List of Excipients in Branded Drug DIETHYLPROPION HYDROCHLORIDE ER

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Apotheca Inc	DIETHYLPROPION HYDROCHLORIDE ER	diethylpropion hydrochloride er	12634-691	CARBOMER HOMOPOLYMER TYPE B
Apotheca Inc	DIETHYLPROPION HYDROCHLORIDE ER	diethylpropion hydrochloride er	12634-691	MANNITOL
Apotheca Inc	DIETHYLPROPION HYDROCHLORIDE ER	diethylpropion hydrochloride er	12634-691	POVIDONES
Apotheca Inc	DIETHYLPROPION HYDROCHLORIDE ER	diethylpropion hydrochloride er	12634-691	TARTARIC ACID
Apotheca Inc	DIETHYLPROPION HYDROCHLORIDE ER	diethylpropion hydrochloride er	12634-691	ZINC STEARATE

Generic Drugs Containing DIETHYLPROPION HYDROCHLORIDE ER

Company	Ingredient	NDC	Excipient
Chartwell RX LLC	diethylpropion hydrochloride	62135-489	CARBOMER HOMOPOLYMER TYPE A
Chartwell RX LLC	diethylpropion hydrochloride	62135-489	HYPROMELLOSE ACETATE SUCCINATE 06081224
Chartwell RX LLC	diethylpropion hydrochloride	62135-489	MAGNESIUM STEARATE
Chartwell RX LLC	diethylpropion hydrochloride	62135-489	MANNITOL
Chartwell RX LLC	diethylpropion hydrochloride	62135-489	POVIDONE K30

What are the Most Frequently-Used Excipients in DIETHYLPROPION HYDROCHLORIDE ER?

# Of NDCs	Excipient
2	CARBOMER HOMOPOLYMER TYPE A
2	HYPROMELLOSE ACETATE SUCCINATE 06081224
2	MAGNESIUM STEARATE
2	MANNITOL
2	POVIDONE K30

Diethylpropion Hydrochloride ER Excipient Strategy and Commercial Opportunities

Last updated: August 7, 2026

Diethylpropion hydrochloride extended-release, historically marketed as Tenuate Dospan 75 mg, is an old, controlled-release anorectic with no meaningful remaining innovator patent barrier. The commercial opportunity is therefore formulation execution rather than patent exclusivity. The strongest strategy is a low-cost, once-daily extended-release tablet supported by robust dissolution control, abuse-deterrence considerations, and a focused generic or 505(b)(2) regulatory plan.

The principal risks are limited market size, Schedule IV controls, declining use of older obesity medicines, and competition from newer GLP-1 and dual incretin therapies. A differentiated formulation could still have value in price-sensitive markets, but it would need manufacturing simplicity, reliable bioequivalence, and broad geographic registration.

What is diethylpropion hydrochloride extended-release?

Diethylpropion hydrochloride is a sympathomimetic amine indicated for short-term use in the management of exogenous obesity as part of a weight-reduction regimen involving caloric restriction. The extended-release dosage form is generally administered as a 75 mg tablet once daily, typically in the midmorning or approximately 10 to 14 hours before the patient’s desired bedtime.[1]

Attribute	Diethylpropion hydrochloride ER
Active ingredient	Diethylpropion hydrochloride
Dosage form	Extended-release tablet
Historical strength	75 mg
Historical brand	Tenuate Dospan
Therapeutic class	Sympathomimetic anorectic
Controlled-substance status	U.S. Schedule IV
U.S. indication	Short-term adjunct for exogenous obesity
Administration	Once daily
Key formulation issue	Controlled release without dose dumping
Primary commercial pathway	ANDA generic or 505(b)(2) reformulation

The drug is chemically distinct from phentermine, although both are sympathomimetic anorectics. Diethylpropion hydrochloride is metabolized to active metabolites, including ethcathinone, which makes release-rate control and abuse-liability management relevant to product development.[1]

What patents protect diethylpropion hydrochloride ER?

No material active U.S. Orange Book patent barrier is associated with the historical Tenuate Dospan product. The original product and its extended-release technology are legacy assets, and any basic composition, dosage-form, or method-of-use patents would generally have expired based on the age of the product.

The commercial position is summarized below.

