Generic DILTIAZEM MALATE; ENALAPRIL MALEATE INN entry, drug patent expiration information and freedom to operate

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Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Biovail	TECZEM	diltiazem malate; enalapril maleate	TABLET, EXTENDED RELEASE;ORAL	020507-001	Oct 4, 1996		DISCN	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Exclusivity Expiration

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Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Biovail	TECZEM	diltiazem malate; enalapril maleate	TABLET, EXTENDED RELEASE;ORAL	020507-001	Oct 4, 1996	⤷ Start Trial	⤷ Start Trial
Biovail	TECZEM	diltiazem malate; enalapril maleate	TABLET, EXTENDED RELEASE;ORAL	020507-001	Oct 4, 1996	⤷ Start Trial	⤷ Start Trial
Biovail	TECZEM	diltiazem malate; enalapril maleate	TABLET, EXTENDED RELEASE;ORAL	020507-001	Oct 4, 1996	⤷ Start Trial	⤷ Start Trial
Biovail	TECZEM	diltiazem malate; enalapril maleate	TABLET, EXTENDED RELEASE;ORAL	020507-001	Oct 4, 1996	⤷ Start Trial	⤷ Start Trial
Biovail	TECZEM	diltiazem malate; enalapril maleate	TABLET, EXTENDED RELEASE;ORAL	020507-001	Oct 4, 1996	⤷ Start Trial	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>Patent No.	>Patent Expiration

Last updated: September 8, 2026

Diltiazem malate and enalapril maleate have sharply different commercial profiles. Enalapril maleate is an established, widely genericized ACE inhibitor with low unit pricing, fragmented supply, and limited branded revenue. Diltiazem malate does not appear to have a material U.S. commercial market under that exact salt designation. The commercially established diltiazem products in the United States use diltiazem hydrochloride, including immediate-release tablets, extended-release capsules, and injectable products.

Neither molecule has meaningful remaining U.S. regulatory exclusivity. Commercial value depends on manufacturing cost, supply reliability, dosage-form differentiation, institutional contracts, and geographic market access rather than originator patent protection.

Attribute	Diltiazem malate	Enalapril maleate
Therapeutic class	Calcium-channel blocker	ACE inhibitor
Primary uses	Hypertension, angina, atrial fibrillation rate control, supraventricular tachycardia	Hypertension, heart failure, left-ventricular dysfunction
Established U.S. active moiety	Diltiazem hydrochloride	Enalapril maleate
U.S. FDA approval under exact name	No material approval or commercial listing identified under “diltiazem malate”	Yes
Originator brand	Cardizem, Tiazac, Dilacor and related products	Vasotec
U.S. generic status	Diltiazem hydrochloride products are genericized	Enalapril maleate is genericized
Current patent leverage	No meaningful active-originator estate identified	No meaningful active-originator estate identified
Revenue outlook	Limited unless a differentiated salt or dosage form gains approval	Stable low-price generic demand with limited margin expansion

What is the current market status of diltiazem malate?

Diltiazem malate has no established U.S. branded market comparable with diltiazem hydrochloride. FDA-approved diltiazem products are generally identified by the hydrochloride salt, not the malate salt, across oral and injectable dosage forms listed in FDA databases and labeling records (FDA, n.d.-a; FDA, n.d.-b).

This distinction is commercially important. A different salt may require its own pharmaceutical development, chemistry, manufacturing and controls package, bioequivalence strategy, and regulatory filing. The existence of approval for diltiazem hydrochloride does not automatically provide approval for diltiazem malate.

Does diltiazem malate have a meaningful U.S. revenue base?

No public, salt-specific revenue base is identifiable for diltiazem malate in the United States. Public prescription datasets generally aggregate products by active ingredient, dosage form, manufacturer, and national drug code. They do not support a reliable standalone estimate for an unestablished salt without confirmed product listings.

The addressable commercial market is therefore better measured through diltiazem hydrochloride:

Immediate-release tablets are mature generic products.
Extended-release capsules and tablets support somewhat higher unit prices because of release-control technology.
Injectable diltiazem retains institutional demand for acute rate control and supraventricular tachycardia.
Generic competition limits average selling prices across all major presentations.
Shortages or manufacturer exits can temporarily improve pricing for injectable and extended-release products.

