List of Excipients in Branded Drug GUANFACINE

Generic Drugs Containing GUANFACINE

Company	Ingredient	NDC	Excipient
Teva Pharmaceuticals USA Inc	guanfacine	0093-5960	CELLULOSE, MICROCRYSTALLINE
Teva Pharmaceuticals USA Inc	guanfacine	0093-5960	CROSPOVIDONE
Teva Pharmaceuticals USA Inc	guanfacine	0093-5960	FUMARIC ACID
Teva Pharmaceuticals USA Inc	guanfacine	0093-5960	GLYCERYL DIBEHENATE
Teva Pharmaceuticals USA Inc	guanfacine	0093-5960	LACTOSE MONOHYDRATE
Teva Pharmaceuticals USA Inc	guanfacine	0093-5960	METHACRYLIC ACID

What are the Most Frequently-Used Excipients in GUANFACINE?

# Of NDCs	Excipient
2	ALUMINUM OXIDE
6	ANHYDROUS CITRIC ACID
16	ANHYDROUS LACTOSE
56	CELLULOSE, MICROCRYSTALLINE
1	CI 77492
1	COLLOIDAL SILICON DIOXIDE

Guanfacine Excipient Strategy and Commercial Opportunities: Formulation, Regulatory and Patent Analysis

Last updated: September 9, 2026

Guanfacine is a mature small-molecule product with two commercial platforms: immediate-release guanfacine hydrochloride, historically marketed as Tenex, and extended-release guanfacine hydrochloride, marketed as Intuniv and by multiple generic manufacturers. The principal opportunity is not API differentiation. It is dosage-form engineering around pediatric acceptability, controlled release, dose flexibility, food-effect control, and manufacturing efficiency.

Extended-release guanfacine has the stronger commercial position because ADHD treatment supports chronic pediatric use and differentiated formulations. The most attractive excipient strategies are multiparticulate extended release, sprinkle capsules, orally disintegrating tablets, low-dose liquids, and palatable pediatric products. Each strategy requires careful control of alcohol dose-dumping, pH-dependent release, food effects, content uniformity, and excipient exposure.

What products contain guanfacine hydrochloride?

Guanfacine is an alpha-2A adrenergic receptor agonist available principally in immediate-release and extended-release tablets.

Product platform	Reference product	Primary use	Typical strengths	Commercial status
Immediate-release tablet	Tenex	Hypertension	1 mg, 2 mg	Generic and mature
Extended-release tablet	Intuniv	ADHD	1 mg, 2 mg, 3 mg, 4 mg	Generic competition established
Generic extended-release tablet	Guanfacine ER	ADHD	1 mg, 2 mg, 3 mg, 4 mg	Multiple manufacturers
Potential reformulations	No dominant reference product	Pediatric adherence and specialty distribution	Variable	Development opportunity

The FDA approved immediate-release guanfacine hydrochloride for hypertension in 1986. The FDA approved Intuniv extended-release tablets for ADHD in 2009.[1,2]

Guanfacine is not a biologic. Biosimilar risk is therefore not relevant. Competitive risk comes from abbreviated new drug applications, 505(b)(2) products, authorized generics, and reformulated products.

How does immediate-release guanfacine compare with extended-release guanfacine?

Immediate-release and extended-release guanfacine have different formulation objectives and substitution risks.

Attribute	Immediate-release guanfacine	Extended-release guanfacine
Release mechanism	Rapid dissolution and absorption	Controlled oral release
Main indication	Hypertension	ADHD
Formulation complexity	Low	High
Excipient value	Manufacturability, swallowability, stability	Release control, food-effect management, dose dumping prevention
Pediatric suitability	Limited unless modified	Established ADHD use
Generic barrier	Low	Moderate
Commercial differentiation	Low-cost supply	Pediatric delivery and adherence
Key safety issue	Hypotension and sedation	Hypotension, sedation, bradycardia, rebound hypertension if abruptly discontinued

The extended-release product must not be substituted milligram-for-milligram with immediate-release guanfacine. The release profile changes exposure and dosing behavior. The Intuniv labeling instructs once-daily administration and warns against crushing, chewing, or breaking the tablet because these actions can alter release.[2]

What excipients are used in guanfacine formulations?

