Parenterals

Question 1

What are advantages of parenteral administration?

Answer 1

*immediate physiological response-important in acute scenarios like cardiac arrest, asthma
*poor bioavailability drugs or those destroyed by GI secretions
*for unresponsive/uncooperative or nauseas patients
*physician controlled administration

Question 2

What are disadvantages of parenteral administration?

Answer 2

*requires aseptic technique
*skill for admin required
*pain on admin
*rapid development of allergy reactions
*hard to reverse effects of drugs

Question 3

What is the intradermal route?

Answer 3

Drug injected into superficial layer of skin
Small volumes
Slow absorption
For diagnostics and limited va

Question 4

What is the subcutaneous route?

Answer 4

Drug injected into loose subcutaneous tissue beneath skin
Upper arm or thigh
Insulin
More rapid onset

Question 5

What is the intramuscular route?

Answer 5

Drug injected into muscle
Shoulder (deltoid), thigh and butt (gluteal)
Suitable for aqueous and oily solutions and irritants to SC route
More rapid onset

Question 6

What is the intravenous route?

Answer 6

Simple formulation
Rapid predictable results
Irritant drugs diluted in blood

Question 7

What are the two main classes of parenterals?

Answer 7

*small volume parenterals <100ml
*large volume parenterals <500ml (IV)

Question 8

If infusion is necessary via SC or IM route, what enzyme must be administered?

Answer 8

Hyaluronidase- increases permeation

Question 9

What are all LVP’s required to be?

Answer 9

*sterile
*non- pyrogenic
*free of particulate matter
*packed as single dose containers

Question 10

Why are bacteriostatic preservatives never added to LVP’s?

Answer 10

Toxicity may result from large volume

Question 11

What vehicles are used in parenterals?

Answer 11

Water for injection
*free from pyrogens (mainly from g-ve bacteria)

Question 12

What is a pyrogen?

Answer 12

Substance that induces fever

Question 13

How are endotoxins removed?

Answer 13

*distillation
*reverse osmosis

Question 14

How do you test for pyrogens?

Answer 14

Rabbit rectal temperature- rabbit injected with product and temp measured

Question 15

How is CO2 removed from water for injection?

Answer 15

Boiling for at least 10 mins followed by sterilisation

Question 16

When is an oil vehicle used?

Answer 16

*drug insoluble in water
*depot effect (slow release)
*diagnostic purposes

Question 17

What are disadvantages of oil vehicles?

Answer 17

*highly viscous in cold conditions
*pain on injection
*syringe and needle may be difficult to clean
*care needed on admin-IV may cause thrombosis

Question 18

What is an example of an oil vehicle?

Answer 18

*cottonseed oil
*sesame oil
*maize oil

Question 19

When is Ethanol used as a vehicle?

Answer 19

When others impractical

Question 20

What are colligative properties?

Answer 20

The properties that’s arise when a solute has been added to a solvent. They depend on nature and concentration of solute

Question 21

What colligative properties arise in parenterals?

Answer 21

*lowering of vapour pressure
*elevation of BP
*freezing point depression
*osmotic pressure

Question 22

What is osmotic pressure?

Answer 22

Minimum pressure needed to prevent osmosis

Question 23

What is a hypotonic solution?

Answer 23

Dilute solution, water moves into cell-swells bursts

Question 24

What is a hypertonic solution?

Answer 24

Concentrated solution. Water moves out of cell-shrinks

Question 25

What is an isotonic solution?

Answer 25

In equilibrium with conc in cell
NB in parenterals- one that has same osmotic pressure as blood

Question 26

How do you render a hypotonic solution isotonic?

Answer 26

Adding compounds such as dextrose and glucose-increases osmotic pressure

Question 27

What two methods are used to calculate the mass of compound (dextrose, glucose) required to render a solution isotonic?

Answer 27

*gram molecular concentration-no of moles of substance in 100g solvent
*freezing point depression