List of Excipients in Branded Drug GUAIFENESIN EXTENDED RELEASE

Generic Drugs Containing GUAIFENESIN EXTENDED RELEASE

Company	Ingredient	NDC	Excipient
NCS HealthCare of KY Inc dba Vangard Labs	guaifenesin	0615-7712	COPOVIDONE K25-31
NCS HealthCare of KY Inc dba Vangard Labs	guaifenesin	0615-7712	HYDROXYETHYL CELLULOSE
NCS HealthCare of KY Inc dba Vangard Labs	guaifenesin	0615-7712	SILICON DIOXIDE
NCS HealthCare of KY Inc dba Vangard Labs	guaifenesin	0615-7712	ZINC STEARATE
Perrigo New York Inc	guaifenesin	45802-325	CELLULOSE, MICROCRYSTALLINE

What are the Most Frequently-Used Excipients in GUAIFENESIN EXTENDED RELEASE?

# Of NDCs	Excipient
1	CELLULOSE, MICROCRYSTALLINE
2	COPOVIDONE K25-31
1	FD&C BLUE NO. 1
1	HYDROXYETHYL CELLULOSE
1	HYPROMELLOSE

Guaifenesin Extended-Release Excipient Strategy and Commercial Opportunities

Last updated: August 21, 2026

Guaifenesin extended-release products compete primarily on release control, tablet robustness, consumer convenience, price, and brand recognition. The core formulation opportunity is a 12-hour hydrophilic matrix tablet using hypromellose or a comparable release-controlling polymer. The active ingredient is inexpensive and widely available, so commercial value depends on manufacturing efficiency, dissolution consistency, packaging, retailer access, and differentiated dosage forms rather than active-ingredient exclusivity.

What is the commercial status of guaifenesin extended release?

Guaifenesin is an expectorant used to loosen phlegm and thin bronchial secretions. The leading U.S. extended-release product is Mucinex, marketed by Reckitt under the legacy Adams Laboratories brand portfolio. Common strengths are 600 mg and 1,200 mg administered every 12 hours.

Attribute	Guaifenesin extended release
Active ingredient	Guaifenesin
Therapeutic category	Expectorant
Common dosage forms	Extended-release tablets, caplets, bi-layer tablets, oral granules
Common strengths	600 mg and 1,200 mg
Typical dosing interval	Every 12 hours
U.S. regulatory status	OTC expectorant product; branded products may be supported by NDA records
Leading brand	Mucinex
Primary commercial channel	Mass retail, pharmacy, grocery, club, e-commerce
Primary patent risk	Legacy formulation patents, trademarks, trade dress, and manufacturing know-how
Biosimilar risk	None; guaifenesin is a small-molecule drug

Guaifenesin has a long history of nonprescription use. FDA’s OTC expectorant framework identifies guaifenesin as a permitted active ingredient when used within specified conditions, although extended-release products may rely on product-specific regulatory records and formulation data rather than only the OTC monograph pathway (U.S. Food and Drug Administration [FDA], 2023).

What excipients are used in guaifenesin extended-release tablets?

The commercial formulation target is usually a high-load hydrophilic matrix tablet. Guaifenesin has adequate oral absorption but requires release control to avoid immediate liberation of the full dose. Excipients must maintain tablet integrity during storage, ingestion, and gastrointestinal transit while producing a reproducible 12-hour dissolution profile.

Release-controlling polymers

Hypromellose, also called hydroxypropyl methylcellulose or HPMC, is the most practical starting polymer for a 12-hour matrix. Upon hydration, HPMC forms a gel layer that slows water penetration and active diffusion. Polymer grade, viscosity, particle size, substitution pattern, and concentration materially affect release.

Potential polymer systems include:

• High-viscosity HPMC for slower release.
• Medium-viscosity HPMC for faster hydration and easier compression.
• Polyethylene oxide for high-viscosity matrix formation.
• Carbomer for stronger gel formation, subject to processing and pH considerations.
• Ethylcellulose in multiparticulate or coated systems.
• Combinations of HPMC and insoluble polymers for more stable release across food conditions.

A high-drug-load guaifenesin tablet may require a substantial polymer fraction. The commercial trade-off is direct: more polymer can improve release control but increases tablet size, compression force, cost, and risk of incomplete release.

Diluent and compressibility system

Microcrystalline cellulose is useful for dry granulation and direct compression. It improves tablet strength and reduces friability, but excessive use can increase water uptake and accelerate matrix erosion.

