List of Excipients in Branded Drug HYDROMET

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Generic Drugs Containing HYDROMET

Company	Ingredient	NDC	Excipient
Actavis Pharma Inc	hydrocodone bitartrate and homatropine methylbromide	0472-1030	ANHYDROUS CITRIC ACID
Actavis Pharma Inc	hydrocodone bitartrate and homatropine methylbromide	0472-1030	CHERRY
Actavis Pharma Inc	hydrocodone bitartrate and homatropine methylbromide	0472-1030	D&C RED NO. 33

What are the Most Frequently-Used Excipients in HYDROMET?

# Of NDCs	Excipient
1	ANHYDROUS CITRIC ACID
1	CHERRY
1	D&C RED NO. 33

Hydromet Excipient Strategy and Commercial Opportunities

Last updated: October 22, 2026

Hydromet is an oral prescription solution containing hydrocodone bitartrate and homatropine methylbromide. Its commercial profile is defined by three factors: a mature active-ingredient combination, Schedule II opioid controls, and a liquid dosage form with meaningful excipient, taste, stability, and abuse-deterrence considerations. The strongest commercial opportunities are differentiated liquid presentations, pediatric and geriatric usability improvements, preservative and sugar reformulation, and supply-chain advantages rather than new-molecule patent protection.

What is Hydromet and how is it regulated?

Hydromet is indicated for the temporary relief of cough in adults and patients 6 years of age and older when the potential benefits outweigh the risks associated with opioid exposure. The labeled strength is hydrocodone bitartrate 5 mg and homatropine methylbromide 1.5 mg per 5 mL of oral solution.[1]

Product attribute	Hydromet profile
Active ingredients	Hydrocodone bitartrate and homatropine methylbromide
Dosage form	Oral solution
Labeled concentration	Hydrocodone bitartrate 5 mg and homatropine methylbromide 1.5 mg per 5 mL
Therapeutic use	Antitussive
FDA pathway	Approved prescription drug product
Controlled-substance classification	Schedule II
Key safety restrictions	Respiratory depression, misuse, addiction, overdose, pediatric exposure
Primary commercial issue	Controlled-opioid distribution and demand volatility
Main formulation opportunity	Stable, palatable, measurable, tamper-resistant liquid

Hydromet is not a biologic. Biosimilar approval pathways therefore do not apply. Competition would arise through generic drug applications, authorized-generic arrangements, line extensions, or reformulated products rather than biosimilar development.

What excipients are used in Hydromet?

The Hydromet label identifies a conventional liquid formulation based on water, sweetening, buffering, solvent, viscosity, flavor, coloring, and preservation functions.[1]

Reported inactive ingredients include:

• Citric acid
• FD&C Yellow No. 6
• Flavor
• Glycerin
• Methylparaben
• Propylene glycol
• Purified water
• Sodium citrate
• Sucrose

The excipient system has several technical functions:

Excipient or excipient class	Likely formulation role	Commercial implication
Purified water	Primary vehicle	Requires microbiological control and validated manufacturing
Sucrose	Sweetener and mouthfeel modifier	Limits suitability for diabetic patients and increases dental-care concerns
Glycerin	Co-solvent, humectant, viscosity and mouthfeel contributor	Can improve palatability and pour characteristics
Propylene glycol	Co-solvent and flavor-solubilizing agent	Requires attention to exposure limits, tolerability, and pediatric use
Citric acid and sodium citrate	Buffer system and pH control	Supports taste, chemical stability, and preservative performance
Methylparaben	Antimicrobial preservative	Can create preservative-sensitivity and label-positioning issues
Flavor	Taste masking	Central to adherence and product differentiation
FD&C Yellow No. 6	Color identification	Creates a colorant-free reformulation opportunity

The commercial value of the excipient platform is higher than the apparent simplicity of the formulation. Hydrocodone is intensely bitter, and homatropine methylbromide can contribute to taste and mouthfeel challenges. In an oral solution, taste masking must work across repeated doses while preserving dose accuracy, chemical stability, and microbial control.

