List of Excipients in Branded Drug DIETHYLPROPION HYDROCHLORIDEER

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Generic Drugs Containing DIETHYLPROPION HYDROCHLORIDEER

Company	Ingredient	NDC	Excipient
Aidarex Pharmaceuticals LLC	diethylpropion hydrochloride	33261-354	CARBOMER HOMOPOLYMER TYPE A
Aidarex Pharmaceuticals LLC	diethylpropion hydrochloride	33261-354	HYPROMELLOSE ACETATE SUCCINATE 06081224
Aidarex Pharmaceuticals LLC	diethylpropion hydrochloride	33261-354	MAGNESIUM STEARATE
Aidarex Pharmaceuticals LLC	diethylpropion hydrochloride	33261-354	MANNITOL
Aidarex Pharmaceuticals LLC	diethylpropion hydrochloride	33261-354	POVIDONE K30

What are the Most Frequently-Used Excipients in DIETHYLPROPION HYDROCHLORIDEER?

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

Diethylpropion Hydrochloride Excipient Strategy and Commercial Opportunities

Last updated: August 1, 2026

Diethylpropion hydrochloride is a mature, low-complexity oral anorectic with limited patent protection and modest commercial scale. The main opportunities are generic supply, contract manufacturing, formulation-cost reduction, excipient substitution, and reliable controlled-substance distribution rather than new chemical-entity exclusivity. Products are marketed primarily as 25 mg immediate-release tablets and 75 mg extended-release tablets or capsules for short-term obesity treatment under FDA labeling.[1]

What is the FDA and commercial status of diethylpropion hydrochloride?

Diethylpropion hydrochloride is a sympathomimetic anorectic related pharmacologically to amphetamine. FDA labeling limits treatment to short-term use, generally several weeks, as an adjunct to caloric restriction in patients with an initial body-mass index meeting the labeled threshold.[1]

Attribute	Diethylpropion hydrochloride
Active ingredient	Diethylpropion hydrochloride
Common dosage forms	25 mg immediate-release tablet; 75 mg extended-release tablet or capsule
FDA pathway for a conventional generic	ANDA under Section 505(j)
Controlled-substance status	Schedule IV under the U.S. Controlled Substances Act
Primary therapeutic category	Short-term appetite suppressant
Reference products	Tenuate and Tenuate Dospan legacy products
Exclusivity profile	No meaningful current new-drug exclusivity expected for the legacy active ingredient
Biosimilar risk	None; this is a synthetic small molecule
Main commercial constraints	Small market, controlled-substance compliance, obesity-drug competition, limited treatment duration

The commercial market is structurally different from the market for newer chronic weight-management products. GLP-1 receptor agonists and related agents have shifted prescriber and payer attention toward long-term obesity treatment. Diethylpropion remains relevant for low-cost, short-duration therapy, but its clinical positioning limits total prescription volume and recurring revenue.

What patents protect diethylpropion hydrochloride products?

The core diethylpropion hydrochloride molecule is an old active ingredient, and the principal patent barriers associated with its original development have expired. Current generic competition is therefore governed primarily by FDA approval requirements, manufacturing controls, controlled-substance obligations, and product-specific formulation or process patents rather than active compound exclusivity.

Are there active Orange Book patents for diethylpropion hydrochloride?

The FDA Orange Book should be checked for the current listing status of each reference product and dosage form before filing or acquisition decisions. Legacy diethylpropion products generally do not present the type of active patent estate associated with recently approved branded drugs. A sponsor should distinguish among:

1. Listed patents for the reference listed drug.
2. Expired historical patents.
3. Unlisted formulation know-how.
4. Manufacturing process controls that may be difficult to replicate but are not patent barriers.
5. Controlled-substance supply obligations.

For a conventional 25 mg immediate-release tablet or 75 mg extended-release product, the principal regulatory route is normally an ANDA if the proposed product matches the reference product in active ingredient, dosage form, strength, route, and applicable bioequivalence requirements.[2]

When does diethylpropion lose exclusivity?

Diethylpropion has already lost practical market exclusivity. The relevant commercial question is not the date of compound-patent expiry but whether a new entrant can obtain approval, secure controlled-substance supply, and compete profitably at generic pricing.

