What Are Tablets Made Of? Ingredients & Formulation Guide

Content

1 What Tablets Are Actually Made Of: The Core Answer
2 Fillers and Binders: The Structural Foundation
- 2.1 Common Fillers Used in Tablets
- 2.2 Binders: Holding Everything Together
3 Disintegrants, Lubricants, and Glidants: The Processing Agents
4 Tablet Coatings: More Than Just Appearance
5 Flavors, Sweeteners, and Other Functional Additives
6 Different Types of Tablets and Their Ingredient Profiles
7 How Tablet Manufacturing Turns Raw Materials Into a Finished Dose
8 Tablets vs. Natural Empty Capsules: Understanding the Formulation Choice
9 Regulatory Standards and Safety Requirements for Tablet Ingredients
10 Emerging Trends in Tablet Excipient Technology
11 Summary: Key Ingredients in Tablet Formulations at a Glance

What Tablets Are Actually Made Of: The Core Answer

Tablets are compressed solid-dose forms made from a combination of active pharmaceutical ingredients (APIs) and a range of excipients — inactive substances that control how the tablet holds together, dissolves, and delivers its active content. The API is what produces the therapeutic effect; everything else in the formula exists to serve that purpose.

A finished tablet typically contains five to fifteen distinct ingredients, each chosen for a specific functional role. These include binders, fillers, disintegrants, lubricants, glidants, coatings, and colorants. The proportions vary significantly depending on the drug's potency, target release profile, required shelf life, and patient population.

While tablets dominate the pharmaceutical market — accounting for roughly 70% of all solid oral dosage forms — their construction is far more complex than their smooth exterior suggests. Understanding what goes into a tablet also clarifies why some manufacturers and formulators choose natural empty capsules as an alternative delivery system, particularly when simplifying the ingredient list matters.

API

Active Pharmaceutical Ingredient

The compound producing the therapeutic effect — often just 1–30% of the tablet by weight

EXC

Excipients

Inactive ingredients making up the majority of most tablets by volume

5–15

Typical Ingredient Count

Complex formulations can involve even more distinct components

Fillers and Binders: The Structural Foundation

The bulk of most tablet formulations is made up of fillers (also called diluents) and binders. Because APIs are often required in doses far too small to form a handleable tablet on their own, fillers provide the physical mass needed for compression.

Common Fillers Used in Tablets

The most widely used filler materials include:

Microcrystalline cellulose (MCC) — derived from refined wood pulp, MCC is one of the most versatile excipients available, used in both direct compression and wet granulation
Lactose — a sugar derived from milk whey, valued for its compressibility and low moisture absorption, though it excludes lactose-intolerant patients
Dicalcium phosphate — a mineral excipient that compresses well and provides a source of calcium; commonly found in supplement tablets
Mannitol and sorbitol — sugar alcohols used in chewable tablets for their cool mouthfeel and acceptable sweetness profile
Starch — corn or potato starch functions as both a filler and a disintegrant in many tablet formulas

Binders: Holding Everything Together

Binders create cohesion between particles, allowing them to compress into a solid tablet without crumbling. They can be added dry (for direct compression) or in solution (for wet granulation). Common binders include:

Hydroxypropyl cellulose (HPC)

A water-soluble cellulose derivative, widely used in both wet granulation and direct compression processes. Typically used at concentrations of 2–6%.

Polyvinylpyrrolidone (PVP / Povidone)

One of the most frequently used binders globally, available in multiple viscosity grades. Soluble in both water and alcohol.

Gelatin

A protein-based binder with excellent film-forming properties. Also the primary material used in traditional hard-shell capsules — though natural empty capsules made from HPMC (hydroxypropyl methylcellulose) now offer a plant-based alternative.

Methylcellulose (MC)

A cellulose ether with gel-forming properties at elevated temperatures; commonly used in sustained-release systems.

Disintegrants, Lubricants, and Glidants: The Processing Agents

Disintegrants

Disintegrants ensure the tablet breaks apart after swallowing, releasing the API for absorption. Without them, a highly compressed tablet could pass through the GI tract largely intact.

