Formulation of non-ionic surfactant vesicles for therapeutic delivery of siRNA in cancer treatment

  • Mohammad Ali Radi Obeid

Student thesis: Doctoral Thesis

Abstract

RNA interference (RNAi) is a post-transcriptional gene regulatory mechanism that involves the degradation of a target messenger RNA (mRNA) through the incorporation of short interfering RNAs (siRNA) which is complementary to the target mRNA. Unmodified, naked siRNA is unstable and cannot freely penetrate the cell membrane. The application of siRNA based therapeutics is limited by the development of an effective delivery system to deliver therapeutic siRNA to the cytoplasm of the target cells. Lipid-based nanoparticles, such as liposomes, are the most commonly investigated systems for siRNA delivery. However, another type of lipid-based system known as non-ionic surfactant vesicles (NISV) which are commonly used for drug delivery of various therapeutic agents, are relatively safe and non-expensive have not been extensively studied for siRNA delivery. Therefore, the aim of this study was to investigate the potential of NISV in siRNA delivery. Different manufacturing methods are used for the preparation of NISV and most of them are limited to bench scale and cannot be used on a larger industrial scale. This project sought to optimise the formulation method of NISV and to investigate their potential to effectively deliver siRNA to tumour cells in vitro and in vivo. Different methods of NISV manufacturing were compared including: thin-film hydration method (TFH), heating method, and microfluidic mixing. The formation of spherical nanoparticles was confirmed by examining the morphology of the NISV prepared by the three methods with atomic force microscopy (AFM) or scanning electron microscopy (SEM). TFH and heating methods were able to produce small (<200 nm) and homogeneous NISV only after using a post-manufacturing size reduction step such as extrusion.This was time consuming and it was difficult to control batch to batch variations. Microfluidic mixing was found to produce NISV of the desired size and dispersity required for regulatory approval, in a single step, without the need of size reduction and homogenisation. Moreover, the preparation time was significantly reduced with controllable parameters, which suggested this method would make production feasible on a larger scale.Therefore, microfluidic mixing was chosen to prepare different NISV formulations and to investigate the optimisation of the factors related to this method, including the mixing time, mixing ratio, and the type of hydration media used. These were found to have significant effects on the physical characteristics of the vesicles such as size, polydispersity index, and charge. Particle size was shown to be decreased significantly (p
Date of Award1 Oct 2017
LanguageEnglish
Awarding Institution
  • University Of Strathclyde
SupervisorValerie Ferro (Supervisor) & Rothwelle Tate (Supervisor)

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