List of Excipients in Branded Drug PHENTERMINE HCL C-IV

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Generic Drugs Containing PHENTERMINE HCL C-IV

Company	Ingredient	NDC	Excipient
Direct_Rx	phentermine hcl c-iv	61919-865	ALCOHOL
Direct_Rx	phentermine hcl c-iv	61919-865	ALUMINUM OXIDE
Direct_Rx	phentermine hcl c-iv	61919-865	BUTYL ALCOHOL
Direct_Rx	phentermine hcl c-iv	61919-865	D&C RED NO. 28
Direct_Rx	phentermine hcl c-iv	61919-865	D&C YELLOW NO. 10

What are the Most Frequently-Used Excipients in PHENTERMINE HCL C-IV?

# Of NDCs	Excipient
2	ALCOHOL
1	ALUMINUM OXIDE
1	AMMONIA
2	BUTYL ALCOHOL
1	CROSPOVIDONE

PHENTERMINE HCL C-IV Excipient Strategy and Commercial Opportunities

Last updated: August 25, 2026

Phentermine hydrochloride is an established Schedule IV sympathomimetic amine marketed primarily as immediate-release tablets and capsules for short-term obesity treatment. Its active ingredient is old and broadly genericized, so commercial differentiation depends on dose flexibility, excipient performance, patient acceptability, manufacturing reliability, controlled-substance compliance and formulation innovation rather than new-molecule exclusivity.[1][2]

The strongest opportunities are low-dose tablets, orally disintegrating or taste-masked products, abuse-risk mitigation, robust direct-compression platforms, pediatric-resistant packaging and international contract-manufacturing supply. The commercial ceiling is limited by short-duration labeling, stimulant safety restrictions and competition from chronic weight-management products, including GLP-1 and GIP/GLP-1 therapies.

What is PHENTERMINE HCL C-IV?

PHENTERMINE HCL C-IV refers to phentermine hydrochloride, a Schedule IV controlled substance. "C-IV" is the controlled-substance classification, not a proprietary formulation or a separate active ingredient.

Attribute	Phentermine hydrochloride
Drug class	Sympathomimetic amine anorectic
Primary use	Short-term adjunct to weight reduction
Common U.S. strengths	8 mg, 15 mg, 30 mg, 37.5 mg, depending on product
Dosage forms	Immediate-release tablets and capsules
Controlled-substance schedule	Schedule IV
Typical regulatory pathway	Abbreviated New Drug Application for generics; NDA for branded reformulations
Biosimilar exposure	None
Primary commercial constraint	Short-term indication and controlled-substance requirements
Key competing categories	GLP-1 receptor agonists, GIP/GLP-1 agonists, phentermine/topiramate

FDA labeling describes phentermine as a short-term adjunct to caloric restriction and exercise. The approved labeling does not establish it as a chronic monotherapy comparable to newer long-term anti-obesity treatments.[1][2]

What excipients are used in phentermine hydrochloride products?

Phentermine products generally use conventional tablet and hard-gelatin capsule excipients. The exact composition varies by manufacturer, strength and dosage form.

Common excipient classes include:

Excipient function	Representative materials	Commercial purpose
Diluent	Lactose, microcrystalline cellulose, dibasic calcium phosphate	Controls tablet mass and improves manufacturability
Binder	Povidone, pregelatinized starch	Improves granule and tablet strength
Disintegrant	Sodium starch glycolate, crospovidone, croscarmellose sodium	Accelerates tablet breakup
Lubricant	Magnesium stearate, stearic acid	Reduces tooling friction and ejection force
Glidant	Colloidal silicon dioxide, talc	Improves powder flow
Colorant	FD&C and D&C dyes, iron oxides	Supports product identification
Capsule materials	Gelatin or hypromellose	Provides unit-dose containment
Film-coating materials	Hypromellose, polyethylene glycol, titanium dioxide	Improves handling, appearance and swallowability

Adipex-P labeling lists conventional tablet and capsule excipients, including lactose, microcrystalline cellulose, povidone, magnesium stearate and disintegrant systems. Lomaira uses a low-dose tablet design with a separate inactive-ingredient profile.[1][2] These differences create formulation-selection opportunities without changing the active pharmaceutical ingredient.

Which excipient attributes matter most?

For phentermine hydrochloride, the most important excipient attributes are:

1. Consistent content uniformity at low dose.
2. Rapid and reproducible disintegration.
3. Low moisture sensitivity.
4. Low risk of sticking and picking during compression.
5. Compatibility with direct compression or low-shear granulation.
6. Acceptable color and visual differentiation.
7. Low allergen and regulatory complexity.
8. Reliable global supply.

