Lec 8- Solutions and preservatives

Question 1

Solution

Answer 1

A stable, homogenous one-phase system consisting of two or more components

Question 2

Solvent

Answer 2

Dispersion phase or vehicle

Question 3

Solute

Answer 3

Dissolved as small molecules or ions in the solvent

Question 4

What are the advantages of pharmaceutical solutions over solid dose forms?

Answer 4

1. Ease of swallowing
2. Increased absorption
3. Even dosage
4. Flexible dosing
5. Gastric irritation reduced

Question 5

What are the disadvantages of pharmaceutical solutions?

Answer 5

1. Bulky containers
2. Hydrolysis or oxidation of active ingredients
3. Contamination
4. Accuracy of dosage, need measure
5. Unpleasant taste difficult to mask

Question 6

Aqueous solvents

Answer 6

1. Relatively cheap and available
2. Palatable
3. Non-toxic
4. Non-irritant for topical use
5. Polar so dissolves salts and ions

Question 7

Linctus

Answer 7

A liquid oral preparation used for a demulcent, expectorant or sedative purpose
-> treatment of a cough

• sipped slowly and allowed to trickle down the throat in an undiluted form.
• viscous solutions which contain sugars

Question 8

Syrup

Answer 8

A concentrated viscous solution containing one or more sugar components

• chiefly sucrose at conc at least 45%
• flavoured syrups provide a sweet vehicle to mask taste of nauseous medicaments

Question 9

What does an antitussive do?

Eg codeine linctus

Answer 9

• Works against a cough
• Acts on the central and peripheral nervous systems to suppress cough reflex
• Not desirable with a productive cough

Note: codeine is sedating -> may cause drowsiness and increase effects of alcohol

Question 10

Elixir

Eg. paediatric paracetamol elixir

Answer 10

A liquid oral preparation that usually contains potent or unpleasant tasting drugs
- formulation is clear and generally contains high proportion of sweeteners and non aq solvents like alcohol, glycerin or popylene glycol

Question 11

Enema

Answer 11

An oily or aq solutions which is administered rectally

• used to treat conditions such as constipation or ulcerative colitis
• used in x-ray examination of the lower bowel and for systemic effects

eg. diazepam in epilepsy and febrile convulsions

Question 12

Non aq solutions

Answer 12

1. Non toxic
2. Non irritant
3. Non sensitizing
4. Cost effective
5. Stable
6. Compatible with medicament

Question 13

Examples of non aq solutions

Answer 13

1. Alcohol
2. Propylene glycol
3. Glycerol
4. Oils

Question 14

Solubility

Answer 14

The saturation solubility or solubility of a chemical in a solvent
- max conc of a solution which may be prepared at a given temperature

Question 15

Dissolution

Answer 15

Process of dissolving

- improve dissolution by increasing SA and decreasing particle size

Question 16

Solution additives (excipients)

Answer 16

• added to improve palatability- taste, feel and appearance

Question 17

Stabiliser/ buffer

Answer 17

An antioxidant to prevent oxidation

• ascorbic acid, citric acid
• tasteless, ordourless and non-toxic

Question 18

Colourants

Answer 18

Enhance appearance- match flavour

- distictive colour for identification of strength

Question 19

Flavourants

Answer 19

improve tastye
Children enjoy fruit or sweet flavours
- antacid-> peppermint

Question 20

Anti-microbial preservative

Answer 20

Kills micro organisms or inhibits their groqth and replication

Question 21

Disinfectant perservative

Answer 21

To eliminate many or all pathogenic micro organisms

Question 22

Antiseptic preservative

Answer 22

Inhibits growth and reproduction of organisms

Question 23

Preservative

Answer 23

Chemical or other agent that reduces the rate of decomposition of a substance

Question 24

Ideal properties of a preservative

Answer 24

1. Non-toxic, non allergenic
2. Bactericidal rather than bacteriostatic
3. Active against a wide range of micro organisms
4. Inexpensive
5. High resistance to attack by micro organisms
6. Stable under wide range of storage conditions
7. Free from unpleasant odour
8. Unaffected by other formulation ingredients