This document provides information on saline cathartics, also known as osmotic laxatives. Saline cathartics work by drawing water from the circulation into the gastrointestinal tract through osmosis, which increases intestinal bulk and produces diarrhea. Two examples are discussed in detail: magnesium sulfate (Epsom salt) and sodium potassium tartrate. Magnesium sulfate occurs as colorless needle-like crystals with a bitter taste. It is used to treat constipation and electrolyte deficiencies. Sodium potassium tartrate, also called Rochelle salt, is obtained by neutralizing sodium carbonate with potassium bitartrate and is used as a laxative and food additive.

1. SALINE CATHARTICS
Presented by,
G.Revathi, M.Pharm.,
Assistant Professor
Dept. of Pharmaceutical chemistry
SVCP

2. Introduction
➢ Saline cathartics (purgatives) – agents that fasten and
increase evacuation from the bowels
➢ also called Osmotic laxatives
➢ Mild cathartics used for short-term therapy
➢ Used to ease defecation in patient with painful
haemorrhoids (piles) or other rectal disorders.

3. Drugs when given orally
retained in GIT
increases the intestinal bulk
by drawing water from circulation by osmosis
acts as mechanical stimulants
produces increased peristalic movement causing diarrhoea
also called as saline purgatives or osmotic laxatives.
Mechanism of Cathartics

4. EXAMPLES
1. Magnesium Sulphate (EPSOM Salt)
2. Sodium potassium tartarate

5. 1. Synonym: Epsom salt
2. Molecular formula: MgSO4.7H2O
3. Molecular weight: 120 gm
4. Preparation:
By neutralizing hot, dilute sulphuric acid with magnesium oxide or magnesium
carbonate.
MgO + H2SO4 → MgSO4 + H2O
1. Magnesium Sulphate

6. 5. Physical properties:
✓ Occurs in small, colourless
✓ Needle like crystals or prisms
✓ Odourless and
✓ Cooling saline or bitter taste
✓ Efflorescent in nature → when exposure to air
6. Chemical Properties:
On addition of ammonium phosphate in the presence of ammonia → Mg phosphate precipitate
Mg ammonium phosphate precipitate - dried & ignited when Mg pyrophosphate is formed.
2MgNH4PO4 → Mg2P2O7 + 2NH3 + H2O
Mg pyrophosphate

7. 7.Assay:
complexometric assay
8.Test for Purity:
✓ Arsenic
✓ Iron
✓ Heavy metals
✓ Chloride
✓ Sulphate

8. 9. Storage:
It is efflorescent , so stored in a well-closed container
10. Medicinal Use:
1. Used for constipation.
2. Evacuation of gall bladder (in case of chole cystitis)
3. Treatment for electrolyte deficiency
4. Osmotic laxative → anticonvulsive properties
5. Used to control seizures

9. 2. SODIUM POTASSIUM TARTRATE
Synonym : Rochelle salt
M.F : CH (OH) – COONa . CH (OH) – COOK ,4H2O;NaKC4H4O6.4H2O
Molecular Weight: 282 gm
Preparation
It is obtained by neutralizing a solution of sodium carbonate with potassium bitartrate. The solution is
boiled for few mts and then allowed to stand at 60 0C for the completion of the reaction. (till the CO2
ceases). The solution is filtered and evaporated.
2KHC4H4O6 + Na2CO3 → 2KNaC4H4O6 + CO2 + H2O

10. Physical Properties
Colourless,
crystalline efflorescent powder
soluble in water,
insoluble in alcohol.
Chemical Properties
Upon heating at high temperature gives sodium and potassium carbonates.
2 KNa C4H4O6 + 5O2 → K2CO3 + Na2CO3 + 6 CO2 + 4H2O

11. Assay : Back titration method
Identification Test :
When heated the salt emits an odour of burning sugar and leaves a residue → alkaline to litmus paper.
Storage
It should be stored in air tight container.
Pharmaceutical and medicinal uses:
1.Laxative and food additive
2.Used in fehling’s solution and Seidlitz powder
3.Used as stabilizers in meat and fish products

12. THANK YOU