List of Excipients in Branded Drug PENICILLAMINE

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Oceanside Pharmaceuticals	PENICILLAMINE	penicillamine	68682-020	D&C YELLOW NO. 10
Oceanside Pharmaceuticals	PENICILLAMINE	penicillamine	68682-020	GELATIN
Oceanside Pharmaceuticals	PENICILLAMINE	penicillamine	68682-020	LACTOSE MONOHYDRATE

Generic Drugs Containing PENICILLAMINE

Company	Ingredient	NDC	Excipient
Endo USA Inc	penicillamine	0254-2000	ANHYDROUS LACTOSE
Endo USA Inc	penicillamine	0254-2000	COPOVIDONE K25-31
Endo USA Inc	penicillamine	0254-2000	EDETATE DISODIUM

What are the Most Frequently-Used Excipients in PENICILLAMINE?

# Of NDCs	Excipient
1	ALCOHOL
6	AMMONIA
4	ANHYDROUS LACTOSE

Penicillamine Excipient Strategy and Commercial Opportunities

Last updated: August 10, 2026

Penicillamine is an established oral chelating agent with continuing medical use in Wilson disease and cystinuria, plus a declining role in severe rheumatoid arthritis. The commercial opportunity is concentrated in dependable generic supply, formulation quality, pediatric and dysphagia-friendly presentations, and improved adherence rather than in new-molecule exclusivity. The main excipient constraints are metal-ion contamination, oxidation, food-drug interaction risk, moisture control, and preservation of rapid oral availability.

What is the current FDA status of penicillamine?

Penicillamine is an FDA-approved prescription drug marketed in oral capsules and tablets. U.S. labeling identifies indications for Wilson disease, cystinuria, and severe active rheumatoid arthritis that has not responded adequately to conventional therapy [1, 2].

Attribute	Penicillamine
Active ingredient	Penicillamine
Drug class	Thiol-containing chelating agent
Main U.S. indications	Wilson disease, cystinuria, severe rheumatoid arthritis
Administration	Oral
Dosage forms	Capsules and tablets
Key brands	Cuprimine, Depen
Generic pathway	ANDA for therapeutically equivalent oral products
Food administration	Usually on an empty stomach
Key interaction concern	Iron, antacids, mineral supplements, food
Biosimilar pathway	Not applicable; penicillamine is a synthetic small molecule

Cuprimine is associated with Valeant Pharmaceuticals, now within the Bausch Health corporate history. Depen has been marketed by legacy pharmaceutical companies, including Meda Pharmaceuticals. Generic availability has varied by dosage strength and supplier.

The product is not a biologic, so biosimilar competition is irrelevant. Competition comes from authorized generics, ANDA-approved products, specialty distributors, and manufacturer-controlled supply.

What excipients are used in penicillamine products?

The exact inactive-ingredient profile differs by manufacturer and dosage form. Public product labels identify conventional oral excipients such as lactose, magnesium stearate, gelatin, titanium dioxide, microcrystalline cellulose, crospovidone, povidone, colloidal silicon dioxide, stearic acid or calcium stearate, and coloring agents, depending on the product [1-3].

A formulation team should not treat these excipients as interchangeable. The active ingredient has a reactive thiol group and is administered at doses that can range from low daily doses for cystinuria to substantially higher divided doses for Wilson disease. Tablet mass, capsule fill, disintegration, and dose flexibility therefore matter.

Typical excipient functions

Excipient category	Commercial function	Penicillamine-specific consideration
Diluent	Controls tablet weight or capsule fill	Lactose may create suitability issues for some patients; mineral-containing diluents require impurity control
Binder	Provides tablet mechanical strength	Excessive binding can delay disintegration and dissolution
Disintegrant	Promotes rapid breakup	Important because the product is generally used as an immediate-release dosage form
Lubricant	Supports manufacturing	Magnesium or calcium salts require control because penicillamine chelates divalent metals
Glidant	Improves powder flow	Colloidal silicon dioxide can improve low-dose blend uniformity
Film coat	Protects tablet and improves handling	Coat should not materially delay release or introduce reactive impurities
Capsule shell	Enables rapid-release dosage form	Gelatin, titanium dioxide and colorants must be evaluated for supply, compatibility and patient acceptability
Antioxidant	Controls oxidation	Must be justified through stability data and assessed for interaction with the thiol group
Chelation-control excipient	Limits trace metals	Excipient specifications should include elemental impurity controls

Public labels do not establish that every listed excipient is present in every penicillamine product. Manufacturers must use the applicable DailyMed label and approved regulatory filing for the precise composition [1-3].

