Preparation and in vitro evaluation of an acidic environment-responsive liposome for paclitaxel tumor targeting

Abstract

Paclitaxel (PTX) is an important cancer chemotherapeutic drug. To ameliorate the disadvantages of paclitaxel, this study designed liposomes to load paclitaxel, adding the acid-sensitive material cholesteryl hemisuccinate (CHEMS) to increase the accumulation of the drug in the tumor site. To begin, we used a high-performance liquid chromatography (HPLC) method to determine the content of PTX and the encapsulation efficiency. Then, we prepared paclitaxel-loaded acid-sensitive liposomes (PTX ASLs) by a thin-film dispersion method. We investigated the physical and chemical properties of the liposomes. The particle size was 210.8 nm, the polydispersity index (PDI) was 0.182 and the ζ-potential was −31.2 mV. The liposome shape was observed by transmission electron microscopy (TEM), and the results showed that the liposomes were round with a homogenous size distribution. The release characteristics of the liposomes in vitro were studied via a dynamic dialysis method. The results showed that the prepared liposomes had acid sensitivity and sustained release properties. An in vitro cellular uptake assay of MCF-7 cells showed that the cell uptake of coumarin-6-loaded acid-sensitive liposomes was significantly higher than that of free coumarin-6. The cytotoxicity of the PTX ASLs was significantly higher than that of paclitaxel. In conclusion, these results showed that the prepared liposomes had clear acid-sensitive release characteristics and a higher cell uptake rate and cytotoxicity than free PTX. The system is very suitable for targeted cancer therapy with paclitaxel.