Preparation and anticancer activity evaluation of an amorphous drug nanocomposite by simple heat treatment

The solubility of drug molecules is closely related to its bioactivity as it affects the dissolution rate and bioavailability, especially in the case of BCS IV drugs like camptothecin (CPT), a potential broad-spectrum anticancer agent. In this study, we construct a novel boric acid (BA)-coated CPT nanocomposite by means of a simple heat-treatment approach, which combines nanoscale size range and amorphous solid state together to improve the overall dissolution rate of CPT. This new CPT formulation showed a rod-like structure with nanoscale size and amorphous solid nature. These BA-coated CPT nanocomposites exhibited a dramatically improved dissolution rate, water dispersion property, and long-term chemical and physical stability. More importantly, the specific reactivity of BA groups to diols in the cell glycocalyx facilitated a rapid cross-membrane translocation of the drug nanocomposite, leading to efficient intracellular drug delivery. When tested on A549 cells and SKBR3 cells, this formulation demonstrated a much higher anticancer activity in comparison with free CPT, naked amorphous CPT nanoparticles, and control CPT nanocrystals. This formulation has great potential for clinical application; it is easy to scale up and be applied on other hydrophobic drugs.