Pharmaceutics: Emulsions to Suspensions

A system where tiny droplets of one liquid are dispersed throughout another, creating a stable mixture.

A characteristic of emulsions where the droplets of the dispersed phase are small enough to prevent them from settling or separating out quickly.

A type of emulsion where oil droplets are dispersed in water.

A type of emulsion where water droplets are dispersed in oil.

A substance that helps to stabilize an emulsion by reducing the interfacial tension between the oil and water phases.

The minimum concentration of an emulsifier needed for it to effectively stabilize an emulsion.

The change in surface area between two phases when creating an emulsion. It's always positive and large.

The interfacial tension between two phases, representing the energy needed to overcome the forces holding them apart.

The energy required to create an emulsion with a specific droplet size, measured in Joules (J).

The process of forming an emulsion, where tiny droplets of one liquid disperse throughout another.

A phenomenon that occurs when the dispersed phase particles are less dense than the continuous phase, causing them to rise to the surface. This forms a cream-like layer in an O/W emulsion.

A phenomenon that occurs when the dispersed phase particles are denser than the continuous phase, causing them to sink to the bottom of the container.

A type of instability in emulsions where droplets collide and merge, leading to a reduction in surface area and a less stable emulsion.

The process of emulsifiers reducing interfacial tension between two liquids, allowing them to mix more easily.

Increasing the density of the continuous phase (e.g., adding sugar) reduces the difference in density between phases, lowering the rate of creaming or sedimentation.

The rate at which dispersed particles move due to gravity, influenced by factors like density difference and particle size.

The measure of the electrostatic repulsion between particles in a dispersion. A higher Zeta potential indicates greater stability due to increased repulsion forces.

A threshold value for Zeta potential, often considered the minimum required for colloidal stability. Above this value, particles repel strongly enough to prevent aggregation.

The property of a fluid that affects its resistance to flow. It's a measure of how easily a substance can be poured or spread.

The viscosity of a liquid when it is at rest, undisturbed. This can change when the liquid is moved (e.g., stirred)

The ratio of the volume of the internal phase to the total volume of the emulsion. It affects the consistency and stability of the emulsion.

The ability of a fluid to behave differently under different shear stresses. A shear-thinning fluid becomes less viscous at higher shear rates.

A property of some materials that causes them to exhibit different viscosities at different shear rates. They become less viscous when shaken or stirred, and regain their viscosity when left undisturbed.

A type of suspension where the dispersed phase is finely divided particles, often in the colloidal range, suspended in a liquid.

A system where particles are dispersed in a liquid and exhibit a tendency to clump together, leading to instability.

A system where particles are dispersed in a liquid and remain individually suspended, resulting in a stable dispersion.

The ability of a suspension to return to a homogeneous state after being disturbed by shaking or agitation.

The property of a material to exhibit a decrease in viscosity under increasing shear stress. It flows more easily when stirred or shaken.

The process where solid particles in a suspension settle down due to gravity, leading to a concentrated layer of particles at the bottom.

The formation of a hard, compact mass of particles at the bottom of a suspension, often making it difficult to redisperse.

A substance that controls particle clumping in a suspension, preventing caking and promoting stability.

A suspension where particles are loosely grouped together, preventing caking but allowing for quick redispersion.

A suspension where particles are completely dispersed and evenly distributed, providing optimal stability but prone to caking.

The process where drug particles in a suspension change size, often due to dissolving and recrystallizing, potentially affecting stability and bioavailability.

The size range of drug particles in a suspension, influencing stability, release rate, and bioavailability.

A suspension where the drug is already dispersed in the liquid medium, ready for immediate use.

A liquid's ability to spread over a solid surface. A low contact angle indicates high wetting, where the liquid easily spreads and covers the solid surface.

A substance that helps a liquid spread more easily over a solid surface by reducing the interfacial tension between them. This helps prevent particles from clumping together.

A controlled process where particles in a suspension are kept from settling too quickly and forming a compact mass at the bottom. This involves carefully balancing attractive and repulsive forces between particles.

A thickener increases the viscosity of a liquid, making it more resistant to flow and slowing down particle sedimentation. This helps create a stable suspension.

Substances that increase the viscosity of a liquid, making it thicker and helping to slow down sedimentation in a suspension.

The rate at which particles settle in a suspension. It is affected by factors like particle size, density difference between the particles and the liquid, and the viscosity of the liquid.