Superdisintegrants like croscarmellose sodium and crospovidone work by rapidly swelling when they contact moisture — they can increase a tablet's disintegration time from minutes down to under 60 seconds when used at concentrations of just 2–5%.

Lubricants

Lubricants prevent the tablet mixture from sticking to the punch faces and die walls during compression. The most widely used lubricant is magnesium stearate, typically at concentrations of 0.25–1%. It is effective at very low levels but reduces dissolution rate if overused.

Vegetable-grade magnesium stearate is available for manufacturers producing tablets or filling natural empty capsules that require vegan or halal certification.

Glidants

Glidants improve powder flowability during tablet compression. The most common is colloidal silicon dioxide (fumed silica), used at 0.1–0.5% levels. Better flow means more uniform die filling and tighter weight control across a production run.

Tablet Coatings: More Than Just Appearance

Coatings are applied to tablet cores for multiple reasons — taste masking, improved swallowability, moisture protection, API stability, and controlled release. Roughly 40% of commercial tablets carry some form of coating.

Table 1: Major tablet coating types, their materials, functions, and typical coating thickness values
Coating Type	Primary Materials	Primary Function	Typical Thickness
Film Coat	HPMC, HPC, ethylcellulose	Appearance, taste masking, moisture barrier	20–100 µm
Enteric Coat	HPMCP, Eudragit L/S series	Delays dissolution until intestine (pH > 5.5)	50–200 µm
Sugar Coat	Sucrose, talc, gelatin	Taste masking, polished appearance	500–1500 µm
Extended-Release Coat	Ethylcellulose, Eudragit RS/RL	Controls drug release rate over hours	50–300 µm

Colorants and opacifiers — such as titanium dioxide, iron oxides, and FDA-approved synthetic dyes — are added to film coat formulations for product identification and brand differentiation. The color of a tablet is never merely cosmetic; regulatory bodies require that dosage form appearance be consistent and distinguishable from other products.

Flavors, Sweeteners, and Other Functional Additives

Chewable tablets, orally disintegrating tablets (ODTs), and pediatric formulations require additional ingredients to ensure patient compliance. Bitter or chemically unpleasant APIs present a significant formulation challenge — particularly for oral solid doses where taste is not masked by a coating.

Sweeteners in Tablet Formulations

Common sweeteners include:

Sucralose — approximately 600 times sweeter than sucrose, used at very low concentrations; suitable for diabetic patients
Aspartame — widely used but contraindicated for phenylketonuria (PKU) patients; must be labeled
Sorbitol and xylitol — sugar alcohols with a natural cooling sensation, used in chewable and lozenges
Acesulfame potassium (Ace-K) — heat-stable sweetener, often combined with sucralose for a cleaner taste profile

Flavors and Taste Masking Agents

Natural and artificial flavor additives are typically used at 0.1–1% concentrations. Common examples include peppermint oil, cherry flavor, and vanilla extract. For pediatric and geriatric tablets where taste compliance is critical, companies may also evaluate whether natural empty capsules offer an easier delivery route — capsule shells inherently mask the taste of the enclosed ingredient without the need for flavoring agents.

Antioxidants and Preservatives

APIs susceptible to oxidative degradation require antioxidants. Common choices include butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and vitamin E (tocopherol). These are used at trace levels — often under 0.1% — but are critical for maintaining potency over the product's 2–3 year shelf life.

Different Types of Tablets and Their Ingredient Profiles

Not all tablets are formulated the same way. The intended release profile, target patient group, and route of administration all dictate which excipients are selected and at what levels.

Immediate-Release (IR) Tablets

Designed to release the API within 30–45 minutes. Formula typically includes a disintegrant at 2–8%, a binder, a filler making up 50–80% of the tablet, and magnesium stearate. These are the most common tablet type on the market.

Extended-Release (ER/XR) Tablets

Rely on hydrophilic matrix polymers like HPMC (Methocel) or insoluble matrix materials like ethylcellulose. Drug release is controlled over 8–24 hours by the swelling or erosion of the matrix. Higher polymer concentrations (20–40%) replace much of the traditional filler content.

Orally Disintegrating Tablets (ODTs)

Formulated to dissolve on the tongue within 30 seconds without water. Require special superdisintegrants, sugar alcohols for mouthfeel, and freeze-dried or spray-dried filler structures. Low hardness and high porosity distinguish their physical characteristics.

