OPTIMISATION OF POLYMERIC NANOPARTICLES FOR BRAIN TUMOURS: A TRANSITION FROM CONVENTIONAL METHODS TO MICROFLUIDICS

Abstract

Glioblastoma multiforme (GBM) is one of the predominant causes of cancer-related mortality worldwide, affecting individuals across various age groups. The blood-brain barrier (BBB) is a substantial obstacle for chemotherapeutics, as it restricts their ability to penetrate the brain and complicates the management of GBM. Nanoparticles (NPs) offer a customisable, non-invasive approach to improve drug delivery to the brain. This thesis aimed to develop poly(lactide-co-glycolide) (PLGA) NPs with enhanced drug loading (DL) capacity for Irinotecan hydrochloride (IRN) and the scaling up of their production through microfluidics. These NPs can overcome the challenges associated with the BBB and improve therapeutic efficacy. Various IRN-PLGA NPs were produced using the single emulsion evaporation technique to enhance DL while keeping the particle size under 300 nm. The production of NP was scaled up via the microfluidics technique. The processing parameters for microfluidics were optimised using blank PLGA NPs, followed by incorporating IRN into the PLGA NPs. The Box-Behnken Design (BBD) of the experiment was conducted using the optimal microfluidics processing parameters to determine the optimal formulation conditions for achieving the smallest particle size, lowest zeta potential, and high encapsulation efficiency (EE) and DL. The influence of formulation variables, specifically PLGA, IRN, and polyvinyl alcohol (PVA), on the physicochemical properties of the NPs was assessed. The cytotoxicity, cellular uptake, and mechanisms of cell death were evaluated in GBM cells. The permeability of the NPs across the BBB model was assessed through transendothelial electrical resistance (TEER) measurements. The results indicated that the NPs generated by the traditional method (F7 NPs) exhibited an increase in DL to approximately 5% with a particle size of 292 nm. The variation of microfluidic parameters, which include flow rate ratio (FRR) and total flow rate (TFR), impacted the physicochemical properties of the blank PLGA NPs. The findings demonstrated that the optimal processing parameters for microfluidics were an FRR of 1:7 and a TFR of 8 ml. The loading study demonstrated that IRN was efficiently incorporated into the PLGA NPs at concentrations determined based on F7 NPs using optimal microfluidic conditions. The BBD determined the optimum formulation using independent variable values of 128.3 mg of PLGA (X1), 13.9 mg of IRN (X2), and 2.4% PVA (X3). This formulation yielded a particle size of 161.36 nm and a DL of 6% (MF13 NPs). The characterisations of the NPs produced by the conventional technique and microfluidics were comparable, except for particle size and DL. Microfluidics generated NPs with a smaller particle size and enhanced DL compared to those produced by the traditional method. The release of IRN from the PLGA matrix was affected by the pH of the release media, with a higher IRN release observed under acidic conditions. MF13 NPs exhibited enhanced cellular uptake, cytotoxicity, and permeability across the BBB model compared to F7 NPs due to their smaller particle size, which improved their biological interaction. Overall, MF13 NPs exhibit potential effectiveness in the treatment of GBM. Therefore, future in vivo studies are essential to further evaluate the biodistribution and therapeutic efficacy of MF13 NPs.