Physical incompatibilities involve changes in the appearance, texture, or stability of pharmaceutical formulations when substances with different physical properties are mixed.
These incompatibilities can affect product quality, efficacy, and safety.
Examples of Physical Incompatibilities:
Immiscibility
Occurs when two liquids do not mix to form a homogeneous solution, leading to phase separation.
Example: Mixing castor oil with water results in two immiscible layers.
Insolubility
Refers to a substance's inability to dissolve in a particular solvent, causing particle formation or sedimentation.
Example: Barium sulfate does not dissolve in water, forming an insoluble suspension.
Precipitation
The formation of solid particles from a solution, usually due to a chemical reaction or exceeding solubility limits.
Example: Mixing silver nitrate with sodium chloride results in the precipitation of silver chloride.
Liquefaction
Occurs when a solid substance becomes liquid due to temperature changes or interactions with other substances.
Example: Camphor and menthol form a eutectic mixture, causing liquefaction.