Polyelectrolyte coated polymeric nanoparticles for controlled release of docetaxel

Polyelectrolyte coatings are effective means of minimizing the rate of release of small molecules from a nanoparticle system. The current investigation aim at developing biodegradable drug delivery carriers composed of three types of polymers viz poly(lactide-co-glycolic) acid [PLGA], poly(lactide-co-glycolic) acid-polyethylene imine [PLGA-PEI] and poly lactic acid [PLA]. The PLGA and PLGA-PEI nanoparticles were in the size range approximately 150 nm while PLA nanoparticles were approximately 80 nm in size respectively. The nanoparticles were found to encapsulate 66%, 62% and 65% of the hydrophobic drug, Docetaxel (DOCE) respectively. "Layer by Layer (LbL)" self assembly technique was then performed to coat these particles with polyelectrolyte thin films (PEs). DLS studies showed hydrodynamic diameter of 330 nm, 350 nm and 310 nm for the coated PLGA, PLGA-PEI and PLA nanoparticles respectively, while SEM and TEM studies demonstrated that after coating the particle sizes were approximately 200 nm for all the three nanoparticles. In vitro drug release studies demonstrated that at the end of 24 hours, about 83%, 90% and 88% of drug was released from uncoated PLA, PLGA-PEI and PLGA nanoparticles respectively. Using LbL coating, the same amount of the drug was found to be released in a sustained way for up to 7 days for PLGA and up to 6 days for PLGA-PEI and PLA nanoparticles. In vitro cytocompatibility studies were carried out with each system and the cell viability at end of 48 hours was found to be in the range of 70% to 100%. Current approach of sustained drug delivery can help in improving the therapeutic efficiency of the breast cancer drug, DOCE.