Microrheology techniques for pharmaceutical research

Drugs need to be formulated into medicines before they can be given to patients in a useful form. Injections are an important group of formulations and their viscoelasticity, that is, the ease in which the fluid can be deformed as it passes through the syringe, is an important consideration. However, bulk testing of the viscoelastic behaviour of injectables is often not feasible since they are available only in limited amounts. Here we will investigate new techniques in the field of microrheology, which have been demonstrated to measure the viscoelasticity of very small volumes of sample. The volumes that can be measured are so small that the technique can be applied to the measurement of the viscoelasticity of sub-cellular compartments such as the nucleus and mitochondria. Therefore, in addition to addressing the key issue of pharmaceutical formulation the work will also attempt to measure changes in the viscoelastic environment of a drug as it is internalised into a cell via a process known as endocytosis.

Rheology is the scientific investigation of the viscoelasticity of a material i.e. the degree to which it displays solid and liquid behaviours. For samples of limited availability, or intracellular measurements, current bulk rheological techniques are of little use. Microrheology has obvious advantages in this respect and will be applied as a technique to address two important issues in pharmaceutical science: (1) the formulation of drugs for intravenous delivery and (2) viscoelastic properties of sub-cellular compartments and their relation to gene transfection. The discipline hopping award is an ideal mechanism to allow the lead applicant to explore these two issues in collaboration with a co-applicant experienced in the relevant fields within the pharmaceutical sciences.