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PF4015 > Targeted Drug Delivery - Cancer 1 > Flashcards

Targeted Drug Delivery - Cancer 1 Flashcards

1
Q

Briefly explain EPR

A

Combination of leaky vasculature and poor lymphatic drainage

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2
Q

Explain the difference between blood vessels in normal and tumour tissue

A

Normal tissues contain linear blood vessels maintained by pericytes.
Tumour tissues contain defective blood vessels with many sac like formations and fenestrations.

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3
Q

Explain the differences between extracellular matrix in normal and tumour tissue

A

Normal tissues contain collagen fibres, fibroblasts and macrophages
Tumour tissues contain more collagen fibres, fibroblasts and macrophages than in normal tissue

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4
Q

Explain the difference between lymph vessels in tumour and normal tissue.

A

Normal tissues - Lymph vessels are present.
Tumour tissues - Lymph vessels are lacking.

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5
Q

Name 6 barriers to drug delivery to tumours

A
  1. MPS
  2. Non specific distribution
  3. Hemorrheological limitations
  4. Intratumoral pressure
  5. Cell membrane internalisation/ endosomal escape
  6. Multidrug resistance
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6
Q

What is the particle size cleared by MPS

A

0.1 - 7 micrometres

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7
Q

Why are PEG coated nanoparticles considered stealth particles?

A

It is energetically unfavourable for macromolecules to approach surfaces carrying these chains
Suppress opsonisation by steric stabilisation and prolong circulation time

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8
Q

What shape of drug carrier is best?

A

Short filomicelle - has high contact area. is the most efficient

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9
Q

What is myocet

A

Liposomal doxorubicin

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10
Q

What is Doxil/Caelyx

A

PEG-Liposomal Doxorubicin

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11
Q

Application of Caelyx

A

Advanced cancers
AIDS related Kaposi’s sarcoma

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12
Q

Describe the look of Caelyx

A

Suspension is translucent and red

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13
Q

Describe the formulation of Caelyx

A

Surface bound MPEG - “stealth” properties. inhibits opsonisation and premature clearance
Exploits EPR

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14
Q

Name the 4 elements of Caelyx formulation

A
  • Phosphatidylcholine
  • Cholesterol
  • DPSE
  • Alpha tocopherol
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15
Q

What drug loading technique is used in Caelyx?

A

Remote drug loading

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16
Q

Why is drug loading more challenging for drugs with intermediate log P (1.7–5)?

A

Because they partition between aqueous and lipophilic compartments, leading to drug loss.

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17
Q

What is used inside the aqueous core of Caelyx liposomes to create a gradient?

A

Ammonium sulphate

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18
Q

How does Doxorubicin (DoxHCl) get trapped inside Caelyx liposomes?

A

DoxHCl diffuses across the membrane with the ammonium sulphate gradient and forms a drug-sulphate complex, trapping it inside the vesicle.

19
Q

What type of drug delivery system is used in Myocet®?

A

Liposome vesicle for Doxorubicin HCl delivery

20
Q

What two main components make up the Myocet® liposome membrane?

A

Egg phosphatidylcholine and cholesterol

21
Q

How does the size and surface of Myocet® liposomes differ from Caelyx®?

A

Myocet liposomes are larger (180nm) and lack PEG coating

22
Q

What system is responsible for taking up Myocet® liposomes in the body?

A

Mononuclear Phagocyte System

23
Q

What is the proposed effect of MPS uptake by Myocet?

A

Creates a depot for slow release of the drug

24
Q

How is Myocet supplied?

A

As a three-vial system:

Doxorubicin HCl (red lyophilised powder)

Liposome dispersion (white to off-white, opaque)

Buffer solution (clear, colourless)

25
What two heating methods can be used for Myocet® preparation?
Techne DB-3 DriBlock heater or a water bath.
26
What temperature should the DriBlock heater be set to for Myocet®?
75 - 76
27
What temperature range should the water bath be equilibrated to for Myocet®?
55 -60
28
What is the first step once you remove Myocet® from the refrigerator?
Reconstitute doxorubicin HCl with 20 mL of 0.9% sodium chloride solution and shake well.
29
How long should you heat the reconstituted Myocet® doxorubicin HCl vial?
10 minutes - do not exceed 15 minutes
30
How do you adjust the pH of Myocet® liposomes?
Withdraw 1.9 mL of Myocet® liposomes and inject into the Myocet® buffer vial, shake well.
31
After adjusting the pH, what must be done next?
Withdraw the pH-adjusted liposomes and inject them into the heated reconstituted Myocet® doxorubicin HCl vial.
32
What safety step must be done before adding pH-adjusted liposomes to the doxorubicin vial?
Insert a pressure-venting device with a hydrophobic filter.
33
How soon must you inject the pH-adjusted liposomes into the heated doxorubicin vial after venting?
Immediately - within 2 minutes
34
After combining the liposomes and doxorubicin, what must you do before using Myocet®?
Shake vigorously and wait a minimum of 10 minutes at room temperature
35
List the 5 steps of preparing Myocet
1. Set up heating equipment 2. Reconstitute Doxorubicin HCl 3. Heat 4. Adjust pH of liposomes 5. Add pH adjusted liposomes to doxorubicin
36
What are opsonins and give 3 examples
Molecules that bind to pathogens and particles and facilitate their phagocytosis Fibronectin Immunoglobulins Complement Proteins
37
What drug is in OncoGel
Paclitaxel
38
Indication for OncoGel - ReGel/Paclitaxel
Oesophageal cancer
39
What is ReGel in the OncoGel-ReGel/Paclitaxel formulation?
ReGel is a thermosensitive controlled-release (CR) drug delivery system made from a triblock polymer (PLGA-PEG-PLGA).
40
What is the function of the triblock polymer in ReGel?
Helps to form polymer micelles when combined with a non-ionic surfactant
41
What is the viscosity of OncoGel-ReGel/Paclitaxel at low temperatures?
Free flowing and low viscosity and temps < 2-15
42
What happens to OncoGel-ReGel/Paclitaxel at body temperature?
At body temperature, OncoGel-ReGel/Paclitaxel transforms into a water-insoluble, biodegradable gel.
43
Name 4 angiogenesis associated targeting targets
VEGF receptor A3B3 integrin receptor VCAM-1 Matrix metalloproteinases
44
Name 3 targets for uncontrolled cell proliferation
HER of receptor tyrosine kinases Transferrin receptor Folate 1

PF4015 (16 decks)

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