List of Excipients in Branded Drug CHLORPROMAZINE HCI

Generic Drugs Containing CHLORPROMAZINE HCI

Company	Ingredient	NDC	Excipient
Dr Reddy's Laboratories Inc	chlorpromazine hci	43598-140	ASCORBIC ACID
Dr Reddy's Laboratories Inc	chlorpromazine hci	43598-140	SODIUM CHLORIDE
Dr Reddy's Laboratories Inc	chlorpromazine hci	43598-140	SODIUM METABISULFITE
Dr Reddy's Laboratories Inc	chlorpromazine hci	43598-140	SODIUM SULFITE
Dr Reddy's Laboratories Inc	chlorpromazine hci	43598-140	WATER

What are the Most Frequently-Used Excipients in CHLORPROMAZINE HCI?

# Of NDCs	Excipient
2	ASCORBIC ACID
2	SODIUM CHLORIDE
2	SODIUM METABISULFITE
2	SODIUM SULFITE
2	WATER

Chlorpromazine HCl Excipient Strategy and Commercial Opportunities

Last updated: September 4, 2026

Chlorpromazine hydrochloride is an established generic phenothiazine antipsychotic with limited branded-patent protection and a broad formulation history. Commercial opportunity is concentrated in differentiated dosage forms, reliable hospital supply, pediatric and geriatric administration, preservative-controlled injectables, and excipient systems that improve palatability, stability, or manufacturability.

The active ingredient is available in oral tablets, oral liquids, and parenteral products. Because the molecule has been marketed for decades, a conventional immediate-release tablet has limited differentiation potential. The strongest opportunities are in products that solve practical problems: taste, dose flexibility, light and oxidation stability, excipient tolerability, vial or ampoule usability, and dependable supply.

What is the regulatory and commercial status of chlorpromazine HCl?

Chlorpromazine HCl is the hydrochloride salt of chlorpromazine, a low-cost conventional antipsychotic used for schizophrenia and other psychiatric indications, severe nausea and vomiting, intractable hiccups, and selected perioperative or behavioral applications. U.S. products have been marketed as prescription drugs under the 505(b)(2) and abbreviated new drug application frameworks, depending on the product and development history.

The original Thorazine product was developed by Smith Kline & French and later associated with GlaxoSmithKline. The market is now primarily generic and includes products from multiple manufacturers and distributors.

Attribute	Commercial assessment
Active ingredient	Chlorpromazine hydrochloride
Drug class	Phenothiazine antipsychotic
Primary U.S. pathways	ANDA for generic equivalents; 505(b)(2) for materially differentiated products
Common dosage forms	Tablets, oral concentrate or solution, injectable solution
Biologic status	Not a biologic
Biosimilar exposure	None
Brand-patent dependence	Low
Main commercial constraint	Market size, supply reliability, formulation complexity, and safety-related handling
Main formulation opportunities	Oral liquids, taste masking, pediatric dosing, injectable stability, preservative strategy, packaging

FDA’s Orange Book identifies approved drug products and, where applicable, listed patents and exclusivity. Chlorpromazine HCl’s commercial environment is primarily that of an established generic drug rather than a protected branded asset. [1]

What patents protect chlorpromazine HCl products?

The original composition-of-matter and early formulation protection for chlorpromazine HCl has expired. Chlorpromazine was introduced in the 1950s, placing the foundational patent estate well outside the ordinary U.S. patent term.

Are active Orange Book patents listed for chlorpromazine HCl?

The relevant question is product-specific because different dosage forms and sponsors may have separate FDA listings. For a mature chlorpromazine HCl tablet or injection, the practical U.S. patent barrier is generally limited. Any current Orange Book patent listing should be checked against the precise reference-listed drug, dosage form, strength, and sponsor entry. [1]

A new formulation could obtain patent protection if it contains a genuinely novel and non-obvious combination of:

• A defined excipient system that produces a measurable stability or dissolution benefit.
• A novel oral liquid or multiparticulate delivery platform.
• A specialized injectable composition with improved precipitation, oxidation, light stability, or compatibility.
• A new dosage form or delivery system with clinical or operational advantages.
• A method of use tied to a legally eligible, previously unapproved indication or dosing regimen.

