List of Excipients in Branded Drug ZAMICET

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Generic Drugs Containing ZAMICET

Company	Ingredient	NDC	Excipient
Pharmaceutical Associates Inc	hydrocodone bitartrate and acetaminophen	0486-4771	ALCOHOL
Pharmaceutical Associates Inc	hydrocodone bitartrate and acetaminophen	0486-4771	CITRIC ACID MONOHYDRATE
Pharmaceutical Associates Inc	hydrocodone bitartrate and acetaminophen	0486-4771	EDETATE DISODIUM
Pharmaceutical Associates Inc	hydrocodone bitartrate and acetaminophen	0486-4771	GLYCERIN
Pharmaceutical Associates Inc	hydrocodone bitartrate and acetaminophen	0486-4771	METHYLPARABEN
Pharmaceutical Associates Inc	hydrocodone bitartrate and acetaminophen	0486-4771	PROPYLENE GLYCOL
Pharmaceutical Associates Inc	hydrocodone bitartrate and acetaminophen	0486-4771	SACCHARIN SODIUM

What are the Most Frequently-Used Excipients in ZAMICET?

# Of NDCs	Excipient
1	ALCOHOL
1	CITRIC ACID MONOHYDRATE
1	EDETATE DISODIUM
1	GLYCERIN
1	METHYLPARABEN
1	PROPYLENE GLYCOL
1	SACCHARIN SODIUM

Zamicet Excipient Strategy and Commercial Opportunities for Hydrocodone-Acetaminophen Oral Solution

Last updated: August 21, 2026

Zamicet is an oral solution containing hydrocodone bitartrate and acetaminophen, generally identified at a strength of 10 mg/325 mg per 15 mL. Its commercial position depends less on novel active-ingredient protection than on formulation performance, dosing safety, taste masking, preservative control, supply reliability, and regulatory execution. The strongest opportunities are differentiated oral-liquid products that improve dose accuracy, reduce excipient-related tolerability issues, and target institutional, specialty-pharmacy, and patients unable to swallow solid dosage forms.

What is Zamicet and how is it regulated?

Zamicet is a prescription opioid analgesic oral solution containing hydrocodone bitartrate and acetaminophen. Hydrocodone is a Schedule II controlled substance in the United States. The product is regulated as a finished drug product under an FDA-approved application and is subject to opioid labeling, controlled-substance distribution requirements, abuse-deterrence considerations, and acetaminophen-related hepatotoxicity warnings. [1,2]

Attribute	Zamicet profile
Active ingredients	Hydrocodone bitartrate and acetaminophen
Dosage form	Oral solution
Common labeled strength	10 mg hydrocodone bitartrate/325 mg acetaminophen per 15 mL
Therapeutic category	Opioid analgesic
U.S. controlled-substance status	Schedule II
Regulatory pathway for a copy product	ANDA or, where appropriate, 505(b)(2)
Primary formulation risks	Taste, viscosity, dose measurement, preservative performance, chemical stability
Principal safety risks	Respiratory depression, misuse, dependence, overdose, acetaminophen hepatotoxicity
Commercial differentiators	Dosing system, excipient profile, palatability, packaging, supply assurance

Zamicet is an immediate-release liquid rather than an extended-release opioid. The product therefore competes with hydrocodone-acetaminophen tablets, capsules, oral solutions, and other immediate-release opioid formulations.

What excipients are used in Zamicet?

The labeled inactive ingredients for hydrocodone-acetaminophen oral solution products have included solvents, sweeteners, buffers, preservatives, viscosity modifiers, and flavoring components. Public product labeling should control any product-specific assessment because formulations can change between manufacturers, strengths, and approved supplements. [1]

A typical excipient architecture for this product class includes:

Excipient function	Common candidate materials	Commercial purpose
Vehicle	Purified water	Main liquid carrier
Cosolvent	Propylene glycol or glycerin	Solubilization and mouthfeel
Sweetener	Sorbitol or other polyol	Taste masking and body
Buffer	Citric acid and sodium citrate	pH control
Preservative	Methylparaben or alternative system	Microbial protection
Flavor	Fruit, berry, citrus, or proprietary flavor	Reduction of opioid bitterness
Chelator	Edetate disodium, where used	Metal-ion control and stability support
Viscosity modifier	Glycerin, hydrocolloid, or polymer	Pourability and dosing behavior

The excipient strategy must account for the full active-ingredient combination. Hydrocodone produces a strong bitter taste, while acetaminophen can add bitterness and lingering aftertaste. A formulation that improves hydrocodone taste but increases acetaminophen precipitation, viscosity, or preservative demand can fail during scale-up or regulatory review.

