Advanced Drug Delivery Flashcards
What does drug delivery/ drug targeting mean?
The drug must get to the right place at the right time.
What is the aim of drug delivery?
To deliver a certain drug to its precise site of action at the right concentration for the right time.
What is meant by Conventional dosage forms?
When drug release and drug plasma levels depend essentially on the physico-chemical properties of the active ingredient.
What is meant by Non-conventional dosage forms?
When drug release and drug plasma levels are determined by the technological characteristics of the formulation. This is known as MODIFIED RELEASE.
How can you modify the rate of drug release?
- Very fast release
- Sustained release
How can time be modified with regards to drug release?
- When the release starts after a certain time following administration
How can you modify ‘space’ with regards to drug release?
- Drug release happens in specific areas or tissues
- These specific areas and tissues are targeted
Why is it difficult to target bacterial infections with regards to drug delivery?
Why is it difficult targeting cancer with regards to drug delivery?
What is the objective of drug targeting?
To localise and concentrate drugs to the desired therapeutic site, therefore avoiding all other tissues. This minimises the risk of side-effects.
1st order targeting. What is targeted?
Organ or tissue. (e.g. liver targeting)
2nd order targeting. What is targeted?
A certain type of cells (e.g. tumour cells)
3rd order targeting. What is targeted?
Intracellular compartment (e.g. lysosomes)
What are the three different targeting approaches?
1) Magic Bullet
2) Prodrug
3) Macromolecular carrier
Briefly describe a characteristic of the magic bullet.
The active ingredient is potent and selective.
Briefly deserve the mechanism of a Prodrug.
The Prodrug is inactive. The drug is then activated in the site of action.
Briefly describe the mechanism of a Macromolecular carrier?
The carrier transports the drug to the desired site of action.
What are polyclonal antibodies?
Antibodies that work against different antigens.
What are Monoclonal antibodies?
Antibodies that work against only ONE antigen.
What are the two groups of commercially available Monoclonal antibodies?
1) Diagnostic agents
2) Therapeutic agents
What are Diagnostic agents used for?
- RIA
- Immunoprecipitation
- ELISA
What are Therapeutic agents used for?
- Immunosuppressants after organ transplants
- Anticancer agents
What bonds are used to connect chains of antibodies?
Disulphide bonds.
Give me three examples of monoclonal antibodies in the market?
- OKT3 (anti-CD3 antibody)
- Abciximab (ReoPro)
- Trastuzamab (Herceptin)
What is OKT3 used for?
Used to prevent rejection of kidney transplants
What is Abciximab (ReoPro) used for?
For the prevention of cardiac ischemic complications.
What is Trastuzumab (Herceptin) used for?
To treat HER-2 positive breast carcinoma.
Why are monoclonal antibodies as imaging agents?
MAb against tumour-associated antigens have been developed. This allows them to be conjugated with a diagnostic imaging agent.
What are some MAb imaging agents commercially available and what are they used for?
- Oncoscint (for imaging of colon and ovarian cancer)
- Prostascint (for imaging of prostate cancer)
- Myoscint (cardiac imaging)
What is the definition of a Prodrug?
A prodrug is a chemically and pharmacologically inactive derivative of the drug. They undergo activation at the target site.§
What are the 4 benefits of using Prodrugs?
1) Improve permeability through biological membranes
2) Site-specific administration
3) Increase duration of drug action
4) Decrease toxicity and side effects
