List of Excipients in Branded Drug PROMETHAZINE HYDROCHLORIDE AND CODEINE PHOSPHATE

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Generic Drugs Containing PROMETHAZINE HYDROCHLORIDE AND CODEINE PHOSPHATE

Company	Ingredient	NDC	Excipient
Pharmaceutical Associates Inc	promethazine hydrochloride and codeine phosphate	0121-0547	ALCOHOL
Pharmaceutical Associates Inc	promethazine hydrochloride and codeine phosphate	0121-0547	CITRIC ACID MONOHYDRATE
Pharmaceutical Associates Inc	promethazine hydrochloride and codeine phosphate	0121-0547	D&C RED NO. 33

What are the Most Frequently-Used Excipients in PROMETHAZINE HYDROCHLORIDE AND CODEINE PHOSPHATE?

# Of NDCs	Excipient
12	ALCOHOL
10	ANHYDROUS CITRIC ACID
10	ASCORBIC ACID

Promethazine Hydrochloride and Codeine Phosphate: Excipient Strategy and Commercial Opportunities

Last updated: September 24, 2026

Promethazine hydrochloride and codeine phosphate is an oral antitussive combination with a constrained but commercially viable market. The main product opportunity is not a new active-ingredient profile. It is a differentiated oral solution that improves taste, reduces alcohol and sugar exposure, supports pediatric-safe labeling boundaries, and simplifies manufacturing and distribution.

The combination carries substantial regulatory and commercial restrictions. Codeine is an opioid controlled substance, and promethazine-codeine products have boxed warnings for respiratory depression, addiction, misuse, and potentially fatal pediatric toxicity. FDA labeling prohibits use in children younger than 12 years and restricts use in certain adolescents after tonsillectomy or adenoidectomy.[1,2] These restrictions narrow the addressable market and increase the value of compliant packaging, controlled distribution, and clear labeling.

What dosage forms and formulations contain promethazine hydrochloride and codeine phosphate?

The principal U.S. dosage form is an oral solution containing promethazine hydrochloride and codeine phosphate. A common concentration is 6.25 mg promethazine hydrochloride and 10 mg codeine phosphate per 5 mL, although products may differ in concentration and inactive ingredients.

Product attribute	Typical commercial profile
Active ingredients	Promethazine hydrochloride and codeine phosphate
Primary dosage form	Oral solution
Common strength	6.25 mg/10 mg per 5 mL
Route	Oral
Therapeutic category	Prescription antitussive and antihistamine combination
Controlled-substance status	Codeine-containing prescription product; scheduling depends on formulation and jurisdiction
Main excipient issues	Taste, alcohol, sugar, viscosity, microbial control, color, sedimentation, dose measurement
Main commercial channels	Retail pharmacy, specialty and independent pharmacies, institutional and limited-distribution channels

The reference formulation commonly includes sucrose, glycerin, flavoring agents, sodium benzoate, citric acid or citrate buffers, saccharin sodium, purified water, and colorants. Some products also contain alcohol. Excipients vary by manufacturer and approved product. A proposed formulation must be assessed against the FDA Inactive Ingredient Database, applicable FDA regulations, compendial standards, and the product’s approved labeling.[3,4]

Which excipients create the greatest commercial value?

Taste masking is usually the highest-value excipient objective. Codeine has a strong bitter taste, while promethazine can contribute bitterness and throat sensation. Pediatric use is restricted, but adult adherence and caregiver acceptance still depend on palatability.

Taste-masking system

A commercially differentiated formulation may combine:

• High-intensity sweetener with controlled aftertaste
• Flavor systems selected for opioid bitterness
• pH adjustment to manage both taste and chemical stability
• Viscosity enhancement to reduce rapid oral spread
• Flavor encapsulation or polymeric taste-masking technology
• Lower levels of colorant to improve patient acceptability

A conventional sucrose-and-flavor system is inexpensive and familiar but has limited differentiation. A formulation that reduces bitterness without increasing viscosity excessively could support line extensions, private-label supply, or a licensing package.

