Colloidal Chemistry Basics

<p>They tend to separate easily (D)</p> Signup and view all the answers

<p>Higher surface area and reduced free energy (A)</p> Signup and view all the answers

<p>For drug delivery and nanoparticle technology (A)</p> Signup and view all the answers

<p>They are solvent loving (B)</p> Signup and view all the answers

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

<p>Colloidal solutions formed in water are termed hydrophilic. (D)</p> Signup and view all the answers

<p>Brownian motion (B)</p> Signup and view all the answers

<p>Oil solution (A)</p> Signup and view all the answers

<p>Increased viscosity of the continuous phase (B)</p> Signup and view all the answers

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

<p>In a zig-zag fashion (A)</p> Signup and view all the answers

<p>Decreases the rate of sedimentation (C)</p> Signup and view all the answers

<p>V = (r^2)(g)(σ-ρ) / (9η) (D)</p> Signup and view all the answers

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

<p>Greater than 25 μm (B)</p> Signup and view all the answers

<p>Improves drug release rate and bioavailability (C)</p> Signup and view all the answers

<p>Dextrin (A)</p> Signup and view all the answers

<p>Ratio of sediment volume to total volume (A)</p> Signup and view all the answers

<p>May cause very small crystal formation (D)</p> Signup and view all the answers

<p>Taste testing (A)</p> Signup and view all the answers

<p>To minimize sedimentation rate while allowing redispersibility (C)</p> Signup and view all the answers

<p>To facilitate the delivery of insoluble drugs (D)</p> Signup and view all the answers

<p>Rapid sedimentation and easy redispersion (C)</p> Signup and view all the answers

<p>Particle growth and caking (C)</p> Signup and view all the answers

<p>Some particles form loose aggregates, while others remain dispersed (B)</p> Signup and view all the answers

<p>Difficult to redisperse once sedimented (A)</p> Signup and view all the answers

<p>Diffusion coefficient (A)</p> Signup and view all the answers

<p>It allows for a rapid and uniform dose of medication (B)</p> Signup and view all the answers

<p>Deflocculated suspension (D)</p> Signup and view all the answers

<p>Formulation class (A)</p> Signup and view all the answers

<p>The behavior of solvents in a concentration gradient (D)</p> Signup and view all the answers

Particles that are dispersed in a medium, but larger than molecules in a true solution and smaller than particles in a coarse suspension. They are visible under an electron microscope and cannot pass through a semi-permeable membrane.

Size range of colloidal particles. They have at least one dimension between 1 nanometer and 1 micrometer, but all three dimensions may not be in this range.

A type of colloid where the dispersed particles have an aversion to the dispersing medium.

A type of colloid where the dispersed particles have an affinity for the dispersing medium.

Colloids are unstable and tend to separate, but they can remain suspended for a long time due to their size and high surface area.

Examples of colloids found in various fields, including pharmaceutics.

The phase that is dispersed in a colloid, like the droplets in a suspension.

The phase that the disperse phase is dispersed in, like the water in an emulsion.

The spontaneous movement of particles from a region of higher concentration to lower concentration.

A mathematical equation that describes the rate of diffusion, factoring in concentration gradient, area, and diffusion coefficient.

A liquid preparation containing finely dispersed insoluble drug particles, often in an aqueous or non-aqueous medium.

The tendency of suspended particles to settle to the bottom due to gravity.

A tightly packed layer of particles at the bottom of a suspension, making it difficult to redisperse.

The formation of loose aggregates of particles within a suspension.

A suspension where particles clump together due to attractive forces, forming a loose structure.

A suspension where particles remain individually dispersed, leading to slow sedimentation and a compact cake formation.

A type of suspension where particles form loose aggregates, balancing sedimentation rate with ease of redispersion.

The tendency of particles to clump together due to attractive forces, leading to instability in the suspension.

Colloids are stable dispersions of tiny particles in a continuous medium, unlike true solutions where particles dissolve completely. These systems form spontaneously, indicating thermodynamic stability. If water is the solvent, the particles are called hydrophilic, as they attract water.

Brownian motion is the random movement of particles in a liquid or gas due to collisions with the medium's molecules. It's why colloidal particles exhibit a zig-zag path even in a seemingly still environment.

Colloidal systems are inherently unstable and prone to aggregation (particles clumping together) or coalescence (liquid droplets merging), eventually destroying the system.

Sedimentation refers to the settling of solid particles in a liquid, while creaming is the separation of liquid droplets in another liquid. Both are driven by gravity and the physical properties of the particles and medium.

Stokes' Law describes the velocity of sedimentation or creaming for spherical particles. It considers factors like particle size, density, and the viscosity of the medium.

Smaller particles, higher viscosity, and a smaller density difference between the particles and the medium all contribute to slower sedimentation or creaming.

The velocity of sedimentation can be calculated using Stoke's Law. It depends on the particle's size and density, the medium's viscosity, and gravity's acceleration.

Knowing the sedimentation velocity allows calculating the distance a particle travels in a given time. This information is crucial for predicting the stability of colloidal formulations.

Large particles in a suspension, typically over 5 micrometers in diameter, lead to issues like a gritty texture, rapid settling, irritation in eyes, and blockage of needles.

Particle size in suspensions is important for controlling the release rate and bioavailability of a drug. Narrow size ranges are generally more desirable for consistent performance.

The process of reducing the size of particles in a suspension to a more uniform and desired range. Helps avoid issues like gritty texture and rapid sedimentation.

Agents that increase the viscosity of a liquid, helping to keep particles suspended and improving stability.

A measure of the final settled volume of sediment (V) divided by the total volume of the suspension (Vo); it reflects the extent of settling.

A key aspect of quality control for suspensions, including checking appearance, particle size, redispersal, and sedimentation volume.