How strong is the Hydromet patent estate?

Hydromet is a mature combination product. Its principal commercial barriers are regulatory, controlled-substance, manufacturing, and distribution requirements rather than a broad, durable patent estate.

What patents protect Hydromet?

The active ingredients and basic oral-solution concept have been known for decades. Any historic patents covering the original product, active ingredients, or conventional liquid formulation are unlikely to create a meaningful long-term barrier to generic competition. Current patent protection must be checked against the FDA Orange Book and applicable patent records for the specific marketed product and sponsor.[2]

For commercial diligence, the relevant questions are:

1. Whether the listed product has any active Orange Book patents.
2. Whether any listed patents claim a specific formulation, concentration, method of treatment, or manufacturing process.
3. Whether a generic applicant can certify Paragraph III, Paragraph IV, or no patent certification.
4. Whether the reference product has regulatory exclusivity separate from patent protection.

A conventional Hydromet generic can generally pursue an ANDA if it demonstrates pharmaceutical equivalence, bioequivalence where required, and compliance with FDA quality and labeling standards.[3]

Are there formulation patents for Hydromet?

A formulation patent could theoretically cover:

• A specific hydrocodone-homatropine concentration;
• A defined pH range;
• A preservative system;
• A taste-masking composition;
• A stabilized oral solution;
• A child-resistant delivery system;
• A unit-dose package;
• An abuse-deterrent liquid platform.

The practical strength of such patents depends on claim specificity and prior art. Broad claims covering water, sucrose, glycerin, propylene glycol, citrate buffer, flavor, color, and methylparaben would face substantial obviousness and anticipation risks because these are standard pharmaceutical excipients and functions.

A stronger patent position would require a narrow technical result, such as unexpected stability, a defined impurity profile, a measurable reduction in abuse potential, or a specific delivery architecture that is not routine.

Are there method-of-use patents for Hydromet?

Method-of-use patents could address cough treatment in a defined patient group or disease setting. Their commercial value is constrained because Hydromet is an old antitussive product and its core use is established. A method patent would also need to withstand written-description, enablement, obviousness, and infringement challenges.

Method-of-use protection may still matter in a branded product strategy if the sponsor develops:

• A lower-exposure regimen;
• A defined indication with limited alternatives;
• A specific patient population;
• A combination with another treatment;
• A dosing protocol tied to a measurable clinical benefit.

Such patents would not necessarily block all generic sales. They could support labeling-based enforcement or a partial indication carve-out.

When does Hydromet lose exclusivity?

Hydromet has effectively operated in a mature market for many years. The product’s core regulatory exclusivity is not the primary commercial issue. Generic hydrocodone-homatropine oral solutions have been available, and the product category is exposed to ANDA competition.

Exclusivity category	Hydromet assessment
New chemical entity exclusivity	Not commercially relevant for this mature combination
New clinical investigation exclusivity	Not the principal barrier to current competition
Orphan exclusivity	Not applicable to the broad cough indication
Pediatric exclusivity	No current blocking significance identified
Patent exclusivity	Requires current Orange Book confirmation; likely limited for the mature product
Regulatory exclusivity	No known current exclusivity period that would block ordinary generic competition

The practical loss of exclusivity occurred through product aging, generic entry, and the absence of a durable patent moat. The remaining value lies in brand recognition, supply reliability, packaging, prescriber familiarity, and differentiated formulation attributes.

What is the Orange Book status of Hydromet?

The FDA Orange Book is the controlling source for listed patents, therapeutic-equivalence determinations, and reference-listed-drug information.[2] Hydromet diligence should distinguish among:

• The branded reference product;
• Generic hydrocodone bitartrate and homatropine methylbromide oral solutions;
• Authorized generics;
• Different strengths or concentrations;
• Products with different sponsors and labeling histories.

Because Orange Book entries can change with product ownership, patent declarations, and listing updates, a static patent conclusion is insufficient for transaction diligence. The principal expected outcome for a generic applicant is an ANDA referencing the listed drug, subject to any current patent certification and regulatory requirements.