Chewable Tablets

Built around mannitol, sorbitol, or calcium carbonate as the primary filler for pleasant texture when chewed. Require more intensive flavor and sweetener use. Disintegrants are typically omitted since mechanical chewing replaces their function.

Effervescent Tablets

Contain citric acid and sodium bicarbonate as the effervescent couple. When dissolved in water, the acid-base reaction produces CO₂ that disintegrates the tablet and aids absorption. These tablets are very sensitive to moisture and require strict packaging controls.

Sublingual / Buccal Tablets

Designed to be absorbed through the oral mucosa, bypassing first-pass metabolism. They use mucoadhesive polymers like sodium alginate or carbopol to extend contact time with the mucosa. Extremely small size and very low binder content compared to standard oral tablets.

How Tablet Manufacturing Turns Raw Materials Into a Finished Dose

Knowing what tablets are made of is only part of the picture. The manufacturing process determines whether those ingredients perform as intended. Three main manufacturing routes exist:

Direct Compression (DC)

The simplest and most cost-effective method. API and excipients are blended and compressed directly into tablets. Requires excipients with good flowability and compressibility — typically MCC, lactose, or co-processed excipients. Around 20–30% of tablet products use direct compression. No solvent or heat is involved, making it suitable for moisture-sensitive and heat-sensitive APIs.

Wet Granulation

A binder solution is used to agglomerate powders into granules before compression. Granulation improves powder flow, reduces segregation, and allows higher drug loads. It involves mixing, wet massing, drying (fluid-bed or tray drying to below 2% moisture), milling, and final blending before compression. The most widely used method for complex formulations.

Dry Granulation (Roller Compaction)

Used when the API cannot tolerate moisture or heat. Powder blends are compressed into ribbons under high force by rollers, then milled into granules. The granules are blended with lubricants and compressed into tablets. No liquid is involved, but the process generates more fines than wet granulation.

Tablets vs. Natural Empty Capsules: Understanding the Formulation Choice

Tablet formulations are powerful and versatile, but they are not always the right choice. Formulators and product developers regularly evaluate natural empty capsules as an alternative when certain properties of the API or the target market make encapsulation more practical.

Compressed Tablets

High-speed production once optimized (up to 1 million tablets/hour on rotary presses)
Lower material cost per unit for high-volume production
Multiple release profiles achievable through matrix or coating design
Require APIs to withstand compression forces (typically 5–50 kN)
Longer development timelines due to excipient selection and compression optimization
Larger ingredient list needed for binding, flow, and disintegration

Natural Empty Capsules

Can be filled with powders, pellets, granules, liquids, or semi-solids
No compression needed — suitable for fragile or low-compressibility APIs
HPMC-based natural empty capsules offer plant-based, halal, and kosher compliance
Gelatin-based capsule shells dissolve within 5–10 minutes in gastric fluid
Reduced formulation complexity — fewer excipients required
Taste masking inherent to the shell; no flavor agents needed
Faster product development cycle for early-phase clinical trials

The choice between tablets and natural empty capsules depends on the API's physical and chemical properties, the target dose, the regulatory pathway, and the patient population. For nutraceutical and supplement manufacturers, natural empty capsules have gained significant market share due to their cleaner label perception and the growing consumer preference for plant-derived ingredients.

Regulatory Standards and Safety Requirements for Tablet Ingredients

Every ingredient in a tablet — API and excipient alike — must meet strict regulatory standards. In the United States, excipients used in approved drug products must comply with the FDA's Generally Recognized as Safe (GRAS) list or be supported by sufficient safety data under 21 CFR.

Pharmacopeial Standards

Major pharmacopoeias set purity and identity standards for excipients:

United States Pharmacopeia (USP) — sets limits for heavy metals, microbial contamination, and specific impurities for each listed excipient
European Pharmacopoeia (Ph. Eur.) — harmonized standards for use across EU member states and often referenced in export markets
Japanese Pharmacopoeia (JP) — required for products marketed in Japan; may have different acceptable limits from USP/Ph. Eur.

