Lecture 4- Role of dosage forms and excipients

Question 1

Why are drugs not administered as pure substances?

Answer 1

This is because it is hard to administer a uniform dose each time if drug is used in powder form, for example. A patient wouldn’t be able to weigh the dose themselves at home especially if it is a small amount. It is more convenient and effective to formulate the dosage form.

Question 2

Dosage form

Answer 2

the way in which a drug molecule is delivered to site of action within the body

Question 3

What is an excipient?

Answer 3

All the other components of a formulation other than the active drug. Should be chemically and physiologically inert- it should not have any effect on the body and should not interact with the drug.

Question 4

Give some uses for excipients.

Answer 4

• control rate of absorption
• aid processing of the system during manufacture
• accurate dose control
• protect/support/enhance stability, bioavailability or acceptability (film coatings prevent gastric mucosal irritation and make drug taste better)
• assist in product identification
• enhance the overall safety and effectiveness of drug during storage and use.

Question 5

types of dosage forms can be categorised into route of administration…

Answer 5

oral, topical, transdermal, rectal, parenteral, vaginal, inhaled, otic

Question 6

Dosage forms can be categorised into physical forms…

Answer 6

solid, semisolid and liquid

Question 7

What is a tablet/ what is it composed of?

Answer 7

A tablet is hard, compressed medication in round oval or square shape. The excipients include diluents (compressible bulking agents), binders, glidants (flow aids)and dry lubricants, disintegrants (ensure the tablets break up in the GI tract), sweeteners/ coatings to mask the taste of APIs.

Question 8

Properties of an ideal solid dosage form.

Answer 8

drug should remain stable, drug must be bioavailable, uniform drug content, robust and resistant to disintegration during handling, easy and cost effective to mass produce, pleasant to take.

Question 9

Buccal and Sublingual tablets. Explain. Why are they given to people with digestion problems?

Answer 9

Administered by placing them in the mouth either under the tongue (sublingual) or between the gum and the cheek (buccal). The medications dissolve rapidly and are absorbed through mucous membranes in the mouth where they enter the bloodstream. They bypass the stomach and liver. Given to people with problems with digestion.

Question 10

What is an effervescent tablet?

Answer 10

uncoated tablets and generally contain acid substances like citric acid and bicarbonates which react rapidly in the presence of water, releasing CO2. They are intended to be dissolved.

Question 11

In effervescent tablets the lubricants must be….
And packaging is critical for….

Answer 11

water soluble.
Stability.

Question 12

What is a capsule?

Answer 12

a dosage form in which formulation is contained in a gelatine matrix. This masks the unpleasant taste of API.

Question 13

Two types of capsules

Answer 13

Two types= hard shelled (used for dry, powdered ingredients) or soft shelled (used for oils and active ingredients that are dissolved or suspended in oils or emulsions).

Question 14

What are oral granules?

Answer 14

Consist of solid, drug aggregates of powder particles often supplied in single-dose sachets. Some granules are placed on the tongue and swallowed with water before taking. Effervescent granules release CO2 when added to water.

Question 15

What is another name for fast dissolving oral delivery formations?

Answer 15

orodispersible tablets/melts.

Question 16

What is an orodispersible tablet?

Answer 16

solid dosage form that dissolves or disintegrate rapidly in the oral cavity, resulting in solution or suspension without the need of water.

Question 17

List some liquid dosage forms.

Answer 17

solutions, emulsions, suspensions, syrups, elixir, linctus, oral drops

Question 18

Solutions

Answer 18

• Clear liquid preparations for oral use containing one or more dissolved API. Some solvents may be…. diluted alcohol, glycerine, purified water.

Question 19

Emulsions.

Answer 19

Oil emulsions are stabilized oil-in-water dispersions. Either or both phases may contain dissolved solids.

Question 20

Suspensions

Answer 20

Liquid preparations for oral use containing one or more APIs suspended in a suitable vehicle- eg. Water with cellulose derivative polymers and thickening agents.

Question 21

Syrups

Answer 21

Concentrated aqueous solution of sugar. Masks taste.