Which excipient attributes have the greatest commercial value?

The highest-value attributes are dose accuracy, palatability, preservative reliability, and patient-specific tolerability.

Taste masking

Taste masking is the main technical opportunity. Conventional sweeteners alone are unlikely to eliminate the bitterness of hydrocodone. A more effective system can combine:

• Polyol sweetness from sorbitol or glycerin.
• Acidulant and buffer optimization.
• Fruit or citrus flavors selected through sensory testing.
• Bitter-blocking agents.
• Ion-pairing or complexation approaches, where compatible with drug release and absorption.
• Viscosity control that reduces rapid contact between the drug and taste receptors.

Taste masking should be assessed using trained sensory panels and, where appropriate, electronic-tongue screening. The target is not simply a lower bitterness score. The product must avoid delayed bitterness, throat irritation, excessive sweetness, and flavor persistence.

Dose measurement

Liquid opioid products have a high risk of dosing errors. A commercial formulation should be supplied with a calibrated oral syringe rather than relying only on a household spoon or an unmarked cup. The syringe should match the concentration and intended administration volume.

For a 10 mg/325 mg per 15 mL product, the labeled dose volume can be relatively large compared with concentrated oral liquids. A reformulated product could reduce administration volume by increasing drug concentration, but that strategy creates new risks:

• Greater overdose consequences from small measurement errors.
• More difficult pediatric or caregiver dosing.
• Increased taste intensity.
• Higher need for child-resistant packaging and dispensing controls.
• Potential regulatory scrutiny of concentration changes.

A lower-volume formulation is commercially attractive only if the dosing device and labeling reduce, rather than increase, medication-error risk.

Preservative system

An oral solution containing water, sugars or polyols, and flavoring agents requires validated microbiological control. The preservative system must remain effective across the product’s pH range and throughout the in-use period.

Potential commercial strategies include:

1. Retaining a conventional paraben-based system with strong historical precedent.
2. Developing a preservative-free unit-dose presentation.
3. Using a multidose package with an antimicrobial closure or integrated dispensing system.
4. Combining low water activity with pH control and validated packaging.

A preservative-free presentation could command a premium in hospitals, specialty pharmacies, and patients with preservative sensitivities. It would also raise packaging, stability, and manufacturing costs.

Buffer and pH control

Citric acid and sodium citrate are commonly useful for pH adjustment and flavor balance. pH affects:

• Hydrocodone and acetaminophen stability.
• Preservative efficacy.
• Flavor perception.
• Container compatibility.
• Potential precipitation or crystallization.
• Long-term color and odor changes.

The commercial target should be the narrowest pH range that supports stability, preservative performance, acceptable taste, and packaging compatibility. Broad pH specifications can create batch variability and weaken product consistency.

What formulation patents could protect a Zamicet follow-on product?

The active ingredients are established, so a follow-on product would generally seek protection around formulation and delivery features rather than composition of matter.

Potentially protectable subject matter includes:

Patent strategy	Potential claim focus	Commercial value
Taste-masked solution	Specific bitter-blocking system, flavor combination, or drug-excipient ratio	Differentiates patient experience
Concentrated solution	Higher-strength liquid with defined stability and dosing properties	Reduces administration volume
Preservative-free product	Unit-dose or specialized package configuration	Targets hospitals and sensitive patients
Dosing system	Integrated syringe, adapter, cap, or metering closure	Reduces dose errors
Stability formulation	Defined pH, chelator, antioxidant, or solvent system	Supports shelf life
Abuse-deterrent liquid	Gelling, aversive, or tamper-responsive technology	May support institutional contracting
Manufacturing process	Mixing order, temperature control, filtration, or deaeration	Protects scale-up know-how
Packaging	Light-resistant, child-resistant, unit-dose, or tamper-evident container	Supports safety and procurement differentiation
Method of use	Administration to patients unable to swallow tablets or capsules	May have limited enforcement value

A formulation patent is stronger when the claimed excipient combination produces measurable results, such as improved chemical stability, lower extractables, superior preservative efficacy, reduced bitterness, or improved dose uniformity. Broad claims to conventional excipients alone are vulnerable to written-description, enablement, obviousness, and lack-of-novelty challenges.

