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 (C(6)HCA) and calix[8]arene octo-carboxylic acid (C(8)OCA), were synthesized by introducing ace-toxyls into the hydroxyls of calix[n]arene (n=6, 8). C(6)HCA and C(8)OCA nanoparticles (NPs) were prepared successfully using the dialysis method. CnCA NPs had regular spherical shapes with an average diameter of 180-220nm and possessed negative charges of greater than -30 mV. C(6)HCA and C(8)OCA NPs were stable in 4.5% bovine serum albumin solutions and buffers (pH 5-9), with a low critical aggregation concentration value of 5.7mg.L-1 and 4.0 mg-L-1, respectively. C(6)HCA and C(6)OCA 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 C(8)OCA NPs had a slower release rate compared with C(6)HCA NPs. These favorable properties of CnCA NPs make them promising nanocarriers for tumor-targeted drug delivery.