Paclitaxel release from hollow PMMA nanoparticles: Factors affecting release rate as quantified via dialysis and membrane centrifugation

Despite known limitations, dialysis and centrifugation remain standard methods for quantifying in vitro drug release kinetics. In the context of quantifying drug release from nanoparticles, dialysis uses a membrane to retain nanoparticles whilst drug released from the nanoparticles transfers across the membrane. The present work investigates the use of dialysis and solely for comparison membrane centrifugation for quantitative characterisation of Paclitaxel (PAX) release from hollow poly(methyl methacrylate) (PMMA) nanoparticles (PAX-NPs) synthesised using a simple one-pot miniemulsion polymerisation system. The impact on drug release rate when using GSH to cleave disulphide crosslinked PMMA, the incorporation of methacrylic acid as a co-monomer, and use of a hydrotrope (sodium subsalicylate) for enhanced drug solubility are discussed. Finally, we summarise the limitations of dialysis and membrane centrifugation due to a complex interplay of factors including drug concentration, molecular weight, hydrophobicity, internal to external dialysis volume and partitioning.