List of Excipients in Branded Drug QUINAPRIL HYDROCHLORIDE/HYDROCHLOROTHIAZIDE

Generic Drugs Containing QUINAPRIL HYDROCHLORIDE/HYDROCHLOROTHIAZIDE

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Company	Ingredient	NDC	Excipient
Lake Erie Medical DBA Quality Care Products LLC	quinapril hydrochloride/hydrochlorothiazide	35356-998	CROSPOVIDONE
Lake Erie Medical DBA Quality Care Products LLC	quinapril hydrochloride/hydrochlorothiazide	35356-998	FERRIC OXIDE RED
Lake Erie Medical DBA Quality Care Products LLC	quinapril hydrochloride/hydrochlorothiazide	35356-998	FERRIC OXIDE YELLOW
Lake Erie Medical DBA Quality Care Products LLC	quinapril hydrochloride/hydrochlorothiazide	35356-998	HYDROXYPROPYL CELLULOSE
Lake Erie Medical DBA Quality Care Products LLC	quinapril hydrochloride/hydrochlorothiazide	35356-998	HYPROMELLOSE 2910
Lake Erie Medical DBA Quality Care Products LLC	quinapril hydrochloride/hydrochlorothiazide	35356-998	LACTOSE MONOHYDRATE
Lake Erie Medical DBA Quality Care Products LLC	quinapril hydrochloride/hydrochlorothiazide	35356-998	MAGNESIUM CARBONATE
>Company	>Ingredient	>NDC	>Excipient

What are the Most Frequently-Used Excipients in QUINAPRIL HYDROCHLORIDE/HYDROCHLOROTHIAZIDE?

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# Of NDCs	Excipient
2	CROSPOVIDONE
2	FERRIC OXIDE RED
2	FERRIC OXIDE YELLOW
2	HYDROXYPROPYL CELLULOSE
2	HYPROMELLOSE 2910
2	LACTOSE MONOHYDRATE
2	MAGNESIUM CARBONATE
># Of NDCs	>Excipient

Quinapril Hydrochloride/Hydrochlorothiazide Excipient Strategy and Commercial Opportunities

Last updated: November 7, 2026

Quinapril hydrochloride/hydrochlorothiazide is a mature fixed-dose antihypertensive combination with no meaningful composition-of-matter exclusivity remaining. Its commercial opportunity is not an innovative-drug patent play. It is a formulation, supply-chain, quality, and market-reentry opportunity centered on generic tablets, reliable API sourcing, impurity control, and differentiated patient packaging.

The principal product, Accuretic, combined the ACE inhibitor quinapril hydrochloride with the thiazide diuretic hydrochlorothiazide. The product was marketed in 10 mg/12.5 mg, 20 mg/12.5 mg, and 20 mg/25 mg strengths. Pfizer discontinued Accuretic in the United States, while generic quinapril hydrochloride/hydrochlorothiazide products have faced commercial and regulatory disruption, including recalls related to nitrosamine impurities. FDA approval and market access therefore depend more on manufacturing controls and product reliability than on patent barriers.[1][2]

What is the commercial status of quinapril hydrochloride/hydrochlorothiazide?

Quinapril hydrochloride/hydrochlorothiazide is an oral, immediate-release fixed-dose combination indicated for hypertension. Quinapril inhibits angiotensin-converting enzyme, while hydrochlorothiazide promotes sodium and water excretion.

Product characteristic	Details
Active ingredients	Quinapril hydrochloride and hydrochlorothiazide
Original brand	Accuretic
Original sponsor	Pfizer
Dosage form	Immediate-release tablet
Historical strengths	10 mg/12.5 mg, 20 mg/12.5 mg, 20 mg/25 mg
Regulatory pathway	NDA for the brand; ANDA pathway for generics
Therapeutic category	Antihypertensive fixed-dose combination
Biosimilar relevance	None; this is a small-molecule drug
Current patent leverage	No meaningful remaining composition-of-matter exclusivity
Main commercial barriers	API supply, nitrosamine control, regulatory maintenance, low pricing

The product has limited growth potential in developed markets because physicians can prescribe separate ACE inhibitor and diuretic products, while newer antihypertensive combinations compete for formulary preference. The strongest opportunity is a dependable generic product in markets where fixed-dose combinations improve adherence and pharmacy substitution is common.