A patent directed only to routine use of common fillers, binders, lubricants, or flavorants would face substantial obviousness risk. The strongest patent claims would link excipient selection to unexpected technical data.

When does chlorpromazine HCl lose exclusivity?

Chlorpromazine HCl has already lost its foundational market exclusivity. The commercial issue is therefore not an approaching loss-of-exclusivity event. It is whether a sponsor can create protectable differentiation in a low-cost generic category.

Is a Paragraph IV challenge relevant?

A Paragraph IV certification is relevant only when an ANDA applicant identifies a listed patent for the reference product and asserts that the patent is invalid, unenforceable, or not infringed. For a mature chlorpromazine HCl product with no meaningful listed patent barrier, an ANDA applicant may instead use a certification that no patent information is listed or rely on the applicable regulatory pathway. [1,2]

A Paragraph IV strategy would become relevant if a sponsor obtained Orange Book listing for a new formulation or method-of-use patent. The commercial value of that patent would depend on:

1. Whether the product has material demand.
2. Whether the patent claims the marketed dosage form rather than an easily substituted formulation.
3. Whether the patent survives validity and infringement challenges.
4. Whether the listed patent creates a meaningful delay to competing approval or launch.
5. Whether the formulation offers enough clinical or operational value to support premium pricing.

What excipients are used in chlorpromazine HCl products?

Excipients vary by manufacturer, dosage form, strength, and jurisdiction. Oral tablets commonly use conventional solid-dose excipients such as diluents, disintegrants, binders, lubricants, glidants, coating materials, and colorants. Oral liquids may contain purified water, sweeteners, flavoring agents, viscosity modifiers, buffers, preservatives, and solubilizing or wetting agents. Injectable products require a narrower excipient set because of parenteral safety, sterility, particulate, endotoxin, and compatibility requirements.

The exact composition must be taken from the current product label and approved regulatory file. DailyMed provides manufacturer-specific labeling and ingredient information for marketed U.S. products. [3]

Which excipient issues matter most for tablets?

Chlorpromazine HCl tablet development should focus on:

• Dose uniformity across low-strength units.
• Adequate mechanical strength without delayed disintegration.
• Control of photodegradation and oxidation.
• Compatibility with lactose, reducing sugars, alkaline excipients, and metal-containing processing aids.
• Low dust generation and robust content uniformity.
• Film-coating opacity and protection from light.
• Scalable direct-compression or wet-granulation processing.

A conventional tablet can be manufactured at low cost, but the formulation has little commercial defensibility. Value increases if the sponsor can demonstrate improved stability, reduced discoloration, lower tablet friability, or better dose flexibility.

What excipients are most relevant to oral liquids?

Oral liquids create the clearest excipient opportunity because chlorpromazine HCl has a strong bitter taste and is used in populations that may have difficulty swallowing tablets.

Relevant excipient categories include:

Formulation objective	Excipient strategy
Taste masking	High-intensity sweeteners, flavors, ion-exchange resins, polymeric coatings, or multiparticulate encapsulation
Dose uniformity	Suspending agents, viscosity modifiers, controlled particle size, and validated redispersion
Chemical stability	pH control, chelators where justified, antioxidants, oxygen-control packaging, and light protection
Microbial control	Preservative system validated against the finished-product formulation
Palatability	Fruit or vanilla flavor systems, reduced bitterness, and low aftertaste
Pediatric usability	Oral syringe compatibility, low viscosity, small dose volume, and flexible concentration
Excipient tolerability	Sugar-free, alcohol-free, dye-free, and allergen-conscious options

A liquid product has the potential to command a higher price than a basic tablet if it improves adherence, dose titration, or institutional administration. A sponsor should avoid relying solely on flavor selection. Taste masking must be supported by sensory data, stability data, and dissolution or release testing.

