A tablet binder is an inactive ingredient (excipient) added to a pharmaceutical or nutraceutical formulation with the intent of enhancing flow and compressibility of the blend. It holds active ingredients and other formulation components by forming agglomerates. Binders act like a “glue” to ensure granules and other formulation components forms a cohesive solid tablet.
The binders market is expected to grow at a CAGR of 8.9% from 2026 to 2033, with increasing demand for natural or plant based binders like starches and gums.
When powders or granules are compressed into a tablet, several microscopic forces come into play:
Adhesion & Cohesion: Particles stick to each other (cohesion) and to surrounding surfaces (adhesion), creating a solid structure.
Liquid Bridges: Small amounts of moisture or binder solution can form “bridges” between particles, strengthening the tablet.
Compression Forces: During manufacturing, high pressure brings particles close enough for van der Waals forces and solid-state bonds to lock them together. The combination of these mechanisms gives the tablet its mechanical strength while still allowing it to break apart when swallowed.
The success of a tablet depends on the physical and chemical properties of its ingredients:
The selection of the right excipients in optimal ratio ensures the tablet integrity during manufacture, storage and transportation and still disintegrates at the right time in the body to offer its therapeutic efficacy.
This type of design-of-experiments (DoE) approach allows scientists to predict outcomes and optimize formulations efficiently.
Tablet binders are essential excipients that improve the mechanical properties of a tablet by holding its ingredients together, ensuring uniformity, and facilitating tablet production. Here are some of the key benefits:
A summary of the binders by type, including examples and typical use cases.
|
Binder Type |
Examples |
Typical Use |
Key Characteristics |
|
Natural Binders |
|
Wet granulation Direct compression |
Inexpensive and widely available. Biocompatible; some natural binders may have variable quality or stability issues. |
|
Semi-synthetic Binders |
Wet granulation Direct compression |
Stable with good reproducibility. Consistent quality. Adjustable solubility/viscosity - can modify drug release. |
|
|
Synthetic Binders |
|
Wet granulation |
Excellent binding. Good solubility. Consistent quality. Inert with many APIs. |
|
Sugar Binders |
|
Chewable tablets Wet granulations |
Improve tase and palatability. Add bulk. May cause hygrosopicity and affect diabetic patients. |
|
Polymeric Binders |
|
Specialized formulations Modified release systems |
Strong binding, film forming. Can aid in controlled release. |
|
Direct Compression Binders |
|
Direct compression |
Excellent compressibility. Good flow properties. Widely used in modern tableting. |
During wet granulation, binders may be added either as dry powders, as a slurry or in a solution form. In most cases, they are introduced as a liquid spray at a controlled rate which facilitate agglomeration of fine powder particles into larger, stronger, and more uniform granules. The binder solution initiates a series of micro-mechanisms that lead to particle adhesion and granule growth. . This process forms a stable network that allows the granules to maintain their integrity during drying and subsequent processing. Examples of binders used in wet granulation are Starch 1500, Povidone (PVP) or cellulose derivatives like HPMC.
In the dry granulation process, binders are usually added in powder form rather than liquids. They can be mixed directly into the powder blend just before lubrication and compression step, or just before the material is compacted into slugs or ribbons.
The binder works by helping particles stick together under compaction pressure. The mechanical force of compression activates the binder, strengthening the bonds between particles without the need for a liquid bridge. This approach makes dry granulation especially useful when working with ingredients that are sensitive to heat or moisture. Examples of binders used in dry granulation are Starch 1500, HPMC, PVP and copovidone.
Direct compression is often preferred for its simplicity and efficiency, but it relies heavily on selecting the right binder and excipients to ensure consistent tablet strength and quality. Examples of binders used in direct compression are Starch 1500 and microcrystalline cellulose (MCC).
Natural binders are increasing in popularity following growing demand for label friendly and sustainable ingredients, although some natural binders can present challenges including variability, or microbial contamination. Some widely used examples of natural binders include starches, gum arabic or sodium alginate.