Sugar-free formulation

A sugar-free oral solution can target adults with diabetes, reduced-sugar preferences, and institutional formularies seeking lower excipient burden. Suitable sweetener systems may include sorbitol, sucralose, acesulfame potassium, or combinations of sweeteners. Each option creates formulation tradeoffs:

Excipient strategy	Commercial advantage	Main technical risk
Sucrose-based	Strong taste profile and low cost	Sugar exposure; unsuitable for some patients
Sorbitol-based	Sugar-free positioning and body	Gastrointestinal tolerability and osmolarity
Sucralose-based	High sweetness at low concentration	Aftertaste and flavor interaction
Acesulfame potassium blend	Strong sweetness and low solids	Bitter or metallic notes if poorly balanced
Polyol blend	Mouthfeel and sugar-free profile	Dose-dependent laxation risk

A sugar-free claim requires disciplined control of residual sugars, manufacturing cross-contamination, labeling, and analytical verification. The formulation must also retain acceptable viscosity and microbial stability without relying on sucrose as a major solids contributor.

Alcohol-free formulation

Alcohol-free products address patients who avoid ethanol, institutional purchasing policies, and product-positioning concerns. Removing alcohol can affect:

• Solubilization of flavor components
• Preservative performance
• Taste and mouthfeel
• Microbial robustness
• Chemical stability
• Container-closure compatibility

An alcohol-free product may need a revised preservative system, better water activity control, optimized pH, or higher packaging controls. The commercial value is strongest when the formulation can preserve stability and palatability without a material increase in cost or dosing complexity.

How should formulators select preservatives and buffers?

Oral solutions containing water and organic flavor components require validated microbial control. Sodium benzoate is common in acidic oral liquids, but its performance depends on pH because the unionized form provides the principal antimicrobial activity. A citrate or citric acid buffer can support preservative effectiveness and improve taste, but excessive acidity may increase sourness or irritate the throat.

The formulation-development program should assess:

1. Preservative efficacy across the proposed pH range.
2. Compatibility with codeine phosphate and promethazine hydrochloride.
3. Flavor stability during long-term and accelerated storage.
4. Interaction with plastic bottles, liners, caps, and dosing devices.
5. Microbial limits and preservative content at release and expiry.
6. Impact of sugar replacement on water activity and microbial growth.

A formulation that uses less preservative may be commercially attractive, but the benefit is limited unless it produces a measurable improvement in tolerability, labeling, or stability. Preservation claims should be supported by USP antimicrobial effectiveness testing and product-specific stability data.[5]

What manufacturing and packaging barriers affect commercial entry?

The product is relatively simple compared with sterile injectables, but oral solutions have several failure points. Promethazine hydrochloride and codeine phosphate must remain uniformly distributed in every dose. The product must avoid precipitation, crystal growth, color drift, flavor loss, and microbial contamination.

Manufacturing controls

Key manufacturing controls include:

• Order of addition for active ingredients and excipients
• Control of solution pH
• Mixing time and shear
• Temperature exposure
• Filtration strategy
• Bulk-hold time
• In-process assay and uniformity testing
• Control of preservative and flavor concentrations

Codeine phosphate is water soluble, but the full formulation still requires compatibility evaluation. Flavor oils, dyes, sweeteners, and preservatives can alter solubility or stability. A high-viscosity system may improve dosing behavior but can complicate transfer, filtration, filling, and cleaning validation.

Packaging and dose delivery

Packaging is a meaningful differentiation area. A 5-mL dose can be measured inaccurately with household spoons, creating an opioid-exposure risk. Commercial products should use a calibrated oral syringe or dosing cup, with clear volume markings and child-resistant packaging.

Potential packaging innovations include:

• Unit-dose cups for institutional use
• Metered oral syringes
• Tamper-evident closures
• Light-protective bottles where stability data support the requirement
• Low-sorption container systems
• Smaller bottle sizes to reduce diversion and waste
• Serialization and controlled-distribution packaging

Packaging claims must be supported by extractables and leachables, container-closure integrity, dose-delivery accuracy, and stability studies.

What FDA regulatory pathway applies to a new product?

A new product containing the same active ingredients and dosage form would generally require an abbreviated new drug application if it can demonstrate pharmaceutical equivalence and bioequivalence to a suitable reference listed drug. Differences in inactive ingredients may be acceptable when they do not affect safety, efficacy, bioequivalence, or labeling requirements.[6]

A formulation with a materially different dosage form, delivery mechanism, concentration, or therapeutic claim may require a different regulatory strategy. A novel excipient or unusually high level of an excipient can create additional FDA review risk, particularly where the ingredient is not established for the proposed route and patient population.

The commercial advantage of an ANDA-based product is lower development cost and a shorter clinical pathway. The disadvantage is narrower freedom to make claims and limited ability to protect routine formulation changes through strong patent claims.

