List of Excipients in Branded Drug CARDIZEM LA

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Bausch Health US LLC	CARDIZEM LA	diltiazem hydrochloride	0187-2045	CARNAUBA WAX
Bausch Health US LLC	CARDIZEM LA	diltiazem hydrochloride	0187-2045	CELLULOSE, MICROCRYSTALLINE
Bausch Health US LLC	CARDIZEM LA	diltiazem hydrochloride	0187-2045	CROSCARMELLOSE SODIUM

Cardizem LA Excipient Strategy and Commercial Opportunities

Last updated: August 9, 2026

Cardizem LA is an extended-release oral formulation of diltiazem hydrochloride. Its commercial value is tied less to active-ingredient exclusivity than to controlled-release performance, tablet manufacturability, dose flexibility, and patient-administration advantages. The strongest excipient opportunities are in release-mechanism replication, lactose and colorant differentiation, high-dose tablet design, and specialized formulations that improve adherence without changing the approved therapeutic profile.

What is Cardizem LA and how does its formulation work?

Cardizem LA contains diltiazem hydrochloride in once-daily extended-release tablets. It is approved for the treatment of hypertension and chronic stable angina. The product is available in multiple strengths, including 120 mg, 180 mg, 240 mg, 300 mg, 360 mg, and 420 mg, depending on the marketed presentation and labeling version.[1]

The tablets must be swallowed whole. They should not be crushed, chewed, or divided because physical disruption can alter drug release and undermine the intended once-daily pharmacokinetic profile.[1]

Cardizem LA formulation architecture

The formulation uses a matrix or polymer-controlled release approach rather than a simple immediate-release tablet. Public labeling identifies excipients associated with tablet structure, lubrication, coating, and release control, including:

Excipient category	Representative excipients identified in product labeling	Primary function
Release-control polymer	Hypromellose	Hydration, gel formation, diffusion control
Diluent	Lactose monohydrate, microcrystalline cellulose	Tablet mass, compressibility
Binder	Povidone	Granule and tablet strength
Lubricant	Magnesium stearate	Ejection from tooling
Glidant	Colloidal silicon dioxide, where used	Powder flow
Surfactant or wetting aid	Sodium lauryl sulfate, where used	Wetting and processing
Coating materials	Polyethylene glycol, talc, titanium dioxide	Film formation, appearance, protection
Colorants	Strength-specific pigments or dyes	Product identification

The commercial challenge is to reproduce the drug-release curve rather than merely match the ingredient list. Small changes in hypromellose grade, particle size, viscosity, compression force, tablet porosity, coating weight, or lubricant concentration can change dissolution performance.

What excipients are protected by Cardizem LA?

Cardizem LA does not create broad exclusivity over conventional excipients such as hypromellose, lactose, microcrystalline cellulose, povidone, or magnesium stearate. These materials are widely used in generic extended-release products.

The potentially protectable elements are more specific:

1. The quantitative composition of the tablet.
2. The polymer grade and viscosity range.
3. The spatial distribution of diltiazem and release-controlling polymer.
4. The granulation and compression process.
5. The dissolution profile across multiple pH conditions.
6. The relationship between tablet dimensions and dose strength.
7. Coating structure and moisture-control parameters.
8. Manufacturing controls that prevent dose dumping or strength-to-strength variability.

An excipient patent can be commercially valuable only if it claims a meaningful formulation distinction and survives validity and infringement challenges. A broad claim covering a conventional hydrophilic matrix with hypromellose and diltiazem would face substantial prior-art exposure because hydrophilic matrix tablets are well established.

How strong is the patent estate for Cardizem LA?

Cardizem LA's principal commercial protection is not the original diltiazem molecule. Diltiazem was discovered decades ago, and basic compound protection has expired. Any remaining protection must be evaluated through current FDA Orange Book listings, issued formulation patents, manufacturing patents, and non-patent regulatory exclusivity.[2]

Patent and exclusivity profile

Protection category	Cardizem LA position
Active pharmaceutical ingredient	Old molecule; basic compound exclusivity expired
New chemical entity exclusivity	Expired
Original extended-release formulation rights	Historical protection; current enforceability depends on specific patent claims
Orange Book-listed patents	Must be verified against the current NDA entry
Pediatric exclusivity	No principal commercial relevance identified
Orphan exclusivity	Not applicable
Biosimilar exclusivity	Not applicable
Generic substitution risk	High where approved ANDA products are available
Manufacturing know-how	Potentially relevant, especially for dissolution and scale-up

The business risk is that formulation know-how can remain commercially important even when no enforceable patent blocks a generic. A generic manufacturer may design around the reference product's excipient composition while matching its in vitro and in vivo performance.

