What is the role of starch in zinc and salicylic acid paste?

Starch is used in zinc and salicylic acid paste as a thickening agent to give the paste a proper consistency for application. It helps to create a spreadable paste that can adhere to the skin, allowing the active ingredients like zinc and salicylic acid to work effectively. Starch also helps to absorb excess moisture and oils from the skin, aiding in the treatment of conditions like acne.