ICH Q8 and Formulation Science

The International Council for Harmonisation's ICH Q8 (R2) guideline on pharmaceutical development requires manufacturers to understand how each excipient and its level interacts with the API and the manufacturing process. This means that what a tablet is made of cannot be determined arbitrarily — it must be justified through systematic development studies, including compatibility testing, dissolution profiling, and stability data under accelerated conditions (typically 40°C / 75% RH for 6 months).

GMP Manufacturing Controls

The physical tablet you swallow is the end product of a manufacturing process governed by current Good Manufacturing Practice (cGMP) regulations. Key controls include incoming material testing, in-process checks (tablet weight, hardness, friability, disintegration), and finished-product release testing. Tablets must meet the label claim — typically within 90–110% of stated potency — across the entire batch.

Emerging Trends in Tablet Excipient Technology

The excipient landscape is not static. As pharmaceutical science advances and patient expectations evolve, several trends are reshaping what tablets are made of:

Co-processed Excipients

These are physical combinations of two or more excipients processed together to achieve properties that neither could deliver individually. Avicel PH-200 (MCC) combined with colloidal silicon dioxide, for example, delivers improved flow at high-speed compression. Co-processed excipients are enabling more APIs to be processed by direct compression, reducing development time and complexity.

Plant-Based and Clean-Label Excipients

Consumer demand for products with fewer synthetic or animal-derived ingredients is influencing excipient selection. Natural empty capsules made from HPMC are part of this broader trend, but it also extends to fillers (pea starch over lactose), lubricants (vegetable magnesium stearate), and coatings (carnauba wax over shellac). The global plant-based pharmaceuticals market is expected to grow at over 6% CAGR through 2030.

Continuous Manufacturing

Traditional batch manufacturing is being replaced by continuous tablet production in some facilities. This requires excipients with consistent flow and compression properties across extended run times. Continuous direct compression lines running 24/7 demand tighter specification control on all raw materials than conventional batch processes.

3D-Printed Tablets

FDA-approved 3D-printed tablet technology (Spritam, approved 2015) uses a binder jetting process to produce highly porous tablets with very fast disintegration. The composition still relies on conventional excipients, but the architecture is structurally impossible to achieve through compression. This approach enables dose customization down to the individual patient level.

Hot Melt Extrusion (HME)

HME converts poorly soluble APIs into solid amorphous dispersions by processing them with polymers above their glass transition temperatures. The resulting material is then milled and compressed. This approach can improve bioavailability of BCS Class II drugs by 100–1000 fold, dramatically changing the excipient composition compared to crystalline tablet formulations.

Functional Coatings with Active Layers

Advanced coating systems now incorporate APIs directly into the coat layer, enabling combination products where a fast-release coating delivers one drug while the tablet core delivers a second drug on a slower timeline. This requires careful compatibility assessment between the two APIs and all excipients in each layer.

Summary: Key Ingredients in Tablet Formulations at a Glance

The following table consolidates the major ingredient categories found in tablet formulations, their typical concentration ranges, and their functional roles:

Table 2: Summary of common tablet ingredient categories, typical concentration ranges, and examples
Ingredient Category	Typical Level (%)	Common Examples	Primary Role
Active Ingredient (API)	1–80%	Drug compound, herbal extract	Therapeutic effect
Filler / Diluent	20–80%	MCC, lactose, dicalcium phosphate	Bulk / compressibility
Binder	2–20%	PVP, HPC, HPMC, gelatin	Cohesion / tablet strength
Disintegrant	2–10%	Croscarmellose sodium, crospovidone, SSG	Rapid tablet breakup in GI tract
Lubricant	0.25–2%	Magnesium stearate, stearic acid	Prevent die wall sticking
Glidant	0.1–0.5%	Colloidal silicon dioxide, talc	Improve powder flowability
Coating	2–10% (weight gain)	HPMC, Eudragit, ethylcellulose	Protection, release control, aesthetics
Sweetener / Flavor	0.1–5%	Sucralose, mannitol, peppermint oil	Palatability (chewable/ODT)
Colorant	0.01–1%	Iron oxide, FD&C dyes, titanium dioxide	Appearance, identification

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