When does Cardizem LA lose exclusivity?

Cardizem LA has already passed the principal statutory exclusivity periods associated with its original approval. The relevant commercial question is not the original expiration date but whether any current patents remain listed for the specific NDA and whether approved generic extended-release diltiazem products can substitute for the branded product.

The FDA Orange Book identifies patents and regulatory exclusivities associated with approved drug products. A current diligence review should distinguish:

• Orange Book-listed patents for the Cardizem LA NDA.
• Patents owned by the sponsor but not listed in the Orange Book.
• Expired patents.
• Unexpired patents that do not cover the marketed strength or dosage form.
• Method-of-use patents that may be carved out by an ANDA applicant.
• Formulation or manufacturing patents that may support litigation but not necessarily block all generic entry.[2]

Where no enforceable listed patent remains, a generic applicant can generally pursue an abbreviated new drug application using a paragraph III certification or paragraph IV certification, depending on the Orange Book record and patent status.

What Paragraph IV challenges affect Cardizem LA?

A Paragraph IV certification states that a listed patent is invalid, unenforceable, or will not be infringed by the proposed generic product.[3] For Cardizem LA, the most likely Paragraph IV targets would be:

• Extended-release tablet composition claims.
• Polymer-matrix claims.
• Dissolution-profile claims.
• Dose-strength or tablet architecture claims.
• Manufacturing-process claims listed against the relevant NDA.

A Paragraph IV case does not automatically establish a launch date. The outcome depends on the patent listing, timing of the notice letter, litigation within the 45-day window, possible 30-month stay, court rulings, settlement terms, and whether the generic product remains technically viable after patent amendments or claim construction.[3]

Generic launch scenarios

Scenario	Commercial consequence
No unexpired Orange Book patent	Generic entry can occur upon ANDA approval, subject to FDA approval timing
Paragraph III certification	Entry generally follows the patent expiration date
Paragraph IV with no timely litigation	Approval may proceed without a statutory 30-month stay
Paragraph IV with litigation	Approval may be delayed by the statutory stay or court order
Settlement with licensed entry	Entry occurs on the negotiated date and terms
Formulation patent survives	Non-infringing alternative formulation may still enter
Generic fails bioequivalence	Patent freedom does not produce commercial entry

The most important technical barrier is often FDA approval rather than patent litigation. A formulation that uses a different polymer or excipient ratio must still demonstrate acceptable bioequivalence and extended-release performance.

What formulation patents could protect a Cardizem LA alternative?

A new diltiazem extended-release product could pursue several claim strategies.

Polymer-matrix formulations

A polymer matrix based on hypromellose, polyethylene oxide, carbomer, or a polymer blend can control drug diffusion and erosion. Stronger claims would require measurable limitations, such as:

• Polymer viscosity range.
• Polymer concentration.
• Tablet porosity.
• Specific dissolution windows.
• Resistance to alcohol-induced dose dumping.
• Release performance across pH 1.2, pH 4.5, and pH 6.8 media.

A generic use of hypromellose alone is unlikely to generate strong differentiation. A defined polymer blend with a reproducible dissolution advantage offers a better basis for patenting.

Multiparticulate or coated-pellet systems

Diltiazem can be formulated as coated pellets, granules, mini-tablets, or capsules. These systems may provide:

• More consistent gastrointestinal distribution.
• Lower sensitivity to tablet fracture.
• Potential sprinkle administration.
• Better control over dose escalation.
• Separate populations of immediate-release and extended-release particles.

The regulatory burden is higher because coating uniformity, dose proportionality, food effect, and alcohol interaction must be characterized.

Abuse-deterrent or alcohol-resistant systems

Diltiazem is not generally treated as a controlled substance, so abuse deterrence is not a primary commercial requirement. Alcohol-resistant release can still have value because rapid ethanol exposure can destabilize some extended-release systems. A formulation patent that demonstrates resistance to dose dumping may improve technical differentiation, but the clinical and commercial value must justify added manufacturing cost.

Excipient-reduced and patient-specific formulations

Potential differentiation includes:

• Lactose-free tablets.
• Low-sodium formulations.
• Reduced-colorant products.
• Products without sodium lauryl sulfate.
• Gluten-free products supported by supplier controls.
• Smaller tablets at equivalent strength.
• High-strength tablets with improved swallowability.
• Sprinkle capsules or granules for patients with dysphagia.