What patents protect quinapril hydrochloride/hydrochlorothiazide?

No meaningful active patent barrier is expected to prevent generic development of quinapril hydrochloride/hydrochlorothiazide in the United States. The original quinapril and Accuretic patent rights expired after the product’s initial development period. Hydrochlorothiazide is also a long-established generic active ingredient.

The FDA Orange Book is the controlling source for listed patents and regulatory exclusivity associated with approved drug products. Quinapril/hydrochlorothiazide does not present the type of active patent estate associated with newer combination products, long-acting injectables, inhaled systems, or biologics.[1]

Are formulation patents still relevant?

Formulation patents may still affect a specific generic product if an applicant seeks to protect a novel excipient system, manufacturing process, impurity-control method, or dosage form. Those rights would not restore exclusivity to the underlying quinapril/hydrochlorothiazide combination.

A new formulation patent would need a defensible inventive step over:

Conventional immediate-release tablets
Known quinapril salt forms
Standard hydrochlorothiazide tablet formulations
Common disintegrants, binders, lubricants, and film coatings
Established wet-granulation and direct-compression methods

A patent directed only to replacing one conventional excipient with another would face substantial obviousness risk unless the formulation produces an unexpected result, such as improved stability, reduced impurity formation, or a demonstrated dissolution advantage.

When does quinapril hydrochloride/hydrochlorothiazide lose exclusivity?

Quinapril hydrochloride/hydrochlorothiazide lost practical market exclusivity years ago. The relevant commercial timeline is:

Milestone	Timing or status
Quinapril and hydrochlorothiazide development	Historical
Accuretic approval	Historical NDA approval
Original product and formulation exclusivity	Expired
Generic availability	Established historically
Accuretic commercial discontinuation	Pfizer discontinued U.S. marketing
Recent generic disruption	Associated with product recalls and supply limitations
Current opportunity	Generic relaunch, supply restoration, and formulation optimization

The main commercial question is therefore not when the molecule loses exclusivity. It is whether a manufacturer can obtain or maintain approval and supply the product at a sustainable cost.

What is the FDA regulatory status of quinapril hydrochloride/hydrochlorothiazide?

Quinapril/hydrochlorothiazide remains a small-molecule product eligible for the abbreviated new drug application pathway when the generic matches the reference product in active ingredients, strength, dosage form, route, and applicable performance requirements.

A generic applicant generally must establish:

Pharmaceutical equivalence
Bioequivalence
Adequate stability
Conformance with current good manufacturing practice
Acceptable impurity levels
Adequate controls for nitrosamine risk
Labeling consistent with the reference product, subject to FDA requirements

A 505(b)(2) strategy could be relevant for a materially different formulation, dosage form, or delivery system. It would carry higher development and regulatory costs and would need a clear clinical or commercial rationale. For a conventional immediate-release tablet, ANDA development is generally the more economical route.

What FDA quality issue affects quinapril products?

Quinapril products have been subject to recalls and supply disruption associated with N-nitroso-quinapril, a nitrosamine impurity. FDA has identified nitrosamine contamination as a quality risk across several drug classes, including some products containing ACE inhibitors.[2][3]

This issue changes the excipient and manufacturing strategy. A viable product must control not only the active pharmaceutical ingredients but also:

Nitrite contamination in excipients
Amine-containing excipient interactions
Water activity and residual moisture
Thermal exposure
Hold times during granulation and compression
Packaging-related degradation
Supplier-to-supplier variability
Long-term formation of nitrosamine impurities

Which excipients are suitable for quinapril hydrochloride/hydrochlorothiazide tablets?

The formulation objective is a stable, rapidly disintegrating immediate-release tablet with low impurity formation and robust manufacturability. A conventional formulation may use a diluent, binder, disintegrant, lubricant, glidant, and film coat.

