What are capsules made of?

When people fall ill, they often need to take medication—some in tablet form, others in capsule form. But what are capsules made of?

What Are Capsules Made Of?

Capsules generally serve as protective outer shells for medications. Their primary components include plant-derived cellulose, gelatin, and its derivatives. There are three main types: hard capsules, soft capsules, and enteric-coated capsules—each formulated with distinct raw materials. Hard capsules consist mainly of gelatin, plasticizers, and water. Additional ingredients such as colorants, preservatives, and UV protectants may be incorporated as needed. Based on the source material, hard capsules are further classified into animal-derived gelatin capsules and plant-based capsules. Animal-derived gelatin capsules are produced by partial hydrolysis of collagen extracted from animal skins and bones.

Soft capsules comprise both a shell (the “capsule wall”) and internal contents. The capsule wall itself consists of gelatin, plasticizers, and water. Plasticizers regulate the wall’s plasticity and elasticity; commonly used plasticizers include glycerin, sorbitol, or their mixtures. Enteric-coated capsules incorporate specialized pharmaceutical polymers or enteric coating agents—such as cellulose acetate phthalate (CAP), hydroxypropyl methylcellulose phthalate (HPMCP), or polyvinyl acetate phthalate (PVAP)—into the capsule shell. These materials remain intact in gastric fluid but dissolve in the intestinal environment.

This formulation offers excellent bioavailability, enabling rapid, reliable, and safe dissolution and absorption. Enteric-coated capsules are frequently used to encapsulate drugs that exert strong irritant or therapeutic effects on the gastrointestinal tract. Wishing you good health and happiness!