Low-dose products create a greater content-uniformity challenge than 37.5 mg products. An 8 mg tablet contains substantially less active material, increasing the importance of particle-size control, geometric dilution, blend uniformity, segregation resistance and in-process sampling.

What excipient strategy is best for phentermine HCl tablets?

The most practical strategy is a low-risk immediate-release formulation using microcrystalline cellulose or another compressible diluent, a high-performance superdisintegrant, a low-level binder and a controlled lubricant level.

A development platform could use:

• Microcrystalline cellulose for compactibility.
• Lactose or dibasic calcium phosphate for bulk and blend-density control.
• Crospovidone or croscarmellose sodium for rapid disintegration.
• Povidone for granulation where needed.
• Colloidal silicon dioxide to improve flow.
• Magnesium stearate at the minimum validated level to avoid dissolution delay.
• A film coat or opaque color system for identification and light protection.

Direct compression offers lower processing cost and fewer unit operations. Roller compaction or wet granulation may be preferable where the active ingredient has poor flow, low bulk density or segregation risk. The manufacturing choice should be driven by blend uniformity and dissolution data rather than excipient novelty.

How can excipients improve content uniformity?

Content uniformity is a central technical issue for low-dose phentermine products. Useful controls include:

• Matching active and excipient particle-size distributions.
• Using ordered mixtures or carrier-based blending.
• Selecting excipients with compatible bulk density.
• Limiting blend residence time where segregation occurs.
• Validating lubricant addition time.
• Monitoring blend uniformity at multiple blender locations.
• Using process analytical technology for continuous blending, where economically justified.

A formulation that achieves tight uniformity with fewer processing steps can reduce batch failure risk and support contract-manufacturing differentiation.

What formulations are protected by phentermine patents?

The original phentermine active-ingredient opportunity is highly mature. Commercial protection today is more likely to arise from a specific formulation, dosage form, manufacturing process, combination product or method of use than from phentermine hydrochloride itself.

Potential protection area	Commercial relevance	Likely strength
New chemical entity protection	Not a realistic strategy for conventional phentermine HCl	Very low
Immediate-release tablet composition	May protect a narrow excipient combination	Low to moderate
Low-dose tablet platform	Can support dose-specific differentiation	Moderate if technically demonstrated
Orally disintegrating tablet	May protect taste masking and disintegration performance	Moderate
Modified-release formulation	Could support longer exposure or reduced dosing frequency	Moderate to high if clinically differentiated
Abuse-deterrent system	Potentially valuable but technically and regulatorily demanding	Uncertain
Phentermine/topiramate combination	Separate product and patent analysis required	Potentially high
Manufacturing process	Can protect flow, granulation or segregation controls	Moderate
Packaging system	Usually limited patent value, but useful commercially	Low

A narrow composition patent may have limited enforcement value if competitors can design around the specific excipient ranges. A stronger estate would combine composition claims with dissolution, particle engineering, manufacturing and method-of-use claims.

When does phentermine lose exclusivity?

Phentermine hydrochloride has long been available as a generic active ingredient. The relevant commercial question is not loss of basic-molecule exclusivity but whether a particular branded formulation has remaining FDA regulatory exclusivity, listed patents or other barriers.

Exclusivity category	Current commercial assessment
New chemical entity exclusivity	Expired
Orphan-drug exclusivity	Not applicable to ordinary phentermine monotherapy
Pediatric exclusivity	Product-specific; must be verified in current FDA records
New formulation exclusivity	Product-specific
Orange Book patent protection	Must be assessed by product and current listing
Generic substitution	Broadly established for conventional dosage forms
Biosimilar pathway	Not applicable

The FDA Orange Book remains the controlling source for listed patents, expiration dates, dosage forms and therapeutic-equivalence information.[3] Because phentermine is marketed by multiple sponsors, an exclusivity conclusion for one product cannot automatically be applied to another.

What is the Orange Book status of phentermine hydrochloride?

The Orange Book analysis should be performed at the NDA and dosage-form level. Conventional phentermine tablets and capsules have extensive generic competition, while branded low-dose or specialty formulations may have different listing histories.

The principal diligence questions are:

• Does the reference product have active listed patents?
• Are the patents composition, method-of-use or formulation claims?
• Does the product have remaining FDA exclusivity?
• Is the proposed generic therapeutically equivalent to the reference listed drug?
• Does the dosage strength require a separate ANDA strategy?
• Are there labeling differences that could trigger a suitability petition or other regulatory issue?

For a conventional phentermine HCl product, the risk of a Paragraph IV dispute is generally lower than for newer patented obesity drugs. A Paragraph IV filing could still arise for a specific branded formulation if an active Orange Book patent remains listed.

Which companies are challenging phentermine products?

Phentermine has a mature generic market, so competition generally comes from multiple generic manufacturers rather than a single high-profile patent challenger. Manufacturers may compete through ANDAs, authorized-generic arrangements, contract supply and private-label distribution.

