Medicinal Uses and Varieties of Lactose

What is Lactose?

Lactose is a natural disaccharide. It consists of galactose and glucose and is obtained from the milk of most mammals. It is also known as milk sugar, lactose monohydrate, lactin, saccharum lactis and lactose monohydricum.

It occurs as white (almost white) crystalline powder with faintly sweet taste. It has no odour. It is stable in air but it absorbs odours readily.

Several varieties of lactose are available like

1. Anhydrous alpha lactose
2. Alpha lactose monohydrate
3. Anhydrous beta lactose

It is freely soluble in water. Lactose monohydrate is the monohydrate of O-B-D galactopyranosyl-(1-4)-a–D glucopyranose.

Uses of lactose:

• It is widely used as a diluent or filler in tablets, capsules, infant feed formulae and in dry powder inhalations.
• It is used to prepare sugar coating solutions in combination with sucrose in the ratio of 1:3
• Fine grades of lactose are used in the preparation of tablet by wet granulation method from among various grades of lactose.
• Direct compression grades of lactose are more compressible. They consists of spray dried lactose. This contains pure alpha lactose monohydrate along with little amount of amorphous lactose.
• Other specially produced direct compression grades of lactose does not contain amorphous lactose, but it may contain glassy areas which improves compressibility.
• Direct compression grades of lactose when combined with microcrystalline cellulose or starch requires 0.5% magnesium stearate as lubricant.
• It should be stored in well closed container in a dry cool place.