Poly(amidoamine) Dendrimer/Camptothecin Complex: From Synthesis to In Vitro Cancer Cell Line Studies

Abstract

Camptothecin (CPT), an alkaloid with potent anticancer activity, is still not used in clinical practice due to its high hydrophobicity, toxicity, and poor active-form stability. To address these shortcomings, our research focuses on the encapsulation of this drug in the poly(amidoamine) (PAMAM) dendrimer macromolecule. The PAMAM dendrimer/CPT complex was synthesized and thoroughly characterized. The in vitro drug release study revealed that the drug was released in a slow and controlled manner in acidic and physiological conditions and that more than 80% of the drug was released after 168 h of incubation. Furthermore, it was demonstrated that CPT was released with first-order kinetics and non-Fickian transport. The studies on the hemolytic activity of the synthesized complex indicated that it is hemocompatible for potential intravenous administration at a concentration ≤ 5 µg/mL. Additionally, the developed product was shown to reduce the viability of non-small-cell lung cancer cells (A549) in a concentration- and time-dependent manner, and cancer cells were more susceptible to the complex than normal fibroblasts. Lastly, molecular modeling studies revealed that the lactone or carboxylic forms of CPT had a significant impact on the shape and stability of the complex and that its formation with the lactone form of CPT was more energetically favorable for each subsequent molecule than the carboxylic form. The report represents a systematic and structured approach to develop a PAMAM dendrimer/CPT complex that can be used as an effective drug delivery system (DDS) for the potential treatment of non-small-cell lung cancer.