Adsorption and Controlled Release of Antibiotic Drug from Graphene Oxide Functionalized Polyester Dendrimer

The presented work focused on the production of a novel polyester dendrimer as a promising delivery system for metronidazole drug. The third generation of polyester dendrimers were prepared by esterification reaction between pentaerythritol and phthalic acid on the graphene oxide surface. The surface chemistry and morphology, and chemical structure of the nanocarrier were characterized by field emission scanning electron microscopy, energy-dispersive X-ray, Fourier transform infrared, and N2 adsorption-desorption analyses. The effect of three independent factors including pH, initial drug concentration, and contact time on the drug sorption was studied in the ranges of 3-9, 5-50 mg L-1, and 2-90 min, respectively. The optimum conditions for pH, initial drug concentration, and contact time were found as 5, 15 mg L-1, and 15 min, respectively. The data shown that experimental results were well explained by the pseudo-2nd-order kinetic model and equilibrium data indicated a good fit to the Langmuir isotherm model. The nanocarrier shown a considerably high drug loading and controlled drug release. This nanocarrier can release drug for up to 98.92% in 6 h, at pH=7.4 (simulated intestinal fluid) and 34.92% in simulated gastric fluid (pH=1.2) in 1 h.