1. Practical physical pharmacyΙ
(Lab.(4
Phase diagram for a three-component system (theoretical part)

2. Introduction Phase diagram for ternary mixture:
It is also called as Gibbs phase triangle, triangle plot, ternary graph, simplex plot or Gibbs triangle.
We can independently change the pressure, the temperature, and the two independent composition variables for the system as a whole.
a ternary or three component phase diagram has the shape of a triangular prism with an equilateral triangle as a foundation which is also called as composition triangle.

3. Introduction
In Figure 1, each apex of the triangle indicates one of the pure components A, B, or C.
In this system we need to limit the quantities of two components. So we call for two axes. The measure of the third can be obtained by deducting the aggregate of the two from 100 which means all three components A,B and C represent 100% or the sum of the three components is 100.
Figure1. Ternary graph

4. Introduction
The entire space is divided into a set of small equilateral triangles which can be further subdivided.
Smaller divisions give accurate and precise location of the composition.
Figure1. Ternary graph

5. How can we select components of ternary system?
Solubility differs when there are different components mixing together. When the third component is added to a pair of miscible liquid, it may affect the mutual solubility.
If the third component is more soluble in one of the liquids than in the other, then the miscibility between that pair of liquids decreases.
3rd

6. How can we select components of ternary system?
If the third component is soluble in both components, then the mutual solubility will increase.
3rd

7. Components of our experiment:
Alcohol and water are pair of miscible liquids.
Camphor is practically insoluble in water but soluble in alcohol.
Alcohol 100%
Figure2. Ternary graph
Camphor 100%
Water 100%

8. Components of our experiment:
Addition of Alcohol to a two phase system (water and camphor) would give a single phase system composed all the three components.
Addition of alcohol leads to complete miscibility of two solvents which is achieved by solvent effect.
Water is highly polar whereas camphor is non polar, alcohol is an intermediate polar solvent that provides the electronic equilibrium and provides solvation.
Alcohol
Camphor and water

9. Applications of ternary diagram in pharmacy
Application of ternary phase diagram
Formulation of nanoemulsions
Formulation of elixir
Formulation of injections
Formulation of lotions
Formulation of solid dispersion
Formulation of emulsions
Study the phase behavior of the presence of different components
Figure3. Applications of ternary diagram in pharmacy

10. Rules Relating to Ternary Phase Diagrams:
Ternary phase diagram is an equilateral triangle.
Each corner / apex of the triangle represents 100 % of a component and the side opposite to the corner represents 0 % of that component.
The distance between the apex and its opposite side is divided into 10 parts ( each divided into 10 parts).
As we move from the side of the triangle to the opposite apex, the % of the component increases.
The area within the triangle represents all possible combinations of the three components.
A ternary phase diagram has a miscible region and immiscible region.

11. Construction of phase diagram for a three component system:
A ternary diagram is a triangle, with each of the three apexes representing a composition, such as sandstone, shale, and limestone . For the moment they are labeled A, B, and C. We are going to take the diagram apart to see how it works.
 The drawing to the left has only the skeleton of the triangle present as we concentrate on point A. Point A is at the top of the heavy vertical red line (arrow). Along this line is indicated percent of A. A point plotted at the top of the vertical line nearest A indicates 100% A. A horizontal bar at the bottom of the line (farthest from A) represents 0% of A. Any other percentage can be indicated by a line appropriately located along the line between 0% and 100%, as shown by the numbers off to the right.      The horizontal lines that represent various percents of A can be of any length since they run parallel to the base line and remain the same distance from the bottom and top of the triangle. The lines are projected out to the right of the red arrow line just as far as where the imaginary side of the triangle will be, and their percentage abundances written along the right side of the triangle. By doing this the right side of the triangle becomes the scale for percent abundance of A.      To be complete the hoirizontal lines also extend to the left until they contact the left side of the imaginary triangle, but no percent abundances are written there. In the final ternary diagram the red vertical arrow is removed.

12. Construction of phase diagram for a three component system:
     Point B is at the lower left apex of the triangle. We construct a percent abundance scale for B by rotating the heavy red scale line 120 degrees counter clock wise so that it runs from the right side of the triangle to the lower left corner. The right side of the triangle now becomes the base line for the percent scale for B, and a series of red lines have been drawn parallel to the triangle's right side to mark off the percentages. These lines are projected out to the left and bottom sides of the triangle, and the percent scale for B laid out along the left side.

13. Construction of phase diagram for a three component system:
Point C is at the lower right apex of the triangle. We construct the percent abundance scale for C by rotating the heavy red scale line another 120 degrees so that it runs from the left side of the triangle to the lower right corner, and the percent scale lines and percent
The sum result is the ternary diagram to the right with all the scales present. Note that the heavy red lines are not included in this final triangle. Also observe that the ternary diagram is read counter clockwise.      So, some practice. Note the numbers on the diagram. The composition for each of these points is shown below. See if you agree. 1.   60% A | 20% B | 20% C = 100% 2.   25% A | 40% B | 35% C = 100% 3.   10% A | 70% B | 20% C = 100% 4.   0.0% A | 25% B | 75% C = 100%abundance numbers rotate with it.

14. Principle of experiment:
Camphor can be dissolved in water by using a co-solvent like alcohol.
This is called ((co-solvency effect)) and alcohol is called co-solvent.
The effect of alcohol on solubility of camphor in water can be studied by constructing a ternary phase diagram. A ternary phase diagram is a graphical plot showing the conditions under which we get a clear camphor solution. It has a miscible region and immiscible region.
Alcohol 100%
Camphor 100%
Water
100%

15. Next: experimental part
Principle of experiment:
In the present experiment a series of solutions (systems) containing different amounts of camphor and alcohol are prepared. To these solutions water is added from a burette until turbidity is produced.
From the quantity of water required to produce turbidity, the composition of the system is calculated and a ternary phase diagram is constructed.
Next: experimental part