Lactose, dibasic calcium phosphate, mannitol, and starch-based diluents are possible alternatives. Dibasic calcium phosphate can improve density and reduce tablet volume but may alter hydration and release. Mannitol can support a smoother mouthfeel in chewable or orally disintegrating presentations, although it is less suitable when the product must remain intact for extended release.

The preferred diluent system depends on the manufacturing route:

Manufacturing approach	Suitable excipient emphasis	Commercial benefit
Direct compression	Microcrystalline cellulose, silicified MCC, flow aids	Low process complexity
Roller compaction	Microcrystalline cellulose, dry binders, glidants	Low solvent use and high throughput
Wet granulation	Povidone, starch, controlled granule moisture	Improved content uniformity and compressibility
Multiparticulate coating	Sugar spheres or inert cores, ethylcellulose, HPMC	Flexible release profile and sprinkle potential

Binders, lubricants, and glidants

Povidone and copovidone can improve granule strength and tablet hardness. Excessive binder levels may slow disintegration of the hydrated matrix or create dissolution variability.

Magnesium stearate is a conventional lubricant, but over-lubrication can reduce tablet strength and make the matrix more hydrophobic. Sodium stearyl fumarate may be evaluated where magnesium stearate produces dissolution drift. Colloidal silicon dioxide can improve powder flow, particularly in high-load direct-compression blends.

Process controls matter as much as ingredient selection. Lubrication time, lubricant concentration, blend uniformity, compression force, tablet porosity, and granule moisture can each shift the dissolution curve.

Film coatings and product protection

A film coat can reduce friability, mask taste, improve swallowability, and protect the tablet from moisture. Typical coating components may include hypromellose, polyethylene glycol, titanium dioxide where permitted, and colorants.

The coating should not materially change the intended release profile unless the product uses a functional coating. For a matrix tablet, the main release mechanism should remain the hydrated polymer matrix. A thick or poorly controlled film can create a delayed initial release or increase batch-to-batch variability.

What dissolution profile should a guaifenesin extended-release formulation target?

A commercially viable product should demonstrate controlled release over approximately 12 hours, with sufficient early release to establish therapeutic exposure and no excessive late-stage retention.

Key development targets include:

1. Consistent initial release after hydration.
2. Controlled mid-period release without a pronounced dose dump.
3. Near-complete release by the end of the test period.
4. Low sensitivity to agitation, pH, and food-related changes.
5. Acceptable mechanical strength after coating and packaging.
6. Reproducibility across commercial-scale batches.

USP dissolution testing should be supported by discriminatory development methods capable of detecting changes in polymer grade, compression force, granule density, and lubricant exposure. A single compendial endpoint may not identify clinically relevant changes in the release curve.

The formulation should be evaluated in media representing gastric and intestinal conditions. Food-effect testing is commercially important because consumers frequently take cough and cold products with meals, snacks, or other medications.

What formulations are protected by guaifenesin extended-release patents?

The historical patent estate for guaifenesin extended release focused on controlled-release compositions rather than the chemical compound itself. A notable U.S. patent associated with extended-release guaifenesin is U.S. Patent No. 6,372,252, assigned to Adams Laboratories, Inc. The patent covered extended-release guaifenesin compositions and related dosage-form technology. Based on its 1998 priority period, the ordinary 20-year patent term would have reached the late 2010s, subject to patent-term adjustment and any related continuation rights (U.S. Patent and Trademark Office [USPTO], 2002).

The commercial barriers today are more likely to arise from:

• Later formulation patents, if any remain enforceable.
• Trademarks covering Mucinex and related brand names.
• Trade dress and packaging.
• Manufacturing processes and scale-up know-how.
• Regulatory data and product-specific equivalence requirements.
• Retail shelf position and consumer recognition.

A generic manufacturer should conduct a current patent and Orange Book review before launch because a historical core patent does not establish freedom to operate for every later formulation, dosage form, or combination product.

What is the Orange Book status of guaifenesin extended release?

The FDA Orange Book identifies approved drug products and patent or exclusivity information associated with approved applications. Branded extended-release guaifenesin products may appear through product-specific NDA records, while other manufacturers may use the OTC monograph route if their product meets applicable conditions.

For a prospective entrant, the critical questions are:

Regulatory question	Commercial implication
Is the reference product listed under an NDA?	An ANDA may be required if the product is eligible for abbreviated approval
Does the product comply with the OTC monograph?	A monograph pathway may reduce application burden
Are patents listed for the relevant strength and dosage form?	Patent certifications and possible Paragraph IV litigation may apply
Is the product a combination drug?	Separate active-ingredient and labeling analysis is required
Does the proposed product match the reference release profile?	Comparative dissolution and bioequivalence risk increase

FDA’s electronic Orange Book and Drugs@FDA records remain the controlling sources for application, patent, and exclusivity information. Guaifenesin itself has no new chemical entity exclusivity because it is an established active ingredient (FDA, 2024).