Which companies are challenging Hydromet?

Competition is likely to come from generic manufacturers and branded-generic suppliers rather than from biosimilar developers. Potential competitors include companies with:

• Existing controlled-substance manufacturing licenses;
• DEA-compliant supply-chain systems;
• Oral-liquid manufacturing capability;
• Established retail-pharmacy distribution;
• Experience with opioid quota management;
• FDA-approved liquid products in adjacent cough or analgesic categories.

The competitive set should be evaluated by FDA approval status, current commercial availability, shortage history, supplier reliability, and ability to maintain controlled-substance inventory. A company may hold an approved ANDA yet have limited commercial impact if it lacks quota, active distribution, or dependable raw-material supply.

What excipient strategies could differentiate a Hydromet competitor?

Sugar-free Hydromet oral solution

Replacing sucrose with a noncaloric sweetener system could address diabetic use, calorie exposure, and dental concerns. Candidate systems may include:

• Sorbitol;
• Sucralose;
• Acesulfame potassium;
• Saccharin sodium;
• Steviol glycosides;
• Polyols combined with high-intensity sweeteners.

The principal risks are bitterness, cooling effects, gastrointestinal tolerability, osmolality, and aftertaste. A sugar-free product should not be positioned as interchangeable with the reference product unless it meets FDA requirements for pharmaceutical equivalence and labeling.

Dye-free formulation

Removing FD&C Yellow No. 6 could appeal to patients, caregivers, and institutions seeking colorant reduction. A dye-free product would need replacement visual controls, such as a clear or naturally colored solution, without creating confusion in medication administration.

Preservative-free unit-dose packaging

A preservative-free presentation could use single-dose containers, blow-fill-seal packaging, or another validated sterile or microbiologically controlled format. This strategy has potential in hospitals, long-term-care facilities, and specialty dispensing channels.

The tradeoff is higher packaging cost and more complex distribution. A multidose preservative-free product would require robust antimicrobial-control data and container-closure validation.

Improved taste masking

Taste masking is a direct commercial opportunity. Useful approaches include:

• Flavor systems that suppress hydrocodone bitterness;
• Sweetener combinations with delayed-release flavor profiles;
• Ion-pairing or complexation technologies;
• Resin-based taste-masking systems;
• Viscosity adjustment using compatible polymers;
• pH optimization within the product’s stability and tolerability range.

A formulation patent is more credible when the taste-masking system produces a measurable result without impairing dose uniformity, assay, dissolution, stability, or bioavailability.

Lower-volume concentration

A higher concentration could reduce the volume required per dose and improve portability. It also raises safety risks because a small measurement error would deliver more opioid. Any concentrated formulation would need strong safeguards, clear dosing devices, human-factors testing, and careful pediatric-risk analysis.

Unit-dose and adherence packaging

Unit-dose cups or oral syringes can improve dose accuracy and reduce diversion opportunities. Packaging innovation may support institutional contracts even where the liquid composition is not novel.

Potential features include:

• Calibrated oral syringes;
• Tamper-evident bottles;
• Unit-dose containers;
• Child-resistant closures;
• Serialized packaging;
• Smaller dispensing quantities;
• Integrated dose-recording labels.

Packaging patents can provide incremental protection, but they generally do not block a conventional generic bottle-and-cup presentation.

What manufacturing and intellectual-property barriers affect Hydromet?

The principal manufacturing barriers are operational:

1. Hydrocodone is a controlled substance, requiring DEA compliance and inventory controls.
2. The product must meet oral-liquid content-uniformity and dose-measurement expectations.
3. Multidose bottles require validated microbial-control systems.
4. Flavor and sweetener systems can affect chemical stability.
5. API sourcing may be constrained by quota and approved supplier requirements.
6. Controlled-substance recalls can create heightened regulatory and commercial exposure.
7. Packaging must reduce accidental pediatric ingestion and dosing errors.

The homatropine component adds a product-specific supply requirement. A competitor needs reliable sourcing for both active ingredients, not only hydrocodone.

