List of Excipients in Branded Drug HYDROCODONE BITARTRATE AND CHLORPHENIRAMINE MALEATE

Generic Drugs Containing HYDROCODONE BITARTRATE AND CHLORPHENIRAMINE MALEATE

Company	Ingredient	NDC	Excipient
Acella Pharmaceuticals LLC	hydrocodone bitartrate and chlorpheniramine maleate	42192-612	ANHYDROUS CITRIC ACID
Acella Pharmaceuticals LLC	hydrocodone bitartrate and chlorpheniramine maleate	42192-612	GLYCERIN
Acella Pharmaceuticals LLC	hydrocodone bitartrate and chlorpheniramine maleate	42192-612	METHYLPARABEN
Acella Pharmaceuticals LLC	hydrocodone bitartrate and chlorpheniramine maleate	42192-612	PROPYLENE GLYCOL
Acella Pharmaceuticals LLC	hydrocodone bitartrate and chlorpheniramine maleate	42192-612	PROPYLPARABEN

What are the Most Frequently-Used Excipients in HYDROCODONE BITARTRATE AND CHLORPHENIRAMINE MALEATE?

# Of NDCs	Excipient
1	ANHYDROUS CITRIC ACID
1	GLYCERIN
1	METHYLPARABEN
1	PROPYLENE GLYCOL
1	PROPYLPARABEN

Last updated: October 1, 2026

Hydrocodone bitartrate and chlorpheniramine maleate are commercialized primarily as an extended-release oral suspension using ion-exchange resin complexes. The strongest opportunities are sugar-free and dye-free reformulations, improved dose metering, preservative optimization, pediatric-adjacent palatability work for legally permitted populations, and generic or 505(b)(2) products that address the complexity of a controlled-substance liquid. The principal barriers are Schedule II controls, opioid safety requirements, bioequivalence for a modified-release suspension, resin-complex manufacturing, and limited long-term growth in opioid cough products.

Hydrocodone Bitartrate and Chlorpheniramine Maleate Excipient Strategy and Commercial Opportunities

What product uses hydrocodone bitartrate and chlorpheniramine maleate?

The reference product is Tussionex Pennkinetic Extended-Release Oral Suspension, marketed in the United States for cough associated with upper respiratory allergies or a common cold. Its active drug substances are delivered as hydrocodone polistirex and chlorpheniramine polistirex, which provide the hydrocodone and chlorpheniramine equivalents.

A 5 mL dose contains:

Component	Amount per 5 mL
Hydrocodone bitartrate equivalent	10 mg
Chlorpheniramine maleate equivalent	8 mg
Dosage form	Extended-release oral suspension
Administration	Oral
Controlled-substance status	Schedule II because of hydrocodone

The product uses the Pennkinetic delivery system, an ion-exchange resin platform intended to control release and reduce rapid availability of the active ingredients. The product label identifies hydrocodone polistirex and chlorpheniramine polistirex as the active complexes rather than presenting the active ingredients as freely dissolved salts.[1]

Current U.S. labeling limits use to adults and includes opioid-related warnings, including respiratory depression, misuse, addiction, overdose and death risks. FDA required labeling changes for prescription cough and cold products containing hydrocodone or codeine to limit use to adults 18 years and older.[2]

What excipients are used in the reference formulation?

The labeled inactive ingredients include:

Excipient	Likely formulation function
Croscarmellose sodium	Suspending or matrix-modifying aid
Ethylcellulose	Release-control polymer and resin-coating component
FD&C Yellow No. 6	Colorant
Flavor	Taste and odor masking
High-fructose corn syrup	Sweetening and viscosity contribution
Methylcellulose	Suspending and viscosity-control agent
Povidone	Binder, dispersant or processing aid
Polysorbate 80	Wetting and surfactant function
Propylene glycol	Solvent, humectant and flavor carrier
Purified water	Vehicle
Sodium benzoate	Preservative
Sucrose	Sweetener and viscosity contributor
Xanthan gum	Suspension stabilizer and rheology modifier

The precise function of several excipients depends on concentration, processing order and interaction with the resin complexes. In particular, methylcellulose, xanthan gum, croscarmellose sodium, ethylcellulose and polysorbate 80 form part of a multidimensional suspension and release-control system rather than operating as isolated ingredients.[1]

How does the Pennkinetic excipient system control release?

The formulation’s technical value is the combination of active-drug ion-exchange complexes and a structured aqueous vehicle. The resin complexes bind drug ions and release them gradually in the gastrointestinal environment. The vehicle must keep the complexes uniformly distributed during storage and dosing while avoiding excessive release in the bottle.

