Oral Solution Dosage Forms - ALL NOTES

Question 1

How can rate of absorption be limited?

Answer 1

-By precipitation when a solution is overly concentrated so will come out of solution

Question 2

What is a pharmaceutical solution?

Answer 2

-Liquid preparations in which the therapeutic agent and the various exipients are dissolved in the chosen solvent system

Question 3

What are advantages of pharmaceutical products as solutions?

Answer 3

-Aids young children and people that struggle;e to swallow
-Can be flavoured
-Drug is already dissolved so quicker uptake

Question 4

What are disadvantages of pharmaceutical products as solutions?

Answer 4

-Not as stable as a tablet
-bulky to store, ship and carry
-Bottle could break
-Not suitable for drugs that are hydrolised or insoluble

Question 5

What is an example of a co-solvent?

Answer 5

-Ethanol
-Glycerol

Question 6

What is an example of an antioxidant ?

Answer 6

-Ascorbic acid

Question 7

What is an example of an antimicrobial preservative ?

Answer 7

-Benzalkonium chloride

Question 8

What is an example of a pH adjuster?

Answer 8

-citric acid

Question 9

What is an example of an isotonic adjuster?

Answer 9

-Sodium chloride
-glucose

Question 10

What is an example of a viscosity enhancer?

Answer 10

-Hydroxmethylcellulose

Question 11

What is an example of a chelating agent?

Answer 11

-EDTA

Question 12

What is an example of a natural sweetener?

Answer 12

-Sucrose

Question 13

What is an example of an artificial sweetener ?

Answer 13

-Aspartame

Question 14

What kind of water must be used in parenteral solutions?

Answer 14

-Distilled then further purified to remove pyrogens

Question 15

What kind of water must be used in non-parenteral solutions?

Answer 15

-Distilled

Question 16

What is high solubility?

Answer 16

-Readily incorporated into the vehicle and formulated as an oral solution

Question 17

What is moderate solubility?

Answer 17

-Solubility enhanced using co-solvents or related methods

Question 18

What is low solubility?

Answer 18

-Formulated as an alternative dosage form eg suspension

Question 19

What physicochemical factors affect solubility of therapeutic agents?

Answer 19

-Molecular weight
-Particle size
-Number of hydrogen bonds
-Hydrophilic groups
-Amorphous properties

Question 20

What happens if the pH>pKa of an acid drug?

Answer 20

-Solubility of acidic drug increases

Question 21

What happens if the pH<pKa of a basic drug?

Answer 21

-Solubility of basic drug increases

Question 22

Aspirin pKa =3.0
pH stomach = 1.2
Will the weak acid more mainly ionised or unionised?

Answer 22

-Unionised

Question 23

Aspirin pKa =3.0
pH stomach = 6.8
Will the weak acid more mainly ionised or unionised?

Answer 23

-ionised

Question 24

Chlorpromzine pKa = 5.0
pH stomach = 1.2
will the weak base more mainly ionised and unionised?

Answer 24

-Ionised

Question 25

Chlorpromzine pKa = 5.0 pH stomach = 6.8 will the weak base more mainly ionised and unionised?

Answer 25

-unionised

Question 26

What is the acceptable pH range for oral administration?

Answer 26

-5 to 8

Question 27

How can pH be optimised?

Answer 27

-use of a buffer

Question 28

How can you convert a weak acid to a salt?

Answer 28

-If you increase the pH in the diffusion layer the dissolution rate and saturation solubility will increase even though the bulk pH is the same

Question 29

Why can't some weak acids be converted to salts to increase solubility?

Answer 29

-May be more prone to hydrolysis, chemical stability, manufacturability

Question 30

How can co-solvents increase solubility?

Answer 30

-Used as well as water to enhance the solubility by allowing more ionisation

Question 31

How does micellar solubilisation work?

Answer 31

-Incorporates drugs into or onto micelles

Question 32

What is cyclodextrin complexation?

Answer 32

-Enzymatically modified starches composed of glucopyranose with a hydrophobic cavity, hydrophilic exterior that holds a hydrophobic drug with poor water solubility

Question 33

What approaches can help drug solubilisation?

Answer 33

-pH -Co-solvent -Complexation -Change to salt -Disperse phase -More amorphous

Question 34

What is a vehicle ?

Answer 34

-Drugs can put themselves in to be transported

Question 35

What is pourability?

Answer 35

-How well a solution can be poured, relates to viscosity

Question 36

What is palability?

Answer 36

-How agreeable the taste of a solution is

Question 37

What are the purposes of excipients ?

Answer 37

-Facilitate administration -Protect the formulation from issues regarding physical and chemical stability

Question 38

What are the purposes of buffers?

Answer 38

-Control pH of the formulated product to maintain solubility and enhance stability

Question 39

What are the purpose of sweetening agents?

Answer 39

-Increase the palatability of the therapeutic agent

Question 40

What are the purpose of viscosity-enhancing agents?

Answer 40

-Ensure the accurate measurement of the volume to be dispensed

Question 41

How is viscosity increased?

Answer 41

-The addition of non-ionic or ionic hydrophilic polymers

Question 42

What is the purpose antioxidants ?

Answer 42

-Enhance the stability of therapeutic agents that are susceptible to chemical degradation by oxidation

Question 43

What are chelating agents?

Answer 43

-Form complexes with heavy metal ions involved in oxidative degradation of therapeutic agents

Question 44

What do preservatives do?

Answer 44

-Control the microbial bioburden of the formation

Question 45

What are the ideal properties of preservative?

Answer 45

-Broad antimicrobial spectrum -chemically and physically stable over the shelf life -low toxicity