Any commercial plan based specifically on diltiazem malate would require evidence of an approved product, a defined jurisdiction, and a differentiated clinical or manufacturing profile. Without those elements, the salt is a development concept rather than an established revenue-producing asset.

What is the financial trajectory for diltiazem products?

The financial trajectory for diltiazem hydrochloride is mature and volume-driven. Originator revenue has largely migrated to generic manufacturers. The market has limited pricing power because multiple suppliers compete in common oral presentations.

A diltiazem product can still achieve commercial value through:

Extended-release delivery systems.
Low-cost, high-volume tablet production.
Injectable supply contracts.
Hospital and government tenders.
Reliable supply during competitor shortages.
Geographic markets with fewer registered suppliers.

The most attractive segment is not the conventional immediate-release tablet. It is the combination of technically difficult modified-release products and dependable injectable supply. These segments can produce better margins, although the opportunity remains vulnerable to price erosion and buyer concentration.

A diltiazem malate product would face an additional barrier: physicians, pharmacists, and regulators are familiar with diltiazem hydrochloride. A new salt would need to demonstrate equivalent exposure, stability, manufacturability, and practical prescribing value. A salt change without a clear benefit would have weak pricing power.

What is the current market status of enalapril maleate?

Enalapril maleate is an established generic ACE inhibitor marketed in tablets and oral solution products. The originator product, Vasotec, was developed by Merck and approved by FDA in 1985 for hypertension and heart failure-related indications (FDA, n.d.-c).

The product has passed through the full genericization cycle:

Originator launch and clinical adoption.
Multiple generic approvals.
Loss of branded pricing power.
Consolidation toward contract manufacturing, retail generics, and institutional supply.
Continued demand because hypertension and heart failure are chronic, high-prevalence conditions.

Enalapril remains clinically relevant despite competition from lisinopril, losartan, valsartan, ramipril, and other renin-angiotensin system agents. Its use is supported by long clinical experience, low cost, and availability in pediatric and liquid formulations in some markets.

When did enalapril maleate lose exclusivity?

Enalapril maleate lost practical market exclusivity decades ago. The first U.S. generic enalapril maleate products were approved in the early 2000s, and the active-ingredient market is now fully genericized. The original Vasotec patent estate no longer provides a meaningful barrier to routine generic entry.

The commercial implication is more important than the historical date. Enalapril maleate is now a procurement product rather than an originator-led franchise. Buyers typically prioritize:

Approved manufacturing sites.
Supply continuity.
Product quality.
Lowest sustainable price.
Packaging and dosage-form availability.
Regulatory compliance.

What is the Orange Book status of diltiazem malate and enalapril maleate?

The exact salt and dosage form determine Orange Book treatment. Enalapril maleate has long-standing approved generic listings, while diltiazem hydrochloride products are listed under diltiazem hydrochloride formulations. Diltiazem malate should not be treated as interchangeable with diltiazem hydrochloride merely because both contain the same active moiety.

The relevant U.S. regulatory positions are:

Question	Diltiazem malate	Enalapril maleate
Approved reference product under exact salt	No established U.S. reference product identified	Vasotec
Current originator exclusivity	None identified	None identified
Current generic pathway	Would likely require product-specific approval	Established ANDA pathway
Orange Book litigation exposure	No material listed-product exposure identified	Historical patent and generic-entry issues are no longer commercially material
Substitution assumptions	Cannot be assumed from diltiazem hydrochloride approval	Established for approved equivalent products, subject to state law and product labeling

FDA’s Orange Book identifies approved drug products and relevant patents or exclusivities. It does not convert one salt form into another for regulatory purposes (FDA, n.d.-d).

What patents protect diltiazem and enalapril products?

The principal composition-of-matter and early product patents for both active ingredients are expired or commercially exhausted in the United States.

Diltiazem patent landscape

The meaningful historical patent value in diltiazem involved:

The active pharmaceutical ingredient.
Controlled-release formulations.
Capsule or bead technologies.
Dosing schedules.
Specific therapeutic uses.

Any remaining patent risk would be formulation-specific rather than directed to diltiazem as a molecule. A modified-release product could still encounter patents covering release profiles, pellet composition, coating systems, capsule architecture, or manufacturing processes. The risk must be assessed against the specific product design and filing jurisdiction.

Enalapril patent landscape

Enalapril’s historical protection involved:

Enalapril and related ACE-inhibitor chemistry.
Enalapril maleate compositions.
Therapeutic use in hypertension and heart failure.
Formulation and dosing claims.

