Whats in a medicine

1
Whats in a medicine?

• Storylines WM1 The development of modern ideas
  about medicines

2
Useful definitions

• Pharmaceuticals
• Drugs
• Poison
• Pharmacology
• Pharmacy

• Complex compounds
• Active ingredients of medicines that alter the
  bodys chemistry.
• A drug which is not beneficial to the body.
• The study of drugs.
• The art and science of making and dispensing
  medicines.

3
WM1 The development of modern ideas about
medicines.

• 1000s of years ago, medicines were used by trial
  and error no-one knew how they worked.
• Today, molecular pharmacologists design drugs
  which have specific effects.
• gtgtgt activity WM1 The origins and development of
  the modern pharmaceutical industry.

4
WM2 Medicines from nature.

• Modern pharmacy is based on herbal and folk
  remedies. Remedies from old wives tales are
  investigated to find the active ingredient.
• Doctrine of signatures the idea that illnesses
  can be cured by plants which are associated with
  them.
• Eg dock leaves for stinging nettle stings.

5
Medicines from willow bark

• Old Doctrine of signatures idea marshy ground
  causes fevers. Willow trees grow there so use
  them as the remedy!
• Hippocrates (400 BC) willow leaf brew eases
  pain of childbirth.
• Edward Stone (1763) willow bark reduces fevers.

6
Culpepers Herbal

• Nicholas Culpeper (1616-1654) published his
  astrological botany book Herbal in 1640.
• His decoction of bruised leaves with pepper in
  wine was most effective at staunching the
  bleeding of wounds suppressing vomiting
  clearing acne.
• Modern uses salicin, found in the bark, is used
  to make aspirin for treating malaria.

7
The salix drug

• Salicin, named after salix (Latin for Willow),
  has no pharmaceutical effect.
• The body converts salicin to salicylic acid by
  hydrolysis and then oxidation.
• gtgt Do activity WM2 and extract your own
  salicylic acid!

8
WM3 Identifying the active chemical in willow
bark.

• Whats the structure of salicylic acid?
• These chemical tests give some clues
• The compound is weakly acidic in aqueous
  solution.
• Reactions with alcohols produce fruity-smelling
  ESTERS.
• It turns a neutral solution of iron (III)
  chloride an intense PINK.

9
What do these tests show?

• Tests 1 and 2 are characteristic of CARBOXYLIC
  ACIDS.
• COOH
• OH
• Test 3 shows that PHENOL is present.