Practical Aspects in Drug Delivery (D4)

Question 1

When monitoring Drug Delivery, what is the equation that links effective diffusion to porosity, tortuosity (degree of twisting of the path) and the diffusion coefficient of the molecule

Answer 1

Question 2

What is meant by effective diffusion?

Answer 2

• The term effective diffusion refers to the diffusion rate when considering factors such as, porosity, tortuosity, medium characteristics, the diffusion coefficient

Question 3

What is this? and its purpose?

Answer 3

• Franz diffusion cell
• For calculating the diffusion coefficient across specific membranes

Question 4

Explain how Magnetic Resonance Spectroscopy can be used to calculate diffusion coefficients of biological tissues

Answer 4

Principle: MRS measures the concentration of certain metabolites within tissues and can provide information about their diffusion properties.

Implementation: By observing changes in the signal over time, MRS can indirectly infer information about the diffusion of metabolites.

Question 5

Explain how pulse oximetry works

Answer 5

Pulse oximetry measures the absorption of light by oxygenated (oxyhemoglobin) and deoxygenated (deoxyhemoglobin) hemoglobin in arterial blood

By comparing the absorption of these wavelengths, the device calculates the percentage of oxygen saturation in arterial blood.

Question 6

What is this device?

Answer 6

This is a device used in the formulation of emulsion droplets
- The small nozzle and pressure from the fluids ensures that the droplets are all uniform in size

Question 7

List a few methods of analysis that could be used to assess cellular response to a drug

Answer 7

• Cell Viability using dyes (determines leakage)
• Apoptosis assays
• assess morphology using microscopes
• Assess enzymatic activity by measuring relevant markers
• Assess for DNA damage using stains

Question 8

How is the stability of drug formulations tested?

Answer 8

1) Drugs are stored in an environmental chamber at various temperatures, including room temperature, refrigeration, and freezing, to assess their stability under different conditions.

2) Samples are analyzed at predefined intervals over an extended period, often up to several years, to monitor changes in key parameters.