Those rights no longer prevent ordinary generic manufacture. Potential residual risk could arise from a newly developed liquid formulation, device, combination product, or manufacturing process, but such claims would not restore exclusivity to conventional enalapril maleate tablets.

Are there Paragraph IV challenges or patent litigation risks?

Neither product presents a current, high-value Paragraph IV battlefield comparable with a protected specialty drug.

For enalapril maleate, historical Paragraph IV activity would have related to generic entry against Vasotec patents. Because the relevant product is fully genericized, new challenges would have limited strategic importance unless directed at a newly patented formulation or combination.

For diltiazem, litigation risk is concentrated in modified-release products. Generic applicants can face patent assertions involving release-control systems even when the active ingredient itself is unprotected. The risk is higher for branded extended-release products than for conventional immediate-release tablets.

There is no identified current litigation pattern that materially changes the market outlook for either conventional product. Patent risk remains product-specific, not molecule-wide.

What generic entry risks exist for a new diltiazem malate product?

A new diltiazem malate product would face regulatory and commercial risks beyond ordinary generic competition.

Regulatory risk

A sponsor could not assume that a diltiazem hydrochloride reference product supports automatic approval of diltiazem malate. The sponsor would need to establish the appropriate regulatory pathway, pharmaceutical equivalence, bioavailability or bioequivalence, and product quality.

Clinical and substitution risk

Pharmacists and prescribers may not treat a new salt as automatically substitutable. A new product could require separate prescribing and formulary review, particularly for modified-release or injectable use.

Manufacturing risk

Salt formation can affect:

Solubility.
Hygroscopicity.
Crystal form.
Stability.
Dissolution.
Excipients and process controls.
Packaging requirements.

A theoretically lower-cost salt may not generate lower total cost if it requires specialized process validation or faces low production scale.

Commercial risk

The product would compete against inexpensive diltiazem hydrochloride products with established supply chains. Without improved stability, tolerability, dosing convenience, or a delivery advantage, a new salt would likely need to compete on price.

How does enalapril maleate compare with competing ACE inhibitors and ARBs?

Product	Market maturity	Pricing power	Main commercial advantage	Main risk
Enalapril maleate	Very mature generic	Low	Low cost, long clinical history, liquid availability in some markets	ACE-inhibitor cough, generic price erosion
Lisinopril	Very mature generic	Low	Broad use and simple tablet supply	Intense competition
Ramipril	Mature generic	Low to moderate	Strong cardiovascular positioning in some markets	Smaller volume than leading agents
Losartan	Very mature generic	Low	ARB class avoids ACE-inhibitor cough for many patients	Large generic field and price pressure
Valsartan	Mature generic	Low to moderate	Heart failure and hypertension demand	Historical supply and impurity scrutiny
Perindopril	Mature generic	Low to moderate	Strong use in selected countries	Geographic concentration

Enalapril’s commercial durability comes from chronic demand, not premium pricing. Its financial trajectory is likely to remain stable in volume and weak in price. Growth is more likely to come from emerging markets, pediatric formulations, combination products, or supply-constrained territories than from the U.S. branded market.

What licensing deals or partnerships affect these products?

No major current licensing transaction appears to create material value for conventional diltiazem malate or enalapril maleate. Historical originator licensing and commercialization arrangements have little effect on present-day generic economics.

Potential transaction value would be concentrated in:

Regional registration rights.
Approved manufacturing sites.
Hospital supply contracts.
Controlled-release technology.
Pediatric or oral-liquid platforms.
Combination products.
Rights in markets with limited generic penetration.

A licensing deal for a plain immediate-release tablet would generally have limited strategic value unless it includes regulatory approvals, high-volume tenders, or an established distribution network.

What is the geographic market outlook?

The United States is a low-growth, low-price market for both product families. Europe is also highly genericized, with national reimbursement systems placing pressure on prices. Emerging markets can offer stronger volume growth but have greater exposure to tender pricing, currency volatility, local registration requirements, and manufacturing competition.

Diltiazem products may retain stronger commercial value in markets where:

Rate-control therapy remains common.
Injectable supply is limited.
Extended-release products are underpenetrated.
Local manufacturers face quality or capacity constraints.

Enalapril maleate has broad geographic utility because it is inexpensive and familiar. It is likely to maintain longer demand duration than premium cardiovascular products, but its revenue per prescription should remain low.

