disintegrants

Disintegrants are pharmaceutical excipients added to solid dosage forms to promote the breakup of a tablet or capsule when it encounters fluids in the gastrointestinal tract. Their primary purpose is to facilitate rapid disintegration, which in turn promotes timely release and absorption of the active pharmaceutical ingredient (API).

Disintegration occurs mainly through three mechanisms: capillary action (wicking) that draws water into the dosage form; swelling of the disintegrant particles, which disrupts interparticle bonds and structure; and, in some cases, rapid hydration that forms a porous network aiding breakup. Some disintegrants act predominantly by swelling, others by enhancing water penetration, and some by a combination of both effects.

Common types of disintegrants include natural starches (native starch and pregelatinized starch), crosslinked cellulose derivatives (such as croscarmellose sodium), crosslinked polyvinylpyrrolidone (crospovidone), and sodium starch glycolate. Each class has characteristic properties related to swelling capacity, water uptake, and compatibility with APIs. The choice depends on the dosage form, compression force, moisture conditions, and the desired disintegration profile.

In formulation, disintegrants are typically used at approximately 1–5% w/w, though the level may vary with the API and tablet design. They are evaluated using pharmacopeial disintegration tests and dissolution testing to ensure reliable performance. Compatibility with the API, stability under storage conditions, and effects on tablet hardness and friability are also considered.

Regulatory guidance for disintegrants follows pharmacopeial monographs (such as USP and EP) and ensures that selected materials meet safety, quality, and performance criteria for oral solid dosage forms.