The strongest defensible IP strategy would combine a formulation patent with proprietary taste-masking data, validated packaging, manufacturing know-how, and a regulatory pathway that produces measurable product differentiation. A basic excipient substitution alone is unlikely to create a durable moat.

What FDA regulatory issues affect Hydromet reformulation?

A reformulated Hydromet product would normally require an FDA submission appropriate to the change and the sponsor’s product status. Key regulatory issues include:

• Pharmaceutical equivalence to the reference product;
• Bioequivalence where formulation changes could affect exposure;
• Stability under ICH conditions;
• Microbial limits and preservative effectiveness;
• Dose uniformity;
• Container-closure integrity;
• Human-factors validation for dosing devices;
• Abuse, misuse, and accidental-ingestion risk;
• Pediatric labeling and safety;
• Controlled-substance security and recordkeeping.

FDA labeling warns against use in children younger than 6 years and identifies serious opioid risks, including respiratory depression, addiction, misuse, abuse, overdose, and death.[1] Any pediatric-oriented commercial strategy must therefore emphasize measurement accuracy and risk reduction rather than simply expanding use.

What Paragraph IV challenges and litigation risks exist?

A Paragraph IV certification could arise if an Orange Book-listed patent were asserted against a generic applicant. The commercial significance would depend on:

• The number and scope of listed patents;
• Whether the patent covers the full product or only a method of use;
• The timing of the ANDA notice;
• Whether the sponsor files an infringement action within the statutory period;
• The availability of a noninfringing label;
• The expected 30-month stay;
• The probability of patent invalidity or noninfringement.

For a mature Hydromet product, litigation risk is more likely to arise from a newly developed differentiated formulation than from the original oral solution. A new sugar-free, abuse-deterrent, or unit-dose product could create a separate patent estate, but it would also invite validity challenges if claims rely on conventional excipient choices.

No biosimilar litigation pathway applies. Any dispute would ordinarily involve patents, ANDA approval, controlled-substance compliance, labeling, manufacturing, or trade secrets.

What commercial opportunities exist for Hydromet?

Generic and authorized-generic supply

The lowest-risk opportunity is dependable generic supply. Buyers may value a second source where competitors experience shortages, quota limitations, or manufacturing interruptions. Margin potential is limited by generic pricing pressure, but supply reliability can support hospital and pharmacy contracts.

Institutional packaging

Long-term-care facilities, hospitals, and specialty pharmacies may value unit-dose packaging, calibrated oral syringes, and reduced medication-administration error. This opportunity is more defensible than a simple bottle reformulation.

Sugar-free and dye-free positioning

A sugar-free, dye-free presentation could create a differentiated branded-generic position. Commercial success would depend on superior taste, broad pharmacy availability, and evidence that the formulation solves a meaningful patient or caregiver problem.

Abuse-deterrent liquid technology

An abuse-deterrent formulation could command a premium if it produces a credible reduction in tampering or extraction while preserving therapeutic performance. The development burden is high, and the regulatory and clinical evidence requirements would exceed those for a conventional generic.

Contract manufacturing

Controlled-liquid manufacturing capacity is itself a commercial asset. A qualified manufacturer could offer Hydromet or generic equivalents through licensing, private-label arrangements, or supply agreements, subject to DEA and FDA requirements.

How does Hydromet compare with competing cough products?

Product category	Active ingredient type	Controlled substance	Excipient opportunity	Commercial risk
Hydromet	Opioid plus anticholinergic	Yes	Taste, sugar-free, packaging, abuse deterrence	High regulatory and safety burden
Codeine-containing cough products	Opioid antitussive	Yes or restricted depending on product	Similar liquid formulation issues	Pediatric and misuse concerns
Dextromethorphan liquids	Non-opioid antitussive	No federally controlled status	Taste, sugar-free, preservative-free	Strong OTC competition
Benzonatate capsules	Non-opioid antitussive	No	Capsule design and swallowability	Different dosage-form preference
Nonprescription combination liquids	Multiple active ingredients	Usually no	Flavor, sugar-free, dosing device	Heavy retail competition

Hydromet has a narrower market and higher compliance burden than non-opioid cough products. Its value is concentrated in prescription channels where clinicians specifically select an opioid-containing antitussive.