What patents can protect a promethazine-codeine formulation?

Routine excipient substitutions generally have weak patent value. Stronger protection may arise from a formulation that demonstrates an unexpected technical result, such as:

• Superior taste masking at a defined pH
• Improved stability without alcohol
• Lower preservative concentration with equivalent microbial protection
• Reduced precipitation or crystallization
• Controlled viscosity with improved dosing accuracy
• A novel flavor-encapsulation system
• A distinctive unit-dose or metered-delivery system
• A manufacturing process that materially improves impurity control

Potential patent categories include composition-of-matter claims directed to the oral liquid, concentration ranges, excipient ratios, pH ranges, preservative systems, taste-masking complexes, packaging combinations, and manufacturing processes.

Patent scope must be tested against prior art in oral opioid solutions, promethazine formulations, pharmaceutical taste masking, preservative systems, and pediatric liquid medicines. Orange Book listing is not automatic for every formulation patent. A patent must satisfy FDA listing requirements and relate to the approved drug substance, drug product, or method of use.[7]

What is the Orange Book and exclusivity position?

Promethazine-codeine products are prescription drug products subject to FDA approval and, where applicable, Orange Book listing. The commercial value of any specific patent position depends on the reference listed drug, approved NDA, listed patents, expiration dates, pediatric exclusivity, and the existence of approved ANDAs.

A product-by-product Orange Book review should examine:

Review item	Commercial relevance
Reference listed drug	Determines the ANDA reference point
Listed formulation patents	May delay or complicate generic approval
Method-of-use patents	Relevant only to the approved and labeled use
Patent expiration dates	Determines potential entry timing
30-month litigation stay	May delay ANDA approval after a timely Paragraph IV suit
Regulatory exclusivity	May restrict approval independently of patents
Approved generic applicants	Indicates competitive entry pressure

Paragraph IV risk is usually more relevant to the reference product and listed patents than to a newly developed line extension. An ANDA applicant may challenge listed patents by certifying that they are invalid, unenforceable, or will not be infringed. A patent owner can initiate litigation within the statutory period, potentially creating a 30-month stay of approval under the Hatch-Waxman framework.[8]

Current patent numbers, assignees, litigation status, and expiry dates require a live review of FDA Orange Book records, USPTO records, and federal court dockets. They should not be inferred from legacy product labels or discontinued listings.

Which commercial opportunities are most attractive?

The best opportunities are differentiated products that address a clear purchasing or adherence problem while remaining compatible with an ANDA or 505(b)(2) strategy.

Opportunity ranking

Opportunity	Market rationale	Development difficulty	IP potential
Sugar-free oral solution	Broad excipient differentiation and institutional relevance	Moderate	Moderate
Alcohol-free oral solution	Clear positioning and reduced excipient burden	Moderate to high	Moderate
Improved taste-masked solution	Better adherence and caregiver acceptance	Moderate	Moderate to high
Unit-dose packaging	Reduced dosing and diversion risk	Low to moderate	Low to moderate
Preservative-optimized product	Differentiation for sensitive patients	Moderate	Moderate
Novel extended-release product	Potentially differentiated dosing profile	High	High, but regulatory risk is high
Pediatric-positioned product	Limited by FDA safety restrictions	High commercial risk	Low unless indication changes

The strongest near-term strategy is usually a sugar-free, alcohol-free oral solution with effective taste masking, calibrated dosing, robust stability, and controlled packaging. The product should not be positioned for children outside the approved label. Pediatric marketing claims would create significant FDA and liability exposure because of codeine-associated respiratory depression and pharmacogenetic variability.

How does the product compare with competing cough medicines?

Promethazine-codeine competes with non-opioid antitussives, antihistamine combinations, dextromethorphan products, benzonatate, and prescription cough products without codeine. Its commercial weakness is regulatory restriction and opioid-related safety scrutiny. Its potential advantage is perceived efficacy for severe cough in selected adult patients.

Product category	Main advantage	Main limitation
Promethazine-codeine	Established prescription combination	Opioid controls, respiratory risk, restricted populations
Dextromethorphan	Broad availability and lower regulatory burden	Variable efficacy and abuse concerns
Benzonatate	Non-opioid prescription option	Swallowing and overdose risks
Promethazine alone	Antihistamine and antiemetic utility	Does not provide opioid antitussive activity
Nonprescription antihistamine combinations	Low access barrier	Sedation and limited cough specificity

A manufacturer should avoid relying on opioid efficacy alone. Differentiation should focus on formulation quality, supply reliability, label compliance, packaging, and pharmacy-channel execution.

