List of Excipients in Branded Drug ENALAPRIL MALEATE AND HYDROCHLOROTHIAZIDE

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Generic Drugs Containing ENALAPRIL MALEATE AND HYDROCHLOROTHIAZIDE

Company	Ingredient	NDC	Excipient
Mylan Pharmaceuticals Inc	enalapril maleate and hydrochlorothiazide	0378-0712	ANHYDROUS LACTOSE
Mylan Pharmaceuticals Inc	enalapril maleate and hydrochlorothiazide	0378-0712	MAGNESIUM STEARATE
Mylan Pharmaceuticals Inc	enalapril maleate and hydrochlorothiazide	0378-0712	MALEIC ACID
Mylan Pharmaceuticals Inc	enalapril maleate and hydrochlorothiazide	0378-0712	MICROCRYSTALLINE CELLULOSE 103
Mylan Pharmaceuticals Inc	enalapril maleate and hydrochlorothiazide	0378-0712	MICROCRYSTALLINE CELLULOSE 112

What are the Most Frequently-Used Excipients in ENALAPRIL MALEATE AND HYDROCHLOROTHIAZIDE?

# Of NDCs	Excipient
1	ALUMINUM OXIDE
2	ANHYDROUS LACTOSE
1	FD&C BLUE NO. 2
1	FD&C RED NO. 40
1	FD&C YELLOW NO. 6

Enalapril Maleate and Hydrochlorothiazide Excipient Strategy and Commercial Opportunities

Last updated: October 30, 2026

Enalapril maleate/hydrochlorothiazide is an established immediate-release fixed-dose combination for hypertension. Its patent and regulatory barriers are largely exhausted, making the commercial opportunity depend on manufacturing cost, dissolution performance, supply reliability, tablet usability, and differentiated dosage forms rather than exclusivity.

The core product opportunity is a robust generic tablet containing enalapril maleate and hydrochlorothiazide, commonly marketed in 5 mg/12.5 mg and 10 mg/25 mg strengths. The combination is associated with historical brands including Vaseretic, while multiple manufacturers supply generic equivalents. The principal technical challenge is controlling low-dose content uniformity and dissolution for two chemically distinct active ingredients in a stable, scalable tablet platform.

What is the FDA and Orange Book status of enalapril maleate/hydrochlorothiazide?

Enalapril maleate/hydrochlorothiazide is an FDA-approved immediate-release oral tablet combination. Vaseretic was approved under NDA 019891, and generic products have been approved through the ANDA pathway.[1]

Attribute	Commercial position
Active ingredients	Enalapril maleate and hydrochlorothiazide
Therapeutic area	Hypertension
Dosage form	Immediate-release oral tablet
Common strengths	5 mg/12.5 mg and 10 mg/25 mg
Primary FDA pathway for new generics	ANDA under section 505(j)
Reference product history	Vaseretic
New chemical entity exclusivity	Expired
Expected patent barrier	No material remaining composition-of-matter barrier
Current competitive basis	Price, supply, quality, packaging, and formulation execution

The Orange Book should be checked for the specific reference-listed drug and strength at the time of filing because listing status, applicant records, and any residual patents can change.[2] For this mature combination, the commercial significance of Orange Book patents is substantially lower than for recently approved fixed-dose products.

When does enalapril maleate/hydrochlorothiazide lose exclusivity?

The principal exclusivity periods expired decades ago. Enalapril was approved in the 1980s, and fixed-dose enalapril/hydrochlorothiazide products have been marketed for many years. No meaningful period of new-drug exclusivity remains for a conventional generic version.

The commercial timeline is therefore governed by ANDA review, patent certification, manufacturing readiness, and launch economics.

Exclusivity and patent timeline

Milestone	Timing and effect
Enalapril approval	1980s
Enalapril/hydrochlorothiazide brand approval	Historical approval under Vaseretic NDA
Original compound and formulation patents	Expired
Generic ANDA pathway	Available
Paragraph IV opportunity	Relevant only if a current Orange Book-listed patent exists
Biosimilar exclusivity	Not applicable
Current market barrier	Primarily operational and commercial

A conventional generic applicant would typically certify under Paragraph III or Paragraph IV depending on the status of any listed patent. Paragraph IV litigation risk appears limited for an old, widely genericized combination, but the applicant must evaluate the current Orange Book record rather than rely only on historical patent expiration dates.[2,3]

What excipients are suitable for enalapril maleate/hydrochlorothiazide tablets?

The preferred excipient strategy is a conventional direct-compression or dry-granulation platform that supports low-dose uniformity, rapid dissolution, tablet strength, and moisture control.