Immediate-release excipient strategy

Immediate-release guanfacine tablets generally use conventional solid-dose excipients:

• Lactose or another diluent
• Microcrystalline cellulose
• Pregelatinized starch or other binder/disintegrant
• Sodium starch glycolate or crospovidone
• Colloidal silicon dioxide
• Magnesium stearate
• Film-coating polymers and pigments

The formulation objective is rapid, reproducible disintegration with low tablet weight and adequate mechanical strength. Because guanfacine is administered at low milligram strengths, content uniformity is a major development issue. Low-dose API blending, ordered mixing, granulation choice, and segregation control can determine batch success.

A low-cost generic formulation can use standard excipients, but excipient selection still affects:

• Blend uniformity
• Tablet weight variation
• Dissolution
• Hardness and friability
• Moisture sensitivity
• Coating adhesion
• Packaging requirements

Extended-release excipient strategy

Extended-release guanfacine products require a polymer matrix or coating system that controls water ingress, API diffusion, erosion, or a combination of these mechanisms. Typical excipient classes include:

• Hydrophilic matrix polymers such as hypromellose
• Film-forming polymers
• Methacrylic acid copolymers or other pH-responsive polymers
• Fillers such as lactose or microcrystalline cellulose
• Povidone binders
• Crospovidone or other processing aids
• Colloidal silicon dioxide
• Lubricants such as magnesium stearate or glyceryl behenate
• Colorants and coating aids

The reference Intuniv label identifies a controlled-release excipient system that includes hypromellose, lactose monohydrate, povidone, crospovidone, colloidal silicon dioxide, and other tablet-processing ingredients.[2] Exact quantitative composition is not generally disclosed in the public label.

Which excipient strategies create the strongest commercial opportunities?

1. Sprinkleable multiparticulate extended-release guanfacine

A capsule containing coated pellets or minitablets could address children who cannot swallow tablets. The product could be administered with a soft food vehicle if the release performance remains unchanged.

The technical requirements are stringent:

• Uniform API loading across pellets
• Controlled coating weight gain
• Low friability during capsule filling
• Stability after opening the capsule
• No rapid release when sprinkled
• No chewing requirement
• Demonstrated bioequivalence to the reference product

A sprinkle formulation can obtain commercial protection through composition, coating architecture, manufacturing process, and administration method claims. Its strongest value is patient access rather than raw material cost.

2. Orally disintegrating guanfacine tablets

An orally disintegrating tablet could improve administration in pediatric patients and reduce tablet-swallowing barriers. For immediate-release guanfacine, the development path is relatively straightforward. For extended-release guanfacine, maintaining controlled release after rapid oral dispersion is more difficult.

Key excipients may include:

• Mannitol for mouthfeel and rapid dissolution
• Crospovidone or croscarmellose sodium
• Low-substituted hydroxypropyl cellulose
• Poloxamers or surfactants where justified
• Flavoring and sweetening systems
• Silica-based flow aids

The primary risks are bitterness, dose uniformity at low strength, friability, moisture uptake, and unintended acceleration of release.

3. Pediatric oral liquid

A guanfacine liquid could provide flexible dosing for initiation, titration, and patients with swallowing difficulties. The product could be immediate-release or a carefully engineered extended-release suspension.

An immediate-release liquid would require control of:

• API solubility and pH
• Chemical stability
• Preservative effectiveness
• Sedimentation or crystallization
• Palatability
• Dosing-device accuracy
• Compatibility with common oral syringes

A suspension may be preferable where solubilized guanfacine creates an unacceptable taste or stability profile. Potential excipients include suspending polymers, wetting agents, buffers, sweeteners, flavors, and preservatives.

A liquid extended-release product carries higher regulatory risk because the formulation must reproduce the clinical release profile while remaining physically stable during storage and dosing. A 505(b)(2) pathway may be commercially relevant if the product relies on a new dosage form or delivery system rather than a conventional ANDA approach.

4. Low-dose and titration-focused tablets

Guanfacine treatment often requires gradual dose adjustment. A product line with lower strengths, scoreable tablets, or more precise dose increments could improve initiation and discontinuation management.