Potential competitive groups include:

• Branded reference-product sponsors.
• Large generic manufacturers.
• Specialty controlled-substance suppliers.
• Contract development and manufacturing organizations.
• Regional manufacturers serving non-U.S. markets.
• Combination-product sponsors developing phentermine with other active ingredients.

Exact challenger identity, litigation status and settlement terms are product-specific. FDA Orange Book records, FDA approval histories, federal court dockets and SEC filings should be reconciled before making a legal or launch decision.[3][4]

What patent litigation affects phentermine HCl?

Traditional phentermine HCl products have a lower litigation profile than newer anti-obesity products because the active ingredient and basic immediate-release dosage forms are mature. Litigation risk increases when a product includes:

• Extended release.
• A novel multiparticulate system.
• A controlled-release matrix.
• A taste-masked or orally disintegrating formulation.
• A fixed-dose combination.
• A proprietary manufacturing process.
• A narrow method-of-use claim.

Phentermine/topiramate products require separate analysis because the combination, dosing regimen and extended-release technology can create a more substantial patent estate. Patent conclusions for the combination should not be transferred to phentermine monotherapy.

How strong is the phentermine patent estate?

The patent estate for conventional phentermine HCl monotherapy is weak as a molecule-level barrier and potentially moderate for differentiated delivery systems.

Estate component	Strength assessment
Active ingredient	Weak due to age and generic availability
Standard immediate-release tablet	Weak
Low-dose formulation	Moderate if uniformity and performance are distinctive
Orally disintegrating formulation	Moderate
Modified release	Moderate to strong if clinical value is demonstrated
Abuse-deterrent formulation	Potentially strong, but validation burden is high
Combination therapy	Product-specific and potentially stronger
Manufacturing process	Moderate where process conditions are difficult to replicate
Trade secrets	Potentially useful for process capability, not a substitute for broad patent claims

The strongest defensible position would combine a differentiated clinical profile with formulation claims. An excipient list alone rarely creates durable market exclusivity unless the formulation produces unexpected dissolution, stability, bioavailability, tolerability or abuse-deterrence results.

What commercial opportunities exist for excipients and formulation technology?

Low-dose phentermine tablets

Low-dose products, including 8 mg formulations, offer a practical opportunity for excipient suppliers and manufacturers. They require better dose uniformity and may support titration-oriented prescribing. A supplier that can provide high-flow, low-segregation excipient systems can reduce development time.

Orally disintegrating and taste-masked products

An orally disintegrating tablet could improve administration for patients with swallowing difficulty. The technical barriers include bitterness, dose loading, tablet friability, moisture sensitivity and adequate mechanical strength.

Taste masking may use:

• Polymer coating.
• Ion-exchange resin complexation.
• Lipid or polymeric barriers.
• Multiparticulate encapsulation.
• Flavor systems compatible with controlled-substance labeling.

The product would need to demonstrate acceptable disintegration, dissolution and stability without creating unintended rapid exposure.

Modified-release formulations

A modified-release product could reduce dosing frequency and potentially improve tolerability. It would face a higher development burden because pharmacokinetic exposure, dose dumping, food effects and abuse-related concerns would require careful evaluation.

Modified release is commercially attractive only if it produces a meaningful clinical or adherence benefit. A simple extended-release claim without a strong pharmacokinetic or clinical rationale may not justify the development cost.

Abuse-risk mitigation

Phentermine is a Schedule IV stimulant, although its abuse-liability profile and regulatory treatment differ from Schedule II opioid products. A formulation designed to resist crushing, extraction or rapid release could have commercial value, but the benefit must be demonstrated and communicated within the applicable FDA framework.

Potential approaches include hard matrices, multiparticulate systems, tamper-resistant coatings and chemical barriers. These systems add cost and may reduce release flexibility.

Excipient supply and contract manufacturing

The most immediate opportunity may be B2B rather than a new branded drug. Suppliers can compete by offering:

• Validated direct-compression platforms.
• Low-dose uniformity packages.
• Controlled-substance manufacturing capacity.
• Dual-sourced excipient systems.
• Stability-tested color and coating systems.
• Private-label tablet and capsule production.
• Regulatory documentation for global filings.

Controlled-substance manufacturing requires inventory controls, recordkeeping, security and quota management under Drug Enforcement Administration requirements.[4]

How does phentermine compare with newer obesity drugs?