How does the FDA pathway affect commercial entry?

A therapeutically equivalent generic oral solution would normally be evaluated through the ANDA pathway if the applicant can match the reference product’s active ingredients, dosage form, strength, route, and relevant performance characteristics. A materially different excipient system, concentration, delivery device, or labeling position may require a 505(b)(2) application rather than a conventional ANDA. [3,4]

ANDA opportunity

An ANDA offers the clearest route when the product matches the reference listed drug. The principal requirements include:

• Pharmaceutical equivalence.
• Bioequivalence or an FDA-accepted waiver where applicable.
• Same dosage form, strength, route, and conditions of use.
• Appropriate labeling.
• Manufacturing controls and product-quality data.
• Demonstrated control of microbial quality and impurities.

The limitation is differentiation. A substantially improved taste profile, new concentration, novel package, or preservative-free design may not fit comfortably within an ANDA.

505(b)(2) opportunity

A 505(b)(2) product can support a differentiated formulation or delivery system that relies partly on FDA findings for an existing product. Potential advantages include:

• Novel concentration.
• New excipient system.
• Unit-dose or metered delivery.
• Preservative-free presentation.
• New administration route or patient population, if clinically supported.
• Reformulation with improved stability or tolerability.

The pathway can produce stronger differentiation but generally requires more regulatory, clinical, and patent-certification analysis than an ordinary ANDA.

What Orange Book and exclusivity issues affect Zamicet?

The relevant regulatory questions are whether the reference product has active Orange Book-listed patents, whether FDA exclusivity remains active, and whether the product is currently eligible for an abbreviated application. FDA’s Orange Book identifies approved products, therapeutic equivalence evaluations, patents submitted by applicants, and certain exclusivity periods. [5]

For an established hydrocodone-acetaminophen oral solution, the most likely commercial barriers are not long-lived active-ingredient patents. They are:

• Any remaining formulation or method-of-use patents.
• Regulatory exclusivity linked to a later-approved product or supplement.
• Controlled-substance manufacturing and distribution requirements.
• Product-specific bioequivalence and stability demands.
• Limited manufacturing capacity for Schedule II products.
• Contracting and wholesaler access.

Paragraph IV certification could become relevant if an ANDA applicant challenges an unexpired Orange Book patent. A patent-holder suit filed within the statutory period can trigger a 30-month stay of approval under the Hatch-Waxman framework, subject to the statute and litigation outcome. [6]

The commercial significance of a Paragraph IV challenge depends on the patent claim. A narrow flavor or package patent may have limited market impact. A patent covering the full formulation, concentration, or dosing system could delay entry or require a non-infringing design-around.

When does Zamicet lose exclusivity?

Zamicet’s practical exclusivity depends on the current FDA Orange Book record, applicable patent certifications, and whether the reference product retains regulatory exclusivity. The original approval date alone does not establish current market exclusivity.

For mature opioid-acetaminophen products, generic entry typically depends more on:

• Whether an approvable reference listed drug remains available.
• Whether an ANDA applicant can establish bioequivalence.
• Whether the reference formulation is adequately characterized.
• Whether active patents or regulatory exclusivity remain.
• Whether the applicant can obtain DEA manufacturing and distribution capacity.

The absence of a broad active-ingredient patent does not guarantee immediate generic competition. Oral solutions can require more formulation development than tablets because of taste, microbial quality, viscosity, container closure, and dose-delivery issues.

What commercial opportunities exist for a Zamicet excipient strategy?

Hospital and post-operative use

Hospitals need oral liquid opioids for patients who cannot swallow tablets, patients transitioning from parenteral therapy, and selected post-operative populations. A unit-dose, preservative-free, barcoded product with an oral syringe could support hospital purchasing even when a lower-cost generic exists.

Specialty pharmacy and home care

Home-care patients and caregivers benefit from a formulation with:

• A calibrated syringe.
• Clear dose-volume markings.
• Child-resistant packaging.
• Tamper evidence.
• Low spill risk.
• Stable flavor over the labeled shelf life.
• Simplified storage requirements.

Packaging and device integration may create more defensible differentiation than a new flavor alone.

Pediatric and adolescent formulations

Hydrocodone products have significant pediatric safety restrictions and opioid-prescribing limitations. A pediatric commercial strategy cannot rely only on a smaller dose volume. It would require age-appropriate labeling, dosing controls, safety data, and careful assessment of the product’s abuse and accidental-ingestion risks. The opportunity is therefore regulatory-intensive and narrower than the adult liquid market.