Excipient function	Candidate excipient classes	Strategic considerations
Diluent	Microcrystalline cellulose, lactose, mannitol, dibasic calcium phosphate	Select for compatibility, compressibility, and moisture control
Binder	Povidone, copovidone, pregelatinized starch, hydroxypropyl cellulose	Avoid excessive granule density and delayed dissolution
Disintegrant	Croscarmellose sodium, crospovidone, sodium starch glycolate	Optimize rapid breakup without increasing friability
Lubricant	Magnesium stearate, sodium stearyl fumarate	Control mixing time and lubricant overcoating
Glidant	Colloidal silicon dioxide	Improve flow while limiting segregation
Film coating	Hypromellose, polyethylene glycol, titanium dioxide, iron oxides	Use a low-moisture coating process
Moisture control	Low-water-content excipient grades, protective packaging	Relevant to stability and impurity risk

How should the excipient system address nitrosamine risk?

The most important principle is risk assessment by material lot and process stage, not reliance on a generic excipient list. Excipients may contain trace nitrite or nitrate impurities. Some excipients can also influence local pH, moisture, or chemical microenvironments that affect impurity formation.

A risk-based development program should include:

Screening of excipients and suppliers for nitrite and nitrate content.
Qualification of multiple suppliers with comparable impurity profiles.
Assessment of the active ingredients and excipients as a complete formulation.
Evaluation of wet granulation versus direct compression.
Stress testing under heat and humidity.
Measurement of N-nitroso-quinapril during stability studies.
Packaging studies using moisture-barrier systems.
Defined incoming-material specifications and change-control procedures.

A manufacturer may gain a practical commercial advantage by using a low-nitrite excipient platform and documenting the effect through long-term stability data. That advantage is regulatory and supply-chain based rather than necessarily patent-based.

What formulation strategy offers the strongest commercial opportunity?

The strongest near-term strategy is a conventional immediate-release tablet with a tightly controlled excipient and impurity profile. A company should avoid unnecessary formulation complexity because the market has limited willingness to pay for premium technology.

Strategy 1: Low-risk generic relaunch

This approach reproduces the reference product’s essential characteristics with common excipients and standard manufacturing equipment.

Advantages include:

Lower development cost
Familiar regulatory pathway
Broad contract manufacturing availability
Easier scale-up
Straightforward pharmacy substitution

The weakness is price competition. Several approved generic manufacturers may compete for a relatively small market.

Strategy 2: Nitrosamine-controlled formulation

This formulation uses excipient grades and process conditions selected to minimize N-nitroso-quinapril formation.

Commercial value may include:

Improved regulatory resilience
Lower recall risk
More reliable shelf life
Better supply continuity
Potential contract supply opportunities

The manufacturer must support the strategy with analytical data. A marketing claim without demonstrated impurity control has limited value.

Strategy 3: Bilayer or multiparticulate dosage form

A bilayer tablet or multiparticulate capsule could separate quinapril hydrochloride and hydrochlorothiazide physically. This may help address compatibility, dissolution, or stability concerns.

The approach could support a formulation patent if it produces a measurable technical benefit. Its disadvantages are higher equipment costs, more complex process validation, and greater risk that FDA will require additional development work.

Strategy 4: Modified-release product

A modified-release version could theoretically differentiate dosing convenience. It would not be a simple generic substitution and could require a 505(b)(2) application, clinical bridging, or additional pharmacokinetic work.

The commercial case is weak unless the product demonstrates a clear benefit in blood-pressure control, adherence, tolerability, or dosing frequency. Generic immediate-release tablets and separate once-daily antihypertensives already provide inexpensive alternatives.

How strong is the patent estate for quinapril hydrochloride/hydrochlorothiazide?

The patent estate is weak for a conventional product and potentially moderate only for a genuinely differentiated formulation.