What revenue exposure and launch scenarios exist?

Product-specific revenue exposure cannot be inferred reliably from the brand name alone because sales may be divided among the brand owner, authorized distributors, generic suppliers, and institutional purchasers.

Launch scenario	Expected commercial effect
Conventional generic oral solution	Rapid price pressure and limited differentiation
Sugar-free or dye-free generic	Moderate differentiation with higher formulation risk
Unit-dose institutional product	Potentially stronger contract value and operational switching costs
Preservative-free product	Niche opportunity with higher packaging expense
Abuse-deterrent formulation	Higher potential price but substantial development and evidence burden
Supply-constrained second source	Attractive during shortages, vulnerable when capacity normalizes

The most realistic near-term opportunity is a high-quality generic or branded-generic product supported by reliable supply, calibrated dosing equipment, and one or two clinically relevant excipient improvements.

Key Takeaways

• Hydromet is a hydrocodone bitartrate and homatropine methylbromide oral solution regulated as a Schedule II opioid product.
• Its core formulation uses conventional excipients, including sucrose, glycerin, propylene glycol, citrate buffer, methylparaben, flavor, and FD&C Yellow No. 6.
• The original product has limited apparent long-term patent strength; current Orange Book records control the definitive patent analysis.
• Biosimilar competition is irrelevant because Hydromet is a small-molecule drug.
• The strongest reformulation opportunities are sugar-free, dye-free, preservative-free unit-dose, improved taste-masking, calibrated dosing, and abuse-deterrent presentations.
• Controlled-substance manufacturing, DEA quota, API supply, microbial control, and pediatric safety are more significant barriers than basic excipient selection.
• Generic entry would likely create price pressure unless a competitor differentiates through packaging, supply reliability, or clinically meaningful formulation attributes.
• A conventional excipient substitution is unlikely to support a durable patent estate without unexpected technical results.

FAQs

Can Hydromet be reformulated without sucrose?

Yes. A sugar-free formulation could use polyols, high-intensity sweeteners, or a combination of both. The sponsor would need to establish palatability, stability, dose uniformity, microbial control, and regulatory comparability.

Would a sugar-free Hydromet be automatically therapeutically equivalent?

No. Therapeutic equivalence depends on FDA requirements for the specific submission, including pharmaceutical equivalence and bioequivalence where applicable. Removing sucrose can alter viscosity, taste, osmolality, preservative performance, and absorption-related characteristics.

Can a company patent a Hydromet taste-masking formulation?

Potentially. Patent strength would depend on claim scope, technical evidence, prior art, and proof of an unexpected result. Conventional flavor and sweetener substitutions would face higher validity risk than a demonstrably novel taste-masking platform.

Is Hydromet suitable for a biosimilar development program?

No. Hydromet is a small-molecule combination product, not a biologic. Competition would proceed through generic, branded-generic, reformulation, licensing, or other small-molecule pathways.

What is the most attractive commercial Hydromet opportunity?

A dependable generic or branded-generic oral solution with improved taste, no artificial color, sugar-free positioning, and a calibrated oral syringe offers the most practical balance of development cost, regulatory feasibility, and market differentiation.

References

1. U.S. Food and Drug Administration. (n.d.). Hydromet: Hydrocodone bitartrate and homatropine methylbromide oral solution prescribing information. FDA-approved labeling.
2. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. FDA, Center for Drug Evaluation and Research.
3. U.S. Food and Drug Administration. (n.d.). Abbreviated new drug application process. FDA, Center for Drug Evaluation and Research.
4. U.S. Food and Drug Administration. (2020). Development of abuse-deterrent formulations of opioids: Guidance for industry.
5. U.S. Food and Drug Administration. (2017). General principles for evaluating abuse-deterrent formulations of opioids.
6. United States Pharmacopeial Convention. (2024). United States Pharmacopeia and National Formulary. USP.