Effervescent salts (sometimes called effervescent powders) are a special type of bulk powders or granules containing sodium bicarbonate, a suitable organic acid (citric or tartaric), or inorganic (sodium biphosphate) acid and medicinal agent in addition to drugs and other excipients.
When mixed with water, the acid and the base react to form carbon dioxide, which produces effervescence.
Preparation Effervescent salts
Effervescent salts can be prepared using two methods:
a. Heat method
This method requires blending of all the components, with 15% – 20% of the acid ingredients as citric acid monohydrate, and heating on a bath (about 100 C). The mole of water released from citric acid during heating moistens the powder, and granules are formed from this moistened powder mass.
b. Wet method
The citric acid is moistened and added to sodium bicarbonate. Granules are then formed from this partially fused mass, using a suitable granulator.
Representative formula for an effervescent salt
Sodium bicarbonate (dry powder) 477 g
Tartaric acid (dry powder) 252 g
Citric acid crystals 162 g
Read Also: Manufacture of Effervescent Tablets
Advantages of effervescent salts
a. Effervescent salts mask the unpleasant taste of many drugs.
b. Carbon dioxide stimulates the flow of gastric juice and accelerates the absorption of many drugs.
c. Effervescent salts have a favorable psychological effect on the patient.
d. They have enhanced stability since they are stored in low moisture-content packages.
Dash, A., Singh, S. and Tolman, J. (2014). Pharmaceutics – Basic Principles and Application to Pharmacy Practice. USA: Academic Press.
Ghosh, T. and Jasti, B. (2005). Theory and Practice of Contemporary Pharmaceutics. USA: CRC Press LLC.