What is the likely financial trajectory through the next five years?

Diltiazem malate

The base case is no meaningful standalone revenue in the United States unless an approved product emerges. An investment thesis would depend on regulatory validation and differentiation rather than on the existing diltiazem market alone.

Diltiazem hydrochloride comparators

Revenue should remain mature and price-sensitive. Modified-release and injectable presentations have the best margin prospects. Supply disruptions can create temporary revenue spikes but do not establish durable pricing power.

Enalapril maleate

Revenue should remain stable to modestly declining in developed markets. Volume persistence will offset some price erosion. Higher growth is more plausible in emerging markets and in specialized presentations such as oral solutions, pediatric dosage forms, and fixed-dose combinations.

How strong are the patent estates?

Product	Composition patent strength	Formulation patent strength	Regulatory exclusivity	Overall current estate
Diltiazem malate	None identified for a commercial U.S. product	Potentially relevant only after new formulation development	None identified	Weak or unestablished
Diltiazem hydrochloride immediate release	Expired	Limited	None	Weak
Diltiazem extended release	Expired	Product-specific patents may exist	None	Moderate only for specific designs
Enalapril maleate tablet	Expired	Limited	None	Weak
Enalapril maleate liquid or combination	Expired active ingredient rights	Potentially relevant for new products	Product-specific only	Weak to moderate, depending on claims

Key Takeaways

Enalapril maleate is a mature, fully genericized cardiovascular product with durable volume but minimal pricing power.
Diltiazem malate has no established U.S. commercial position under that exact salt designation.
The established diltiazem market uses diltiazem hydrochloride, particularly in immediate-release, extended-release, and injectable forms.
Neither conventional product has meaningful remaining U.S. composition-of-matter exclusivity.
Financial upside is concentrated in modified-release technology, injectable supply, pediatric formulations, regional tenders, and manufacturing reliability.
Paragraph IV and litigation exposure is low for conventional products and higher for patented release-control systems.
A new diltiazem malate product would need regulatory approval and a clear clinical, manufacturing, or economic advantage over diltiazem hydrochloride.
Enalapril maleate’s five-year outlook is stable in volume and pressured in price, with the strongest opportunities outside commoditized U.S. tablet sales.

FAQs

Is diltiazem malate the same as diltiazem hydrochloride?

No. They contain the same active moiety but are different salt forms. Approval, bioequivalence, pharmaceutical equivalence, and substitution must be assessed separately.

Is enalapril maleate still profitable for generic manufacturers?

It can be profitable at scale, but conventional tablets generally have low margins. Profitability depends on manufacturing cost, volume, supply reliability, and market concentration.

Can a company file an ANDA for diltiazem malate using a diltiazem hydrochloride reference product?

Not automatically. The proposed salt and product must satisfy FDA requirements for the selected regulatory pathway, including pharmaceutical characterization and bioavailability or bioequivalence where applicable.

Which diltiazem formulation has the strongest commercial profile?

Extended-release and injectable products generally offer more defensible economics than immediate-release tablets because manufacturing, supply, and formulation requirements are more demanding.

Does enalapril maleate face biosimilar competition?

No. Enalapril maleate is a chemically synthesized small molecule, not a biologic. It faces conventional generic competition rather than biosimilar competition.

References

U.S. Food and Drug Administration. (n.d.-a). Drugs@FDA: FDA-approved drugs database. https://www.accessdata.fda.gov/scripts/cder/daf/
U.S. Food and Drug Administration. (n.d.-b). DailyMed: Diltiazem hydrochloride prescribing information. National Library of Medicine. https://dailymed.nlm.nih.gov/
U.S. Food and Drug Administration. (n.d.-c). Vasotec (enalapril maleate) prescribing information. Drugs@FDA. https://www.accessdata.fda.gov/scripts/cder/daf/
U.S. Food and Drug Administration. (n.d.-d). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book
U.S. Food and Drug Administration. (n.d.-e). Electronic Orange Book patent and exclusivity information. https://www.accessdata.fda.gov/scripts/ob/default.cfm
U.S. Food and Drug Administration. (n.d.-f). Generic drug facts. https://www.fda.gov/drugs/generic-drugs/generic-drug-facts

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Tradenames:	1
Applicants:	1
NDAs:	1
DailyMed Link:	diltiazem malate; enalapril maleate at DailyMed

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