Critical formulation attributes include:

• Particle-size distribution of the drug-resin complexes.
• Resin loading and ion-exchange capacity.
• Suspension viscosity at low and high shear.
• Sedimentation rate and redispersibility.
• Dose uniformity from the first to the final dose.
• Release profile in dissolution or in vitro release testing.
• Compatibility between preservatives, surfactants and resin sites.
• Microbial limits during the in-use period.
• Flavor and sweetness after storage.
• Pourability and measuring-device accuracy.

An excipient change can alter both pharmacokinetics and dose delivery. Surfactants may accelerate wetting or drug release. Ionic excipients may compete for resin-binding sites. Excessive polymer concentration may impair redispersion or create an inaccurate dose. A formulation that appears physically stable can still fail comparative release or pharmacokinetic testing.

What excipient strategy is most commercially attractive?

Sugar-free and low-sugar versions

The reference formulation contains high-fructose corn syrup and sucrose. A sugar-free product could target patients with diabetes, reduced-sugar preferences or dental concerns. Candidate sweetening systems include sucralose, acesulfame potassium, saccharin sodium, steviol glycosides and polyols.

The primary risks are bitterness, cooling effects, aftertaste, viscosity loss and preservative compatibility. Polyols can introduce gastrointestinal tolerability concerns and may alter water activity. High-intensity sweeteners often require flavor modulation because hydrocodone and chlorpheniramine can produce persistent bitterness.

A commercially viable sugar-free formulation would need comparable:

• Drug release.
• Sedimentation and redispersibility.
• Dose uniformity.
• Microbial protection.
• Palatability.
• Stability under shipping and temperature excursions.

Dye-free formulation

FD&C Yellow No. 6 creates a straightforward differentiation opportunity. A dye-free product could appeal to patients and caregivers seeking to avoid artificial colorants and could reduce exposure to colorant-related sensitivities.

The main technical issue is visual product identification. Without a colorant, the manufacturer must maintain a consistent appearance despite suspension settling, resin particles and potential haze. A white or lightly opaque suspension can be acceptable if the label, bottle and dosing instructions support reliable product identification.

Preservative optimization

Sodium benzoate is used in the reference formulation. Alternatives include potassium sorbate, parabens, benzalkonium chloride in limited contexts, or preservative-free packaging. Each option carries compatibility and acceptability issues.

Preservative-free multidose packaging would be difficult because the product is an aqueous oral suspension used over multiple doses. Single-dose sachets, unit-dose cups or a reconstitutable powder could reduce microbial risk but would raise packaging, filling and dosing costs.

A preservative system should be assessed against:

• pH.
• Water activity.
• Container-closure interaction.
• Antimicrobial effectiveness.
• Flavor impact.
• Resin adsorption.
• Compendial microbial limits.

The FDA Inactive Ingredient Database can support excipient precedent analysis, but it does not eliminate the need to justify concentration, route, dosage form and product-specific safety.[3]

Improved suspension and dose metering

Dose uniformity is one of the strongest product-development opportunities. A controlled-rheology suspension can reduce settling while remaining easy to pour. Candidate systems include xanthan gum, low-viscosity cellulose ethers, microcrystalline cellulose with carboxymethylcellulose, and selected carbomer systems.

The formulation should be designed around the dosing device. Oral syringes generally provide better volume accuracy than household spoons, but high viscosity, air entrapment and nozzle retention can cause delivery errors. A commercial product could combine:

• A low-retention oral syringe.
• A bottle designed for complete resuspension.
• A standardized shake time.
• A wide-mouth closure.
• A calibrated adapter.
• Unit-dose packaging for institutional settings.

These changes can create meaningful differentiation without changing the active drug strength.

What formulation patents and intellectual-property barriers matter?

The principal intellectual-property value lies in the extended-release resin-complex platform, manufacturing process, excipient ratios, particle engineering, suspension rheology and device configuration. Broad composition-of-matter protection for hydrocodone and chlorpheniramine is not the main barrier because both active ingredients are long-established drugs.

Relevant IP categories include:

IP category	Commercial relevance
Drug-resin complex formation	Controls release and may limit direct formulation copying
Resin particle size and loading	Affects bioavailability and release comparability
Polymer coating or matrix construction	Can create formulation-specific protection
Suspension vehicle	May protect viscosity, redispersibility and dose uniformity
Flavor and taste masking	Can support a differentiated formulation
Container and dosing device	May protect administration accuracy
Manufacturing process	Can create trade-secret protection even after patent expiry
Method of use	Limited value where the reference indication is mature and narrow

U.S. generic applicants must address the listed Orange Book patents for the reference product through an ANDA certification. A Paragraph IV certification can trigger patent litigation and a potential 30-month stay under the Hatch-Waxman framework.[4] For an extended-release oral suspension, the regulatory risk is greater than for a conventional immediate-release tablet because the applicant must demonstrate comparable release and exposure while using a potentially different excipient system.

