Advanced Drug Delivery Systems Overview
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Questions and Answers

What is the main focus of advanced drug delivery systems?

  • To optimize drug delivery using temporal and spatial control (correct)
  • To eliminate the need for any drug delivery devices
  • To maximize the volume of drug administered
  • To ensure all drugs are delivered via injection methods only

Which of the following is a benefit of advanced drug delivery systems?

  • They are safer than any other form of drug delivery available
  • They can enhance patient safety by providing steady blood levels of drugs (correct)
  • They always eliminate the need for medical intervention
  • They guarantee patient adherence regardless of dosing frequency

What characterizes the ideal drug delivery system?

  • Delivers drugs at the perfect time and to the site of action (correct)
  • Targets delivery to all bodily systems uniformly
  • Requires only one administration for the entire treatment period
  • Only delivers drugs in high doses

Why might pharmaceutical companies develop extended-release versions of drugs?

<p>To extend patent protection after the original patent expires (B)</p> Signup and view all the answers

Which method is NOT associated with advanced drug delivery systems?

<p>Single-dose products for all patients (B)</p> Signup and view all the answers

What is a primary use of carrier particles in advanced drug delivery systems?

<p>To control drug release and target specific sites (A)</p> Signup and view all the answers

Which of the following routes is NOT typically used for advanced drug delivery systems?

<p>Sublingual (C)</p> Signup and view all the answers

What role do polymers play in advanced drug delivery systems?

<p>They form the basis of most advanced drug delivery systems (C)</p> Signup and view all the answers

What is a primary goal of spatial control in drug delivery?

<p>To precisely target drugs to the specific site of need (C)</p> Signup and view all the answers

Which characteristic of advanced drug delivery systems is most challenging to achieve?

<p>Delivering drugs only to the site of action and at the perfect time (B)</p> Signup and view all the answers

Which characteristic is commonly associated with osmotic systems?

<p>They show near-zero-order release kinetics. (B)</p> Signup and view all the answers

What is the main driving force for drug release in osmotic systems?

<p>Osmotic pressure from water influx. (A)</p> Signup and view all the answers

What happens to the matrix in swelling systems when it contacts body fluids?

<p>It swells, increasing pore size for drug release. (D)</p> Signup and view all the answers

Which statement accurately describes bioerodible polymer systems?

<p>They degrade over time via hydrolysis. (C)</p> Signup and view all the answers

Which of the following is NOT a typical advantage of bioerodible polymer systems?

<p>They are always effective for all drug types. (A)</p> Signup and view all the answers

For which application are swelling systems commonly used?

<p>Oral and intravaginal products. (C)</p> Signup and view all the answers

Why are the degradation products of bioerodible polymers significant?

<p>They are biocompatible and safe. (B)</p> Signup and view all the answers

What typically characterizes the release mechanism of drugs from osmotic systems?

<p>Release is primarily via osmosis and pressure. (C)</p> Signup and view all the answers

Which of the following systems allows for the dual mechanism of drug release?

<p>Bioerodible polymer systems. (C)</p> Signup and view all the answers

What is a major limitation of swelling systems compared to osmotic systems?

<p>Swelling systems are limited in product variety. (B)</p> Signup and view all the answers

Which statement describes the primary function of polymers in advanced drug delivery systems?

<p>To control the rate of drug release (D)</p> Signup and view all the answers

In a reservoir system, which condition is critical for achieving zero-order release kinetics?

<p>The concentration gradient across the membrane must remain constant (D)</p> Signup and view all the answers

What is a defining characteristic of matrix systems in drug delivery?

<p>The drug is uniformly dispersed throughout a polymer matrix (C)</p> Signup and view all the answers

Which model of drug release shows a release rate that decreases over time but is slower than first-order release?

<p>Square Root of Time Release (B)</p> Signup and view all the answers

What role does the concentration gradient play in the rate of drug release from a polymer system?

<p>A greater concentration gradient leads to faster drug release (B)</p> Signup and view all the answers

Which type of system relies on osmotic pressure to control drug release?

<p>Osmotic Systems (D)</p> Signup and view all the answers

How does a bioerodible polymer enhance drug delivery?

<p>By allowing the polymer to be absorbed by the body (D)</p> Signup and view all the answers

What is the main characteristic that differentiates first-order release from zero-order release?

<p>First-order release decreases as the drug is consumed (C)</p> Signup and view all the answers

What type of drug release pattern is achieved with a ghost matrix?

<p>Square root of time release kinetics (B)</p> Signup and view all the answers

What property of polymers affects their permeability in drug delivery systems?

<p>Interactions between the drug and polymer (C)</p> Signup and view all the answers

Flashcards

Advanced Drug Delivery

A method to improve how drugs are delivered to the body, optimizing their effect.

Temporal Control (drug delivery)

Controlling when a drug is released into the body.

Spatial Control (drug delivery)

Targeting a drug to a specific area in the body.

Patient Benefits (advanced drug delivery)

Improved safety, efficacy, convenience, and compliance through better drug delivery.

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Ideal Drug Delivery

A drug delivery system that releases the drug perfectly over time and only to the desired area.

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Carrier Particles (drug delivery)

Materials like liposomes or microspheres that help deliver and control drugs.

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Polymer-based Systems (drug delivery)

Common material used to create drug delivery systems that release drugs in a specific manner.

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Drug Release Control

Precisely controlling when a drug is released into the body from a carrier or system.

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Drug Targeting (to specific sites)

Delivering drugs to the needed area in the body, avoiding other tissues.

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Patent Extension Strategy

Developing new drug forms (extended-release) to extend a drug's patent protection after the initial patent expires.

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Antibody Drug Targeting

Attaching a drug to an antibody to deliver it specifically to cells with the target.

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Polymer Drug Delivery

Using polymers to control drug release rate and targeting.

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Mass Transfer in Polymers

Movement of drug molecules through a polymer.

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Zero-Order Release

Constant drug release rate over time.

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First-Order Release

Drug release rate decreases over time, proportional to drug remaining.

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Square Root of Time Release

Drug release rate decreases over time but slower than first order.

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Reservoir System

Drug stored in a solution, surrounded by a membrane for controlled drug release.

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Matrix System

Drug spread throughout a polymer matrix, releasing over time.

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Flux in Drug Delivery

Rate of drug movement through a polymer.

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Concentration Gradient

Difference in drug concentration between inside and outside of polymer.

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Osmotic Drug Delivery

A system that uses osmotic pressure to deliver drugs. Water is drawn into a compartment, creating pressure that pushes the drug out.

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Osmotic Pressure

The pressure generated within a compartment due to the movement of water across a semi-permeable membrane.

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Zero-Order Release Kinetics

A constant rate of drug release over time, meaning the same amount of drug is released per unit time.

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Swelling Drug Delivery

A system where a polymer matrix swells when in contact with body fluids, releasing the drug as the pores in the matrix enlarge.

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Bioerodible Polymers

Polymers that degrade over time in the body, releasing the drug as they break down.

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Hydrolysis

A chemical reaction where water breaks down bonds in a molecule.

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Biocompatible

Materials that are safe and non-toxic to the body.

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Diffusion

The movement of molecules from an area of high concentration to an area of low concentration.

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Degradation

The breakdown of a material into smaller components.

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Intracranial Implants

Drug delivery systems placed in the brain, often using bioerodible polymers.

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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

  • 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.

  • 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.

  • 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.

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