30 Questions
Which type of drug delivery system involves drug conjugation to natural or synthetic water-soluble polymers or biological systems such as antibodies?
Soluble carrier system
What is a significant barrier to effective drug targeting due to its function in removing foreign materials like bacteria from circulation?
Kupffer cells in the liver
What is the main function of the Mononuclear Phagocytic System in the context of drug delivery?
Drug clearance from the body
Which factor influences opsonisation and clearance by macrophages through non-covalent interactions with drugs or carriers?
Surface charge
What role does opsonisation play in drug delivery systems?
Enhancing phagocytosis by marking particles for recognition by phagocytes
How does adding a hydrophilic polymer coat to a carrier system impact opsonisation in drug delivery?
Reduces opsonisation by steric inhibition of hydrophobic interactions
What is a key requirement for an effective drug-targeting system?
Non-toxicity to target tissues/organs
What is the primary goal of drug targeting?
To control drug distribution for selective interaction with the target tissue
Which of the following is NOT a benefit of drug targeting?
Increasing the overall toxicity of the drug
Which of the following is the most difficult to achieve in drug targeting?
Systemic delivery to specific organs
What is the purpose of controlling drug distribution in drug targeting?
To ensure that most of the dose interacts with the target tissue
Which of the following is a common challenge in drug targeting?
Targeting specific organs or tissue sites
What is a characteristic of continuous endothelium in terms of movement of macromolecules?
Requires active passage for some limited movement of macromolecules
Which type of tissue/organs have fenestrated endothelium?
Spleen and kidney
What is a key feature of passive targeting through local physiological conditions?
Utilizes natural physiological conditions like enzyme presence or pH
Which phenomenon leads to changes in tumour endothelial barrier during passive targeting?
Enhanced permeability and retention
What is the main driving force behind active targeting?
Interaction between a targeting moiety and receptor
In nanotechnology, what dimensions typically enable novel applications not feasible with bulk materials?
~100 nanometers (nm)
What role does nano-engineering have to play in a pharmaceutical to be considered a nanopharmaceutical?
Playing a major role in the manufacturing process
Which of the following is true about PEGylated liposomes used in cancer therapy?
They contain Doxorubicin for cancer treatment
Which type of nanomaterial is most often used as a drug entity in FDA-approved nanopharmaceuticals?
Antibodies
Which class of nanopharmaceuticals is least likely to be approved for therapeutic use due to its immunogenic properties?
Chimeric antibodies
Which type of antibody is produced from a single B cell hybridoma cell line using hybridoma technology?
Monoclonal antibodies
Which type of antibody targets cells expressing human epidermal growth factor receptor (HER2) protein in persistent aggressive metastatic cancers?
Herceptin (trastuzumab)
Which type of nanopharmaceutical is least likely to be used as a drug entity due to its lack of therapeutic activity?
Virosomes
Which type of nanopharmaceutical is most likely to be used for passive immunization against infectious disease and other harmful agents?
Polyclonal antibodies
Which type of antibody is most abundant in humans and most currently approved drugs are based on it?
Immunoglobulin G (IgG)
Which type of nanopharmaceutical is most likely to be used for targeted drug delivery to specific cells or tissues?
Antibodies
Which type of nanopharmaceutical is least likely to be approved for therapeutic use due to its potential for toxicity?
Metal-based nanoformulations
Which type of nanopharmaceutical is most likely to be used for sustained release of drugs over a prolonged period of time?
Polymer-based nanoformulations
Study Notes
Drug Targeting
- Ideal drug targeting system: ensures drugs reach intracellular target sites, non-toxic, and therapeutically acceptable
- Requirements for effective drug-targeting system:
- Non-specific interactions with target tissues/organs
- Ability to deliver drug to specific target site
- Retention of drug during transit to target site
- Release of drug from delivery system once at target site
- Retention of drug over suitable period at target site once delivered
Delivery Systems for Targeting
- Two main types:
- Chemically modified drug (Prodrug)
- Carrier system:
- Soluble carrier systems: drug conjugated to natural or synthetic water-soluble polymer or biological system (e.g., antibodies)
- Particulate carrier system: drug either surface-bound or entrapped within carrier (e.g., liposome, microspheres, nanoparticles)
Barriers to Drug Delivery
- Mononuclear Phagocytic System (MPS):
- Removes foreign material from the body (e.g., bacteria, proteins)
- Involved in antigen processing and presentation (immune response)
- Particles in circulation can be quickly cleared by liver and spleen macrophages, making it a significant barrier to effective drug targeting
- Opsonisation: process where the surface of a particle or pathogen is marked/coated by molecules (opsonins) for easier recognition and destruction by phagocytes
- Phagocytosis: process by which phagocytes engulf and digest marked particles
Factors Influencing Opsonisation and Clearance
- Particle size: particles below 100nm are more difficult to target for elimination, while maximal phagocytosis occurs on particles around 1-2µm
- Surface charge: neutral systems tend to remain longer in circulation compared to charged particles
- Surface hydrophilicity: adding a hydrophilic polymer coat to a carrier system reduces protein adsorption and opsonisation
Advanced Drug Delivery and Targeting
- Nanopharmaceuticals: pharmaceuticals engineered on the nanoscale, where the nanomaterial plays a pivotal therapeutic role or adds additional functionality
- Types of nanopharmaceuticals:
- Liposomes
- Lipid-based (non-liposomal)
- PEGylated macromolecules
- Nanocrystals
- Polymer-based nanoformulations
- Protein-Drug conjugates
- Metal-based nanoformulations
- Virosomes
- Antibodies as drug delivery systems
Antibodies as Drug Delivery Systems
- Antibody: large, Y-shaped protein produced by B cells to recognize and neutralize foreign material
- Antibodies can be used as drugs on their own or as targeting groups attached to a drug or carrier system
- Types of antibodies:
- Immunoglobulin G (IgG)
- Polyclonal antibodies (pAbs)
- Monoclonal antibodies (mAbs)
- Chimeric antibodies
- Humanised antibodies
- Complete human mAbs
- Examples of antibody-based drugs:
- Herceptin (trastuzumab): targets cells expressing human epidermal growth factor receptor (HER2) protein
Test your knowledge on advanced drug delivery, drug targeting, nanopharmaceuticals, and antibody therapy with this quiz. Learn about controlling drug distribution in the body for better therapeutic outcomes.
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