2. Basic Steps
• Choose a disease
• Choose a drug target
• Identify a “bioassay”
bioassay = A test used to determine biological activity.
• Find a “lead compound”
“lead compound” = structure that has some activity against the
chosen target, but not yet good enough to be the drug itself.
• If not known, determine the structure of the “lead compound”
• Synthesize analogs of the lead
• Identify Structure-Activity-Relationships (SAR’s)
3. • Structure-Activity-Relationship (SAR) = How does the activity
change as structure is systematically altered?
• Identify the “pharmacophore”
pharmacophore = the structural features directly responsible for
activity
• Optimize structure to improve interactions with target
• Determine toxicity and efficacy in animal models.
• Determine pharmacodynamics and pharmacokinetics of the drug.
• Pharmacodynamics explores what a drug does to the body,
whereas pharmacokinetics explores what the body does to the
drug.
4. Basic steps (cont.)
• Patent the drug
• Study drug metabolism
• Test for toxicity
• Design a manufacturing process
• Carry out clinical trials
• Market the drug
5. Choosing a
Disease
• Pharmaceutical companies are
commercial enterprises
• Pharmaceutical companies will,
therefore, tend to avoid products with a
small market (i.e. a disease which only
affects a small subset of the population)
6. Choosing a
Disease
• Pharmaceutical companies
will also avoid products that
would be consumed by
individuals of lower economic
status (i.e. a disease which
only affects third world
countries)
7. Choosing a Disease (cont.)
• Most research is
carried out on diseases
which afflict “first world”
countries: (e.g. cancer,
cardiovascular
diseases, depression,
diabetes, flu, migraine,
obesity).
8. The Orphan Drug Act
• The Orphan Drug Act of 1983 was passed to
encourage pharmaceutical companies to develop drugs
to treat diseases which affect fewer than 200,000
people in the US
• Under this law, companies who develop such a drug
are entitled to market it without competition for seven
years.
• This is considered a significant benefit, since the
standards for patent protection are much more
stringent.
9. Identifying a Drug Target
• Drug Target = specific macromolecule,
or biological system, which the drug will
interact with
• Sometimes this can happen through
incidental observation…
10. Identifying a Drug Target (cont.)
•Example: In addition to their being able to inhibit the uptake
of noradrenaline, the older tricyclic antidepressants were
observed to “incidentally” inhibit serotonin uptake. Thus, it was
decided to prepare molecules which could specifically inhibit
serotonin uptake. It wasn’t clear that this would work, but it
eventually resulted in the production of fluoxetine (Prozac).
NH2
N
H
HO
serotonin
O
HN
prozac
N
N CH3
H3C
Imipramine
(a classical tricyclic antidepressant)
F3C