The exact excipient selection must be based on the target formulation, supplier grade, process capability, and comparative dissolution data. Brand and generic labels do not establish that all products use the same excipient system.

Recommended excipient platform

Functional requirement	Suitable excipient classes	Commercial purpose
Dilution and tablet weight	Microcrystalline cellulose, lactose monohydrate, dibasic calcium phosphate	Provides compressible mass and manageable tablet size
Low-dose content uniformity	Spray-dried lactose, silicified microcrystalline cellulose, coprocessed fillers	Improves blending and reduces segregation
Disintegration	Crospovidone, croscarmellose sodium, sodium starch glycolate	Supports rapid release
Binder	Povidone, copovidone, pregelatinized starch	Improves granule and tablet strength
Lubrication	Magnesium stearate, sodium stearyl fumarate	Controls ejection force
Glidant	Colloidal silicon dioxide	Improves powder flow
Film coating	Hypromellose, polyethylene glycol, titanium dioxide, colorants	Protects tablet and improves identification
Moisture management	Low-moisture excipient grades, protective packaging, desiccant where justified	Reduces degradation risk

Direct compression is attractive because it reduces processing steps and cost. Dry granulation is a stronger option where the formulation has poor flow, segregation, or content-uniformity performance.

Wet granulation should be used selectively. It can improve powder handling, but water exposure and drying conditions may affect enalapril-related degradation pathways and can increase process complexity. A low-moisture process is generally preferable unless development data show a clear benefit from aqueous granulation.

What formulation risks affect enalapril and hydrochlorothiazide?

The formulation must manage four principal risks: low-dose uniformity, chemical stability, dissolution alignment, and blend segregation.

Enalapril maleate stability

Enalapril maleate is susceptible to degradation under unfavorable moisture, temperature, and pH conditions. The formulation should avoid unnecessary water exposure and should use controlled excipient moisture levels. Packaging selection is part of the formulation strategy, not a post-development activity.

Potential controls include:

• Low-moisture excipient grades
• Tight control of granulation or coating water
• Reduced hold times for bulk blend
• Aluminum-aluminum blister or high-barrier bottle packaging
• Stability-indicating HPLC methods
• Protection from high temperature and humidity during storage

Hydrochlorothiazide content and dissolution

Hydrochlorothiazide is present at a higher mass than enalapril in common strengths, but it can still present dissolution and blend-uniformity challenges. Particle-size distribution, polymorphic form, wetting, and lubricant concentration can affect release.

Excessive magnesium stearate or prolonged lubrication can reduce wetting and slow dissolution. The formulation should establish a defined lubrication endpoint rather than relying only on a fixed mixing time.

Combination-product compatibility

The two active ingredients should be evaluated as a combined powder system. Separate premixes or ordered addition may be preferable when particle-size differences create segregation risk.

A practical development sequence is:

1. Characterize particle-size distribution, density, flow, and moisture for both actives.
2. Screen direct compression and dry-granulation platforms.
3. Quantify blend uniformity at commercial-scale sampling locations.
4. Compare dissolution across pH conditions.
5. Stress-test tablets in high humidity and elevated temperature.
6. Select packaging based on stability data.

What formulations are protected by enalapril/hydrochlorothiazide patents?

Historical protection centered on the active ingredients, fixed-dose combination, and conventional oral dosage forms. Those rights are generally expired. A new applicant is unlikely to obtain commercially meaningful exclusivity from simply reproducing a standard immediate-release tablet.

Potentially protectable innovations could include:

• A new modified-release profile
• A novel orally disintegrating tablet
• A technically distinct multiparticulate system
• A stability-enhancing formulation with demonstrated performance
• A clinically relevant dosing regimen
• A novel manufacturing process that produces a defined product attribute
• A differentiated combination with another antihypertensive

A formulation patent must contain more than routine excipient substitution. Claim strength improves where the formulation solves a defined technical problem and provides unexpected stability, dissolution, bioavailability, or patient-use results.

How strong is the patent estate for enalapril maleate/hydrochlorothiazide?

The patent estate is weak for a standard generic tablet and stronger only for genuinely differentiated delivery or manufacturing technology.