Commercial options include:

• 0.5 mg or other low-dose units
• Scored 1 mg tablets where technically appropriate
• Unit-dose blister packaging
• Titration kits
• Calendar packaging
• Pediatric starter packs

A lower-strength product may have limited standalone revenue but can increase prescriber adoption and reduce treatment abandonment.

5. Abuse-resistant and dose-dumping-resistant matrices

Guanfacine is not a controlled substance, so classical opioid-style abuse-deterrent positioning has limited commercial value. However, resistance to crushing, chewing, and alcohol-induced dose dumping remains technically and clinically relevant for an extended-release product.

Useful excipient approaches include:

• Robust hydrophilic matrices
• High-viscosity polymers
• Polymer-coated multiparticulates
• Insoluble or semipermeable membranes
• Dual-barrier release systems

The commercial claim should focus on release integrity and administration safety rather than controlled-substance abuse deterrence.

What are the main formulation patents protecting guanfacine?

The patent estate is divided between the API, therapeutic use, extended-release technology, dosage forms, and manufacturing processes.

Patent category	Relevance to guanfacine	Commercial significance
Composition-of-matter patents	Historical protection for guanfacine and salts	Generally expired or commercially weak
Immediate-release composition patents	Tablet excipients and manufacturing	Usually narrow and easy to design around
Extended-release formulation patents	Matrix, coating, dissolution profile, and dosing	Main historic barrier to generic entry
Method-of-use patents	ADHD treatment, pediatric dosing, combination therapy	Potential litigation and labeling restrictions
Sprinkle or multiparticulate patents	Alternative administration	Potential new-product differentiation
Liquid and ODT patents	Pediatric delivery	Opportunity for 505(b)(2) or separate product claims
Process patents	Granulation, coating, drying, and scale-up	More useful as manufacturing barriers than market exclusivity

The core opportunity is a later-generation formulation patent, not ownership of guanfacine itself. Claims covering a defined release profile, polymer ratio, dissolution window, particle coating, or administration method can create commercial value if they distinguish the reference product and survive obviousness review.

Patent owners and applicants should avoid claims that merely recite routine excipient substitution. Stronger claims normally link the excipient system to a measurable performance result, such as:

• A specified dissolution profile
• Reduced food effect
• Lower alcohol-induced release
• Improved stability
• Reduced interpatient exposure variability
• Improved content uniformity at pediatric strengths
• Equivalent exposure after administration with soft food

When does guanfacine lose exclusivity?

Guanfacine immediate-release products have been off patent for many years. The commercial exclusivity period for the original hypertension product is therefore over.

Intuniv received FDA approval in 2009 and obtained the regulatory exclusivities applicable to its approval at that time. The principal commercial protection for extended-release guanfacine came from formulation and regulatory barriers rather than continuing API exclusivity. Generic guanfacine ER products are now marketed, confirming that the primary generic-entry barrier has been overcome.[1,3]

Exclusivity issue	Immediate-release guanfacine	Extended-release guanfacine
API exclusivity	Expired	Expired
Original brand exclusivity	Expired	Expired
Generic availability	Established	Established
Current value of formulation patents	Low to moderate	Product- and claim-dependent
Pediatric exclusivity	Historical regulatory period	Historical regulatory period
New formulation opportunity	Moderate	High

The precise status of any remaining patent claim depends on jurisdiction, terminal disclaimers, patent-term adjustment, maintenance payments, and Orange Book listing status. Patent expiration should be assessed patent by patent rather than inferred from the date of the original approval.

What is the Orange Book status of guanfacine?

The FDA Orange Book is the primary source for approved guanfacine reference products, therapeutic equivalence codes, and listed patent or exclusivity information.[3]

For commercial diligence, the relevant Orange Book questions are:

1. Which product is the reference listed drug for the proposed dosage form?
2. Are patents listed against the specific extended-release strength or product?
3. Is the proposed product eligible for an ANDA or does it require a 505(b)(2) application?
4. Are any method-of-use patents relevant to the proposed labeling?
5. Does the applicant need a Paragraph IV certification?
6. Are there product-specific exclusivity periods that block approval?

Immediate-release guanfacine generally presents a conventional ANDA pathway. Extended-release guanfacine may require more extensive comparative dissolution, food-effect, and bioequivalence work because the release mechanism is clinically material.