These changes are commercially useful when they solve a documented patient or procurement problem. They do not automatically create patentable subject matter.

What excipient substitutions create the greatest regulatory risk?

The highest-risk substitutions are those that affect release, absorption, or tablet mechanical integrity.

Change	Risk level	Main concern
Hypromellose grade or viscosity change	High	Altered release rate and gel strength
Polymer concentration change	High	Failure of dissolution or pharmacokinetic matching
Lactose to microcrystalline cellulose substitution	Moderate to high	Different porosity, compressibility, and water uptake
Magnesium stearate level change	Moderate	Hydrophobicity and slower wetting
Colorant replacement	Low to moderate	Product identification and coating behavior
Film-coating weight change	Moderate	Moisture ingress and release impact
Povidone grade change	Moderate	Granule strength and drug distribution
Particle-size change	Moderate to high	Blend uniformity and dissolution
New surfactant	High	Wetting, permeability, tolerability, and release
Tablet compression-force change	High	Hardness, porosity, and release profile

For an ANDA, the applicant generally seeks pharmaceutical equivalence and bioequivalence to the reference listed drug. A formulation that materially changes excipients may require additional justification, comparative dissolution, food-effect evaluation, or other studies under FDA guidance.[4]

What commercial opportunities exist for Cardizem LA excipients?

1. Generic extended-release substitution

The largest opportunity is a lower-cost generic that matches Cardizem LA's release profile with a simpler or less expensive excipient system. Manufacturing savings may come from:

• Direct compression.
• Fewer granulation steps.
• Lower-cost polymer grades.
• Reduced coating complexity.
• Common excipient platforms shared across multiple strengths.

The key constraint is that cost reduction cannot compromise dissolution similarity or strength proportionality.

2. Lactose-free and excipient-sensitive products

A lactose-free version could target patients with lactose intolerance or institutions that standardize excipient restrictions. The opportunity is narrower than the generic market but may support premium pricing in specialty pharmacies, hospital formularies, and direct-to-patient channels.

3. Dysphagia-oriented delivery

Older patients with hypertension, angina, or atrial tachyarrhythmias may have difficulty swallowing large tablets. A multiparticulate capsule, sprinkle formulation, or smaller high-load tablet could improve adherence. The formulation must preserve extended release when administered with soft food or through an enteral tube.

This opportunity requires careful evaluation of:

• Crushing and chewing risk.
• Food administration.
• Tube compatibility.
• Dose recovery.
• Granule retention.
• Administration instructions.
• Stability after opening.

4. Strength consolidation

A robust 360 mg or 420 mg tablet can reduce pill burden for patients requiring high daily doses. High-strength tablets create technical challenges because diltiazem loading, tablet size, and polymer content must remain compatible with acceptable swallowability.

A commercial platform could use one release technology across the full strength range, reducing validation and manufacturing complexity.

5. Multi-product platform licensing

A company with a validated extended-release matrix platform could license the technology for diltiazem and other cardiovascular drugs. The most attractive licensing package would include:

• Composition claims.
• Process claims.
• Scale-up data.
• Dissolution methods.
• Stability data.
• Demonstrated alcohol resistance.
• A transfer package for multiple strengths.

The value of the platform increases when it supports more than one active ingredient and does not depend on a single branded reference product.

How does Cardizem LA compare with other diltiazem formulations?

Product type	Dosing pattern	Excipient strategy	Commercial position
Immediate-release diltiazem tablet	Multiple daily doses	Conventional disintegrant and immediate-release system	Low-cost, higher adherence burden
Cardizem LA	Once daily	Extended-release polymer matrix	Convenience and sustained exposure
Other once-daily diltiazem products	Once daily	Product-specific matrix, bead, or coated system	Compete through price, tolerability, and substitution
Diltiazem extended-release capsule	Once or twice daily, depending on product	Multiparticulate beads or granules	Potential administration advantage
Diltiazem injectable	Acute or hospital use	Parenteral excipients	Separate market and regulatory pathway

These products are not automatically substitutable. Different extended-release technologies can produce different pharmacokinetic profiles, dosing schedules, food effects, and labeling restrictions. An excipient strategy should begin with the target reference product and its approved dosing regimen rather than treating all diltiazem ER products as interchangeable.

What FDA regulatory status and Orange Book issues matter?

