“EUTECTIC MIXTURE”

Diptarco Singha, Durjoy Ghosh & Hrishav Roychowdhury

B.PHARM, 2nd YEAR, 3RD SEMESTER

What is Eutectic Mixture?

An Eutectic Mixture is a mixture of several components in a particular ratio, which melts sharply below the melting point of any individual component…

Properties of Eutectic Mixtures:-

Melts below the melting

point of individual

component…

The melting point is always fixed…

During formation, the components are miscible

in liquid state but

immiscible in solid state…

Principles of Eutectic Mixture:- Below the eutectic temperature the mixture of the two substances will exist as a solid.While above it the mixture will convert into a liquid.

(e- Eutectic point)

Point ‘e’ is the lowest melting point.

Factors Affecting the Formation of Eutectic Mixtures:-

It is necessary to adjust the ratio of the components in the mixture.

It is also necessary to closely control the components for impurities.

This is because unadjusted ratios & presence of impurities may cause imbalance to the mixture & throw off the solidification point.

Factors governing Eutectic Mixture Formation:-

The components must be miscible in a liquid state & mostly immiscible in solid state…

The molecules which are in accordance to modified VantHoff’s equation can form eutectic mixtures…

The components should have chemical groups that can interact to form physical bonds such has intermolecular hydrogen bonding etc…

Pharmaceutical Uses:-Eutectic Mixtures are commonly used in drug designing and

delivery processes for various routes of administration…Other uses are:-

For the identification of the compounds having similar

melting points.

Local anesthetics in case of children (used topically).

References:-

Martin’s Physical Pharmacy and Pharmaceutical Science,Fifth edition;Page-41…

Agarwal,Khanna; Physical Pharmacy, Page-10-11…