Which excipient risks are most important for penicillamine?

Metal-ion contamination

Penicillamine binds copper, cystine-related disulfide species, and other metals. The formulation should therefore minimize avoidable iron, copper, zinc, calcium and magnesium contamination. This applies to:

• Mineral-based excipients.
• Processing equipment.
• Water systems.
• Milling and blending operations.
• Colorants and pigments.
• Packaging components.
• Container-closure extractables.

Magnesium stearate is used in many oral tablets and capsules, but its use requires a documented compatibility assessment. The issue is not simply the nominal amount of magnesium in the lubricant. Particle size, contact time, surface chemistry, elemental impurities and release behavior can affect the risk profile.

A high-quality generic strategy would establish tight elemental impurity specifications under ICH Q3D principles and demonstrate that trace metals do not reduce assay, alter degradation products or change dissolution [4].

Oxidation and disulfide formation

Penicillamine contains a free thiol. Thiol oxidation can produce disulfide-related degradation products, including penicillamine disulfide. Oxygen exposure, elevated humidity, light, peroxides in excipients and trace metals can accelerate degradation.

The formulation program should screen:

• Peroxide values in povidone, crospovidone and other polymeric excipients.
• Moisture content and water activity.
• Oxygen exposure during blending and filling.
• Light transmission through the package.
• Residual metals in excipients and equipment.
• Compatibility of coating systems and printing inks.

A low-peroxide excipient grade can be commercially useful if the supplier provides consistent lot data and change-control support. Nitrogen flushing may assist stability, but the business case depends on whether the product is packaged in bottles, blisters or unit-dose packs.

Food and mineral interactions

Penicillamine is generally administered on an empty stomach because food can reduce absorption. Iron, antacids and mineral supplements can interfere with administration and absorption or bind the drug in the gastrointestinal tract [1, 2].

Excipient selection cannot eliminate the clinical need for dose separation. A formulation can, however, reduce avoidable variability by using rapidly disintegrating, immediate-release tablets or capsules and by avoiding unnecessary mineral excipients.

Modified-release formulations would face a difficult commercial and regulatory burden. Delayed or prolonged release could conflict with established dosing instructions and would require comparative pharmacokinetic and clinical justification.

What formulation strategy is best for penicillamine?

The lowest-risk strategy is an immediate-release, low-moisture tablet or capsule with robust content uniformity and a packaging system that limits oxygen and humidity.

Recommended development platform

Development objective	Preferred approach
Rapid release	Immediate-release tablet or hard capsule
Oxidation control	Low-peroxide excipients, controlled processing environment, protective packaging
Metal control	Elemental impurity limits for excipients and finished product
Dose flexibility	125 mg and 250 mg strengths, with clinically appropriate scoring where feasible
Pediatric use	Dispersible or sprinkle-capable presentation only if stability and dosing accuracy are demonstrated
Dysphagia support	Smaller capsule, film-coated tablet, or validated sprinkle system
Patient adherence	Blister packs, calendar packaging and clear empty-stomach instructions
Manufacturing efficiency	Direct compression if blend uniformity and tablet robustness permit
Stability	Accelerated and long-term studies focused on thiol oxidation and dissolution

Capsules versus tablets

Capsules can provide rapid disintegration and a relatively simple manufacturing process. They may also allow a lower compression force, reducing stress on the active ingredient. Their weaknesses include gelatin-related supply considerations, shell brittleness under low humidity, and limited tablet-like flexibility for scoring or custom dose adjustment.

Tablets permit better control of unit-dose presentation, branding, score lines and film coating. Direct compression may be attractive if powder flow and content uniformity are adequate. Wet granulation should be approached cautiously because water exposure can increase degradation risk and complicate process control.

A commercial product should generally avoid unnecessary excipient complexity. Each additional excipient creates another source of extractables, elemental impurities, supplier changes and regulatory maintenance.

What formulation patents protect penicillamine products?

Penicillamine is an old small molecule, and the principal compound-level patent opportunity has expired. Commercial protection is therefore more likely to arise from manufacturing know-how, product-specific formulation claims, packaging, pediatric delivery systems or method-of-use claims than from the active ingredient itself.

The FDA Orange Book should be reviewed for current listed patents and exclusivity associated with each reference product and dosage form [5]. Public historical records for old penicillamine products do not create a reliable basis for assuming that a formulation patent remains enforceable. Any launch assessment must distinguish:

• Expired composition-of-matter patents.
• Expired formulation patents.
• Unexpired Orange Book-listed patents, if any.
• Patent litigation under Paragraph IV.
• Regulatory exclusivity unrelated to patent term.
• Trade secrets covering impurity control, process conditions or packaging.

