Folate-mediated targeting of albumin conjugates of paclitaxel obtained through a heterogeneous phase system.

The study developed cytotoxic macromolecular conjugates that specifically target the folate receptor and deliver the drug into cell cytoplasm. The anticancer agent paclitaxel was conjugated to human serum albumin (HSA) and this drug-albumin conjugate was further equipped with folic acid, linked via an extended poly(ethylene glycol) spacer. Preparation was carried out in a heterogeneous phase system exploiting the binding ability of Cibacron Blue dye to HSA. Unreacted reagents were easily removed and, after purification by gel filtration, the conjugate was fully characterized. Binding and in vitro cytotoxicity studies on human nasopharyngeal epidermal carcinoma KB and colorectal carcinoma HT-29 cells (as negative control) demonstrated increased selectivity and anti-tumoral activity.