Question 22

Elixir

Answer 22

Flavoured clear liquid oral preparation of potent or nauseous drugs. The vehicle may contain a high proportion of ethanol in purified water and sucrose together with antimicrobial preservatives which makes it more stable.

Question 23

Linctus

Answer 23

Viscous, liquid oral preparations prescribed for coughs. Contain lots of syrup and glycerol which have lubricating effects on the membranes of the throat.

Question 24

Oral drops

Answer 24

Liquid preparation for oral use that are intended to be administered in small volumes. May be suspensions, solutions or emulsions.

Question 25

Ointments

Answer 25

These are viscous, semi solid and greasy preparations applied to the skin, rectum or nasal mucosa. The base is usually anhydrous and immiscible with skin secretions. May be used as emollients or to apply suspended/dissolved medications to the skin.

Question 26

Creams

Answer 26

semi solid emulsions mixtures of oil and water

Question 27

Describe the two types of creams.

Answer 27

into O/W (oil-in-water) creams and W/O (water-in-oil) creams. O/W are less greasy and wash off using water. W/O creams more difficult to handle but many drugs which are incorporated into creams are hydrophobic and will be released more readily from W/O than O/W creams. More moisturising as they provide an oily barrier which reduce water loss from skin.

Question 28

Gels

Answer 28

• Gels. Semisolid systems in which liquid phase is contained within a 3D polymetric matrix having a high degree of physical/chemical cross linking. They are used for medication and lubrication

Question 29

transdermal patches

Answer 29

medicated adhesive patch placed on skin to deliver specific dose of medication through skin into blood. Provides controlled release of the medication to patient.

Question 30

Suppositories and pessaries.

Answer 30

Solid dosage forms intended for administration of medicine via the rectum, vagina or urethra that melt/soften/dissolve in the body cavity.

Question 31

Injections are parenteral dosage forms What is an injection? Give the four types of injections.

Answer 31

an injection is an infusion method of putting liquid into the body using a hollow needle and syringe which is pierced through the skin to a sufficient depth for the material to be forced into the body. Four different types= IV injection, IM injection, subcutaneous, intradermal

Question 32

IV

Answer 32

liquid is administered directly into the bloodstream via a vein. Quick acting. 100% is bioavailable.

Question 33

IM injection

Answer 33

injection of a substance directly into a muscle. Many vaccines administered this way. Depending on the chemical properties of the drug the medication is absorbed fairly quickly or more gradually.

Question 34

Injection sites for IM injections

Answer 34

Injection sites= deltoid muscle of arm, vastus lateralis of leg and gluteal muscles of butt.

Question 35

Subcutaneous injections

Answer 35

inject a fluid into the subcutis- layer of fatty tissue below the dermis and epidermis. Effective in administering vaccines and insulin.

Question 36

What is an inhaled dosage form?

Answer 36

Any drug or solution of drug administered by the nasal or oral respiratory tract. Inhalers are prepared as solutions, suspensi9ons or dry powder. Delivered in an aerosol form.

Question 37

pMDI stands for and refers to what types two types of inhaler

Answer 37

-pressurized metred dose inhaler
- standard and spacers.

Question 38

DPI stands for and refers to what two types of inhalers

Answer 38

dry powder inhaler
active/passive inhalers

Question 39

LDI stands for

Answer 39

liquid dose inhalers, like nebulisers. Two types- pneumatic and ultrasonic.

Question 40

Two type of ophthalmic dosage forms

Answer 40

• drops and ointments

Question 41

Eye drops

Answer 41

saline containing drops used as a vehicle to deliver medication to the eye. They may not contain medications as they may be used for lubrication and tear-replacing solutions.

Question 42

ophthalmic ointments

Answer 42

sterile/ semi-solid preparations intended for application to the conjunctiva or eyelid margin.

Question 43

Otic dosage forms/ ear drops

Answer 43

Solutions, suspensions or emulsions of drug instilled into the ear with a dropper. Used to treat or prevent ear infections.