Preparation and Characterization of Amphiphilic Calixarene Nanoparticles as Delivery Carriers for Paclitaxel

Two types of amphoteric calix[n]arene carboxylic acid (CnCA) derivative, i.e., calix[6]arene hexa-carboxylic acid (C6HCA) and calix[8]arene octo-carboxylic acid (C8OCA), were synthesized by introducing acetoxyls into the hydroxyls of calix[n]arene (n=6, 8). C6HCA and C8OCA nanoparticles (NPs) were prepared successfully using the dialysis method. CnCA NPs had regular spherical shapes with an average diameter of 180–220 nm and possessed negative charges of greater than −30 mV. C6HCA and C8OCA NPs were stable in 4.5% bovine serum albumin solutions and buffers (pH 5–9), with a low critical aggregation concentration value of 5.7 mg·L−1 and 4.0 mg·L−1, respectively. C6HCA and C8OCA NPs exhibited good paclitaxel (PTX) loading capacity, with drug loading contents of 7.5% and 8.3%, respectively. The overall in vitro release behavior of PTX from the CnCA NPs was sustained, and C8OCA NPs had a slower release rate compared with C6HCA NPs. These favorable properties of CnCA NPs make them promising nanocarriers for tumor-targeted drug delivery.