Patent category	Expected strength
Quinapril composition of matter	Expired
Hydrochlorothiazide composition of matter	Expired
Original fixed-dose combination	Expired
Conventional immediate-release tablet	Weak
Low-nitrite excipient selection	Potentially patentable, but fact-dependent
Novel bilayer or multiparticulate system	Moderate if technical data support it
Modified-release dosage form	Potentially stronger, with higher regulatory cost
Manufacturing process	Potentially useful for trade-secret protection
Packaging and moisture-control system	Usually limited patent scope
Method-of-use claims	Limited value if based on established hypertension use

The best defensible intellectual-property strategy may combine a narrow formulation patent with trade secrets covering excipient qualification, process controls, impurity testing, and scale-up parameters.

Are there Paragraph IV challenges for quinapril hydrochloride/hydrochlorothiazide?

Paragraph IV litigation is unlikely to be a major commercial issue because the original brand patents have expired and the product has already supported generic competition. Paragraph IV certifications are most relevant when an applicant challenges an unexpired Orange Book-listed patent. That framework has limited relevance to a legacy quinapril/hydrochlorothiazide product without meaningful active listed patent protection.[1][4]

A new manufacturer could face ordinary ANDA litigation only if another company obtains and lists a qualifying patent covering a newly approved formulation or method. Such a patent would need to meet statutory listing requirements and would not automatically block approval of a conventional product outside its claim scope.

What generic entry risks exist?

Generic entry risk is high because the active ingredients are old, the dosage form is conventional, and the product has no strong composition-of-matter barrier. The principal risks to a new entrant are operational rather than legal.

Risk	Business effect	Mitigation
Low market price	Limits return on formulation investment	Use efficient manufacturing and targeted markets
API availability	Can interrupt supply	Qualify multiple suppliers
Nitrosamine formation	Recall or regulatory action	Control excipient and process risk
Small market size	Reduces launch scale	Sell through institutional and international channels
Substitution by separate drugs	Reduces demand	Emphasize adherence and fixed-dose convenience
Competitor undercutting	Compresses margin	Secure durable supply contracts
Product discontinuation by suppliers	Creates customer uncertainty	Maintain inventory and dual-source materials

Which companies are challenging or competing with Accuretic?

The competitive field is composed primarily of generic manufacturers and suppliers of separate components. Potential competition includes:

Generic quinapril/hydrochlorothiazide tablet manufacturers
Suppliers of quinapril hydrochloride tablets
Suppliers of hydrochlorothiazide tablets
Manufacturers of other ACE inhibitor/thiazide combinations
Manufacturers of angiotensin receptor blocker/thiazide combinations
Fixed-dose combination products containing lisinopril, enalapril, losartan, valsartan, or similar agents

The relevant commercial comparator is not only another quinapril/hydrochlorothiazide product. It is also a low-cost prescription for separate quinapril and hydrochlorothiazide tablets, or substitution with a newer combination that has greater formulary support.

How does quinapril/hydrochlorothiazide compare with competing combinations?

Combination	Commercial position	Formulation opportunity
Quinapril/hydrochlorothiazide	Mature, disrupted, low-cost opportunity	Nitrosamine control and supply reliability
Lisinopril/hydrochlorothiazide	Broad generic familiarity	Limited differentiation
Enalapril/hydrochlorothiazide	Mature generic combination	Competes on price and availability
Losartan/hydrochlorothiazide	Strong generic and branded history	Larger competitive base
Valsartan/hydrochlorothiazide	Established combination	Greater market recognition
Separate ACE inhibitor plus hydrochlorothiazide	Flexible prescribing	Lower fixed-dose adherence benefit

Quinapril/hydrochlorothiazide may appeal to patients already controlled on quinapril or to payers seeking a low-cost fixed-dose option. It is less attractive as a growth product where prescribers favor newer renin-angiotensin-system agents.

What licensing deals and manufacturing opportunities exist?

Publicly visible licensing value is limited because the foundational product rights are expired. Commercial opportunities are more likely to arise through:

Contract manufacturing agreements
ANDA acquisition or licensing
Regional commercialization rights
API supply agreements
Finished-dose supply to hospitals and wholesalers
Private-label pharmacy distribution
Technology transfer for nitrosamine-controlled manufacturing
Authorized-generic arrangements

A licensee should value an opportunity based on approved status, supply reliability, active customer contracts, manufacturing cost, and recall history. Patent ownership alone is unlikely to justify a significant transaction premium.

