Target DDS FINAL Flashcards
Who proposed the concept of drug targeting as a “Magic Bullet”?
Paul Ehrlich.
What are the two main components of drug targeting?
1) A component that recognizes and binds the target.
2) A component that provides therapeutic action.
What is drug targeting?
The ability of a drug to accumulate selectively and quantitatively in a target organ or tissue, ideally with high concentration at the disease site and minimal concentration in non-target areas.
What three components are currently coordinated in the concept of a magic bullet?
1) drug 2) targeting moiety 3) drug carrier.
Name some examples of targeting moieties.
Antibodies, lectins, lipoproteins, hormones, charged molecules, polysaccharides, low-molecular weight ligands.
What is a drug carrier?
A device or vector that transports drugs effectively to the target area, including polymers, nanoparticles, liposomes, and cells.
How can drug targeting be achieved?
Direct application, passive accumulation through leaky vasculature, physical targeting based on pH/temperature, magnetic targeting, chemical delivery systems, and antibody-directed delivery.
What is an example of direct application of a drug?
Intra-articular administration of hormonal drugs for arthritis.
Describe how drug accumulation occurs in leaky areas.
Increased vascular permeability allows drugs in carriers like liposomes and micelles to extravasate and accumulate in areas such as tumors and inflamed tissues.
What is physical targeting of drugs based on?
Abnormal pH and/or temperature in pathological areas compared to normal tissues.
What is magnetic targeting of drugs?
A method where drugs are immobilized on ferromagnetic carriers that accumulate in a specific area when an external magnetic field is applied.
Define prodrugs.
Pharmacologically inactive drug derivatives that are converted to active forms in vivo.
What is the purpose of polymer drug delivery systems?
To prolong the half-life of drugs and reduce toxicity, such as cardiotoxicity associated with daunorubicin.
How are antibody-drug conjugates utilized in targeted therapy?
They chemically link drugs to monoclonal antibodies that target tumor-associated antigens for precise delivery.
What is ADEPT (Antibody Directed Enzyme Prodrug Therapy)?
A two-step targeting system using an antibody-enzyme conjugate to selectively convert a non-toxic prodrug into an active drug at a tumor site.
What is cellular targeting?
Using cells as carriers for drugs, often derived from the patients themselves, which may affect the properties of the cells.
Name some viral carriers used for gene delivery.
Adenoviruses, Herpes simplex virus, Epstein Barr Virus
How can physical stimuli enhance drug targeting?
Stimuli-response carriers can disintegrate or release drugs in response to changes in temperature or pH specific to diseased tissues.
What is the significance of pH -sensitive liposomes in drug delivery?
They release their drug in acidic environments, such as tumors or inflamed tissues, providing targeted therapy.
What distinguishes radioimmunoconjugates from other antibody-drug conjugates?
They couple antibodies with radioisotopes to deliver targeted radiation therapy to cancer cells.
What are some advantages of using cellular carriers for drug delivery?
Increased biocompatibility and the potential for longer circulation times within the body due to the natural behavior of cells.
What happens during hypotonic hemolysis in drug loading?
Erythrocytes are lysed in a hypotonic solution containing the drug, and then the solution is restored to reseal the cells with the drug inside.
What is the importance of biodegradable bonds in drug carriers?
They allow for the controlled release of drugs as the carrier breaks down, enhancing targeting while minimizing toxicity.
How do antibodies enhance the specificity of drug delivery?
They recognize and bind to specific antigens on target cells, ensuring that the attached drug is delivered directly to those cells.
