Excipients are not inactive: innovation in the ingredients around the drug
New excipients can enable abuse-deterrent and better-absorbed medicines. Why regulators created a special review route, and what it means for formulators.
In this article
In a typical tablet, the active ingredient is only part of the weight. The rest — binders, fillers, disintegrants, coatings, capsule shells — are excipients. They decide how a medicine is made, how stable it is and how it releases its drug.
Why new excipients are hard
Formulators usually stick to excipients already used in approved medicines, because a new one brings extra safety and quality questions. That caution can hold back better medicines.
A regulatory route for innovation
The US FDA’s Center for Drug Evaluation and Research created a voluntary Novel Excipient Review Pilot Program, which lets excipient makers obtain FDA review of certain new excipients before they are used in a drug formulation. It covers excipients not previously used in FDA-approved drugs and without established use in food. CDER planned to accept four initial proposals over two years.
FDA said priority would go to excipients with public health benefits, such as enabling abuse-deterrent opioid formulations, supporting new therapies for serious diseases, or meaningfully improving how a drug is absorbed.
What excipients do
| Function | Examples of what matters |
|---|---|
| Manufacturability | Flow and compression on high-speed presses |
| Release | Coatings and polymers for delayed or extended release |
| Stability | Protection from moisture and light |
| Patient experience | Taste masking, capsule choice |
The workhorses
A handful of excipients appear in a large share of the world’s tablets and capsules: microcrystalline cellulose and lactose as fillers; starch and povidone as binders; croscarmellose sodium and other “superdisintegrants” to help tablets break up; magnesium stearate as a lubricant; and polymers such as hypromellose (HPMC) for coatings, capsules and controlled release. Each comes in several grades, and the grade matters: particle size, moisture and flow can change how a blend behaves on a high-speed press.
Excipient quality is drug quality
Because excipients can make up most of a tablet’s weight, their quality directly affects the medicine. Three issues have drawn particular attention in recent years:
- Supplier GMP — European rules require manufacturers to carry out a formal risk assessment of the GMP appropriate for each excipient they use, taking into account its source and use. Industry bodies such as the International Pharmaceutical Excipients Council publish guidance on good practice for excipient makers.
- Impurities — trace impurities in excipients, such as nitrites, can react with some active ingredients to form nitrosamines, a class of impurities that has led to recalls worldwide. Manufacturers increasingly ask excipient suppliers for data on these traces.
- Consistency — variability between batches of an excipient can cause variability in the finished product, so specifications increasingly include functional properties as well as chemical purity.
Questions for excipient suppliers
- Which grade suits our process and equipment, and can we test samples on our own press?
- What GMP certification and audit reports can you share?
- What data do you have on trace impurities relevant to our products?
- How do you notify customers of changes in manufacturing site or process?
- What technical support do you provide for formulation problems?
Where innovation is heading
Excipient makers are developing co-processed excipients that combine several functions in one material, polymers that keep poorly soluble drugs dissolved for longer, and coatings that release a drug at a chosen point in the digestive tract. Such materials can help a manufacturer make a product that competitors find harder to copy — one route to the complex generics that export strategies increasingly target.
Why it matters for Pakistan
As exporters move from simple generics towards complex generics and specialised dosage forms, excipient choice becomes a competitive skill. Pharma Asia’s exhibitor profile covers pharmaceutical raw materials, enzymes and biochemicals, and coating materials, and the 2026 list includes excipient and capsule suppliers such as Livewell Capsules and Multicaps.
See also 3D-printed medicines, another route to new release profiles, and meet suppliers at Pharma Asia 2026.
