Write all you can, using Organic Chem and Redox knowledge about ...

Objectives

• MUST: Learn definitions of what is a drug ? what is Therapeutic Index ? How can drugs be administered ?

• SHOULD : Use previous knowledge to prepare a saline solution, and model the three parenteral routes using an orange as model for human skin.

• COULD : Apply SL and HL Organic Chemistry knowledge to new molecules, e.g. Aspirin, Morphine, Adrenaline.

What is a Drug ?

• Alters physiological state – consciousness, activity level, coordination

• Alters incoming sensory experience• Alters mood or emotion

• Placebos are drugs containing no active ingredient, which “fool” the human body into healing.

How is Safety Established ?

• First the drug must be isolated or synthetized.• The drug is tested on animals. LD50 and ED50 are determined.

• LD50 is a lethal dose necessary to kill 50 percent of animal population. ED50 is an effective dose, one creating a noticeable effect in 50% of animal population. The ratio between LD50 and ED50 is called the Therapeutic Index.

• Therapeutic Index = LD50 / ED50

Huh ?

• Therapeutic determines a safety of drug. If the therapeutic index of a drug is 10, a person would have to intake ten times more drug than the effective dose for the effects to be lethal.

• During testing, half of the patients receive a real drug and the other half similar-looking placebo. This determines whether the drug has a real effect or the pill only fooled body into healing.

Show me a More !

• So if LD50>>ED50 hard to overdose.

• And if LD50 = ED50 then easy to overdose.

Methods of administering Drugs

• Each student make 100cm3 of a 0.154M saline solution.

• Load your hypodermic needle with an aliquot of saline and inject your orange :-

• Intravenous – veins• Intramuscular – muscles• Subcutaneous – under skin

Plenary Quiz

• What is a drug ?• By what routes may a drug be administered ?• What does ED50 / LD 50 ratio mean ?• How is this related to therapeutic index ?