IP category	Current strategic position
Active-ingredient patent	Expired or unavailable as a practical barrier
Original extended-release patent	Expected to be expired
Method-of-use patents	No meaningful current exclusivity identified
Orange Book patents	No material listed patent barrier expected
Regulatory exclusivity	Expired
Generic entry	Legally feasible, subject to FDA approval
Formulation opportunity	New excipient architecture or manufacturing process
Global patent opportunity	Limited for the old molecule; possible only for new delivery technology

A new patent could potentially cover a specific release-control matrix, coating system, abuse-deterrent architecture, particle-size distribution, manufacturing process, or combination product. Such protection would need to claim a real technical distinction rather than the use of routine excipients in a conventional extended-release tablet.

When did diethylpropion ER lose exclusivity?

Diethylpropion ER lost meaningful market exclusivity decades ago. The product’s remaining value is not based on an innovator monopoly but on the ability to manufacture a compliant product and obtain regulatory approval in markets where demand remains.

The main exclusivity events are:

Exclusivity issue	Status
New chemical entity exclusivity	Expired
Original NDA exclusivity	Expired
Patent term extension	No current commercial relevance
Pediatric exclusivity	No current commercial relevance
Orphan exclusivity	Not applicable
Generic exclusivity	No current barrier identified
Regulatory market protection	Expired

The absence of exclusivity does not eliminate commercial opportunity. It shifts value toward supply reliability, low manufacturing cost, regulatory execution, and geographic registration.

What excipients are used in diethylpropion hydrochloride ER tablets?

Historical extended-release diethylpropion products used conventional solid oral excipients. Public labeling identifies inactive ingredients for the extended-release tablet, but excipient composition can differ between historical products, manufacturers, and markets.[2]

The likely functional excipient groups are:

Excipient function	Candidate materials	Strategic purpose
Diluent	Lactose, microcrystalline cellulose, dibasic calcium phosphate	Provides tablet mass and improves compression
Binder	Povidone, pregelatinized starch, hydroxypropyl cellulose	Supports granule and tablet strength
Disintegrant	Starch or low-substituted hydroxypropyl cellulose	Controls structural breakup where appropriate
Lubricant	Magnesium stearate, sodium stearyl fumarate	Supports ejection and tooling protection
Glidant	Colloidal silicon dioxide, talc	Improves powder flow
Release controller	Ethylcellulose, hypromellose, waxes, polymeric matrix materials	Controls drug liberation
Film coat	Hypromellose, polyethylene glycol, titanium dioxide, iron oxides	Protects tablet and supports identification
Opacifier or colorant	Titanium dioxide or approved colorants	Product appearance and differentiation

A development team should not treat the historical inactive-ingredient list as a complete formulation blueprint. The critical commercial question is whether the formulation reproduces the reference product’s release profile under FDA-relevant conditions without using expensive or difficult-to-source materials.

What is the best excipient strategy for diethylpropion hydrochloride ER?

The strongest starting point is a conventional matrix tablet using excipients with established oral solid-dose regulatory histories.

Hydrophilic matrix strategy

A hypromellose-based matrix can provide controlled hydration, gel formation, and diffusion-based release. It offers broad supplier availability and established manufacturing experience.

Advantages include:

• Simple direct-compression or wet-granulation pathways
• Broad excipient supply base
• Scalable manufacturing
• Flexible release-rate adjustment through polymer grade and loading
• Lower development cost than a multiparticulate system

The main risk is sensitivity to compression force, tablet porosity, polymer viscosity, and gastrointestinal conditions. Diethylpropion hydrochloride’s high aqueous solubility could produce an excessively rapid initial release unless the matrix is sufficiently robust.

Hydrophobic matrix strategy

Ethylcellulose, hydrogenated vegetable oils, glyceryl behenate, or related hydrophobic materials can reduce water penetration and moderate release.

This approach may improve resistance to rapid dissolution and reduce the risk of alcohol-related release acceleration. It can also support a smaller tablet when the drug load and polymer architecture are optimized.

The disadvantages are more complex process development, possible food-effect differences, and greater sensitivity to coating or granulation conditions.

Multiparticulate strategy

Pellets, coated granules, or mini-tablets could provide more consistent gastrointestinal distribution and more flexible release control. A multiparticulate product may reduce the risk that a single damaged tablet releases the full dose.

The commercial drawbacks are higher manufacturing complexity, more extensive process validation, and potentially higher cost of goods. This strategy is more suitable for a differentiated 505(b)(2) product than for a low-cost ANDA generic unless it produces a clear bioequivalence or safety advantage.

Bilayer or dual-phase strategy

A bilayer tablet could combine an immediate-release fraction with an extended-release fraction. This may support a targeted pharmacokinetic profile, but it also introduces additional critical process parameters and may increase regulatory complexity.

For a 75 mg once-daily product, a conventional single-unit matrix is likely to offer the best balance between cost, manufacturability, and regulatory simplicity.

What formulation patents could protect a new diethylpropion ER product?

A new patent estate could focus on technical features that are measurable and difficult to design around.

Potential claim categories include:

1. A defined polymer-to-drug ratio producing a specified dissolution profile.
2. A hydrophilic-hydrophobic polymer combination that limits alcohol-induced dose dumping.
3. A multiparticulate formulation with discrete release populations.
4. A coated matrix tablet with a defined permeability range.
5. A manufacturing process that produces a narrow tablet-density or porosity distribution.
6. A formulation that reduces pharmacokinetic variability under fed and fasted conditions.
7. An abuse-deterrent dosage form that resists crushing, extraction, or rapid solvent release.
8. A composition with improved stability under high humidity or elevated temperature.
9. A low-dose or alternate-strength formulation for titration or tapering.
10. A fixed-dose product combining diethylpropion with another approved therapeutic agent, subject to separate clinical and regulatory requirements.

Routine excipient substitution is unlikely to create a strong patent position. A defensible patent should link composition to a clinically relevant or manufacturing-relevant result, such as controlled release, reduced variability, improved stability, or resistance to manipulation.

How should a generic diethylpropion ER product be developed?

An ANDA program would normally seek to demonstrate pharmaceutical equivalence and bioequivalence to the reference listed drug. The principal workstreams are formulation matching, dissolution, analytical method development, pharmacokinetics, stability, and controlled-substance compliance.

Critical formulation-development tests

The development package should include:

• Comparative dissolution across multiple pH conditions
• Agitation-speed sensitivity
• Discriminating dissolution methods
• Fed and fasted pharmacokinetic studies
• Alcohol-dose-dumping assessment
• Tablet hardness and friability testing
• Content uniformity and assay
• Stability under long-term and accelerated conditions
• Extractables and leachables evaluation if polymeric coatings are used
• Crushability and tamper testing when abuse-deterrence claims are pursued

The release profile should be evaluated across the full dosing interval rather than only through a single time-point specification. A formulation that matches average exposure but produces a materially different early concentration profile could create clinical, regulatory, or safety risk.

What is the FDA regulatory status of diethylpropion hydrochloride ER?

Diethylpropion hydrochloride is an approved prescription drug substance in the United States, but its commercial history is affected by product discontinuations and limited contemporary use. FDA’s Drugs@FDA and Orange Book databases should be used to confirm the current reference-listed-drug and marketed-product status for any live ANDA program.[3,4]

The relevant regulatory considerations are:

Regulatory issue	Commercial impact
Extended-release dosage form	Requires release-profile and PK control
Schedule IV status	Requires DEA registration, quotas, security, recordkeeping, and monitoring
Obesity indication	Label remains a short-term treatment indication
Discontinued brand history	Can affect reference-product strategy and market forecasting
Generic pathway	ANDA may be available if an appropriate reference product is listed
Reformulation pathway	505(b)(2) may be relevant for a materially different dosage form
Postmarketing controls	Controlled-substance reporting and diversion controls apply

A 505(b)(2) route becomes more attractive if the sponsor develops a novel release profile, abuse-deterrent formulation, new strength, or alternate dosage form that cannot be fully addressed through a conventional ANDA.

What generic entry risks exist for diethylpropion ER?

Generic entry is legally feasible, but the market may not support multiple competitors. The main risks are commercial rather than patent-based.

