Abstract

• This research work concerns with the green synthesis and characterization of gold nanoparticles (GNP) and chitosan-gold nanoparticles (CS-GNP) composite beads. The gold nanoparticles (GNP) were prepared from chloroauric acid in the presence of the aqueous extract from fresh papaya leaf as well as dry papaya leaf used as reducing agents, respectively. The existence of prepared GNP in colloidal solutions was determined by using laser pointer, noted as GNP (G) and GNP (D), Tyndall effect and the synthesized gold nanoparticles (GNP) solutions were also characterized by UV-visible spectroscopy, TEM, SEM, EDXRF and XRD analyses. On the other hand, chitosan beads were produced from different concentrations of chitosan (1 % to 5 % w/v) in 1 % v/v acetic acid solution and in 2 % w/v sodium hydroxide solution. The chitosan-gold nanoparticles composites were then prepared from gold nanoparticles and 3 % w/v chitosan solutions. These composites solutions were forced through by syringe into 2 % w/v sodium hydroxide to form beads, were designed as CS-GNP (G) and CS-GNP (D).The physical properties of prepared chitosan beads and chitosan-gold nanoparticles composite beads were studied, such as water content, moisture content, pH and swelling percent in different pH of buffer solutions at different contact times, and these samples were also characterized by using FT IR, EDXRF, SEM and XRD analyses. Then these prepared composite beads were applied in drug delivery system. Aspirin (ASA) was used as a model drug. The absorption of aspirin by the composite beads was determined by using UV-visible spectrophotometer. The physical properties of drug loaded chitosan-gold nanoparticles composite beads such as ASA-CS-GNP (G) and ASA-CS-GNP (D) were studied and these drug loaded samples have been characterized by FT IR, EDXRF, SEM and XRD analyses. Then drug release behaviors of such drug loaded composite beads were investigated in simulated gastrointestinal fluid pH of buffer solutions and acute toxicity of the prepared chitosan-gold nanoparticles colloidal solutions was examined.