What Paragraph IV challenges and litigation affect guanfacine?

Paragraph IV litigation risk has historically focused on generic versions of Intuniv and its extended-release formulation patents. The central litigation issues in this product class generally include:

• Whether the asserted patent claims cover the generic release profile
• Obviousness of the claimed polymer matrix
• Written-description support for broad excipient ranges
• Infringement based on dissolution data
• The scope of method-of-use claims
• Whether a generic applicant can carve out protected ADHD uses

A Paragraph IV certification can trigger litigation under the Hatch-Waxman framework. The filing of a patent lawsuit can impose a statutory stay of FDA approval, subject to the applicable statutory limits. Settlement agreements may include launch dates, licenses, authorized-generic rights, or restrictions on product design.

Because generic guanfacine ER products are already commercial, historical litigation is more relevant to precedent and freedom-to-operate analysis than to a fundamental market-entry block. A new formulation can still face litigation if it practices an unexpired claim or is marketed with a patented indication.

What method-of-use patents protect guanfacine?

Method-of-use protection may cover:

• Treatment of ADHD
• Pediatric ADHD treatment
• Once-daily administration
• Dose titration
• Combination therapy with stimulants
• Treatment of specific symptom profiles
• Reduction of tics, impulsivity, or hyperactivity
• Discontinuation or tapering protocols

Method-of-use patents can affect labeling even when composition patents have expired. An ANDA applicant may use a section viii statement and omit a patented indication if the remaining labeling supports approval. The commercial value of such patents depends on whether the patented use is central to prescribing and whether the generic can market a commercially viable carved-out label.

How strong is the guanfacine patent estate?

The estate is stronger for complex extended-release delivery than for immediate-release tablets.

Estate component	Relative strength	Reason
API and salt protection	Low	Mature, long-commercialized compound
Conventional immediate-release tablet	Low	Routine excipient and manufacturing technology
Extended-release matrix	Moderate	Performance-based claims can be meaningful
Multiparticulate sprinkle product	Moderate to high	New administration format and coating architecture
Pediatric liquid	Moderate	Stability, taste, and release claims may differentiate
ODT	Moderate	Technical barriers exist, but design-around routes are available
Manufacturing process	Low to moderate	Can create supply-chain friction but rarely blocks all competitors
Method-of-use claims	Moderate	Value depends on label and enforceability

The most defensible future claims will combine composition and performance limitations. A claim to "guanfacine plus hypromellose" is vulnerable if the excipients and use are routine. A claim tied to a defined release profile, food-effect limit, alcohol robustness, or pediatric administration benefit is more commercially useful.

What FDA regulatory pathways apply to new guanfacine products?

ANDA

An ANDA is appropriate for a product that matches the reference listed drug in active ingredient, dosage form, strength, route, labeling subject to permissible carve-outs, and performance requirements.

Best candidates include:

• Conventional immediate-release tablets
• Conventional extended-release tablets
• Equivalent strengths of approved guanfacine ER products

505(b)(2)

A 505(b)(2) application may be appropriate for:

• Oral liquids
• Orally disintegrating tablets
• Sprinkle products
• New release systems
• New strengths or dosing regimens
• Products relying partly on FDA findings for an approved guanfacine product

A 505(b)(2) product can create differentiated intellectual property, but it may face listed-patent certifications and clinical bridging requirements.

New drug application

A full NDA is less likely for a conventional guanfacine reformulation unless the product claims a materially new clinical benefit or delivery technology that cannot rely substantially on existing findings.

Which companies are competing in guanfacine?

The commercial field includes:

• The original brand sponsor and successor rights holders associated with Intuniv
• Generic manufacturers supplying immediate-release guanfacine
• Generic manufacturers supplying guanfacine ER
• Contract manufacturers producing tablets, pellets, and oral liquids
• Specialty companies developing pediatric drug-delivery systems

Competition is primarily price-based for standard tablets. Differentiation is more viable in:

• Pediatric adherence
• Flexible dosing
• Specialty pharmacy distribution
• Drug shortages and supply reliability
• Low-dose titration
• Flavor and administration convenience
• Alternative dosage forms

A company entering with another standard guanfacine ER tablet is likely to face limited pricing power. A product with a protected pediatric delivery feature has a better chance of sustaining margins.