When does guaifenesin extended release lose exclusivity?

Guaifenesin’s active ingredient has no meaningful molecule-level exclusivity. The principal branded product has historically relied on formulation differentiation, trademarks, distribution, and consumer marketing.

The relevant exclusivity categories are:

• New chemical entity exclusivity: not applicable to guaifenesin.
• Pediatric exclusivity: product-specific and not inherent to the active ingredient.
• Orphan exclusivity: not applicable.
• Formulation patent exclusivity: depends on each patent’s claims and enforceability.
• Trademark exclusivity: continues while marks are maintained and used.
• Trade-secret protection: potentially indefinite for undisclosed manufacturing information.

Legacy core formulation patents from the original extended-release development period would generally have expired by the late 2010s under the standard U.S. patent term. A current launch analysis must distinguish expired foundational patents from any later patents covering coatings, combinations, manufacturing methods, or alternative release systems.

Which companies are challenging the branded guaifenesin market?

Competition comes from three groups:

1. Private-label retailers and pharmacy chains.
2. Generic and contract manufacturers supplying OTC products.
3. Branded competitors selling guaifenesin alone or in combination products.

The market is structurally favorable to private label because the active ingredient is inexpensive and the dosage form can be manufactured using standard high-speed tablet equipment. Brand competition remains strong because Mucinex has substantial consumer recognition and broad distribution.

Potential entrants include established OTC manufacturers, contract development and manufacturing organizations, and companies with existing cough-and-cold portfolios. A new entrant does not need to replicate every attribute of the leading brand. It can target a lower price, smaller tablet, alternative pack size, e-commerce channel, or combination therapy.

What generic entry risks exist for guaifenesin extended release?

The principal generic risks are formulation and regulatory risks rather than active-ingredient supply.

Bioequivalence and dissolution risk

A formulation may match the label strength but fail to reproduce the reference product’s pharmacokinetic profile. Extended-release products require control of exposure over time, not only total drug release.

The highest-risk variables are:

• Polymer viscosity and substitution grade.
• Tablet porosity.
• Granule density.
• Compression force.
• Drug particle size.
• Lubrication level.
• Coating weight.
• Food-related release changes.
• Dose dumping under altered agitation or alcohol exposure.

Manufacturing risk

High-dose guaifenesin tablets can be large and difficult to swallow. Reducing tablet size through higher drug loading may weaken the matrix or increase dissolution variability. A two-layer design can separate immediate-release and extended-release portions, but it increases tooling and process-control requirements.

Moisture management is important. Water uptake can change polymer hydration, tablet hardness, stability, and release performance. Blister packaging or high-barrier bottles may be needed for products with moisture-sensitive excipient systems.

Labeling and safety risk

The product must maintain clear directions for 12-hour dosing and warnings against crushing or chewing if those actions compromise extended release. Combination products create additional risks from duplicate active ingredients, particularly acetaminophen and dextromethorphan.

What commercial opportunities exist for guaifenesin extended release?

Private-label 600 mg and 1,200 mg tablets

The most direct opportunity is a store-brand equivalent to established 12-hour products. Value depends on manufacturing cost, retailer placement, package design, and reliable supply rather than novel pharmacology.

Smaller and easier-to-swallow tablets

A smaller tablet can differentiate a product in a category where tablet size is a consumer complaint. This requires higher drug loading, a more efficient polymer system, or a multiparticulate approach. Any size reduction must preserve dissolution equivalence and dose uniformity.

Extended-release caplets and coated tablets

Film-coated caplets can improve swallowability and reduce tablet odor or taste. A functional coating may create additional intellectual property but also increases process complexity.

Oral granules and sprinkle products

Multiparticulate granules may support consumers who have difficulty swallowing tablets. The product must preserve extended-release performance when dispersed in an approved vehicle or consumed without chewing. This category has a larger formulation and labeling burden but can create a differentiated product position.

Combination products

Guaifenesin can be combined with dextromethorphan, pseudoephedrine, phenylephrine, or antihistamines. Combination products offer higher retail value but face more complex regulatory, stability, dissolution, and labeling requirements. The formulation must prevent one active ingredient from accelerating or retarding the release of another.

International licensing and contract manufacturing

Licensing opportunities are strongest for manufacturers that have:

• Validated hydrophilic matrix technology.
• Existing OTC registrations.
• Regional distribution in Latin America, Asia-Pacific, or the Middle East.
• Ability to produce multiple strengths on common equipment.
• Packaging and serialization capability.

