Pharmaceutics - Excipients for IR tablets

What is an Immediate-Release (IR) Tablet?

A tablet that releases 70-75% of the drug content within 45 minutes.

Name three types of excipients based on function.

Process aids, tablet formers, drug release enhancers.

What are common fillers/diluents?

Starch, lactose, microcrystalline cellulose.

What is the role of a binder in IR tablets?

Acts as an adhesive, increases compactability and tablet hardness.

Name a downside of excessive binder use.

It can hinder tablet disintegration and drug dissolution.

List three excipients used to improve powder flow and prevent sticking.

Magnesium stearate (lubricant), talc (anti-adherent), colloidal silica (glidant).

What is boundary lubrication?

A mechanism where lubricant molecules coat particle surfaces, reducing friction.

Name three types of disintegrants.

Regular disintegrants, superdisintegrants, and effervescent disintegrants.

Give an example of a superdisintegrant.

Sodium starch glycolate or crospovidone.

What's the mechanism of wicking in disintegration?

Water is drawn into the tablet via capillary action, helping it break apart.

What is strain recovery in disintegration?

Compressed particles return to original shape upon wetting, breaking the tablet.

What causes repulsion during disintegration?

Ionized particles repel each other electrostatically in the presence of water.

What ingredients make an effervescent disintegrant?

Carbonates or bicarbonates with a weak acid like citric acid.

Why can lubricants negatively affect dissolution?

Most are hydrophobic and can reduce tablet wettability.

Can a formulation contain both a binder and a disintegrant?

Yes, they serve different purposes and are often balanced in a formula.