The most durable commercial protection may therefore be a combination of:

1. A narrowly drafted formulation patent.
2. Device or packaging claims.
3. Manufacturing know-how.
4. Trade-secret control of resin processing.
5. FDA exclusivity or approval timing.
6. Commercial differentiation through sugar-free, dye-free or unit-dose presentations.

When does hydrocodone-chlorpheniramine lose exclusivity?

Hydrocodone bitartrate, chlorpheniramine maleate and the basic cough indication are mature. The relevant exclusivity question is product-specific rather than molecule-specific.

Exclusivity category	Assessment
New chemical entity exclusivity	Not available for these established active ingredients
Orphan exclusivity	Not relevant to the marketed cough indication
Pediatric exclusivity	Must be verified against the applicable FDA record
Listed patent exclusivity	Depends on current Orange Book entries
Formulation protection	May continue through valid formulation or process patents
Regulatory exclusivity for a new reformulation	Possible for qualifying 505(b)(2) products
Trade-secret protection	Potentially important for resin processing and release control

A new applicant should not assume that expiry of an earlier formulation patent removes all barriers. A later patent can cover a specific release profile, excipient range, particle-size distribution, packaging configuration or method of administration. Conversely, an excipient change that is clinically useful may be difficult to protect if it is an obvious substitution without unexpected performance.

What FDA pathway is available for a new product?

ANDA pathway

An ANDA is the most direct route for a product that is therapeutically equivalent to the reference extended-release suspension. The applicant must address active ingredients, strength, route, dosage form, labeling and bioequivalence. Inactive ingredients may differ, but the differences must not affect safety, efficacy, manufacturability or bioequivalence.

The principal ANDA risks are:

• Failure to match release behavior.
• Inadequate comparative pharmacokinetic data.
• Poor suspension uniformity.
• Different resin-complex performance.
• Inadequate labeling for controlled-substance handling.
• Device-related dose variation.
• Patent litigation after Paragraph IV certification.

505(b)(2) pathway

A 505(b)(2) application may be more suitable for a meaningful reformulation, such as:

• Sugar-free and dye-free presentation.
• New dosing device.
• Unit-dose packaging.
• Different release profile.
• Reconstitutable powder.
• New indication or population.
• Improved stability or preservative system.

The 505(b)(2) pathway can support formulation differentiation but may still require clinical or pharmacokinetic data. It can also generate new patent and regulatory exclusivity opportunities if the product contains a qualifying innovation.

What generic entry risks exist?

Generic entry risk is moderate to high for a conventional copy but lower for a technically differentiated product. The market is protected less by the age of the active ingredients than by the difficulty of reproducing a controlled-release liquid with consistent dosing.

High-risk scenarios for the originator

• A generic reproduces the resin-complex system with comparable release.
• An ANDA applicant obtains a first-filer position with Paragraph IV certification.
• Several applicants enter after patent disputes are resolved.
• Prescribers shift toward generic substitution because of price pressure.
• Wholesalers favor a lower-cost equivalent in a mature cough market.

Lower-risk scenarios for the originator

• The reference product has reliable supply while generic manufacturers face resin or controlled-substance constraints.
• The originator owns defensible formulation or device patents.
• The generic has difficulty matching pharmacokinetics.
• The market remains concentrated in prescribers who prefer the established suspension.
• A differentiated originator version addresses excipient concerns that a standard generic does not address.

Controlled-substance manufacturing adds operational friction. Hydrocodone API quotas, DEA registration, inventory controls, theft prevention, serialization and diversion monitoring raise fixed costs for new entrants.[5]

What licensing opportunities exist?

The product creates licensing opportunities in four areas:

Excipient and delivery-system licensing

An excipient supplier could license a validated suspension platform with:

• Controlled particle settling.
• Improved redispersibility.
• Lower sugar content.
• Dye-free appearance.
• Better flavor masking.
• Compatibility with oral syringes.

Resin-complex technology

A company with ion-exchange resin expertise could license resin selection, loading, coating and particle-engineering technology. The value is highest if the platform can demonstrate comparable exposure with a differentiated release profile.

Device and packaging licensing

A calibrated oral syringe, unit-dose cup, child-resistant bottle or single-dose pouch could be licensed independently of the drug formulation. Device licensing may provide a lower clinical-development burden than a new active formulation.