A Paragraph IV strategy is unlikely to create material value unless an applicant identifies a still-listed patent covering a specific reference product, formulation, or method of use. For an old active ingredient, the greater risk is often unnecessary litigation expense rather than a durable market advantage.

What excipient strategy is appropriate for 25 mg immediate-release tablets?

The immediate-release product is the simplest formulation opportunity. A conventional tablet can use direct compression or wet granulation, subject to powder-flow, content-uniformity, dissolution, and tablet-strength requirements.

Recommended excipient functions

Formulation function	Candidate excipient classes	Commercial rationale
Diluent	Microcrystalline cellulose, lactose monohydrate, dibasic calcium phosphate	Controls tablet weight, compressibility, and cost
Binder	Povidone, pregelatinized starch, hydroxypropyl cellulose	Supports granule strength and tablet integrity
Disintegrant	Crospovidone, croscarmellose sodium, sodium starch glycolate	Promotes rapid release
Glidant	Colloidal silicon dioxide	Improves flow and die filling
Lubricant	Magnesium stearate, sodium stearyl fumarate	Reduces sticking and ejection force
Optional colorant	Approved iron oxides or other permitted colorants	Product identification and differentiation
Film coat	Hypromellose-based coating system	Improves appearance, handling, and swallowability

A direct-compression platform using microcrystalline cellulose, a superdisintegrant, colloidal silicon dioxide, and magnesium stearate can minimize manufacturing steps. Wet granulation may be preferable when the active ingredient has poor flow, low bulk density, segregation risk, or inadequate tabletability.

Excipient selection should prioritize rapid and reproducible dissolution. The target should be a formulation that does not introduce unnecessary hydrophobicity or excessive compression force, both of which can delay release. Lubricant concentration and blending time require control because over-lubrication can reduce tablet strength and slow dissolution.

Which excipient substitutions create commercial value?

The strongest opportunities are operational rather than patent-driven:

• Replacing a supply-constrained excipient with a qualified alternative.
• Removing lactose to address customer requirements for lactose-free products.
• Using a direct-compression grade to reduce granulation and drying costs.
• Improving flow to reduce weight variability and reject rates.
• Using a lower-cost coating system without changing dissolution or appearance requirements.
• Developing a common platform for 25 mg and other low-dose strengths.

A sponsor should avoid unnecessary excipient novelty. Each change can increase comparative dissolution work, stability studies, supplier qualification, and regulatory documentation without creating meaningful market protection.

What formulation strategy is appropriate for 75 mg extended-release diethylpropion?

The 75 mg extended-release product is the more technically valuable formulation opportunity. It must reproduce the reference product’s extended-release profile while avoiding dose dumping, excessive peak exposure, and premature release.

Which controlled-release technologies are suitable?

Potential approaches include:

• Hydrophilic matrix tablets using hypromellose or related cellulose ethers.
• Hydrophobic matrix systems using waxes or insoluble polymers.
• Multiparticulate beads or pellets with polymeric coatings.
• Osmotic or membrane-controlled systems, although these may be economically excessive for this market.
• Coated granules compressed into tablets or filled into capsules.

A hydrophilic matrix is generally the most practical starting point because it can be manufactured with conventional equipment and can support low-cost scale-up. The key variables are polymer viscosity, polymer loading, particle-size distribution, compression force, tablet geometry, and medium-dependent release behavior.

A multiparticulate approach may offer improved resistance to mechanical failure and lower risk of a single-unit dose-dumping event. Its disadvantages are higher process complexity, more equipment, and greater risk that the development cost will exceed the commercial value of the product.

What tests are critical for an extended-release generic?

A development program should include:

• Comparative dissolution across multiple media and agitation conditions.
• Robustness testing after tablet splitting or mechanical stress if relevant.
• Alcohol-interaction studies where required by the product profile.
• Stability under long-term and accelerated conditions.
• Pharmacokinetic comparison against the reference product.
• Evaluation of food effects and fed-state performance when required.
• Assessment of dose dumping under abnormal-use conditions.

For a controlled substance, manufacturing and testing controls must also protect reconciliation, inventory accountability, and diversion prevention.