What geographic markets offer the best opportunity?

The United States offers a regulatory pathway and established substitution infrastructure but also has severe price pressure and a history of supply disruption. European markets may support fixed-dose combinations through national reimbursement systems, although country-specific approvals and pricing controls apply. Emerging markets may offer stronger demand for low-cost combination therapy but impose additional requirements for local registration, pharmacovigilance, and distribution.

A regional strategy should prioritize:

Markets with a registered reference product or recognized abridged pathway.
Countries with established demand for ACE inhibitor/thiazide combinations.
Regions where fixed-dose adherence has reimbursement value.
Markets with manageable nitrosamine testing and release requirements.
Territories where local manufacturing or packaging reduces landed cost.

What revenue exposure is associated with the product?

Revenue exposure is difficult to quantify without a defined market, manufacturer, and sales period. The product should be classified as a low-revenue, high-availability opportunity rather than a high-growth branded asset.

Potential revenue sources include:

U.S. generic prescriptions
Institutional purchasing
International tender contracts
Private-label supply
Shortage-driven procurement
Separate-market supply of quinapril and hydrochlorothiazide APIs
Formulation technology licensing

The highest-margin opportunity may occur during supply shortages, but shortage-dependent pricing is unstable and can create regulatory and reputational risk. A sustainable business case requires low manufacturing cost, multiple customers, and validated impurity control.

Key Takeaways

Quinapril hydrochloride/hydrochlorothiazide has no meaningful remaining composition-of-matter exclusivity.
Accuretic is a legacy brand, and Pfizer discontinued U.S. marketing.
Generic opportunity exists, but competition and price pressure are substantial.
Nitrosamine control is the central formulation and manufacturing issue.
Low-nitrite excipient sourcing, moisture control, packaging, and stability testing should guide development.
A conventional immediate-release ANDA is more commercially credible than a complex reformulation.
A differentiated formulation may support narrow patent claims only if it produces measurable stability, impurity, or dissolution benefits.
Biosimilar risk is irrelevant because both active ingredients are small molecules.
The strongest commercial channels are generic relaunch, institutional supply, private-label manufacturing, and regional licensing.
The product’s value is operational and supply-chain based, not driven by residual brand patent rights.

FAQs

Does quinapril hydrochloride/hydrochlorothiazide have biosimilar competition?

No. Biosimilars apply to biological products. Quinapril hydrochloride/hydrochlorothiazide is a small-molecule combination marketed through generic-drug pathways.

Can a new excipient combination receive patent protection?

Yes, but a patent would require more than selecting standard excipients. The applicant would need a novel and non-obvious formulation with evidence of a technical benefit, such as reduced nitrosamine formation or improved stability.

Is Accuretic still a strong commercial brand?

No. Accuretic is a legacy product with expired exclusivity and discontinued U.S. marketing. Its remaining value is as a reference product for generic development and as a recognized fixed-dose combination.

Would a bilayer quinapril/hydrochlorothiazide tablet improve marketability?

It could improve product differentiation if physical separation improves stability or dissolution. The higher manufacturing and regulatory burden makes the approach unattractive without strong analytical and commercial evidence.

What is the most valuable excipient strategy for this product?

A low-moisture, low-nitrite immediate-release tablet with qualified suppliers, controlled processing, protective packaging, and validated N-nitroso-quinapril stability performance offers the strongest balance of regulatory risk reduction and commercial feasibility.

References

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/
U.S. Food and Drug Administration. (2023). Nitrosamine impurity risk in medications. https://www.fda.gov/drugs/drug-safety-and-availability/information-about-nitrosamine-impurities
U.S. Food and Drug Administration. (n.d.). Control of nitrosamine impurities in human drugs. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/control-nitrosamine-impurities-human-drugs
U.S. Food and Drug Administration. (n.d.). Abbreviated new drug application approvals and patent certifications. https://www.fda.gov/drugs/abbreviated-new-drug-application-anda/anda-submissions-and-approvals

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