CH 2 Flashcards
(11 cards)
Why does it take so long for a company to develop a new drug?
years worth of research & development, significant testing & mandated trials and evaluation by Health Canada before a drug can be marketed
What are the 4 stages of drug development? Outline what happens during each stage.
Stage 1: Discovery of a new drug:
Preliminary studies in a lab (computer model, fungi, bacteria) to determine if has intended effect and if any toxic properties
Stage 2: Safety/Efficacy
Preclinical studies:
Tests on Lab animals to determine safety
Toxicity studies (short and long-term)
Drug reaction studies
Organ systems, repro, carcinogenicity, teratogenicity studies
Clinical trials:
On target species evaluating safety and effectiveness
Toxicity or adverse reactions?
Tissue withdrawal times and residue limits
Shelf life/stability
Stage 3: Licensing for Manufacturing
Stage 4: Long-term Manufacturer monitoring of drug to ensure product safety and efficacy
What is the difference between a preliminary study and a preclinical study?
Preliminary in lab on computer or bacterial
Preclinical on lab animals (commonly mice
What is the difference between a preclinical study and a clinical trial?
Preclinical tests on lab animals for safety, toxicity & reactions
Clinical trials on target species for safety & effectiveness
Define carcinogenicity and teratogenicity.
carcinogenicity.
Ability of a drug to cause cancer
teratogenicity.
Ability of a drug to cause birth defects and/or embryo deaths
How long does a company have to monitor a drug after it has been released?
As long as it is manufactured
Why are both short term and long term testing important?
Short term testing for safety & efficacy: monitor hours after a dose for ADRs
Long term testing for safety & efficacy: run 3-24 months, repeated dosing, for organ function & any other toxic effects
What special tests are performed to assess new drugs?
Toxicity evaluations
ED50 and LD50
Define ED50 and LD50
LD50 Amount of a drug (dosage) that is lethal in 50% of the animals that receive it
ED50 Amount of a drug (dosage) that produce desired effect in 50% of the animals that receive it
What is a therapeutic index? How is this calculated?
Margin of safety determined during short term toxicity phase
LD50 ÷ ED50
- Higher the number, the wider the margin of safety
What are systems oriented screens, and how are they performed?
Next step after toxicity study – tests particular effects of a specific system. Uses blood, tissue, urine samples etc.