How does diethylpropion compare with competing obesity drugs?

Diethylpropion competes on price and simplicity, not on duration of treatment, weight-loss magnitude, or cardiovascular and metabolic positioning.

Product category	Typical use profile	Formulation complexity	Patent risk	Commercial position
Diethylpropion hydrochloride	Short-term appetite suppression	Low for IR; moderate for ER	Low	Low-cost legacy generic
Phentermine	Short-term appetite suppression	Low	Low	Larger legacy stimulant market
Phentermine/topiramate ER	Chronic weight management	High	Higher	Branded and generic formulation competition
Naltrexone/bupropion ER	Chronic weight management	Moderate	Higher	Branded/generic transition dynamics
GLP-1 receptor agonists	Chronic obesity and metabolic treatment	High	High	Large branded market and biosimilar-like follow-on interest
Orlistat	Chronic weight management	Low	Low	OTC and prescription competition

Diethylpropion’s short-term labeling reduces refill continuity. Its controlled-substance status adds pharmacy and wholesaler friction. In exchange, the product has a relatively simple synthetic supply chain and low formulation cost.

What manufacturing and intellectual-property barriers exist?

The principal barriers are operational:

Controlled-substance manufacturing

Manufacturers must maintain appropriate Drug Enforcement Administration registration, procurement controls, inventory records, security procedures, quota management, and distribution controls. These requirements can discourage small entrants even when the formulation is technically straightforward.[3]

Active pharmaceutical ingredient supply

API qualification should address:

• Assay and impurity profile.
• Residual solvents.
• Particle size and morphology.
• Bulk density and flow.
• Hygroscopicity and salt stability.
• Supplier change-control procedures.
• Capacity for controlled-substance shipments.

API particle-size variation can affect blend uniformity and dissolution, particularly in low-dose immediate-release tablets. A supplier with consistent physical attributes may create more value than a nominally lower-cost source.

Manufacturing know-how

For immediate-release tablets, manufacturing know-how is unlikely to provide durable exclusivity. For extended-release products, process parameters can be commercially important even when they are not patent-protected. Granule porosity, polymer distribution, coating weight gain, and compression conditions can materially alter release profiles.

A proprietary extended-release platform could support a formulation patent or process patent, but the filing must be justified by a meaningful product distinction. A patent that covers only routine polymer substitution is vulnerable to obviousness challenges and may not justify the cost of prosecution.

Which licensing and partnering opportunities are available?

Licensing value is more likely to arise from an approved product, manufacturing capacity, or a reliable controlled-substance supply chain than from the active ingredient itself.

Potential transaction structures include:

1. Acquisition of an approved ANDA with established wholesaler distribution.
2. In-licensing of an extended-release formulation with demonstrated bioequivalence.
3. Contract manufacturing for regional generic companies.
4. Private-label supply for pharmacy or institutional channels.
5. API supply agreements with dual-source qualification.
6. Co-development of a differentiated excipient platform for international markets.

A licensee should evaluate annual prescription volume, net price, returns, DEA compliance costs, API security, product liability exposure, and the likelihood of new generic entrants. An apparently inexpensive ANDA can produce weak returns if the market has several suppliers and low annual demand.

What generic launch scenarios are most realistic?

Scenario 1: Low-cost immediate-release launch

A sponsor launches a 25 mg tablet using a conventional formulation and competes through reliable supply and low manufacturing cost. This is the lowest-risk path but also the most exposed to price erosion.

Scenario 2: Extended-release supply replacement

A sponsor develops or acquires a 75 mg extended-release product after a competitor exits or experiences manufacturing disruption. The opportunity depends on sustained reference-product demand and the ability to demonstrate bioequivalence.

Scenario 3: Regional or institutional supply

A manufacturer targets state programs, correctional healthcare, cash-pay pharmacies, or other price-sensitive channels. Volume may be limited, but contracts can reward supply reliability.

Scenario 4: Excipient-led reformulation

A sponsor develops a lactose-free, low-allergen, or more robust tablet. This can support customer differentiation, but it is unlikely to create substantial clinical or patent-based pricing power.

What litigation and settlement risks affect diethylpropion?