Market risks

The U.S. obesity-treatment market has shifted toward chronic therapies, including GLP-1 receptor agonists and dual incretin products. Diethylpropion is labeled for short-term use, has stimulant-related contraindications and warnings, and lacks the clinical positioning of newer chronic weight-management medicines.[1]

Regulatory and technical risks

The highest technical risk is failure to match the reference product’s extended-release behavior. Potential causes include:

• Excessive initial release from a highly soluble hydrochloride salt
• Food-related changes in absorption
• Alcohol-induced release acceleration
• Polymer variability
• Tablet porosity differences
• Inadequate control of granule size
• Inconsistent coating weight gain
• Metabolite exposure differences

Supply-chain risks

The active pharmaceutical ingredient is a controlled substance. Supply planning must address:

• DEA procurement controls
• Supplier qualification
• Annual manufacturing quotas
• Secure storage
• Batch reconciliation
• Diversion monitoring
• Serialization and distribution controls where applicable

These requirements raise operating costs compared with an uncontrolled generic tablet.

Which companies are challenging diethylpropion ER?

No major current Paragraph IV litigation landscape is associated with diethylpropion hydrochloride ER. The product is an old molecule with no apparent high-value active patent estate comparable to recently launched obesity medicines.

The practical competitive set is more likely to include:

• Small generic manufacturers
• Contract development and manufacturing organizations
• Regional pharmaceutical companies
• Suppliers serving Latin American, Asian, Eastern European, and selected Middle Eastern markets
• Companies offering immediate-release diethylpropion or other sympathomimetic anorectics

A sponsor should expect price competition if several products enter the same market. A differentiated extended-release formulation, reliable supply, or regional registration package may provide more durable value than a patent-only strategy.

What commercial opportunities exist for diethylpropion hydrochloride ER?

The best opportunities are narrow and execution-driven.

U.S. generic opportunity

A U.S. generic could target patients and prescribers who continue to use older short-term anorectics. The opportunity is constrained by the relatively small treatment population and competition from higher-growth obesity medicines.

Potential advantages include:

• Low API dose
• Simple tablet manufacturing
• No need for biologic manufacturing
• Possible use of standard oral-solid-dose equipment
• Low development cost compared with modern obesity therapies
• Potential shortage or supply-continuity opportunities

505(b)(2) reformulation opportunity

A differentiated product could pursue:

• Abuse-deterrent release
• Lower peak concentration
• Improved tolerability
• More predictable fed and fasted exposure
• Alternative strength
• Sprinkle or orally disintegrating presentation, if technically justified
• Longer duration of appetite suppression
• Reduced dosing frequency, if clinically supported

A 505(b)(2) product would require a clearer clinical and regulatory value proposition. A minor excipient change alone would not support a strong commercial case.

International opportunity

Markets with established use of sympathomimetic anorectics may offer better opportunities than the United States, particularly where GLP-1 access is limited by price or reimbursement. Registration requirements, controlled-substance rules, and local obesity-treatment guidance vary materially by country.

A global strategy should prioritize:

• Countries with existing diethylpropion registrations
• Markets permitting short-term anorectic use
• Regions with limited access to injectable obesity products
• Jurisdictions where local manufacturing or licensing improves procurement access
• Countries with stable controlled-substance distribution channels

Licensing and partnering

The most credible licensing asset would be a formulation platform, not the old active ingredient. A partner may pay for:

• Regional rights to an approved or near-approval ER product
• Controlled-release technology
• Abuse-deterrent claims
• Existing manufacturing capacity
• Regulatory dossiers in markets where the sponsor lacks infrastructure
• Reliable controlled-API sourcing

No major current licensing transaction is required to commercialize a conventional generic product. Licensing becomes more relevant for geographic expansion or a differentiated formulation.

How strong is the patent estate for diethylpropion hydrochloride ER?

The legacy patent estate is weak from a current commercial perspective. A new formulation patent could have value, but its strength would depend on measurable performance and claim breadth.

Patent factor	Assessment
Basic molecule protection	None of practical current value
Original ER protection	Expected to be expired
Method-of-use protection	Weak or expired
Formulation whitespace	Available
Freedom-to-operate risk	Generally lower than for modern branded products
New patent potential	Moderate for technically differentiated systems
Patent litigation exposure	Low based on the legacy product profile
Commercial patent value	Dependent on formulation differentiation

A formulation patent would be more valuable if it supported a 505(b)(2) product with a clinically meaningful label distinction. A patent covering only conventional excipients and routine manufacturing parameters would face validity and enforcement challenges.

How does diethylpropion ER compare with newer obesity drugs?