Are Paragraph IV challenges a major penicillamine risk?

For a legacy product with generic competition, Paragraph IV activity is usually less important than supply economics and the completeness of the ANDA filing. A Paragraph IV certification could still arise against any currently listed patent, but the commercial value of such litigation depends on the remaining market, patent scope and the reference product’s actual sales.

A generic applicant should review:

1. Current Orange Book patent listings for Cuprimine and Depen.
2. FDA approval dates and dosage-form-specific reference products.
3. Existing ANDA approvals and therapeutic-equivalence ratings.
4. Patent assignments and litigation databases.
5. Any settlement restricting launch timing or distribution.

No biosimilar litigation is relevant because penicillamine is not a biologic.

When does penicillamine lose exclusivity?

Penicillamine’s core small-molecule exclusivity has expired. The relevant commercial question is not when the active ingredient loses exclusivity but whether a specific product, strength or formulation retains regulatory or patent protection.

Protection category	Penicillamine position
Compound patent	Historically expired
New chemical entity exclusivity	Expired
Orphan exclusivity	Not generally the basis of the established U.S. product market
Pediatric exclusivity	Product-specific and must be confirmed in FDA records
Formulation patent	Must be checked by product and jurisdiction
Method-of-use patent	Must be checked by product and indication
Generic entry	Possible through ANDA, subject to reference-product and patent status

The absence of compound exclusivity does not guarantee profitable entry. Small markets can support only a limited number of suppliers, and low-volume products are vulnerable to shortages, API disruption and wholesaler concentration.

What commercial opportunities exist for penicillamine?

1. Reliable generic supply for Wilson disease

Wilson disease is the strongest durable indication because treatment is long term and alternatives may be clinically unsuitable for some patients. Trientine and zinc products compete with penicillamine, but treatment selection depends on disease stage, prior therapy, tolerability and physician preference [6].

A supplier that maintains both 125 mg and 250 mg strengths, avoids back orders and supports specialty-pharmacy distribution can compete on supply reliability rather than price alone.

2. Pediatric and adolescent dosing

Wilson disease frequently requires long-term management across changing body weights. Dose titration creates an opportunity for:

• Lower-strength units.
• Accurate splitting.
• Dispersible or sprinkle-capable dosage forms.
• Unit-dose packaging.
• Clear separation instructions for food, iron and mineral products.

A pediatric formulation would require evidence that the product remains chemically stable after dispersion, that dose withdrawal is accurate, and that the delivery vehicle does not introduce metal ions or reduce bioavailability.

3. Improved adherence packaging

Empty-stomach administration and multiple daily doses create avoidable adherence problems. Calendar blister packs, time-of-day labeling and patient instructions can create practical differentiation. Packaging cannot claim to alter the pharmacology, but it can reduce administration errors and support specialty-pharmacy programs.

4. Cystinuria-focused supply

Cystinuria is a chronic, low-prevalence condition in which penicillamine is used when other measures are insufficient or poorly tolerated. The opportunity is small but relatively specialized. Commercial success depends on maintaining product availability and providing dose strengths that support gradual titration.

5. Contract manufacturing and API supply

Penicillamine API manufacturing has strategic value because limited-volume legacy drugs can become vulnerable to single-source dependency. Opportunities include:

• Dual-source API qualification.
• Low-metal manufacturing trains.
• Improved impurity profiling.
• Stability-indicating analytical methods.
• Regional finished-dose production.
• Backup packaging for specialty products.

Process know-how may provide greater competitive protection than a new excipient claim.

How strong is the penicillamine formulation opportunity?

The formulation opportunity is moderate, but the patent opportunity is weak unless a product introduces a clinically meaningful delivery improvement.

Factor	Assessment
Compound patent moat	Weak; legacy molecule
Regulatory barrier	Moderate for a conventional ANDA
Excipient differentiation	Moderate
Pediatric opportunity	Moderate, with higher development cost
Manufacturing barrier	Moderate because of oxidation and metal control
Market size	Niche relative to major chronic medicines
Supply-value opportunity	High if competitors are limited or unreliable
Litigation value	Usually limited unless active product patents remain
Generic price pressure	High
Long-term demand	Strongest in Wilson disease and selected cystinuria patients

A formulation patent based only on routine excipient substitution is vulnerable. Stronger protection would require a defined stability advantage, a specific low-metal or low-oxidation composition, a validated pediatric delivery system, or a clinically relevant pharmacokinetic benefit.

