PHYPHAR LAB - EXP 7: Temperature-Composition Diagram of Binary Systems Containing Liquid Phases

Solution

• a chemically and physically homogeneous mixture of two or more substances

• aside from liquid mixtures, they can even be gases or solids

• very common type of liquid dosage form in pharmacy

• a one-phase system

Size of the disersed particle

Solutions can be classified based on the _____ as true solutions, colloidal solutions, or dispersed systems.

True Solutions

Examples of _____:

• Syrups

• Tinctures

• Elixirs

Colloidal Solutions

Examples of _____:

• Protein-containing solutions

Dispersed Systems

Examples of _____:

• Suspensions

• Emulsions

Phase

Refers to a distinct homogeneous part of a system separated by definite boundaries from other parts of the system.

System

Refers to a bounded space or a definite quantity of substance that is under observation and experimentation.

Binary Solution

A solution composed of only two substances:

• Solvent

• Solute

Solvent

The component present in greater amount on a binary solution.

Solute

The component present in lesser amount on a binary solution.

Solubility

The extent to which the solute dissolves in a solvent at a given temperature.

Saturated Solution

At a specific temperature, this results when an equilibrium is established between the molecules leaving the solid phase and those returning to it.

Solubility Defined in Quantitative Terms

The concentration of solute in a saturated solution at a certain temperature.

Solubility Defined in Qualitative Terms

The spontaneous interaction of two or more substances to form a homogeneous mixture.

Phase Diagram

• Used in practice to formulate systems containing more than one component where it may be advantageous to achieve a homogeneous liquid product.

• The temperature and composition of the mixture at which phenol is completely soluble can be deduced from this.

Phenol

This exhibits a partial solubility in water.

Critical Solution Temperature

• The maximum temperature at which the two-phase region exists.

• Beyond this temperature, all combinations of phenol and water are completely miscible and form one-phase liquid systems.

Nonhalogenated Wastes Container

Where do we dispose the phenol-water mixtures?

Phase Equilibrium

A state where multiple phases (solid, liquid, gas) coexist at equilibrium without net phase change over time.

Phase Rule

F = C - P + 2

• F = degrees of freedom

• C = number of components

• P = number of phases

Condensed System

A system where the gas phases are ignored, focusing only on liquid and/or solid phases.

Phenol-Water

Example of a two-component system with an Upper Critical Solution Temperature (UCST)

• mixes above a certain temperature

Triethylamine-Water

Example of a two-component system with a Lower Critical Solution Temperature (LCST)

• single phase below LCST

Nicotine-Water

Example of a two-component system with both Upper and Lower Critical Solution Temperature (UCST & LCST)

• single phase between UCST and LCST