Patent category	Current commercial relevance
Enalapril compound patents	Expired
Hydrochlorothiazide compound patents	Expired
Historical fixed-dose combination patents	Expired or commercially exhausted
Conventional tablet composition	Low protection potential
Method-of-use claims for hypertension	Limited value because of longstanding clinical use
Modified-release or novel delivery	Potentially protectable
Manufacturing process claims	Potentially protectable if non-routine and difficult to design around
Device or packaging claims	Narrow, product-specific value

For a conventional ANDA, freedom-to-operate analysis should focus on any active formulation, process, or method-of-use listings rather than expired historical patents. A patent search should include U.S. Patent and Trademark Office records, Orange Book listings, assignment data, and litigation databases.[2,4]

What generic entry risks exist?

Generic entry risk is high because the product has no meaningful biological complexity and has long-established therapeutic use. There is no biosimilar issue because enalapril maleate and hydrochlorothiazide are small-molecule active ingredients.

The main entry risks are commercial rather than legal:

• Multiple established generic competitors
• Low reimbursement and price compression
• Limited differentiation between suppliers
• Active-pharmaceutical-ingredient price volatility
• Manufacturing-site qualification delays
• Dissolution or stability failures
• Product recalls caused by content uniformity or impurity deviations
• Weak channel access for a new supplier

A new entrant should avoid a purely price-based strategy unless it has a structural cost advantage. The combination is better suited to a reliable-supply strategy, contract manufacturing, private-label distribution, or portfolio bundling with other cardiovascular generics.

Which companies are challenging or supplying the product?

The market has historically included Merck as the Vaseretic innovator and numerous generic manufacturers. Generic availability has included products from large and mid-sized ANDA holders, although supplier participation and active marketing status vary by strength and time.

A current competitive review should distinguish among:

• Approved ANDA holders
• Commercially marketed products
• Discontinued products
• Authorized generics
• Contract manufacturers
• Products listed as available but not actively promoted

The most relevant competitive metric is not the number of historical approvals. It is the number of reliable suppliers with current distribution, acceptable quality history, and formulary access.

What commercial opportunities exist for excipient suppliers?

Excipient suppliers can target this product through performance and supply-chain propositions rather than new chemical entities.

Low-cost direct-compression platform

A co-processed filler containing microcrystalline cellulose and a soluble diluent could reduce blending and granulation steps. The value proposition is lower conversion cost, improved flow, and more consistent low-dose distribution.

Moisture-controlled formulation

A low-moisture excipient package combined with high-barrier packaging may reduce stability risk for enalapril-containing tablets. The commercial opportunity is strongest for manufacturers operating in humid climates or using bottle packaging.

Robust disintegration platform

Crospovidone or croscarmellose sodium can support rapid tablet breakup without requiring a high tablet porosity. The excipient supplier should demonstrate performance across compression forces and storage conditions.

Film-coating system

A ready-to-use coating system can simplify color matching, tablet identification, and manufacturing transfer. This is a modest opportunity but may reduce operational variability.

Pediatric or geriatric dosage forms

An orally disintegrating tablet, dispersible tablet, or extemporaneous suspension platform could create differentiation where a clinically justified population exists. Such products would require new formulation development, palatability work, stability studies, and FDA regulatory assessment.

How does enalapril/hydrochlorothiazide compare with other fixed-dose antihypertensives?

Enalapril/hydrochlorothiazide competes with ACE inhibitor/thiazide combinations and with newer fixed-dose products containing angiotensin receptor blockers, calcium-channel blockers, or other diuretics.

Combination	Commercial profile
Enalapril/HCTZ	Mature, low-cost, generic, established clinical use
Lisinopril/HCTZ	Strong generic competition and broad prescriber familiarity
Losartan/HCTZ	Large generic market and strong brand history
Irbesartan/HCTZ	Generic product with differentiated ARB positioning
Benazepril/HCTZ	Smaller market and lower commercial scale
ACE inhibitor/CCB combinations	Often positioned around alternative efficacy or tolerability profiles

Enalapril/hydrochlorothiazide can compete where prescribers prefer an ACE inhibitor and where cost is important. It is less attractive as a premium product because the active ingredients and dosage form are widely available.

What regulatory pathway applies to a new product?

A standard immediate-release generic would normally use the ANDA pathway and demonstrate pharmaceutical equivalence and bioequivalence to the reference product.[1,5]

Key development requirements include:

• Same active ingredients and strength
• Same dosage form and route
• Pharmaceutical equivalence
• Comparative dissolution
• In vivo bioequivalence where required
• Impurity and degradation-product control
• Stability data
• cGMP-compliant manufacturing
• Labeling consistent with the reference product

A reformulated product with a new dosage form, modified release, or new indication may require a 505(b)(2) application rather than an ANDA. That route can support differentiation but increases clinical, regulatory, and development costs.

What licensing and partnership opportunities exist?