What generic launch scenarios exist?

Conventional ANDA launch

This is the most practical route. The product should match the reference dosage form, strength and release profile, with comparative dissolution and bioequivalence data. The main risks are low market size, reference-product availability, manufacturing scale and reimbursement pressure.

Differentiated immediate-release product

A tablet or capsule with improved packaging, lower impurity burden or better dose flexibility could support specialty distribution. FDA approval would still require evidence that the change does not alter bioequivalence or safety.

Pediatric 505(b)(2) strategy

A pediatric dispersible or sprinkle formulation could support a 505(b)(2) pathway if it relies partly on published data or an approved product while introducing a distinct dosage form. The strategy would carry greater clinical, CMC and lifecycle-management costs than a standard ANDA.

Authorized generic or licensing arrangement

A branded manufacturer could license production to a generic company or launch an authorized generic. This model may be attractive where the reference product owner wants supply continuity without building a new manufacturing network. Any deal should address API ownership, quality agreements, shortage obligations, field alerts, pharmacovigilance and territorial rights.

What geographic opportunities exist?

The U.S. market has the clearest regulatory pathway through FDA-approved oral products and Orange Book reference standards. Europe and other jurisdictions may offer opportunities in Wilson disease, but regulatory requirements, reimbursement and brand histories differ.

Geographic expansion should prioritize markets with:

• Established diagnosis and treatment pathways for Wilson disease.
• Reimbursement for orphan or specialty medicines.
• Reliable import and cold-chain-free oral distribution.
• Limited local competition.
• Clear acceptance of the selected API supplier.
• Demand for pediatric or low-strength products.

Penicillamine does not generally require refrigerated distribution, but humidity and oxygen protection remain relevant. Alu-Alu blistering or high-barrier bottles may increase packaging cost while improving shelf-life protection.

Key Takeaways

• Penicillamine is a legacy oral chelator with expired core exclusivity and limited compound-level patent value.
• The strongest ongoing demand is in Wilson disease, followed by selected cystinuria use.
• Excipient design should focus on oxidation control, elemental impurities, rapid release and dose flexibility.
• Magnesium- and calcium-containing excipients require compatibility and impurity assessment because penicillamine chelates metals.
• Low-peroxide excipients, controlled moisture and high-barrier packaging can reduce CMC risk.
• Pediatric, dispersible and adherence-oriented presentations offer the clearest product-differentiation opportunities.
• A conventional generic has a lower development burden but faces price and market-size constraints.
• Commercial advantage is more likely to come from reliable supply, specialty distribution and manufacturing quality than from broad patent protection.
• Current Orange Book listings, FDA labels and litigation records must control any live launch or freedom-to-operate conclusion.

FAQs

Can penicillamine be formulated with lactose?

Yes, lactose is present in some oral penicillamine products. The manufacturer must assess lactose compatibility, patient labeling and lot-to-lot quality. Lactose should not be assumed suitable for every target population or formulation platform.

Is a liquid penicillamine product commercially attractive?

A liquid could improve administration for selected pediatric patients, but chemical stability, oxidation, preservative compatibility, metal contamination and in-use shelf life create substantial development risks. A dispersible solid may offer a lower-risk alternative.

Does penicillamine need an enteric coating?

Usually not. Established products are immediate-release oral dosage forms, and enteric protection could complicate bioequivalence and conflict with administration requirements.

Can a penicillamine product use iron-containing excipients?

It should generally avoid unnecessary iron exposure. Any iron-containing component would require a strong compatibility rationale, tight elemental impurity controls and evidence that assay, degradation and dissolution remain acceptable.

Which indication offers the best commercial return?

Wilson disease offers the most defensible long-term opportunity because treatment is chronic and specialist-driven. The addressable population is limited, so supply reliability, formulation usability and reimbursement access are more important than mass-market volume.

References

1. U.S. Food and Drug Administration. (2023). Cuprimine (penicillamine) capsule prescribing information. DailyMed.

2. U.S. Food and Drug Administration. (2023). Depen (penicillamine) tablet prescribing information. DailyMed.

3. U.S. National Library of Medicine. (2024). Penicillamine product labeling and inactive ingredient information. DailyMed.

4. International Council for Harmonisation. (2014). ICH Q3D(R2): Guideline for elemental impurities. https://www.ich.org

5. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.fda.gov

6. European Association for the Study of the Liver. (2012). EASL clinical practice guidelines: Wilson’s disease. Journal of Hepatology, 56(3), 671-685.