Augmented cytotoxicity of hydroxycamptothecin-loaded nanoparticles in lung and colon cancer cells by chemosensitizing pharmaceutical excipients.

Noha M Zaki

Index: Drug Deliv. 21(4) , 265-75, (2014)

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Abstract

The aim of this was to investigate and compare the chemosensitizing effect of some pharmaceutical excipients (TPGS, Pluronic P85 and chitosan) by evaluating the cytotoxicity of the chemotherapeutic drug Hydroxy Camptothecin (HCPT) loaded into PLGA nanoparticles. Different nanoparticles formulations were developed and evaluated for size, zeta potential, morphology, loading and encapsulation efficiency as well as in vitro drug release. The cytotoxicity of the nanoparticles was evaluated by MTT assay in A549 (human lung carcinoma cell line) and HT29 (human colon carcinoma cell line) whereas their cellular uptake was determined by confocal laser scanning microscopy and microfluorimetry assay. The results revealed that nanoparticles possessed a desirable nanometric size (revealed by dynamic light scattering measurements and TEM) with appreciable HCPT encapsulation (>48%) and negative surface charge that was switched to positive upon coating with chitosan. The nanoparticles adopted a sustained release phase preceded by initial burst of HCPT that was reduced by chitosan coating. The cytotoxicity of the nanoparticles in A549 and HT29 cells was significantly augmented compared to simple drug solution and basic nanoparticles without excipients. The excipients could be ranked according to their IC50 lowering effect in the following order [TPGS (sixfold lower IC50) > Pluronic P85 > Chitosan]. The augmented cytotoxicity and chemosensitizing effect might be attributed to overcoming drug efflux (in case of TPGS 1000 or Pluronic P85) and/or maximizing internalization by cancer cells (chitosan coating). Acting as chemopotentiators, the studied excipients could have potential in reducing therapeutic HCPT doses and minimizing adverse effects in lung and colon chemotherapy.