Synthesis and characterization of low generation polyamidoamine dendrimers and release of 5-fluorouracil from their complexes

The aim of this work was to investigate the potential of low-generation polyamidoamine (PAMAM) dendrimers as drug nanocarriers for 5-fluorouracil (5-FU), an anticancer drug, and to determine the type of dendrimer generation (half or full) with the highest drug load capacity and slowest release rate. For this, PAMAM dendrimers (up to 2.0 generation) were synthesized and characterized by means of spectroscopic techniques and thermal analysis. Then, 5-FU was successfully incorporated into dendrimers, and the resulting complexes were characterized in terms of their, elemental composition, spectroscopy, thermal behavior, and loading efficacy. In addition, in vitro release studies of 5-fluorouracil from complexes were conducted using phosphate-buffered saline; and the 5-FU release kinetics was also modeled. The successful synthesis of PAMAM dendrimers was confirmed by Fourier transform infrared spectroscopy (FTIR), H-1-NMR, UV-vis, dynamic light scattering and thermogravimetric analysis (TGA) analysis. Energy-dispersive X-ray spectroscopy (EDX), FTIR, UV-vis and TGA results confirmed the complexation phenomena among PAMAM dendrimers and 5-FU drug. It was found that the encapsulation efficiency and drug release rate are a function of generation type, and that the full-generation dendrimers showed the best results. The Korsmeyer-Peppas model best described the kinetics of drug release for all complexes. These results confirm that the proposed low-generation dendrimers are suitable polymeric nanocarriers for drug delivery applications.