Semi-synthetic binders are the most widely used binders in tablet formulations. They are derived from natural ingredients that are then chemically modified to improve their binding properties. They combine the biocompatibility of natural ingredients with the consistency and functionality of synthetic binders. Examples of semi-synthetic binders include Starch 1500, HPMC or modified guar gum.
Synthetic binders are man-made produced by chemical synthesis. Compared to some natural binders they can offer greater purity, reproducibility and minimal microbial contamination risk. Some synthetic binders may require control of residual solvents. Examples of synthetic binder include PVP, PEG or PVA.
Arguably the most important criteria are the API characteristics. The binder must react with the drug. API solubility, pH and moisture sensitivity should all be considered when selecting an appropriate tablet binder.
Manufacturing process is a key consideration. If a manufacturer wishes to produce in-house, the binder may need to be compatible with the equipment to reduce capital investment. In some cases, manufacturers might choose to outsource manufacture to a third party that can produce using the chosen manufacturing method (e.g. wet or dry granulation).
Binder selection plays a crucial role in determining a tablet’s drug release profile by influencing both disintegration and matrix formation. Water-soluble binders, such as starch or polyvinylpyrrolidone (PVP), dissolve quickly upon contact with gastrointestinal fluids, promoting rapid tablet disintegration and faster drug release.
In contrast, poorly soluble binders, like ethyl cellulose or high-viscosity, water soluble binders, like HPMC, water penetration into the tablet is delayed thereby increasing disintegration time and reducing the drug release rate.
Additionally, certain binders can form a gel or matrix around the drug when hydrated, creating a diffusion barrier that allows the drug to be released gradually. This property is useful for formulating sustained or extended-release tablets, enabling controlled drug delivery without altering the API.
Binder amount is influenced by tablet size, desired hardness, API properties, and disintegration requirements. When used at suboptimal concentration, tablet loses its integrity but when used at higher concentration, it impacts formulation properties such as disintegration and drug release.
Amount of binder is different depending on the manufacturing process. For instance, more binder may be required in wet granulation (typically 3-10%) whereas dry granulation or direct compression may only require 1-5% in the formulation.
When selecting tablet binders, formulators must balance regulatory compliance, safety, and performance. Regulators require ingredients to meet established quality standards. Using a novel binder not previously approved in marketed products requires a full toxicological evaluation and regulatory submission, which can significantly extend development timelines.
From a safety perspective, binders must be non-toxic, non-allergenic, and free from contaminants such as heavy metals, residual solvents, or microbial impurities. Their levels should remain within daily intake limits to avoid unwanted effects like GI irritation or hypersensitivity. A well-chosen binder ensures not only tablet integrity and manufacturability but also regulatory acceptance and patient safety.
The shift towards naturally derived and multifunctional binders continues to be of growing interest. A study presented at the European Conference of Pharmaceutical (ECP) 2025 demonstrated the use of isomalt as a PVP-binder replacement wet granulation manufacturing.
To accelerate the pharmaceutical development process, companies are utilizing predictive modelling and automation to optimize binder selection. One example is the use of a Digital Formulation and Self-Driving Tableting DataFactory. This approach accelerates the timeline from material characterisation to development of an in-specification tablet within 6 hours, utilising less than 5 grams of API.
3D printing in tablet manufacturing enables the creation of personalized medicines designed to meet the unique needs of individual patients. This technology allows for precise control over binder placement and drug release profiles, facilitating the production of customized tablets with optimized therapeutic performance.
Tablet binders play a critical role in pharmaceutical and nutraceutical formulations by ensuring tablets are mechanically strong and biologically effective. The choice of binder depends on drug properties, manufacturing processes, and desired release profiles. With growing interest in sustainable and multifunctional excipients, the industry is embracing innovations such as predictive modelling, 3D printing, and digital formulation platforms to accelerate development and personalise treatment.
For further reading, you can find Colorcon studies on the use of Starch 1500 as a binder for director compression, low and high shear wet granulation and fluid bed granulation.