A platform license covering controlled-release expectorants could be more valuable than a guaifenesin-only license if it applies to other high-dose, water-soluble actives.

How strong is the patent estate for guaifenesin extended release?

The active ingredient estate is weak because guaifenesin is old and widely available. The historical extended-release formulation estate provided meaningful early protection but is unlikely to block ordinary entry today unless later patents remain enforceable.

Protection category	Relative strength
Guaifenesin composition of matter	Very low
Historical extended-release matrix patents	Low after expiration
New polymer combinations	Moderate if claims are narrow and technically supported
Multiparticulate or coated systems	Moderate to high if clinically differentiated
Manufacturing process claims	Moderate; depends on detectability and claim scope
Mucinex trademark and trade dress	High against confusing branding
Consumer brand and retail distribution	High commercial value, not patent protection

The strongest defensible strategy is likely a layered portfolio combining formulation claims, dissolution-defined claims where legally supportable, process claims, packaging, trademarks, and regulatory know-how.

What patent litigation and Paragraph IV issues affect the market?

Paragraph IV risk depends on whether the reference product has unexpired Orange Book-listed patents. A generic applicant that seeks approval before listed patent expiration may certify that a patent is invalid, unenforceable, or not infringed. The reference sponsor can then bring patent litigation, potentially triggering a 30-month stay under the Hatch-Waxman framework (FDA, 2024).

For guaifenesin extended release, litigation risk is more likely to involve:

• A later-generation controlled-release tablet.
• A combination product.
• A specific coating or multiparticulate system.
• A manufacturing process that is difficult to design around.
• A listed patent added after the original product launch.

The absence of active ingredient exclusivity does not eliminate litigation risk. It shifts the analysis toward claim scope, formulation equivalence, and the commercial value of the reference product.

Key Takeaways

• Guaifenesin extended release is an established OTC market with no molecule-level exclusivity.
• The most practical excipient platform is a hydrophilic HPMC matrix supported by microcrystalline cellulose, flow aids, controlled lubrication, and a protective film coat.
• Release control, tablet size, moisture protection, and food-effect performance determine commercial viability.
• Historical core patents associated with extended-release guaifenesin generally reached the end of their ordinary patent terms by the late 2010s.
• Current entry risk depends on product-specific Orange Book listings, later formulation patents, regulatory pathway, trademarks, and manufacturing know-how.
• Private-label 600 mg and 1,200 mg tablets offer the lowest-risk commercial opportunity.
• Smaller tablets, multiparticulate products, sprinkle formats, and combination products provide higher differentiation but greater development and regulatory complexity.
• The strongest new IP position would combine polymer-system claims, manufacturing controls, multiparticulate technology, packaging, and brand protection.

FAQs

Can hypromellose be used as the only release-controlling excipient in guaifenesin extended release?

Yes. Hypromellose can provide the primary matrix-control mechanism, although the final formulation may require additional excipients to improve flow, compression, stability, coating performance, and dissolution consistency.

Is guaifenesin extended release eligible for an OTC monograph pathway?

Eligibility depends on the complete product, dosage form, strength, labeling, and applicable FDA requirements. A product-specific NDA or abbreviated pathway may be required when the formulation or indication falls outside monograph conditions.

Which excipient is most likely to cause dissolution variability?

Polymer grade and concentration are major drivers, but lubricant level, compression force, tablet porosity, granule moisture, and drug particle size can produce comparable effects.

Can an extended-release guaifenesin tablet be made smaller without changing its release profile?

Possibly, through higher drug loading, polymer optimization, or a multiparticulate design. Smaller size increases the risk of weaker tablets, altered hydration, and non-equivalent pharmacokinetics.

Is biosimilar competition relevant to guaifenesin extended release?

No. Guaifenesin is a small-molecule drug. Competitive products are generics, OTC monograph products, private-label products, and branded formulations rather than biosimilars.

References

1. U.S. Food and Drug Administration. (2023). Code of Federal Regulations, Title 21, Part 341: Cold, cough, allergy, bronchodilator, and antiasthmatic drug products for over-the-counter human use. https://www.ecfr.gov/

2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book-over-counter-products

3. U.S. Food and Drug Administration. (2024). Drugs@FDA: FDA-approved drugs. https://www.accessdata.fda.gov/scripts/cder/daf/

4. U.S. Patent and Trademark Office. (2002). U.S. Patent No. 6,372,252: Extended release guaifenesin compositions. https://patents.google.com/

5. United States Pharmacopeia. (2024). United States Pharmacopeia and National Formulary. U.S. Pharmacopeial Convention.