What licensing and partnership models are available?

Licensing opportunities are most credible in four areas:

1. A ready-to-file formulation package with stability and preservative data.
2. A patented taste-masking or alcohol-free formulation.
3. A contract-manufacturing platform with controlled-substance capabilities.
4. A packaging and distribution system designed for pharmacies and institutions.

Controlled-substance manufacturing requires specialized compliance, inventory controls, security procedures, DEA registration, and quota management where applicable. These requirements can make a qualified contract manufacturer more valuable than a conventional oral-liquid manufacturer.

A partnership should allocate responsibility for controlled-substance procurement, forecasting, recalls, serialization, pharmacovigilance, adverse-event reporting, and diversion monitoring. A formulation license without a credible controlled-substance supply chain has limited value.

What generic launch risks exist?

Generic entry risk is high where multiple ANDA applicants can use the same reference product and the formulation has limited technical differentiation. Commercial exposure is greatest for products that compete primarily on price.

Launch timing can be affected by:

• ANDA approval and tentative approval
• Paragraph IV litigation
• Patent expiration
• FDA manufacturing inspections
• Controlled-substance supply limits
• Active pharmaceutical ingredient availability
• Product-specific shortages
• Contract manufacturing capacity
• State prescribing restrictions and payer controls

Revenue forecasts should use scenario analysis rather than a single launch date. A differentiated formulation may preserve margins, but routine sugar-free or flavor changes may not prevent substitution if multiple therapeutically equivalent products are approved.

Key Takeaways

• Promethazine hydrochloride and codeine phosphate is primarily an oral-solution opportunity.
• The highest-value excipient strategies are taste masking, sugar reduction, alcohol removal, preservative optimization, and reliable dose delivery.
• Pediatric positioning is commercially restricted by FDA codeine safety warnings and labeling limits.
• A sugar-free, alcohol-free product has the clearest near-term differentiation path.
• Formulation patents require more than routine excipient substitution. They should focus on unexpected stability, taste, preservation, delivery, or manufacturing results.
• Orange Book, Paragraph IV, patent-expiry, and litigation conclusions must be made at the specific NDA and product level.
• Controlled-substance manufacturing, packaging, distribution, and diversion controls are material barriers to entry.
• The most defensible commercial model combines a differentiated formulation with an experienced controlled-substance manufacturer and pharmacy-focused distribution.

FAQs

Can promethazine-codeine oral solution be reformulated without alcohol?

Yes. An alcohol-free formulation is technically feasible, but the developer must revalidate solubility, preservative efficacy, flavor stability, microbial control, and container compatibility.

Is a sugar-free promethazine-codeine product automatically patentable?

No. Sugar replacement alone is usually weak patent subject matter. Patent value improves when the formulation demonstrates an unexpected technical result, such as superior taste, stability, or microbial protection.

Does codeine make the product unsuitable for all pediatric use?

FDA labeling prohibits use in children younger than 12 years and restricts use in certain adolescents. The approved label, not a general marketing assumption, controls the permitted population.[1,2]

Can a formulation patent be listed in the Orange Book?

Potentially, if it meets FDA listing requirements and claims the approved drug product or an approved method of use. Not every excipient or manufacturing patent qualifies for listing.[7]

What is the most practical product-development concept?

A calibrated-dose, sugar-free, alcohol-free oral solution with improved bitterness control, validated preservative performance, child-resistant packaging, and a controlled-substance-compliant supply chain is the most practical differentiated concept.

References

1. U.S. Food and Drug Administration. (2023). Promethazine hydrochloride and codeine phosphate oral solution: Prescribing information.
2. U.S. Food and Drug Administration. (2017). 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. (n.d.). Inactive Ingredient Database.
4. U.S. Food and Drug Administration. (2024). Code of Federal Regulations, Title 21, Part 172 and Part 182.
5. United States Pharmacopeia. (2023). General chapter <51>: Antimicrobial effectiveness testing. In United States Pharmacopeia and National Formulary.
6. U.S. Food and Drug Administration. (2024). ANDA submissions: Content and format.
7. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations.
8. U.S. Congress. (1984). Drug Price Competition and Patent Term Restoration Act of 1984, Pub. L. No. 98-417.