What generic launch risks exist for guanfacine?

The main launch risks are regulatory and manufacturing rather than API supply.

Technical risks

• Failure to match the reference dissolution profile
• Food-related exposure differences
• Alcohol-induced release acceleration
• Inadequate content uniformity at low strengths
• Tablet damage during coating or packaging
• Stability failure caused by moisture
• Failure of bioequivalence because of release-rate differences

Commercial risks

• Low reimbursement for generic tablets
• Rapid price erosion after multiple ANDA approvals
• Substitution pressure from established suppliers
• Limited prescriber interest in another conventional tablet
• Pediatric adherence products competing with low-cost generics

Legal risks

• Paragraph IV litigation
• Method-of-use patent claims
• Formulation claims based on dissolution performance
• Trade-secret disputes involving coating or process parameters
• False-patent-listing or improper certification allegations

How can excipient selection improve guanfacine revenue exposure?

Excipient selection can affect revenue through product differentiation, approval probability, and cost of goods.

Excipient objective	Revenue effect
Improve palatability	Reduces pediatric discontinuation
Enable sprinkle administration	Expands addressable patient population
Improve release robustness	Supports premium positioning
Reduce tablet weight	Improves swallowability and manufacturing economics
Improve moisture stability	Extends shelf life and reduces waste
Enable low-dose uniformity	Supports titration products
Reduce food effect	Improves prescribing confidence
Simplify manufacturing	Protects gross margin

The highest-value strategy is a product that combines pediatric usability with a measurable pharmacokinetic or release advantage. Taste improvement alone may be insufficient unless it supports adherence, refill persistence, or a differentiated label.

Key Takeaways

• Guanfacine is a mature API with limited value in conventional tablet products.
• Extended-release guanfacine offers the strongest formulation and intellectual-property opportunities.
• Multiparticulate sprinkle products, orally disintegrating tablets, liquids, and low-dose titration packs are the most credible commercial opportunities.
• Excipient claims should be tied to measurable performance, not routine ingredient substitution.
• Generic guanfacine ER competition is established, so another standard tablet is likely to face rapid price erosion.
• Biosimilar risk does not apply because guanfacine is a small molecule.
• The principal regulatory routes are ANDA for equivalent products and 505(b)(2) for differentiated dosage forms.
• Orange Book listings, patent-term calculations, and Paragraph IV history must be evaluated at the specific product and claim level.

FAQs

Is guanfacine compatible with a pediatric oral liquid formulation?

Yes. A liquid can be developed as a solution or suspension, but pH, taste, chemical stability, preservative performance, dose accuracy, and container compatibility require dedicated testing.

Can guanfacine extended-release tablets be crushed?

The reference extended-release labeling instructs patients to swallow the tablets whole. Crushing, chewing, or breaking can alter the controlled-release profile and increase exposure over a shorter period.[2]

Is a guanfacine sprinkle capsule commercially attractive?

Yes. A sprinkle product can address children unable to swallow tablets and may support a 505(b)(2) strategy if it differs materially from the approved tablet dosage form.

What is the most valuable excipient patent opportunity for guanfacine?

A patent linking a defined excipient system to controlled release, reduced food effect, resistance to alcohol-induced dose dumping, improved pediatric administration, or enhanced stability is more valuable than a broad claim to standard tablet ingredients.

Can a generic guanfacine product omit an ADHD indication?

Potentially. A generic applicant may use a permissible labeling carve-out for a patented method of use, subject to FDA requirements and the remaining label supporting approval. The commercial impact depends on the scope of the omitted indication.

References

1. U.S. Food and Drug Administration. (1986). Tenex (guanfacine hydrochloride) prescribing information. FDA Drugs@FDA.

2. U.S. Food and Drug Administration. (2009). Intuniv (guanfacine hydrochloride) extended-release tablets prescribing information. FDA Drugs@FDA.

3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.

4. U.S. Food and Drug Administration. (2019). Guidance for industry: ANDAs for certain highly purified synthetic drug substances. FDA.

5. U.S. Food and Drug Administration. (2022). M13A bioequivalence for immediate-release solid oral dosage forms. FDA.

6. United States Pharmacopeial Convention. (2024). United States Pharmacopeia and National Formulary. USP.