patches, injections and inhalers

Question 1

what is transdermal drug delivery?

Answer 1

drug delivered using a patch on the skin. it is a continuous drug release over a long period of time.
-the rate of delivery to be slower than the rate of absorption

Question 2

does the drug enter systemic circulation in transdermal drug delivery?

Answer 2

yes

Question 3

what are the 2 ways of controlling the rate of the release of the drug from the patches?

Answer 3

by matrix - drug mixed in matrix and released slowly over time,
or rate limiting membrane (drug in the reservoir)

Question 4

what is the patch protected by?

Answer 4

an occlusive backing layer

Question 5

where is the drug stored in the patch?

Answer 5

drug will be in solution or suspension in the matrix or reservoir

Question 6

what are the advantages of transdermal drug delivery?

Answer 6

• avoids the GIT
• it has systemic effects
• no 1st pass metabolism
• there is controlled constant rate of delivery
• it has a long duration of action - up to 7 days

Question 7

what are the disadvantages of transdermal drug delivery?

Answer 7

it can cause skin sensitisation / irritation

• patch may fall off
• not suitable for all drug
• appearance
• hair areas

Question 8

what route of injection are vaccinations?

Answer 8

intramuscular

Question 9

are IV injections O/W or W/O?

Answer 9

Oil in water

Question 10

are IM injections O/W or W/O?

Answer 10

water in oil

Question 11

what are some excipients in injections?

Answer 11

water for injection, preservatives, buffers, tonicity adjusting agents

Question 12

rank the stability of solutions, suspensions, emulsions

Answer 12

solution>suspension>emulsion

Question 13

what are the advantage of injections?

Answer 13

• they can have a local or systemic effect.
• used if oral route isnt suitable
• avoid the problems of the GIT
• no first pass metabolism
• rapid onset of action and prolong release

Question 14

what are the disadvantages of injections

Answer 14

Invasive/painful

• patient could be scared of needles
• there is a risk of infection / embolism
• difficult to reverse effects
• difficult to adminster in some patient

Question 15

can inhalers have local and systemic effects?

Answer 15

yes

Question 16

what does actuation results in?

Answer 16

results in evaporation of propellant to form droplets to be inhaled into the lung?

Question 17

how many actuation per inspiration in MDI’s?

Answer 17

one

Question 18

what type of inhalers are used with spacers?

Answer 18

MDI

Question 19

what do spacers do?

Answer 19

removes the need for co-ordination

Question 20

what are some excipients for MDIs?

Answer 20

propellants, surfactants, co-solvents

Question 21

what do co-solvents do in MDIs?

Answer 21

aid dissolution

Question 22

how do dry powder inhaler work?

Answer 22

they are breath actuated

Question 23

what type of inhalers don’t require propellants?

Answer 23

dry powder inhalers

Question 24

do dry powder inhalers give larger doses?

Answer 24

yes

Question 25

excipients of DPI:

Answer 25

carriers for the drug, pure drug

Question 26

what are the advantages of inhalers

Answer 26

can use small doses, there are reduced systemic side effects, a fast onset of action, can use drugs with poor oral bioavailability

Question 27

what are the disadvantages of inhalers

Answer 27

difficult technique, not suitable for all drugs, only 20% of drug reaches the lung, inflammation can reduce the size of the airways