Cardizem LA is an FDA-approved prescription product. The regulatory pathway for a conventional generic is generally an ANDA, provided the proposed product can demonstrate pharmaceutical equivalence and bioequivalence to the selected reference listed drug.[4]

A reformulated product with a meaningful clinical or delivery distinction may require a 505(b)(2) application rather than an ANDA. Examples could include:

• A new sprinkle dosage form.
• A different release profile.
• A new route of administration.
• A clinically relevant administration method for dysphagia.
• A product with a distinct indication or dosing regimen.

The Orange Book remains the controlling public source for listed patents, therapeutic equivalence codes, reference listed drug status, and approved strengths.[2] A commercial diligence file should map each planned strength and dosage form to its specific reference product.

What manufacturing and intellectual-property barriers remain?

The principal manufacturing barriers are:

• Uniform drug distribution at high tablet loads.
• Reproducible polymer hydration.
• Control of tablet porosity.
• Strength-to-strength dissolution matching.
• Prevention of dose dumping.
• Stability under humidity exposure.
• Scale-up from development tooling to commercial presses.
• Consistent coating weight and appearance.

The principal IP barriers are narrower:

• Unexpired composition claims.
• Process claims covering granulation or coating.
• Claims directed to dissolution profiles.
• Trade secrets covering polymer grade, water activity, compression, or coating parameters.
• Supplier exclusivity for specialized excipients.

A design-around strategy should change both the excipient composition and the process variables that define the claimed invention. Merely replacing one grade of hypromellose while retaining the same claimed polymer ratio and dissolution profile may not provide a meaningful freedom-to-operate position.

Key Takeaways

• Cardizem LA is a once-daily extended-release diltiazem hydrochloride tablet.
• Its commercial differentiation depends on controlled release, not the active ingredient.
• Hypromellose, lactose, microcrystalline cellulose, povidone, magnesium stearate, and coating excipients form the core formulation platform identified in public labeling.
• The most important technical risk is failure to reproduce the reference dissolution and pharmacokinetic profile.
• The strongest commercial opportunities are generic substitution, lactose-free products, dysphagia-friendly multiparticulates, smaller high-strength tablets, and excipient-platform licensing.
• Biosimilar risk does not apply because diltiazem is a small-molecule drug.
• Patent diligence must focus on current Orange Book listings, formulation claims, process patents, and potential Paragraph IV activity.
• A differentiated reformulation may require a 505(b)(2) application rather than an ANDA.
• Manufacturing know-how may remain commercially relevant after the expiration of traditional product patents.

FAQs

Can Cardizem LA be reformulated with a different polymer?

Yes, but the new polymer system must reproduce the required extended-release behavior and satisfy the applicable FDA pathway. A substantial change may require extensive comparative dissolution and bioequivalence work.

Is a lactose-free Cardizem LA generic commercially viable?

Potentially. A lactose-free product could differentiate in institutional and specialty channels, but the market premium must offset development, validation, and manufacturing costs.

Can Cardizem LA tablets be crushed for tube administration?

The product labeling instructs patients to swallow the tablets whole. Crushing can disrupt controlled release and should not be assumed to be acceptable without product-specific evidence.[1]

Would a sprinkle formulation receive patent protection?

It could, if the formulation has novel and non-obvious features such as coated multiparticulates, defined release behavior, food compatibility, or enteral-tube performance. The delivery concept alone may not be sufficient.

Does a generic diltiazem ER product automatically substitute for Cardizem LA?

No. Substitution depends on FDA therapeutic-equivalence coding, the specific reference listed drug, strength, dosage form, and state substitution rules. Different diltiazem extended-release products may not have identical release technologies.

References

1. U.S. Food and Drug Administration. (n.d.). Cardizem LA: Diltiazem hydrochloride extended-release tablets prescribing information. DailyMed. https://dailymed.nlm.nih.gov/

2. 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/

3. U.S. Food and Drug Administration. (2003). Guidance for industry: 180-day exclusivity when multiple ANDAs are submitted on the same day. https://www.fda.gov/

4. U.S. Food and Drug Administration. (2003). Guidance for industry: Bioavailability and bioequivalence studies for orally administered drug products. https://www.fda.gov/ led to=final code:`` We need ensure no phrase "Additionally" etc. Fine. But user expects topic perhaps no explicit ask beyond topic. We deliver. Need maybe citations inline only 4. "Cardizem LA is approved hypertension and chronic stable angina" accurate. "NDA 021892" omitted. Fine. 1000-ish. Need bold only headings/title. We have bold headings due markdown # not bold? Developer says bold only headings; okay. Could title currently # not bold. Fine.

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