Podcast
Questions and Answers
What is the main focus of advanced drug delivery systems?
What is the main focus of advanced drug delivery systems?
Which of the following is a benefit of advanced drug delivery systems?
Which of the following is a benefit of advanced drug delivery systems?
What characterizes the ideal drug delivery system?
What characterizes the ideal drug delivery system?
Why might pharmaceutical companies develop extended-release versions of drugs?
Why might pharmaceutical companies develop extended-release versions of drugs?
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Which method is NOT associated with advanced drug delivery systems?
Which method is NOT associated with advanced drug delivery systems?
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What is a primary use of carrier particles in advanced drug delivery systems?
What is a primary use of carrier particles in advanced drug delivery systems?
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Which of the following routes is NOT typically used for advanced drug delivery systems?
Which of the following routes is NOT typically used for advanced drug delivery systems?
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What role do polymers play in advanced drug delivery systems?
What role do polymers play in advanced drug delivery systems?
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What is a primary goal of spatial control in drug delivery?
What is a primary goal of spatial control in drug delivery?
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Which characteristic of advanced drug delivery systems is most challenging to achieve?
Which characteristic of advanced drug delivery systems is most challenging to achieve?
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Which characteristic is commonly associated with osmotic systems?
Which characteristic is commonly associated with osmotic systems?
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What is the main driving force for drug release in osmotic systems?
What is the main driving force for drug release in osmotic systems?
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What happens to the matrix in swelling systems when it contacts body fluids?
What happens to the matrix in swelling systems when it contacts body fluids?
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Which statement accurately describes bioerodible polymer systems?
Which statement accurately describes bioerodible polymer systems?
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Which of the following is NOT a typical advantage of bioerodible polymer systems?
Which of the following is NOT a typical advantage of bioerodible polymer systems?
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For which application are swelling systems commonly used?
For which application are swelling systems commonly used?
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Why are the degradation products of bioerodible polymers significant?
Why are the degradation products of bioerodible polymers significant?
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What typically characterizes the release mechanism of drugs from osmotic systems?
What typically characterizes the release mechanism of drugs from osmotic systems?
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Which of the following systems allows for the dual mechanism of drug release?
Which of the following systems allows for the dual mechanism of drug release?
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What is a major limitation of swelling systems compared to osmotic systems?
What is a major limitation of swelling systems compared to osmotic systems?
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Which statement describes the primary function of polymers in advanced drug delivery systems?
Which statement describes the primary function of polymers in advanced drug delivery systems?
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In a reservoir system, which condition is critical for achieving zero-order release kinetics?
In a reservoir system, which condition is critical for achieving zero-order release kinetics?
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What is a defining characteristic of matrix systems in drug delivery?
What is a defining characteristic of matrix systems in drug delivery?
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Which model of drug release shows a release rate that decreases over time but is slower than first-order release?
Which model of drug release shows a release rate that decreases over time but is slower than first-order release?
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What role does the concentration gradient play in the rate of drug release from a polymer system?
What role does the concentration gradient play in the rate of drug release from a polymer system?
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Which type of system relies on osmotic pressure to control drug release?
Which type of system relies on osmotic pressure to control drug release?
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How does a bioerodible polymer enhance drug delivery?
How does a bioerodible polymer enhance drug delivery?
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What is the main characteristic that differentiates first-order release from zero-order release?
What is the main characteristic that differentiates first-order release from zero-order release?
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What type of drug release pattern is achieved with a ghost matrix?
What type of drug release pattern is achieved with a ghost matrix?
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What property of polymers affects their permeability in drug delivery systems?
What property of polymers affects their permeability in drug delivery systems?
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Study Notes
Advanced Drug Delivery Systems
- Advanced drug delivery, also known as therapeutic systems, aims to optimize drug delivery.
- Two main approaches:
- Temporal control: Controlling the timing of drug release (extended, controlled, pulsatile).
- Spatial control: Targeting the drug to specific sites.
Why Advanced Drug Delivery?
- Benefits to the patient:
- Improved safety and efficacy by providing steady drug levels.
- Enhanced convenience and compliance due to reduced dosing frequency (e.g., once-daily, monthly, or even less).
- Repatenting drugs:
- Extended-release versions can extend patent protection and generate revenue after a patent expires.
The Ideal Drug Delivery System
- The ideal system delivers the drug at the precise time, and only to the desired site, throughout the treatment. (Ideal is difficult to achieve).
Types of Advanced Drug Delivery Systems
- Many types exist, with polymer-based systems being common.
- Mechanical systems (e.g., pumps) and systems based on carrier particles (e.g., liposomes, microspheres)
- Several routes of administration possible (IV, oral, transdermal, subdermal, intrauterine, ophthalmic).
Carrier Particles
- Use: Controlling drug release and targeting to specific sites.
- Microspheres were mentioned in the context of inhaled insulin therapy (e.g., Afrezza).
- Targeting: attaching drugs to antibodies (binding to specific targets in the body) or other proteins (like albumin, which targets cells that take up albumin).
Polymers in Advanced Drug Delivery
- Polymers are crucial components for most advanced drug delivery systems.
- Made from repeating units, natural or synthetic.
- Uses in systems: Controlling drug release and targeting to specific sites (size of pores and polymer thickness control).
- Act as meshwork / sponge with pores (drug is embedded).
- Drug release is controlled by pore size and polymer thickness.
- Diverse properties amongst polymer types, varying porosities, pore sizes, and interactions with bodily fluids.
- Some swell in body fluids, increasing pore size and faster release.
- Bioerodible polymers can be broken down in the body, useful for implants.
Mass Transfer Across Polymers
- Mass transfer is the movement of molecules between locations.
- In drug delivery, it's the transfer of drug molecules across the polymer.
- Drug release rate depends on the rate of mass transfer, determined by:
- Flux (transport rate through polymer)
- Area (contact area of polymer and environment)
- Permeability (ease of drug passing through polymer)
- Concentration gradient (difference in concentration inside and outside).
Patterns of Drug Release
- Zero-order release: Constant release rate until empty, desired for controlled release. Happens when the concentration is constant. Plotted as a flat line.
- First-order release: Release rate decreases over time. Not useful for controlled systems. Plotted as a decreasing curve.
- Square root of time release: Release rate decreases at a slower rate compared to first-order. More typical in matrix systems. Plotted as a curve, flatter than first-order.
Types of Polymer Systems
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Diffusion Devices:
- Reservoir Systems: Drug in a saturated solution surrounded by a polymer membrane. Drug diffuses out. Constant drug concentration within reservoir (zero-order release). Examples: patches, IUDs, implantable rods, oral products.
- Matrix Systems: Drug uniformly dispersed throughout the polymer matrix. Drug diffuses out. Square-root-of-time release. Forms an empty "ghost matrix." Examples: patches, implants, oral products.
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Solvent Controlled Systems:
- Osmotic Systems: Osmotic pressure forces drug out. Near-zero-order release. Examples: implants, oral products.
- Swelling Systems: Polymer matrix swells, increasing pore size, and increasing drug release. Not many products. Examples: oral products, intravaginal products.
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Chemical Controlled Systems (Bioerodible Polymers): Polymer degrades over time, releasing drug. Biocompatible degradation products. Drug release by diffusion and degradation. Examples: intracranial implants, oral products.
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Description
This quiz delves into advanced drug delivery systems, focusing on temporal and spatial control mechanisms that optimize drug release. Learn about the benefits, ideal characteristics, and various types of drug delivery systems, particularly polymer-based ones. Enhance your understanding of how these systems improve patient compliance and drug efficacy.