Dysphagia and geriatric care

Patients with dysphagia represent a practical target for oral liquids, including long-term-care and home-health settings. Excipient selection should minimize:

• Excessive sweetness.
• High osmotic load.
• Sorbitol-related gastrointestinal effects.
• Alcohol exposure, if present.
• Unnecessary dyes.
• High viscosity that makes syringe delivery difficult.

A sugar-free, alcohol-free, dye-free formulation with controlled viscosity could support institutional and caregiver positioning.

Abuse-deterrent delivery

A liquid product can incorporate tamper-responsive packaging, unit-dose presentation, or formulation features intended to discourage manipulation. These features may improve procurement positioning, but they do not automatically qualify the product as an FDA-recognized abuse-deterrent formulation. Abuse-deterrence claims require alignment with FDA guidance and supporting abuse-potential data. [7]

How strong is the patent estate for a Zamicet reformulation?

The likely patent estate for a conventional hydrocodone-acetaminophen solution is moderate to weak unless the sponsor owns a technically differentiated delivery or excipient platform.

Asset type	Expected strength
Hydrocodone-acetaminophen composition of matter	Low for a mature product
Conventional water-based solution	Low to moderate
Specific taste-masking platform	Moderate if supported by comparative data
Integrated dosing device	Moderate
Preservative-free unit-dose package	Moderate
Abuse-deterrent formulation	Moderate to strong if clinically and technically validated
Manufacturing process	Moderate, but often better protected as trade secret
Method-of-use patent	Variable and generally narrower
Trade dress and brand	Commercially useful but not a substitute for patent protection

The strongest strategy is layered protection: a formulation patent, device or packaging claims, manufacturing know-how, regulatory exclusivity where available, and supply-chain control. Reliance on a single excipient patent creates design-around risk.

Which companies are likely to challenge or compete with Zamicet?

Competitive pressure comes from several product classes:

1. Generic hydrocodone-acetaminophen tablets and capsules.
2. Other hydrocodone-acetaminophen oral solutions.
3. Oxycodone oral solutions.
4. Morphine oral solutions.
5. Tramadol and other lower-schedule analgesics where clinically appropriate.
6. Non-opioid combinations, including acetaminophen with NSAIDs.
7. Compounded oral liquids from pharmacies and outsourcing facilities.

The principal generic competitors are companies with established controlled-substance manufacturing, oral-liquid capabilities, and pharmacy distribution. Competitive entry is more likely from manufacturers already producing hydrocodone, oxycodone, morphine, or acetaminophen liquids than from a company entering the opioid market without Schedule II infrastructure.

What manufacturing and intellectual-property barriers exist?

The main manufacturing barriers are operational rather than purely chemical.

Controlled-substance capacity

Manufacturers need DEA registration, quota access, secure handling, inventory controls, diversion monitoring, and compliant distribution. These requirements can limit the number of credible suppliers and create launch delays.

Oral-liquid scale-up

Critical process controls include:

• Order of excipient addition.
• Mixing temperature and shear.
• Hydrocodone and acetaminophen dissolution.
• Deaeration.
• Filtration, if used.
• Homogeneity throughout the batch.
• Filling accuracy.
• Container-closure integrity.
• Microbial control.

Packaging compatibility

The formulation must be evaluated against the bottle, cap, liner, syringe, adapter, label, and secondary packaging. Extractables and leachables, sorption, light exposure, and closure performance can affect product quality.

Supply-chain resilience

Sorbitol, glycerin, propylene glycol, preservatives, flavors, and specialty dosing devices can each become single-source risks. A commercial product should qualify dual suppliers for critical excipients and maintain alternative flavor and packaging configurations without changing the registered product unnecessarily.

What is the revenue exposure and market outlook?

Public product-level revenue data for Zamicet are not a reliable basis for valuation without current sales disclosures. Revenue potential should be modeled through prescription volume, average net price, payer mix, institutional contracts, and the extent of generic substitution.

The product’s economic exposure is concentrated in:

• Price erosion after generic entry.
• Wholesale and pharmacy substitution.
• Declining opioid utilization in some treatment settings.
• Reimbursement differences between oral solutions and tablets.
• Controlled-substance quota constraints.
• Hospital preference for unit-dose packaging.
• Shortages or discontinuations among competing liquid products.

