Question

why does methylcellulose absorb water? why do we use this and not regular cellulose for a laxative?

Answer 1

Methylcellulose is a polymer that comprises of several linked glucose molecules. It turns viscous on being dissolved in water. Hence, it is used as an emulsifier, thickener and as a stabilizer in various foodstuffs and cosmetics. It is a hydrophilic compound that appears as a white powder and being hydrophilic makes it water soluble.

Regular cellulose can be easily digestible, toxic or allergenic to the body in a certain amount. Hence, it cannotbe used as a laxative to prevent constipation. Methylcellulose forms a viscous solution or gel while dissolving in cold water. It absorbs water in the gastrointestinal tract leading to increased bulk of the stool which eventually leads to stimulation of peristalsis of this tract. Besides, it increases the amount of water in the stool and makes it softer and easier to pass.