Drug Development Process 1 Flashcards
Define a drug
A chemical compound of defined structure that upon administration to a living organism produces a biological effect.
What can a chemical compound be?
- A natural product which is isolated and purified
- Synthetic i.e. made by a chemical process
- Semi - synthetic
What is a medicine?
A chemical preparation which contains a drug and other substances.
What can be prescribed for waterborne parasites?
Pomegranate as it contains a powerful antihelminthic.
When did the Royal Pharmaceutical Society form and what did they do?
In 1841
They began legislating for higher standards
What did the Venereal diseases act of 1917 lead to?
The control of unsubstantiated claims for medicines
- Thought as one of the forbears of evidence based medicine
What happened in 1956 for the development of legal framework?
Previous legislation was rationalised and the control of both the sale and manufacture of medicines was combined into a single piece of legislation.
What is extemporaneous dispensing?
The preparation of a medicinal product for an individual patient by the instruction from a doctor.
State the standards for the following elements of extemporaneous dispensing.
- Personal hygiene
- Personal protective equipment
- Work area and equipment
- Label preparation
- Avoidance of contamination
- Suitable record keeping and processes
Why were galenicals made?
- To separate active compounds from inactive from plants
How were galenicals made?
- By macerating a crude drug with a solvent
Why were pills good to make?
- Easy to make
- Compact
- Could mask foul tastes
What are the problems with pills?
- Were often coated in insoluble materials and too dense
- This meant they often went through the GI tract unchanged and unabsorbed.
What is aromatic water?
- An aqueous solution of a volatile substance
What is aromatic water used for?
- Flavouring agent
- Some do have mild therapeutic actions usually carminative
How are waters now prepared?
- From their concentrates; must be diluted with 39 times its volume of potable water to make a single strength water
How do you make money on a drug?
- Stop other people selling it who don’t have the cost of developing it
- Market it
- Develop a patentable formulation
What must you show to patent an entity (not just a drug)?
- Must be novel
- Must involve an inventive step
- Must have utility
What is the lifespan of patents?
20 years
Describe discovery of a target selection/assay development.
- Starts with research into disease mechanisms to identify potential targets that a drug could work on
What is the next stage of drug discovery?
Finding a chemical agent that will act specifically on the target - which is called a lead
Describe the sources of leads.
- Originally relied on natural sources
- Now we are able to ‘design’ leads
State the 5 sources of leads.
- ‘Design’
- Plant
- Marine
- Microorganism
- Semi - synthetic
Describe lead selection - SAR
- Develop an assay that displays interaction of your molecule with the
target plate based/cell based - This identifies ‘drug like’ chemistry that is active against the target
- Possible to start at this stage if you have a chemical you know has an effect
Describe lead refinement.
- Activity/Potency (how well it works)
- Selectivity (how well it binds just to your target)
- Stability (will the compound fall apart in solution?)
- Toxicity
- Solubility
Describe pre-clinical development.
- Routes of manufacture and purity
- Partition co-efficient and pKa
- Crystal properties- polymorphism
(solid state) - Particle size
- Dissolution
- Biopharmaceutical properties
- Chemical stability- long term
- Robust analytical methodologies
- Routes of administration and
formulation
Why do we use animals?
In the body a drug may have problems we can’t
predict It may:-
* be deactivated before it reaches the part of the
body where it needs to act
* be quickly excreted from the body
* be changed in the body to a different chemical,
may become inactive or toxic
* Affect other parts of the body as well
* have unwanted side effects
What are the principles of 3Rs for animal testing?
Refinement
- Development of methods to reduce distress to animals
Reduction
- Obtain most precise information with smallest number of animals
Replacement
- Use of alternatives to animals
How do we screen the drugs in animals?
- Small doses of drug are given to mice (or rats) with a tumour
- The tumour size is measured
regularly to check for a response - The animal is under close watch to check for side effects
Why do we animals have their own care team?
- To check if the drug kills the cancer cells inside the body and at what dose it does this
What are clinical trials?
Human trials:
Phase 1 - involve a small number of volunteers
People given small doses of drug and carefully monitored
Trial tests whether the new drug is safe and how the body deals with it
Phase 2a/b - involves small number of patients
Designed to test whether the new drug has a positive effect on the disease being treated and determine the dose
Phase 3 - involves a large number of patients
Trails tests efficacy and safety in a larger population
Phase 4 - Post marketing safety and efficacy
Where might drugs come from in the future?
- genomics
- proteomics
- metabolomics
Describe genomics?
Study of the genome of an
organism.
Describe proteomics.
Study of the structure and
function of proteins
Describe metabolomics.
Studying the cell’s activities via its metabolites
