Promoting antitumor activities of hydroxycamptothecin by encapsulation into acid-labile nanoparticles using electrospraying.

PURPOSE: Acid-labile nanoparticles are proposed to enhance the tumor targeting and anti-tumor therapy of hydroxycamptothecin (HCPT) in response to the acidic microenvironment within cells and tumor tissues.
METHODS: HCPT was entrapped into matrix polymers containing acid-labile segments and galactose moieties (PGBELA) through an electrospraying technique. The antitumor activities of HCPT-loaded nanoparticles were evaluated both on HepG2 cells and after intravenous injection into H22 tumor-bearing mice.
RESULTS: The electrosprayed nanoparticles were obtained with enhanced loading efficiency and extended release of HCPT compared with other nanoparticle preparation methods. The acid-lability and targeting capability of PGBELA nanoparticles resulted in a 5 times higher inhibitory activity after incubation in pH 6.8 media compared to that of pH 7.4. Animal studies indicated that both the blood circulation time and tumor distribution of PGBELA nanoparticles were significantly increased. HCPT/PGBELA nanoparticles indicated a superior in vivo antitumor activity and fewer side effects than other treatments on the basis of tumor growth, animal survival rate, tissue necrosis and cell apoptosis evaluation.
CONCLUSION: Biodegradable PGBELA nanoparticles are capable of achieving site-specific drug delivery by active targeting and triggered release by acidic pH both in tumor tissues and after internalization within tumor cells, thereby providing a novel strategy for cancer treatment.