Pharmacology Quiz: Drug Delivery Mechanisms

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Questions and Answers

What does bioavailability refer to in the context of administered drugs?

The fraction of an administered drug that reaches systemic circulation in an active form (correct)

The elimination half-life of a drug

The total amount of drug administered

The time it takes for a drug to exert its effects

Which characteristic is NOT associated with nanodrugs?

Targeted delivery

Enhanced bioavailability

Increased dosage frequency (correct)

Controlled release

In the mechanism of sustained drug release, what role do biodegradable lipids play?

They enable gradual breakdown and drug release (correct)

They enhance raw material cost

They prevent drug degradation

They increase the drug's solubility

What is a significant factor affecting the release profile in in vitro studies?

The characteristics of the membrane used Signup and view all the answers

What can trigger a rapid release of a drug from certain liposomal formulations?

Changes in pH or temperature Signup and view all the answers

What does Dynamic Light Scattering (DLS) primarily measure?

The diffusion speed of particles in suspension Signup and view all the answers

Which technique allows for direct 2-D imaging of nanomaterials?

Transmission Electron Microscopy Signup and view all the answers

What characterizes a liposome?

It has at least one lipid bilayer Signup and view all the answers

Which of the following is NOT a type of nanocarrier used in nanomedicine?

Hydrocarbon vesicles Signup and view all the answers

What is a significant characteristic of polymers used in controlled drug delivery systems?

They should be chemically inert and nontoxic Signup and view all the answers

What is the main use of nanobiotechnology in medicine?

For prevention, diagnosis, treatment, and monitoring of diseases Signup and view all the answers

Which of the following statements about Brownian motion is true?

It results from collisions with fast-moving fluid particles Signup and view all the answers

Which statement about the preparation of liposomes is accurate?

Thin-Film Hydration Method is commonly used for preparation Signup and view all the answers

Study Notes

Nanotechnology and Applications in Medicine

Nanotechnology is used in medicine.
The presentation covers different methods to characterize nanoparticles.
One technique is Dynamic Light Scattering (DLS).

Nanoparticle Characterization

Methods exist to characterize nanoparticles' shape, size, and location.
DLS measures fluctuations in scattered light intensity to determine particle size.
This method is based on Brownian motion.
Smaller particles show greater fluctuations than larger ones.

Brownian Motion

Brownian motion is the random movement of small suspended particles in a fluid.
The motion results from collisions of suspended particles with other fast-moving particles in the fluid.

UV-Vis Spectrophotometry

UV-Vis Spectrophotometry is used for analysis.
It measures optical density at different wavelengths.

Transmission Electron Microscopy (TEM)

TEM enables direct 2-D imaging of particle size, shape, and surface characteristics.

Nanomedicine

Nanomedicine is a field that involves the application of nanotechnology in medical treatments.
It includes the use of nanodrugs.

Nanodrugs

Nanodrugs are delivered in specific ways.
Different delivery systems (nanocarriers) exist.
Some systems are liposomes, solid lipid nanoparticles, and polymeric nanoparticles.

Types of Nanodrug Delivery Systems

Liposomes are suitable for encapsulating hydrophilic and hydrophobic drugs to improve bioavailability.
Solid lipid nanoparticles offer controlled release and stability for lipophilic drugs.
Polymeric nanoparticles excel for loading drugs and targeted delivery, showing versatility in drug release profiles.

Liposomes

Liposomes are spherical vesicles with at least one lipid bilayer.
They are used as vehicles to deliver nutrients and pharmaceutical drugs.

Preparation of Liposomes (Thin-Film Hydration Method)

This method involves several steps.
It includes: solvent evaporation, hydration, liposomal formulation, sonication, and size reduction.
The final product is liposomal suspension.

Types of Liposomes

MLV (Multilamellar Vesicles): 1-5 μm
LUV (Large Unilamellar Vesicles): 100-250 nm
SUV (Small Unilamellar Vesicles): 20-100 nm

Polymers as Nanocarriers

Polymers are the most commonly used nanocarriers.
They are easily and cheaply fabricated in large quantities using various methods.
Key properties in nanocarriers include chemical inertness, nontoxicity, and a lack of impurities.

Polymeric Nanoparticle Preparation Methods

Nanoparticles can be prepared using methods like nanoprecipitation, solvent evaporation, and emulsion polymerization.

Nanoprecipitation

This process is used for creating nanoparticles with controlled size and distribution and is ideal for encapsulating sensitive materials.
It involves a precipitation step after organic solvent evaporation from the organic solution containing the polymer and drug solution.

Factors Affecting Bioavailability

Factors impacting bioavailability of drug include low solubility, poor permeability, instability, and first-pass metabolism.
Nanocarriers are helpful for improving the bioavailability of drug.

Mechanisms for Enhancing Bioavailability

Nanoparticles can enhance bioavailability through several mechanisms.

Controlled Drug Release

Nanodrugs can be designed to release their active components slowly over time to maintain therapeutic levels in the bloodstream for a longer period of time.
This mechanism often is achieved through using biodegradable materials.

Sustained Drug Release Mechanism

Some liposomes are made from biodegradable lipids that degrade over time.
Encapsulated drug releases as the liposome structure breaks down.
Certain liposomal formulations respond to external stimuli, such as changes in pH or temperature, triggering rapid drug release in specific conditions (e.g., acidic tumor environments).

In Vitro Drug Release Studies

Studying in vitro release involves measuring the cumulative release over a specific time period.
Different release profiles could include immediate, sustained, or prolonged release.

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Description

Test your knowledge on drug delivery mechanisms and the bioavailability of administered drugs. This quiz covers key concepts such as the characteristics of nanodrugs, the role of biodegradable lipids, and factors affecting drug release profiles. Perfect for students studying pharmacology and drug formulation.