Factor	Diethylpropion ER	GLP-1 or dual incretin therapies
Dosage form	Oral tablet	Primarily injectable, with some oral products
Use duration	Short-term label	Chronic weight-management use for approved products
Manufacturing	Conventional small molecule	Peptide or advanced small-molecule manufacturing
Development cost	Low to moderate	High
Patent barrier	Minimal	Substantial for leading products
Controlled substance	Yes, Schedule IV	Generally no
Market growth	Limited	High
Differentiation path	Release control, price, access	Efficacy, durability, convenience
Commercial scale	Niche	Large and expanding

Diethylpropion cannot compete directly with newer agents on average weight loss or chronic disease positioning. Its potential advantage is low cost, oral administration, and availability in markets where newer products are inaccessible.

What is the outlook for revenue exposure and generic launch?

Revenue exposure for the historical innovator product is limited because the brand has lost exclusivity and has faced discontinuation issues. The addressable opportunity for a new entrant is likely to be niche unless the sponsor secures broad international distribution or develops a differentiated product.

A practical launch model is:

Launch phase	Commercial objective
Phase 1	Confirm reference-product and regulatory pathway
Phase 2	Develop low-cost matrix formulation
Phase 3	Complete PK, dissolution, stability, and controlled-substance readiness
Phase 4	File ANDA or 505(b)(2) application
Phase 5	Launch through selected distributors and specialty pharmacies
Phase 6	Expand into regional markets with established anorectic demand

The most attractive business case is a focused generic platform with limited SKU complexity, reliable controlled-API access, and selected international licensing. A large-scale U.S. obesity franchise is unlikely to be supported by diethylpropion ER alone.

Key Takeaways

• Diethylpropion hydrochloride ER is a legacy 75 mg once-daily controlled-release anorectic.
• Its original patent and regulatory exclusivity barriers are no longer commercially meaningful.
• The primary opportunity is a low-cost generic or a technically differentiated 505(b)(2) product.
• Hydrophilic or hydrophobic matrix tablets are the most commercially practical excipient platforms.
• High solubility, food effects, alcohol-induced dose dumping, and polymer variability are the main formulation risks.
• A strong new patent would need to claim measurable release, stability, abuse-deterrence, or manufacturing performance.
• Controlled-substance requirements increase supply-chain and compliance costs.
• U.S. demand is likely to remain niche because newer chronic obesity medicines have stronger efficacy and market momentum.
• International markets and licensing arrangements may offer more attractive growth than a U.S.-only launch.
• The commercial case depends on manufacturing cost, regulatory execution, supply continuity, and geographic selection rather than legacy patent exclusivity.

FAQs

Is diethylpropion hydrochloride ER still commercially viable?

It can be viable as a niche generic or regional product, particularly where low-cost oral anorectics remain used. The opportunity is limited by Schedule IV controls and competition from newer obesity therapies.

Can a company patent a new diethylpropion extended-release tablet?

Yes. A sponsor may seek patents covering a specific matrix, coating, multiparticulate system, abuse-deterrent structure, stability improvement, or manufacturing process. Routine excipient substitutions are unlikely to provide strong protection.

Does diethylpropion ER require abuse-deterrent excipients?

FDA approval of a generic does not automatically require abuse-deterrent technology. Abuse-deterrent excipients may still support product differentiation, risk management, and a 505(b)(2) strategy.

Is diethylpropion ER eligible for a generic ANDA?

Potentially, if an appropriate reference listed drug and regulatory pathway are available. The sponsor must establish pharmaceutical equivalence and bioequivalence for the extended-release dosage form.

What is the most attractive geographic market for diethylpropion ER?

The strongest opportunities are likely in markets with established short-term anorectic use, constrained access to injectable obesity therapies, and workable controlled-substance distribution systems. Market-specific registration and scheduling requirements determine final priority.

References

1. U.S. Food and Drug Administration. (n.d.). Tenuate Dospan: Diethylpropion hydrochloride extended-release tablets prescribing information. FDA/DailyMed labeling.

2. National Library of Medicine. (n.d.). DailyMed: Diethylpropion hydrochloride extended-release tablet labeling and inactive ingredients. DailyMed.

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

4. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm

5. U.S. Food and Drug Administration. (2019). Assessing the abuse deterrence of abuse-deterrent opioids: Guidance for industry. FDA.

6. United States Pharmacopeia. (n.d.). General chapter <711> dissolution. United States Pharmacopeial Convention.