Because the base product is generic, licensing value is concentrated in manufacturing and formulation assets.

Potential deal structures include:

• Regional commercialization rights for an approved ANDA
• Supply agreements for low-cost tablets
• Technology licenses for direct-compression or dry-granulation platforms
• Co-development of orally disintegrating or dispersible tablets
• Private-label supply to pharmacy or hospital groups
• Portfolio deals combining enalapril/hydrochlorothiazide with other cardiovascular products

The strongest counterparties are manufacturers with existing cardiovascular portfolios, established regulatory operations, and access to government or institutional tenders.

What revenue exposure should investors expect?

Revenue exposure is generally modest per product and depends on volume, supplier count, reimbursement, and tender pricing. The combination is unlikely to support premium pricing without a differentiated dosage form or protected manufacturing technology.

Revenue drivers include:

• Number of active markets
• Contract volume
• Formulary position
• Product availability
• Pack-size economics
• API sourcing
• Manufacturing yield
• Recall and shortage risk

A company evaluating entry should model a low-price, high-competition base case. Upside is more likely to come from portfolio scale and supply reliability than from price expansion.

What is the most attractive excipient strategy?

The most practical strategy is a low-moisture, direct-compression or dry-granulation formulation using a robust filler system, a controlled superdisintegrant level, limited lubricant exposure, and high-barrier packaging.

The formulation should prioritize:

1. Enalapril stability.
2. Uniform distribution of the low-dose active.
3. Rapid and reproducible dissolution.
4. Low manufacturing complexity.
5. Compatibility with multiple tablet strengths.
6. Easy scale-up and technology transfer.
7. Low-cost global sourcing.

A single platform capable of producing both 5 mg/12.5 mg and 10 mg/25 mg strengths can reduce validation, inventory, and regulatory complexity.

Key Takeaways

• Enalapril maleate/hydrochlorothiazide is a mature, genericized hypertension product with limited remaining exclusivity value.
• The main commercial opportunity is operational: low cost, reliable supply, strong stability, and consistent dissolution.
• Direct compression and dry granulation are the most commercially practical manufacturing approaches.
• Low-dose enalapril drives content-uniformity and segregation risk.
• Moisture control and high-barrier packaging are important for product stability.
• Conventional excipient substitutions are unlikely to create strong patent protection.
• Modified-release, orally disintegrating, dispersible, and stability-enhanced products offer greater differentiation but may require a 505(b)(2) strategy.
• Generic entry risk is high because the product has no biologic complexity and has long-standing market availability.
• Licensing value is concentrated in approved manufacturing capacity, differentiated formulation technology, and distribution access.
• A successful product should compete on total cost, availability, and portfolio leverage rather than premium pricing.

FAQs

Is enalapril maleate/hydrochlorothiazide still patent protected?

The historical compound and conventional fixed-dose product patents are expired. A current Orange Book review remains necessary for any specific reference product and strength.

Can a manufacturer use a new excipient and file an ANDA?

Yes, if the product remains pharmaceutically equivalent and meets FDA requirements for bioequivalence, dissolution, stability, quality, and labeling. A novel excipient or materially different dosage form can alter the regulatory pathway.

Which packaging is best for enalapril/hydrochlorothiazide tablets?

High-barrier blister packaging or a tightly closed high-barrier bottle is generally preferable where moisture sensitivity and long-term stability require enhanced protection.

Is an orally disintegrating enalapril/hydrochlorothiazide tablet commercially attractive?

It can be attractive for swallowing-impaired or adherence-sensitive patients, but the product would require substantial formulation, palatability, stability, and regulatory development. Its commercial value depends on whether the dosage form earns reimbursement or prescribing differentiation.

Does enalapril/hydrochlorothiazide face biosimilar competition?

No. Both active ingredients are small molecules. Competition comes from generic drugs approved through the ANDA pathway, not biosimilar applications.

References

1. U.S. Food and Drug Administration. (n.d.). Abbreviated new drug application (ANDA): Generics. https://www.fda.gov/drugs/types-applications/abbreviated-new-drug-application-anda
2. U.S. Food and Drug Administration. (n.d.). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/
3. U.S. Food and Drug Administration. (n.d.). Paragraph IV patent certifications. https://www.fda.gov/drugs/abbreviated-new-drug-application-anda/paragraph-iv-certifications
4. United States Patent and Trademark Office. (n.d.). Patent Center. https://patentcenter.uspto.gov/
5. U.S. Food and Drug Administration. (n.d.). Bioavailability and bioequivalence studies submitted in support of abbreviated new drug applications. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-D/part-320