Drug Formulation And Absorption

Question 1

What is formulation?

Answer 1

The process in which different chemical substances including the active drug are combined to produce a final medicinal product.

Question 2

What does drug product mean?

Answer 2

A finished dosage form, for example, a tablet.

Question 3

What does active ingredient mean?

Answer 3

Any component of a drug product intended to furnish pharmacological activity.

Question 4

How do drugs move through the transmembrane layer?

Answer 4

Active transport
Facilitated transport
Passive diffusion
Pinocytosis

Question 5

What are the physio-chemical properties of a drug-ionization?

Answer 5

Weak acids = Proton donator

Weak bases = Proton acceptor

Question 6

What is an excipient?

Answer 6

Everything else in the drug product that isn’t the active molecule.

• It may influence pharmacokinetics
• Or make the product more appealing (eg. Flavouring)

Question 7

Give examples of excipients:

Answer 7

Anti-adherents 
Binders 
Coatings 
Emulgents 
Disintegrants 
Colouring, flavours and sweetners 
Preservatives 
Antioxidants 
Buffers

Question 8

Drug formulations that can accept absorption:

Answer 8

• Modified release

- Enteric coating

Question 9

What are the two methods of movement for drugs?

Answer 9

Transcellular = drugs moving through the cell, passing the the phospholipid bilayer.

Paracellular = movement between two adjacent cells.

Question 10

Weak base equation

Answer 10

Proton accepter + proton = proton donator

Question 11

Weak acid equation

Answer 11

Proton donator = proton + proton acceptor

Question 12

What are two drug formulations that affect absorption?

Answer 12

Modified release to deliver drug over a continuous period/ delay absorption for example morphine or isosorbide mononitrate
Immediate release

Enteric coating (to prevent disintegration in the stomach); omeprazole

Question 13

Give examples of other drug delivery methods

Answer 13

Buccaneers wafer
Patches
Ointments
Solid gels that can be implanted for slow/prolonged release

Question 14

State some excipients

Answer 14

Anti-adherents 
Binders 
Coating 
Colouring, flavouring and sweetness 
Disintegrants 
Emulgents 
Preservatives 
Antioxidants
Buffers

Question 15

What is the structure of a phospholipid bilayer?

Answer 15

Hydrophilic head on the outside

Hydrophobic tail on the inside

Question 16

What is pinocytosis?

Answer 16

Part of the cell membrane forms around a drug molecule.
This moves into the cell.
Usually a process for large molecules
For example Doxorubicin

Question 17

What is facilitated diffusion?

Answer 17

Molecules are transported via a carrier in the cell wall.

ATP isn’t required. Molecules move down a concentration gradient

Question 18

What is active transport?

Answer 18

It requires ATP to transfer molecules against their concentration gradient across a cell membrane

Question 19

What is passive diffusion?

Answer 19

Molecules move down its concentration gradient through cell membrane.
Molecules are uncharged.
Smaller molecules diffuse quicker than larger molecules.

Question 20

What is the pKA for:

Aspirin
Diazepam

Answer 20

Aspirin = 3.5 completely ionised in plasma, unionised in the stomach.
Diazepam = 3.5 weak base. Absorbed from small bowel (unionised) and ionised in the stomach

Question 21

Where is aspirin usually absorbed ?

Answer 21

Usually in the small intestine by passive diffusion.