Can a sugar-free chlorpromazine HCl liquid be commercialized?

Yes, a sugar-free formulation is commercially plausible, particularly for patients requiring chronic therapy or for institutional settings managing diabetes and dental-risk concerns. The principal technical issue is replacing sucrose or other bulk sweeteners without creating excessive bitterness, osmolality, viscosity, or preservative interference.

Polyols, high-intensity sweeteners, and polymeric taste-masking systems can be evaluated. The formulation must also address dose measurement, microbial control, container compatibility, and the possibility that a sweetener changes the drug’s apparent solubility or taste profile.

What formulation patents could protect chlorpromazine HCl?

The most defensible patent targets are formulation claims supported by comparative data. Potential claim categories include:

Taste-masked oral solution or suspension

A patent could cover a defined chlorpromazine HCl concentration, pH range, taste-masking agent, viscosity range, and sensory performance. Claims should include measurable limitations such as bitterness scores, dissolution behavior, particle size, or stability.

Pediatric liquid dosage form

A pediatric product could combine a defined concentration with a low-volume dosing regimen, oral-syringe compatibility, improved palatability, and controlled stability. A patent based only on reducing the dose concentration would be vulnerable unless the formulation solves a specific technical problem.

Stabilized injectable composition

Potential claims could target a sterile aqueous composition with defined pH, antioxidant or chelator content, oxygen exposure limits, container system, and impurity profile. Parenteral claims require robust data on sterility, particulate matter, extractables and leachables, photostability, and storage.

Multiparticulate or orally disintegrating product

An orally disintegrating tablet, coated granule, or orally disintegrating multiparticulate product could improve administration for patients with swallowing difficulties. The commercial case is stronger if the system reduces bitterness without delaying release.

Coated light-protective tablet

A high-opacity coating or packaging combination could protect chlorpromazine HCl from light-related degradation. The patent would need comparative photostability data against an unprotected or conventional product.

What FDA regulatory pathway applies to new chlorpromazine HCl formulations?

A conventional tablet that is pharmaceutically equivalent and bioequivalent to an approved reference product would normally be developed through an ANDA. A materially different oral liquid, new dosage form, novel delivery system, or product requiring clinical bridging may be more appropriate for a 505(b)(2) application.

Product concept	Likely U.S. pathway	Key development burden
Conventional generic tablet	ANDA	Pharmaceutical equivalence, bioequivalence, CMC
Generic injectable equivalent	ANDA	Sterility, particulate control, container closure, equivalence
New oral liquid	ANDA or 505(b)(2), depending on reference and differences	Comparative bioavailability, CMC, excipient justification
Novel taste-masked formulation	Often 505(b)(2) if no suitable reference	Clinical bridging, sensory data, CMC, stability
New indication or dosing regimen	505(b)(2) or supplemental pathway	Clinical efficacy and safety evidence
Pediatric-friendly dosage form	ANDA or 505(b)(2)	Dosing accuracy, palatability, age-appropriate usability

FDA’s inactive-ingredient database can help identify excipients with prior route-specific use, but prior use does not eliminate the need to justify concentration, safety, compatibility, and product performance. [4]

How strong is the patent estate for chlorpromazine HCl?

The legacy patent estate is weak because the drug is old, generic, and widely known. A new sponsor’s strength would depend on formulation-specific evidence rather than the active ingredient.

Patent asset	Expected strength
Original chlorpromazine HCl composition patent	Expired
Basic immediate-release tablet	Weak unless technically differentiated
Conventional oral solution	Weak to moderate
Taste-masked liquid with unexpected performance	Moderate to strong
Novel pediatric delivery system	Moderate
Stabilized injectable composition	Moderate if supported by impurity and stability data
New method of use	Variable and indication-dependent
Manufacturing process using routine parameters	Usually weak
Packaging-only patent	Narrow, but potentially useful if tied to stability

The strongest commercial position would combine a formulation patent with manufacturing know-how, supplier qualification, sensory data, packaging specifications, and regulatory exclusivity where available.

