Tablets

A tablet is a solid dosage form made by compressing a powder or granulation containing the active drug and a set of excipients into a coherent, dose-defined unit. Tablets are the most widely used dosage form in medicine because they are inexpensive to manufacture at scale, chemically stable, accurate in dose, and convenient for patients to take by mouth.

Definition

A tablet is a unit solid dosage form prepared by compacting a blend of one or more active ingredients with excipients into a defined shape and dose, intended chiefly for oral administration.

Scope

This entry covers the composition of a compressed tablet, the roles of its excipients, the principal manufacturing routes (direct compression, wet and dry granulation), the main tablet types (immediate-release, modified-release, coated, chewable, orally disintegrating), and the quality attributes by which tablets are tested. It is a reference overview, not compounding or clinical guidance.

Core questions

• What excipients does a tablet require, and what does each contribute?
• How do granulation and direct compression differ as manufacturing routes?
• How do immediate-release and modified-release tablets differ in design and behaviour?
• Which quality attributes — disintegration, dissolution, hardness, content uniformity — define a tablet's performance?

Key concepts

• Compression and compaction
• Granulation versus direct compression
• Disintegrant, binder, diluent, lubricant, glidant
• Disintegration and dissolution
• Immediate-release versus modified-release
• Film and enteric coating
• Content uniformity and friability
• Orally disintegrating tablets

Mechanisms

A tablet is built from a powder blend in which excipients perform distinct functions: diluents bulk out a low-dose drug, binders hold the compact together, disintegrants promote break-up in fluid, and lubricants and glidants ease compression and flow. The blend is densified either after granulation — which improves flow and compressibility — or by direct compression of a free-flowing mixture (Aulton & Taylor, 2018; Allen & Ansel, 2018). On administration, an immediate-release tablet disintegrates and the drug dissolves, while modified-release designs use polymer matrices or coatings to slow or target release. For poorly soluble drugs, enabling formulations such as amorphous solid dispersions can be incorporated to raise apparent solubility and dissolution (Vasconcelos et al., 2016). Newer additive-manufacturing (3D-printing) approaches allow tablet geometry and internal structure to be tuned for tailored release (Awad et al., 2018).

Clinical relevance

Tablets are the dominant oral medicine format, and their design features — coating, scoring, modified release — affect how a product behaves and should be handled. Recognising tablet types supports critical reading of product literature; this entry is descriptive and does not provide dosing or administration advice for individual patients.

Evidence & guidelines

Tablet quality is governed by pharmacopoeial standards that specify tests for disintegration, dissolution, and uniformity of dosage units, providing the compendial basis for product release (USP, 2023). Design principles are codified in standard pharmaceutics texts (Aulton & Taylor, 2018; Allen & Ansel, 2018).

History

The compressed tablet originated in the mid-nineteenth century with the development of tablet-compression machinery, which displaced hand-rolled pills and extemporaneous preparation. Over the twentieth century, granulation science, high-speed rotary presses, and modified-release technologies turned the tablet into the standard industrial dosage form (Aulton & Taylor, 2018), with additive manufacturing emerging more recently as a route to personalised tablets (Awad et al., 2018).

Seminal works

• aulton-2018
• allen-ansel-2018
• vasconcelos-2016

Frequently asked questions

What is the difference between an immediate-release and a modified-release tablet?

An immediate-release tablet is designed to disintegrate and release its drug soon after administration, whereas a modified-release tablet uses polymer matrices or coatings to slow, delay, or target release over time.

Why do tablets contain so many inactive ingredients?

The excipients in a tablet each serve a purpose — bulking the dose, binding the compact, helping it disintegrate, easing manufacture, or controlling release — so that the small amount of active drug can be formed into a reliable, manufacturable product.