A differentiated liquid can preserve pricing when it solves a measurable operational problem. The clearest premium opportunities are calibrated delivery, unit-dose packaging, preservative-free presentation, improved taste, and dependable supply. A new flavor without measurable adherence or dispensing benefits is unlikely to sustain premium pricing.

What generic launch scenarios exist for Zamicet?

Scenario	Product profile	Likely commercial effect
Direct ANDA launch	Same strength and dosage form	Rapid price competition and substitution
Concentrated liquid	Lower administration volume	Differentiated but higher dosing-risk burden
Preservative-free unit dose	Hospital or specialty use	Premium niche opportunity
Improved taste formulation	Same active ingredients with excipient changes	Potential 505(b)(2) positioning
Integrated syringe system	Metered delivery and adapter	Device-led differentiation
Supply-constrained launch	Limited Schedule II capacity	Opportunity to capture shortage-driven demand
Abuse-deterrent liquid	Tamper-responsive formulation or packaging	Higher development cost and regulatory burden

The most defensible launch model is a differentiated oral solution supported by a proprietary delivery system and a clear institutional use case. A conventional copy product is easier to develop but exposed to rapid generic price erosion.

Key Takeaways

• Zamicet is a hydrocodone bitartrate-acetaminophen oral solution, commonly labeled at 10 mg/325 mg per 15 mL.
• Excipient value is concentrated in taste masking, pH control, preservative performance, viscosity, and dose-delivery accuracy.
• A direct generic is likely to face price erosion, while a differentiated product may pursue a 505(b)(2) strategy.
• The most promising commercial features are calibrated oral-syringe delivery, unit-dose packaging, preservative-free presentation, controlled viscosity, and improved palatability.
• Conventional excipient combinations are difficult to patent broadly. Stronger protection requires demonstrated technical effects.
• Controlled-substance manufacturing capacity, DEA requirements, and oral-liquid scale-up are material barriers to entry.
• Current Orange Book patents, exclusivity, litigation, and commercial status must be assessed before setting a launch date or valuation.
• A reliable product-specific revenue estimate is not supported by the public information identified here.

FAQs

Can a sugar-free Zamicet formulation create a meaningful market niche?

Yes. A sugar-free product could target diabetic patients, long-term-care facilities, and caregivers seeking reduced sugar exposure. Sorbitol and other polyols can still create gastrointestinal tolerability concerns, so the full excipient profile matters.

Would a new flavor require a 505(b)(2) application?

Not necessarily. A flavor change may fit within an ANDA if the product remains pharmaceutically equivalent and the formulation satisfies FDA requirements. A materially different taste-masking system or other formulation change may require 505(b)(2) treatment.

Can a Zamicet oral solution be marketed as abuse deterrent?

Only if the formulation or packaging meets FDA expectations for an abuse-deterrent claim and is supported by appropriate testing. Child-resistant packaging and tamper evidence alone do not establish abuse-deterrent status.

Is a preservative-free hydrocodone-acetaminophen solution commercially attractive?

It can be attractive in hospitals, specialty pharmacy, and patients with preservative sensitivities. The opportunity depends on validated in-use stability, microbial control, unit-dose economics, and packaging costs.

Are excipient patents enough to block a hydrocodone-acetaminophen generic?

Usually not by themselves. A blocking position is stronger when claims cover a necessary formulation feature, a specific concentration, a delivery device, or a validated technical effect that cannot be readily designed around.

References

1. U.S. Food and Drug Administration. (n.d.). Zamicet: Hydrocodone bitartrate and acetaminophen oral solution prescribing information. FDA-approved labeling.

2. U.S. Food and Drug Administration. (2023). Acetaminophen prescription combination drug products with more than 325 mg: FDA safety communication. https://www.fda.gov

3. U.S. Food and Drug Administration. (2017). ANDA submissions: Amendments and requests for final approval to tentatively approved ANDAs. FDA guidance.

4. U.S. Food and Drug Administration. (2025). Applications covered by section 505(b)(2). FDA regulatory guidance and resources.

5. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. Orange Book.

6. U.S. Congress. (1984). Drug Price Competition and Patent Term Restoration Act of 1984, 21 U.S.C. § 355(j).

7. U.S. Food and Drug Administration. (2015). Assessment of abuse potential of drugs: Guidance for industry. FDA.