1. ANTACIDS

2. Human Stomach Gastric juices in stomach Contain HCl (aq) Ph 1-3
To suppress growth of bacteria
To help in digestion by hydrolysing proteins to amino acids

3. Indigestion Excess acid production Abdominal discomfort after eating
Over eating
Stress
Certain foods
Acid eats away protective mucus layer
Painful ulcers

4. Antacids Remedy for excess stomach acidity Bases
Metal oxides, hydroxides
Metal carbonates
Metal hydrogencarbonates
(bicarbonates)

5. Effect of Antacids
Neutralise excess acid and adjust stomach ph to desired level
Stomach lining repairs itself
Active ingredients
Aluminium hydroxide
Magnesium hydroxide
Sodium hydrogen carbonate

6. Alginates Combined with antacids Extracted from brown seaweeds
Produce a neutralising layer rthat prevents acid reflux
E.g. they prevent acid from rising into oesophagus
«Heartburn»

7. Dimethicone Anti-foaming agent
Added to reduce surface tension of gas bubbles
Causes bubbles to coalesce (come together)
Produces defoaming action

8. Side effects Aluminium hydroxide may cause constipation
Can prevent uptake of phosphate ions (precipitation of aluminium phosphate)
Large charge to size density leads to binding with other drugs

9. Side Effects Magnesium hydroxide has laxative properties
Calcium carbonate may lead to kidney stones
Sodium ions may lead to hypertension

10. Alkalosis
Taking too much antacid leads to alkalosis (a rise in ph of blood)
Also can lead to excessive amounts of calcium ions in body

11. Question
Two solid antacid products contain same mass of different active ingredients. One contains sodium bicarbonate, the other calcium carbonate. Which is the better buy and why ?

12. To Do Look at active ingredients of antacids on page 410
Also look at chemical equations
Then try question 3 on page 434