60. SACCHARIN SODIUM
Formula: C7H4NNaO3S
Introduction
Saccharin sodium is the sodium salt of saccharin. It is a popular artificial sweetener widely used in pharmaceuticals, toothpaste, and foods. It provides sweetness without calories, which makes it useful for diabetic patients and calorie-controlled diets.
Preparation
There are two general methods for preparing saccharin sodium:
Method 1
- Saccharin is dissolved in aqueous sodium hydroxide.
- This neutralizes the acidic group of saccharin and converts it into saccharin sodium.
Method 2 (Industrial Route)
- Toluene reacts with chlorosulfonic acid → forms o-toluene sulfonic acid.
- o-Toluene sulfonic acid reacts with ammonia → forms a sulphonamide.
- The sulphonamide is oxidized → forms a sulfonic acid.
- This compound undergoes hydrolysis and cyclization → forms saccharin.
- Saccharin is neutralized using sodium hydroxide → gives saccharin sodium.
Test for Purity
- Appearance: White, crystalline solid. Freely soluble in water and the solution should remain clear.
- Acidity/Alkalinity: For 10 ml solution, < 5.5 ml of 0.01 M NaOH should be required.
- Related Substances: Checked by gas chromatography. The sample chromatogram is compared with a standard reference.
- Arsenic: Not more than 2 ppm.
- Heavy Metals: Not more than 20 ppm.
- Water Content: Not more than 15%.
Assay
The assay is carried out using non-aqueous titration:
- Accurately weigh about 0.15 g of sample.
- Dissolve it in 50 ml of anhydrous glacial acetic acid (warming slightly if needed).
- Titrate using 0.1 M perchloric acid and determine the endpoint potentiometrically.
- Perform a blank titration and apply corrections.
Calculation: 1 ml of 0.1 M perchloric acid = 0.02052 g of saccharin sodium.
Uses
- Widely used as a pharmaceutical aid, especially in oral liquids and chewable tablets.
- An ingredient in toothpaste to enhance taste.
- A non-nutritive sweetener used in beverages and diet foods.
- Helpful for reducing sugar intake in diabetic patients.
Detailed Notes:
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PATH: PHARMD/PHARMD NOTES/ PHARMD FIRST YEAR NOTES/ ORGANIC CHEMISTRY/ PHARMACEUTICAL ORGANIC CHEMISTRY/ SACCHARIN SODIUM.