What manufacturing and IP barriers affect chlorpromazine HCl?

Chlorpromazine HCl is not generally difficult to synthesize compared with complex small molecules. The barriers are more operational than chemical.

Oral manufacturing barriers

Tablet manufacturing must control content uniformity, degradation, coating performance, and light exposure. Oral liquids require validated mixing, suspension control if applicable, preservative effectiveness, microbial limits, and accurate dosing through the marketed device.

Injectable manufacturing barriers

Injectables have higher entry barriers because the sponsor must control:

• Sterile manufacturing capacity.
• Endotoxin and particulate levels.
• Container closure integrity.
• Light and oxygen exposure.
• Drug-excipient and drug-container compatibility.
• Fill-volume accuracy.
• Stability under labeled storage conditions.
• Supply continuity for sterile components and packaging.

A reliable injectable supply position can have more value than a second conventional tablet entry, particularly where hospitals depend on a limited number of suppliers.

Supply-chain and supplier barriers

A differentiated formulation may depend on specialized flavors, ion-exchange resins, coating polymers, sterile-grade excipients, or low-extractables packaging. Dual sourcing is important because a single-source excipient can create regulatory change-control and supply risks.

Which companies are challenging chlorpromazine HCl?

The U.S. market is primarily generic and has historically included multiple manufacturers, contract manufacturers, and distributors. Competition is product-specific because a company may distribute a product without being the finished-dose manufacturer.

The relevant competitive groups are:

1. Generic oral solid-dose manufacturers.
2. Generic injectable manufacturers.
3. Contract development and manufacturing organizations.
4. Hospital-focused suppliers.
5. Specialty manufacturers developing liquid or pediatric products.
6. International manufacturers supplying regulated and emerging markets.

A sponsor should compare competitors on current product availability, shortage history, dosage-form breadth, manufacturing location, FDA inspection history, supply reliability, and label excipients. FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations and the agency’s shortage databases are the primary U.S. sources for this review. [1,5]

What licensing deals and commercial partnerships are available?

Chlorpromazine HCl is unlikely to support a large upfront licensing transaction for a standard tablet. Partnership value is more likely in four areas:

• Licensing a taste-masking platform.
• Acquiring a ready-to-file oral liquid or orally disintegrating formulation.
• Contracting sterile injectable manufacturing capacity.
• Partnering with hospital distributors or regional generic suppliers.

A formulation owner could license rights by territory, dosage form, or channel. The commercial terms would depend on regulatory readiness, patent position, demonstrated bioequivalence, manufacturing cost, and whether the product addresses a documented supply shortage.

What geographic opportunities exist for chlorpromazine HCl?

The product has broad historical international use, but regulatory and commercial conditions vary.

United States

The market is mature and price-sensitive. Opportunities are concentrated in differentiated liquids, injectables, supply-reliable products, and products with limited competition.

Europe

European opportunity depends on national reimbursement, local marketing authorization requirements, and the availability of existing oral and injectable presentations. Sugar-free, alcohol-free, and pediatric-friendly formulations may have value where hospital and community prescribing patterns support them.

Emerging markets

Opportunities may exist where chlorpromazine remains clinically used but dosage-form availability is limited. Local registration, pharmacopoeial compliance, pricing controls, tender participation, and local manufacturing rules are central to the business case.

Hospital and institutional markets

Injectable chlorpromazine HCl and oral liquid products may have greater strategic value in hospitals, long-term-care facilities, psychiatric institutions, and correctional-health systems than in retail pharmacy. Institutional buyers tend to prioritize uninterrupted supply, standardized packaging, dose flexibility, and predictable procurement.

What generic launch scenarios exist for chlorpromazine HCl?

Scenario 1: Conventional tablet entry

This is the lowest-cost strategy but also the least differentiated. Price competition can be severe, and the product may be difficult to distinguish from existing suppliers.

Scenario 2: Oral liquid entry

A liquid can support better dose titration, pediatric and geriatric use, and institutional administration. Taste masking and packaging are the central technical and commercial variables.

