PAMAM dendrimers in drug delivery: loading efficacy and polymer morphology

The binding efficacy of anticancer drugs doxorubicin and tamoxifen with polyamidoamine (PAMAM-G4) dendrimers was studied in aqueous solution at physiological pH. The results of multiple spectroscopic methods, transmission electron microscopy (TEM), and molecular modeling of conjugated drug-polymer were examined. Structural analysis showed that drug-polymer conjugation occurs mainly via H-bonding and hydrophilic and hydrophobic contacts. Doxorubicin forms a more stable conjugate with PAMAM-G4 than tamoxifen. The drug loading efficacy was 40%-50%. The TEM images showed major changes in the PAMAM morphology upon drug encapsulation. Modeling showed that drug is located in the polymer surface and in the internal cavities. PAMAM nanoparticles are capable of transporting doxorubicin and tamoxifen in vitro. This minireview presents the most recent work performed with the dendrimers demonstrating their usefulness for drug delivery in cancer therapy.