LIFESTYLE CHEMISTRY
Part 5: The Solubility of Drugs
IDENTIFY THE PARTS OF
THE DIGESTIVE SYSTEM
Mouth
oesophagus
Liver
Gall bladder
duodenum
Small intestine
Stomach
Pancreas
Large intestine
Rectum
OUTLINE THE ROLE OF THE
STOMACH AND THE SMALL
INTESTINE IN BREAKING
DOWN FOOD
Role of the stomach
• Begins digestion of protein and churns food
into a paste
• Protease enzymes digest protein
• The protein is broken down into peptides
• Hydrochloric acid helps the enzymes present
to function and kills microbes
Role of the Small Intestine
The small intestine produces a fluid containing enzymes to
complete digestion of carbohydrates, protein and fats
FAT
OTHER
CARBOHYDRATES
PROTEIN
Lipase
Enzyme
Fatty Acids
&
Glycerol
Other
Enzymes
Glucose
Peptidase
Enzyme
Amino
Acids
Absorbed
across the
small
intestine
wall into
the blood
stream
DISCUSS THE DIFFERENCE
IN PH OF THE STOMACH AND
THE SMALL INTESTINE
pH in the Digestive System
• Stomach pH=3
• Hydrochloric Acid
• Kills Bacteria
• Small Intestine pH= Alkaline
• Neutralise stomach acid
• The stomach and the small intestine have different pH
values as different enzymes function best in differing
levels of acidity and alkalinity
• eg. pepsin functions best in the stomach at a pH of 1 to 2 while
other enzymes such as protease and lipase function best in a pH
range of 6 to 8.
EXPLAIN WHY A KNOWLEDGE
OF THE SOLUBILITY OF
MATERIALS CAN BE USED TO
DESIGN DRUGS FOR
SPECIFIC TASKS
Delivery Methods of Drugs
Inserted into
body cavities
In ears or
eyes
Applied
under skin
Inhaled
Injected
DRUGS
Applied to
skin
Swallowed
Solubility of Drugs
• Injected = absorbed more rapidly
• Weak Acid Drugs
• absorbed in stomach
• Weak Basic Drugs
• insoluble in stomach
• absorbed in small intestine
ACCOUNT FOR THE
ABSORPTION OF A DRUG AND
ITS ACTION ON/IN THE BODY IN
TERMS OF ITS SOLUBILITY
IDENTIFY THAT THE MANNER
OF ADMINISTRATION OF A
DRUG MAY BE RELATED TO ITS
SOLUBILITY
Administering Drugs
• SPOTLIGHT SS pg 157-159
IDENTIFY VITAMINS THAT
ARE WATER-SOLUBLE AND
THOSE THAT ARE FATSOLUBLE
Vitamins
Fat Soluble
Water Soluble
• Dissolve in fat
• Dissolve in water
• Stored in out fatty tissue
• Our bodies don’t store
these vitamins so we
constantly need to ingest
more
• Vitamins A, D, E and K
• The eight B-group
vitamins and Vitamin C
LIKE DISSOLVES LIKE
Water
• Polar solvent
Water-Soluble Vitamins
• Polar molecules (have
high polar end)
Vitamin A
Fat
• Non-polar solvent
Fat-soluble Vitamins
• Non-polar molecules
(non-polar C-C bonds)
REVIEW QUESTIONS
Spotlight pg 162
To Think About Set 1-3