Regional commercialization

Rights could be divided by geography because controlled-substance rules, labeling requirements, pediatric restrictions and opioid prescribing practices differ across the United States, Canada, Europe and other markets. The U.S. market has the clearest commercial relevance for Tussionex-type products, while non-U.S. markets may require separate regulatory strategies for hydrocodone availability and opioid scheduling.

No biosimilar pathway applies. Hydrocodone-chlorpheniramine is a small-molecule combination product, not a biologic. Competition will come from generics, reformulations, non-opioid cough products and antihistamine combinations rather than biosimilars.

How does this product compare with competing cough medicines?

Product category	Main advantage	Main limitation
Hydrocodone-chlorpheniramine ER suspension	Combined antitussive and antihistamine effect with extended release	Schedule II opioid and substantial safety restrictions
Dextromethorphan products	Non-opioid positioning and broad availability	Abuse potential remains relevant at high doses; efficacy varies
Benzonatate	Non-opioid prescription option	Capsule dosage form and swallowing hazard if chewed
Codeine-containing products	Familiar opioid cough category	Similar or greater regulatory and safety pressure
Antihistamine-decongestant products	Broad symptom coverage	Sedation, cardiovascular effects and limited suitability for some patients
Nonpharmacologic cough products	Low regulatory and safety burden	Often weaker symptom-control claims

The product’s commercial advantage is the convenience of a long-acting liquid combination. Its disadvantage is the regulatory and reputational burden associated with hydrocodone.

What is the revenue exposure and commercial outlook?

Revenue potential is concentrated in a mature, controlled prescription market rather than a high-growth therapeutic area. Commercial performance depends on:

• Continued prescribing of opioid cough products.
• Generic entry timing.
• Insurance coverage and substitution.
• Supply reliability.
• Opioid-related state and federal restrictions.
• Differentiation of the liquid dosage form.
• Retail and institutional demand.
• Ability to support premium pricing for formulation improvements.

The most defensible commercial strategy is a portfolio rather than a single copy:

1. A standard generic or authorized-generic product.
2. A sugar-free and dye-free reformulation.
3. A premium oral-syringe or unit-dose presentation.
4. A trade-secret protected resin and suspension manufacturing process.
5. A non-opioid adjacent product for prescribers moving away from hydrocodone.

Key Takeaways

• The main formulation asset is the extended-release ion-exchange resin system, not the mature active ingredients.
• High-value excipient opportunities include sugar-free, dye-free, preservative-optimized and dose-metered suspensions.
• Generic development is technically more difficult than conventional liquid formulations because release, suspension uniformity and pharmacokinetics must align.
• Hydrocodone’s Schedule II status creates manufacturing, distribution, labeling and quota barriers.
• The ANDA pathway is appropriate for a close equivalent; a 505(b)(2) application is better suited to a clinically meaningful reformulation.
• Patent value is likely to reside in resin processing, release-control architecture, excipient combinations, devices and manufacturing know-how.
• Biosimilar competition is irrelevant because the product is a small-molecule combination.
• The strongest commercial opportunity is a differentiated controlled-release suspension with improved excipient acceptability and precise dose delivery.

FAQs

Can hydrocodone-chlorpheniramine be reformulated without high-fructose corn syrup?

Yes. A sugar-free version is technically feasible, but the substitute sweetener system must preserve viscosity, palatability, microbial control, resin compatibility and pharmacokinetic performance.

Is FD&C Yellow No. 6 necessary in the formulation?

No. The colorant is not pharmacologically necessary. A dye-free formulation could improve marketability, provided the manufacturer maintains product identification, stability and acceptable appearance.

Can a generic use different excipients from Tussionex?

Yes. An ANDA may use different inactive ingredients if the product remains pharmaceutically and therapeutically equivalent and the excipients do not alter safety, efficacy, release or bioequivalence.

Does hydrocodone-chlorpheniramine have biosimilar risk?

No. Biosimilar regulation applies to biologics. Competition for this product comes from generic small-molecule products, reformulations and alternative cough therapies.

What is the most difficult CMC issue for a generic version?

The most difficult issue is reproducing consistent release and dose uniformity from an aqueous suspension containing drug-resin complexes. Sedimentation, redispersion, resin loading, particle size and excipient interactions can all affect performance.

References

1. U.S. Food and Drug Administration. (2024). Tussionex Pennkinetic extended-release oral suspension prescribing information.
2. U.S. Food and Drug Administration. (2018). FDA requires labeling changes for prescription opioid cough and cold medicines to limit their use to adults 18 years and older.
3. U.S. Food and Drug Administration. (2024). Inactive Ingredient Database.
4. U.S. Food and Drug Administration. (2015). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book.
5. Drug Enforcement Administration. (2024). Controlled substances quotas and requirements for Schedule II opioid manufacturers.