Diethylpropion is unlikely to generate the patent litigation intensity associated with newer obesity medicines. A Paragraph IV filing could still trigger litigation if the Orange Book contains a listed patent for the specific reference product. The commercial significance would depend on:

• The number of approved ANDA applicants.
• The scope and remaining term of the listed patent.
• Whether the patent covers the 25 mg or 75 mg dosage form.
• The availability of an alternative non-infringing formulation.
• The economics of a 30-month stay and potential settlement.

A settlement agreement would have value only if it provides an earlier launch date, supply rights, or other concrete commercial benefit. For a low-revenue generic, litigation should be modeled against expected annual gross profit rather than against the theoretical value of market exclusivity.

What is the commercial outlook for diethylpropion hydrochloride?

The opportunity is selective. A basic immediate-release product can be economical for an established generic manufacturer with controlled-substance infrastructure and low overhead. An extended-release product can command greater strategic value because development and bioequivalence are more difficult, but the addressable market remains constrained by short-term labeling and competition from chronic obesity therapies.

Revenue exposure is most sensitive to four factors:

Driver	Effect on opportunity
Number of generic suppliers	More suppliers accelerate price erosion
Reference-product availability	Shortages can create temporary supply opportunities
Controlled-substance compliance cost	Raises fixed operating expenses
Extended-release technical success	Can reduce direct competition but increases development cost

The strongest business case is a low-cost, supply-secure product supported by an existing generic portfolio. A standalone investment in novel excipients or advanced delivery technology is harder to justify unless the same platform can be applied to other controlled-release products.

Key Takeaways

• Diethylpropion hydrochloride is a mature synthetic small molecule with little practical compound-patent protection remaining.
• The main U.S. products are 25 mg immediate-release and 75 mg extended-release formulations.
• Immediate-release development favors conventional, low-cost excipients and direct compression where powder properties permit.
• Extended-release development requires tight control of matrix or coating variables and comparative dissolution performance.
• Excipient substitution can reduce cost and supply risk but rarely creates meaningful market exclusivity.
• Controlled-substance compliance, API sourcing, and distribution controls are more important barriers than patent rights.
• A conventional ANDA is generally the appropriate U.S. pathway for a product matching the reference listed drug.
• The best commercial opportunities are generic supply replacement, approved-product licensing, contract manufacturing, and reliable regional distribution.
• Biosimilar risk is irrelevant because diethylpropion is a small-molecule drug.
• Any Paragraph IV or settlement strategy requires confirmation of current Orange Book listings and product-specific patent status.

FAQs

Is diethylpropion hydrochloride still FDA approved?

Yes. FDA labeling covers immediate-release and extended-release diethylpropion hydrochloride products for short-term obesity treatment as an adjunct to caloric restriction.[1]

Does diethylpropion hydrochloride require a controlled-substance license?

Yes. Diethylpropion is a Schedule IV controlled substance in the United States, requiring applicable DEA registration, security, recordkeeping, procurement, and distribution controls.[3]

Can lactose be removed from a diethylpropion tablet?

Yes. Lactose can generally be replaced with microcrystalline cellulose, mannitol, dibasic calcium phosphate, or another suitable diluent, provided the finished product meets quality, dissolution, stability, and bioequivalence requirements.

Is an extended-release diethylpropion product patentable?

A genuinely differentiated extended-release formulation may support patent protection if it meets novelty and non-obviousness requirements. Routine substitution of common polymers or excipients is less likely to provide defensible protection.

Is diethylpropion a good candidate for a 505(b)(2) application?

A conventional generic matching an approved reference product would generally be evaluated through the ANDA pathway. A 505(b)(2) application may be relevant only where the sponsor proposes a sufficiently differentiated dosage form, formulation, route, or other change that cannot rely entirely on an ANDA framework.[2]

References

1. U.S. Food and Drug Administration. (2023). Diethylpropion hydrochloride prescribing information. Drugs@FDA.

2. U.S. Food and Drug Administration. (2024). Abbreviated new drug application (ANDA) process. FDA.

3. U.S. Drug Enforcement Administration. (2024). Controlled substances act: Schedule IV substances. U.S. Department of Justice.

4. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA.