What is pharmacology?
Science of drugs including their origin, composition, pharamcokinetics, therapeutic use and toxicology.
Along with the properties and reaction of drugs especially with relation to their therapeutic value.
What is meant by the terms pharmacodynamics mean?
The effect the drug has on the patient.
What is meant by the term pharamcokinetics mean?
The movement of the drug within the body.
Absorption, Distribution, Metabolism and Excretion.
How is drug excreted?
How the drug gets into the systemic circulation.
What is meant by first pass metabolism?
Is a phenomenon of drug metabolism whereby the concentration of a drug, specifically when administered orally, is greatly reduced before it reaches the systemic circulation
What does lipid soluble mean?
Most drugs are weak acids or bases that exist as ionized or unionized forms. The unionized form is usually lipid soluble (lipophilic) which means that it can dissolve in and cross cell membranes as part of the process of absorption.
Describe a cell membrane and it properties which aid absorption?
- A cell membrane is a double layer of lipids and proteins that surround a cell. Termed “Phospholipid bilayer”
- It keeps the cell contents (cytoplasm) separate to the external environment.
- Carbon dioxide can easily enter and exit through the membrane as can water (more lowly)
- Ionized molecules can’t pass directly through the membrane as they are water soluble, neither can large molecules such as carbohydrates – they must interact with protein “gates/channels” to pass through
- The cell membrane can surround particles and cut off a section to form a small sphere (vesicle) that is transported where needed – the reverse also happens to expel waste products from the cell
- “Fluid mosaic model” where the membrane is described as movable with proteins that can move around