Scenario 3: Premium injectable entry

A sterile injectable can create a stronger supply proposition but requires substantial capital, validation, and manufacturing discipline. The product may benefit from limited supplier availability if competitors experience shortages.

Scenario 4: Platform-based differentiated product

An orally disintegrating, multiparticulate, or taste-masked product could support a 505(b)(2) strategy and formulation patenting. The development timeline and regulatory cost would exceed those of a standard ANDA.

What is the revenue exposure and commercial ceiling?

Chlorpromazine HCl is a mature, low-price product. Revenue exposure for a new entrant is therefore driven by volume, channel access, and product differentiation rather than high unit pricing.

The most attractive commercial segments are:

• Injectable hospital supply.
• Oral liquid products with limited competition.
• Pediatric and geriatric administration.
• Contract supply for institutional buyers.
• Markets with recurrent shortages.
• Multi-country portfolios using a common formulation platform.

A conventional tablet may produce volume but limited margin. A differentiated oral liquid or reliable injectable can produce better gross margin if the sponsor controls manufacturing cost and secures durable distribution.

Key Takeaways

• Chlorpromazine HCl’s foundational patent protection has expired.
• Biosimilar risk is irrelevant because chlorpromazine HCl is a small-molecule drug.
• Paragraph IV value is limited unless a sponsor creates a new Orange Book-listed formulation or method-of-use patent.
• Conventional tablets are commercially mature and difficult to differentiate.
• Oral liquids offer the clearest excipient opportunity through taste masking, sugar-free design, dose flexibility, and pediatric usability.
• Injectable products have higher manufacturing barriers and may offer stronger hospital-channel economics.
• A defensible formulation patent requires comparative technical data, not routine excipient substitution.
• The strongest strategy combines formulation IP, packaging protection, manufacturing know-how, and reliable supply.
• Commercial returns are likely to depend more on shortage resilience and dosage-form differentiation than on active-ingredient exclusivity.

FAQs

Can chlorpromazine HCl be formulated as an orally disintegrating tablet?

Yes. An orally disintegrating tablet is technically feasible, but bitterness, dose uniformity, mechanical strength, moisture sensitivity, and rapid drug release must be controlled. A taste-masked multiparticulate system may perform better than direct drug compression.

Is chlorpromazine HCl suitable for a preservative-free oral liquid?

It can be considered, but the formulation would require a validated microbial-control strategy based on packaging, low water activity, single-dose presentation, aseptic manufacture, or another justified approach. A multidose aqueous product generally requires careful preservative and in-use stability evaluation.

Can a chlorpromazine HCl formulation receive three-year market exclusivity?

Regulatory exclusivity depends on the application type and the nature of the innovation. A new formulation may qualify for certain exclusivity protections only if it meets statutory requirements. Patent protection and FDA exclusivity are separate rights.

What is the most attractive excipient platform for chlorpromazine HCl?

A taste-masking system for a low-volume, sugar-free oral liquid is the strongest general opportunity. It addresses a practical administration problem and can support differentiation across pediatric, geriatric, psychiatric, and institutional markets.

Does chlorpromazine HCl have a meaningful patent cliff?

No. The primary patent cliff occurred decades ago. Current commercial risk relates to generic pricing, manufacturing interruptions, regulatory compliance, and competition between dosage forms.

References

1. U.S. Food and Drug Administration. (2025). 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

2. U.S. Food and Drug Administration. (2024). Abbreviated new drug application submissions: Refuse-to-receive standards. https://www.fda.gov/drugs/guidance-compliance-regulatory-information

3. National Library of Medicine. (2025). DailyMed: Current medication labeling for chlorpromazine hydrochloride products. https://dailymed.nlm.nih.gov/dailymed/

4. U.S. Food and Drug Administration. (2025). Inactive ingredient database. https://www.accessdata.fda.gov/scripts/cder/iig/index.cfm

5. U.S. Food and Drug Administration. (2025). Drug shortages. https://www.fda.gov/drugs/drug-safety-and-availability/drug-shortages-index-availability.