJ / gmol, indicating that the adsorption reaction was performed endothermically. When the kinetics of adsorption were examined, it was determined that the adsorption was suitable for the second-order kinetic model. Encapsulation studies were carried out using chitosan, glutaraldehyde (GA) and sodium tripolyphosphate (TPP) cross-linking agents and alginate and calcium chloride (CaCl2) crosslinking agent using a calcined bauxite clay adsorbed on the surface. The morphological stability chitosan beads using GA as a cross-linker relative to chitosan beads of TPP was related to the crosslinking of GA by chemical bond formation. Alginate with CaCl2 cross-linked bead constructions were also considered suitable for their morphological stability in terms of their release suitability Chitosan-KB-glyphosate beads release 1 mg of the drug in 600 hours while alginate-KB-glyphosate beads release 1.4 mg of drug in 288 hours. Delivery efficiencies were determined as 68.5% and 96% for beads of chitosan and alginate, respectively. Considering the amount of glyphosate released from chitosan-KB-glyphosate and alginate-KB-glyphosate beads, glyphosate is more slowly released from chitosan beads, but delivery efficiencies of alginate beads are higher. Scanning electron microscope (SEM), morphology of chitosan-KB-glyphosate structured beads was determined. In this study it was thought that controlled release products could be developed which are environmentally friendly alternative to glyphosate based products. Keywords: Chitosan, Clay, Alginate, Encapsulation, Controlled release, Bauxite, Adsorption