Fabrication and Optimization of Dp44mT-Loaded Nanoparticles

This paper describes the modulation of polymeric nanoparticle (NP) preparation to produce an optimal nanocarrier for delivery of the potent anti-tumor iron chelator, Di2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone (Dp44mT) towards application in cancer therapy. We have previously shown the potential of poly (lactic-co-glycolic acid) (PLGA) NPs as a nano-carrier for delivery of Dp44mT to malignant cells. The focus of this study is to alter the fabrication parameters to improve the characteristics of these NPs as a delivery vehicle for Dp44mT. To this end, PLGA NPs encapsulating Dp44mT are fabricated using the nanoprecipitation method with systematic variations in (i) the amount of surfactant poly (vinyl alcohol) (PVA) in aqueous phase, and (ii) the drug to polymer ratio in organic phase. The resultant NPs are characterized for size, surface potential, encapsulation efficiency, and drug release profile. Results of this study showed that increasing the PVA % (within the examined range of 0.5-4% w/v) and decreasing the Dp44mT to PLGA ratio (within the tested range of 0.0375-0.3: 1 mg/mL) both led to an increase in drug encapsulation efficiency. Focusing on the optimal PVA percentage, we found that the changes in drug to polymer ratio did not have a significant impact on the size distribution and surface potential of Dp44mT-NPs and these NPs remained in the desirable range of 80-120 nm. Lastly, the release of Dp44mT from NPs differed for different Dp44mT: PLGA ratios, providing a means to further optimize the NP formulation for future cancer treatment applications.