Factor	Phentermine HCl	GLP-1 or GIP/GLP-1 products
Dosage form	Oral tablet or capsule	Primarily injectable, with selected oral programs
Duration of use	Short-term labeling for monotherapy	Chronic weight-management positioning for approved products
Manufacturing complexity	Relatively low	High biologics or complex peptide manufacturing
Patent barrier	Low for conventional products	Often substantial
Price potential	Low to moderate	High
Excipient opportunity	Tablet compression, disintegration, taste masking	Stabilizers, buffers, delivery systems and device materials
Access advantage	Low-cost oral option	Higher clinical efficacy but higher cost and access barriers
Generic threat	Immediate and established	Limited for newer products

Phentermine can remain commercially relevant as a low-cost oral option, but its market position is exposed to chronic therapies with greater average weight-loss efficacy and broader long-term treatment positioning.[5]

What generic launch scenarios exist?

Conventional immediate-release launch

This is the lowest-risk path. The product would use standard excipients, seek therapeutic equivalence and compete primarily on price, supply reliability and wholesaler access.

Low-dose differentiated launch

An 8 mg or comparable low-dose product could target titration, tolerability and flexible dosing. The commercial benefit would depend on physician adoption and payer substitution behavior.

Orally disintegrating launch

This route could create modest product differentiation but would require taste masking and sufficient mechanical robustness. It is more defensible than a standard tablet but remains vulnerable to design-around strategies.

Modified-release launch

This offers the strongest potential product differentiation but carries the highest formulation, clinical, regulatory and patent risk. It may be commercially attractive only if it supports a meaningful dosing or tolerability advantage.

Private-label or licensed launch

A sponsor could acquire or license an existing ANDA, formulation, trademark or manufacturing relationship. This may produce faster market entry than developing a new dosage form, although the differentiation and margin profile would be limited.

What regulatory and geographic barriers apply?

In the United States, phentermine products require controlled-substance compliance, FDA-approved labeling and manufacturing under current good manufacturing practice requirements. International treatment varies widely. Some countries restrict phentermine more heavily, require additional import controls or do not authorize it for routine obesity treatment.

Geographic expansion should assess:

• Controlled-substance scheduling.
• Import and export permits.
• Local pharmacovigilance requirements.
• Prescription restrictions.
• Product registration requirements.
• Stability-zone testing.
• Local serialization and packaging rules.
• Availability of approved reference products.
• Advertising restrictions for weight-loss medicines.

Manufacturing barriers are operational rather than molecule-specific. They include controlled-substance security, reconciliation, inventory limits, diversion controls and specialized distribution procedures.[4]

Key Takeaways

• Phentermine HCl is a mature generic controlled substance with limited molecule-level patent value.
• Excipient strategy should prioritize low-dose content uniformity, rapid disintegration, flow, stability and manufacturing yield.
• The strongest formulation opportunities are low-dose, orally disintegrating, taste-masked and modified-release products.
• Conventional immediate-release products face intense price competition and limited exclusivity.
• A patent estate based only on standard excipients is likely narrow and vulnerable to design-around.
• Phentermine/topiramate requires separate patent, litigation and commercial analysis.
• No biosimilar risk exists because phentermine hydrochloride is a small molecule.
• Controlled-substance compliance is a material manufacturing and distribution barrier.
• The highest near-term B2B opportunity is a validated low-dose excipient and contract-manufacturing platform.
• New product investment must be measured against competition from chronic GLP-1 and GIP/GLP-1 therapies.

FAQs

Can excipients create market exclusivity for phentermine HCl?

They can support formulation patent claims, but an excipient list alone usually provides narrow protection. Stronger exclusivity requires unexpected performance, such as improved stability, dissolution, bioavailability or abuse-risk mitigation.

Is phentermine HCl suitable for an orally disintegrating tablet?

Yes. The principal technical barriers are bitterness, dose uniformity, tablet strength, moisture sensitivity and rapid but controlled dissolution.

Does phentermine HCl have biosimilar competition?

No. Phentermine hydrochloride is a small-molecule drug. Competition proceeds through generic-drug pathways rather than biosimilar applications.

Can a modified-release phentermine product support a new NDA?

Potentially. A modified-release product would need a distinct formulation, appropriate pharmacokinetic support, labeling justification and compliance with FDA requirements for the proposed dosage form.

Is phentermine a strong candidate for a new branded product?

It is a selective opportunity. A standard tablet has limited differentiation, while a low-dose, taste-masked or modified-release product could support a stronger commercial proposition if it demonstrates a clinically relevant benefit.

References

1. U.S. Food and Drug Administration. (n.d.). Adipex-P (phentermine hydrochloride) prescribing information. FDA.

2. U.S. Food and Drug Administration. (n.d.). Lomaira (phentermine hydrochloride) tablets prescribing information. FDA.

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

4. U.S. Drug Enforcement Administration. (n.d.). Phentermine drug fact sheet and controlled-substance requirements. DEA.

5. U.S. Food and Drug Administration. (n.d.). Prescription medications approved for chronic weight management. FDA.