D. Pharmaceutics- Formulation Decisions for Cancer Drugs

Question 1

What are the main types of anti-cancer drugs ?

Answer 1

• Cytotoxic
• Steroids
• Biological agents
• Hormone therapy
• Bisphosphonates

Question 2

What are the common types formulations used to treat cancers?

Answer 2

• Tablets
• Liquids for injections
• Implants

Question 3

What does the formulation of cancer drugs depend on?

Answer 3

• The physiochemical and biopharmaceutical properties of the drug eg solubility, stability, distribution in the body
• Intended dose and route of administration eg, potency of drug and duration of action
• Disease factors eg type of cancer and location of cancer
• The patient eg ADME, disease status

Question 4

How large is the gap within the therapeutic window?

Answer 4

Narrow gap between effective dose and toxic dose for many cancer drugs

Question 5

How is build up of resistance prevented when dosing a patient ?

Answer 5

Dosing schedule is close to the maximum tolerated dose (MTD) to prevent build-up of resistance

Question 6

True or false.

The variation in dosing and tolerance for patients have a significant negative impact on treatment outcomes ?

Answer 6

True

Question 7

What are the main routes of administration of cancer drugs ?

Answer 7

Oral, parenteral, Topical

Question 8

What is oral administration subject to ?

Answer 8

First pass metabolism

Question 9

Explain the route of administration of orally administered drugs

Answer 9

• Drug absorbed via the gut
• Stays in the stomach for 30-45 minutes
• 90% of oral medication metabolised by the liver before reaching the bloodstream
• Drug rapidly transported round the body
• Portal circulation- blood from the intestine is taken to liver for detoxification

Question 10

What are the different types of routes for parenteral administration?

Answer 10

• Intravenous
• Intramuscular
• Subcutaneous
• Minor routes

Question 11

What are the benefits of parenteral formulation/administration ?

Answer 11

• Avoids issues with oral administration eg nausea and vomiting.

Question 12

What are the benefits for IV administration ?

Answer 12

• 100% bioavailability (therefore accurate dosing)
• Flexible dosing and dosing schedule
• Rapid onset of action
• No fed/fasted effects
• Avoids first pass metabolism

Question 13

What are the requirements for IV formulations?

Answer 13

• Sterile production
• Formulation stability:
  
  • Particle size
  • Solubility
  • Clearance time
  • Targeting
• No preservatives, low excipients

Question 14

What are the benefits or sub-cutaneous or intramuscular administration ?

Answer 14

Muscles highly vascularised therefore rapid absorption of drugs that are soluble

Formulation requirements are less severe

Can get delayed release as muscles have high collagen content which can bind charged drugs