Definition of Multiple Emulsions: Multiple emulsions are complex systems where emulsions exist within emulsions. Common types include: W/O/W: Water-in-oil-in-water O/W/O: Oil-in-water-in-oil Example (W/O/W): Internal water droplets are dispersed in oil droplets, which are further dispersed in an external water phase. Applications: Controlled and sustained drug release Masking taste or odor Targeted drug delivery Cosmetics and … Read more
Theories of Emulsification aid in formulating stable pharmaceutical and food emulsions. Theories of Emulsification explain how emulsifying agents stabilize oil-water mixtures. These are theories that explain the formation and stabilization of emulsions: Monomolecular Theory Emulsifying agents like surfactants form a monomolecular film at the oil-water interface. These molecules have hydrophilic (water-loving) and lipophilic (oil-loving) ends, … Read more
Definition of Microemulsions: Microemulsions are thermodynamically stable, transparent or translucent emulsions composed of oil, water, surfactant, and co-surfactant. Key Features: Droplet size: 10–100 nm High clarity (may appear clear or slightly bluish) Spontaneous formation (with gentle mixing) High stability compared to conventional emulsions Types: O/W microemulsion W/O microemulsion Bicontinuous microemulsions Components Oil phase: Medium-chain triglycerides, … Read more
Definition of Emulsions: An emulsion is a biphasic (two-phase) system consisting of two immiscible liquids, where one liquid (the dispersed phase) is finely dispersed in the form of droplets throughout the other (the continuous phase), stabilized by an emulsifying agent. Classification of Emulsions Emulsions can be classified into four types: Oil-in-Water (O/W) Emulsion: Oil droplets … Read more
Deflocculated Suspensions show slow sedimentation but form a hard cake, making redispersion difficult. Deflocculated Suspensions Particles remain separate and discrete. Settle slowly due to small size and mutual repulsion. Can lead to caking—a dense sediment forms that’s hard to redisperse. Advantages of Deflocculated Suspensions: Appears more uniform Slower settling Disadvantages of Deflocculated Suspensions: Risk of … Read more
Flocculated Suspensions are agents (like electrolytes, polymers) are used. Flocculated Suspensions Particles form loosely bound clusters called flocs. Flocs are light and settle rapidly but form a loose sediment that is easily redispersed. Zeta potential is reduced (but not too low) to promote controlled aggregation. Advantages: No caking Easy redispersion Uniform dose upon shaking Disadvantages: … Read more
Settling in Suspensions affects stability, dosage uniformity, and quality of pharmaceutical formulations. Settling In Suspensions is a natural consequence in suspensions due to gravity acting on particles denser than the liquid. Stokes’ Law The rate of settling V of spherical particles in a fluid is described by: $V = \frac{2 r^{2} (\rho_{p} – \rho_{f}) g}{9 … Read more
Rotational Viscometer (Brookfield Viscometer) measures fluid viscosity by spindle rotation resistance. It is widely used in pharma, food, and cosmetic industries. Principle of Rotational Viscometer (Brookfield Viscometer): Measures the torque required to rotate a spindle at constant speed in the sample. The resistance to rotation is a function of the sample’s viscosity. $\eta \propto \frac{\text{Torque}}{\text{Angular … Read more
Optical Properties of Colloids help in particle size analysis and stability studies of colloidal systems. Optical Properties of Colloids explain light scattering, Tyndall effect, and visibility of dispersed particles. Colloidal particles, due to their size (1–1000 nm), interact with light in unique ways. These optical effects help characterize and analyze colloidal systems. Tyndall Effect Definition: … Read more
Kinetic properties of Colloids are related to the movement of colloidal particles due to thermal or external forces. Kinetic Properties of Colloids explain particle stability, transport, and dynamic interactions. These motions contribute to the stability and behavior of colloidal systems. 1. Brownian Motion Definition: The random, zig-zag motion of colloidal particles due to continuous collision … Read more
