List of Excipients in Branded Drug NAPROXEN SODIUM DIPHENHYDRAMINE HCL

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Generic Drugs Containing NAPROXEN SODIUM DIPHENHYDRAMINE HCL

Company	Ingredient	NDC	Excipient
WALGREEN CO	naproxen sodium diphenhydramine hcl	0363-9766	CELLULOSE, MICROCRYSTALLINE
WALGREEN CO	naproxen sodium diphenhydramine hcl	0363-9766	FD&C BLUE NO. 2--ALUMINUM LAKE
WALGREEN CO	naproxen sodium diphenhydramine hcl	0363-9766	HYPROMELLOSE 2910
WALGREEN CO	naproxen sodium diphenhydramine hcl	0363-9766	MAGNESIUM STEARATE

What are the Most Frequently-Used Excipients in NAPROXEN SODIUM DIPHENHYDRAMINE HCL?

# Of NDCs	Excipient
3	CELLULOSE, MICROCRYSTALLINE
3	FD&C BLUE NO. 2--ALUMINUM LAKE
3	HYPROMELLOSE 2910
3	MAGNESIUM STEARATE

Naproxen Sodium and Diphenhydramine HCl: Excipient Strategy, Patent Position and Commercial Opportunities

Last updated: November 5, 2026

Naproxen sodium plus diphenhydramine HCl is a technically straightforward immediate-release OTC combination for nighttime relief of pain and sleeplessness associated with minor aches. The strongest commercial opportunity is a low-cost, private-label or regional brand using a conventional film-coated tablet, differentiated through packaging, dose convenience, retailer placement and supply reliability rather than difficult formulation science.

The combination has limited intrinsic composition-of-matter protection. In the United States, the main regulatory and intellectual-property questions concern OTC monograph compliance, labeling, formulation-specific patents, trade secrets, trademarks and manufacturing economics. The leading branded benchmark, Aleve PM, uses naproxen sodium with diphenhydramine citrate rather than diphenhydramine HCl, creating a potential formulation and labeling distinction for products using the hydrochloride salt. [1]

What is naproxen sodium diphenhydramine HCl?

Naproxen sodium is the sodium salt of naproxen, a nonsteroidal anti-inflammatory drug used for analgesic and antipyretic indications. Diphenhydramine HCl is a first-generation antihistamine with sedating properties and is used in OTC sleep-aid products.

A typical commercial concept would contain:

Component	Typical role
Naproxen sodium	Analgesic and anti-inflammatory active
Diphenhydramine HCl	Sedating sleep-aid active
Microcrystalline cellulose	Filler and compression aid
Croscarmellose sodium or crospovidone	Disintegrant
Povidone	Binder
Colloidal silicon dioxide	Flow aid
Magnesium stearate or sodium stearyl fumarate	Lubricant
Film-coating system	Swallowability, appearance and moisture protection

A common strength strategy would be naproxen sodium 220 mg with diphenhydramine HCl equivalent to 25 mg diphenhydramine per tablet. The exact strength, salt equivalence and labeling must comply with the applicable FDA requirements and the product’s regulatory pathway.

How does diphenhydramine HCl compare with diphenhydramine citrate?

The commercial benchmark matters because diphenhydramine salts are not interchangeable on a mass basis.

Attribute	Diphenhydramine HCl	Diphenhydramine citrate
Salt form	Hydrochloride	Citrate
Active-equivalent calculation	Must be stated against diphenhydramine base	Must be stated against diphenhydramine base
Common dosage-form use	Tablets, capsules, liquids	OTC nighttime products, including Aleve PM
Formulation impact	Can affect hygroscopicity, density and dissolution	Can affect tablet weight, flow and taste
Labeling risk	Risk of confusing salt weight with active-equivalent weight	Same equivalence issue
Commercial implication	Potentially distinct product formulation	Established branded benchmark

The key formulation rule is to control the amount of diphenhydramine free-base equivalent, not simply the milligrams of salt. A product labeled as containing 25 mg diphenhydramine must use the correct salt conversion and analytical assay.

What excipients are most suitable for the combination?

Direct-compression strategy

Direct compression is the most commercially attractive approach when both active ingredients have suitable particle-size distribution, flow and compactability. It minimizes processing steps, lowers manufacturing cost and reduces exposure to heat and water.

A practical platform would use:

• Microcrystalline cellulose for compactability.
• Anhydrous dibasic calcium phosphate or mannitol where higher density is needed.
• Croscarmellose sodium or crospovidone for rapid disintegration.
• Colloidal silicon dioxide to improve powder flow.
• Sodium stearyl fumarate where magnesium stearate may slow dissolution.
• A low-weight hypromellose film coat with titanium dioxide or approved colorants.

The principal challenge is content uniformity. Diphenhydramine HCl is present at a much lower mass than naproxen sodium, which increases segregation risk during blending and tablet compression. Ordered mixing, particle-size matching, geometric dilution and validated blend sampling are more important than exotic excipient selection.

Dry-granulation strategy

Roller compaction is a stronger option when the active blend has poor flow, excessive dusting or segregation. It avoids water exposure and can support high-throughput production. The process may increase tablet tensile strength but can also reduce porosity and delay disintegration if compaction force is excessive.

Dry granulation is particularly relevant for private-label production because it can accommodate different API suppliers without redesigning the entire formulation.

Wet-granulation strategy

Wet granulation should be reserved for blends that cannot achieve acceptable content uniformity or mechanical strength by direct compression and dry granulation. It increases cost, processing time and validation burden. Water, residual moisture and drying conditions must be controlled because they can affect tablet hardness, disintegration and long-term stability.

Film coating and packaging

A film coat can improve swallowability and distinguish the product from plain naproxen tablets. It also provides limited protection against abrasion and environmental exposure. The coating should remain thin enough to preserve immediate release.

High-barrier blister packaging may provide a stronger stability solution than a low-cost bottle, particularly where diphenhydramine HCl or the finished blend shows moisture sensitivity. For mass-market products, HDPE bottles with desiccant can reduce packaging cost, but stability data must support the configuration.

What formulation risks affect product development?

The main technical risks are:

1. Blend segregation. The low-dose diphenhydramine component can separate from the higher-load naproxen component.
2. Dissolution interference. Hydrophobic lubricants and over-compression can slow release.
3. Tablet size. A 220 mg naproxen sodium dose plus excipients and diphenhydramine salt can create a large tablet.
4. Stability. Moisture, heat and packaging permeability may affect assay, dissolution and appearance.
5. Salt-equivalence errors. The label must accurately express diphenhydramine content.
6. Dose-timing risk. The sedating ingredient requires clear nighttime-use directions.
7. NSAID safety labeling. Naproxen products carry gastrointestinal, cardiovascular, renal, bleeding and pregnancy-related warnings.

A bilayer tablet could separate the two actives and create formulation-specific differentiation, but it also adds equipment, yield loss, tooling expense and validation complexity. It is unlikely to be commercially justified unless the sponsor has a demonstrated stability, compatibility or branding objective.

What is the FDA regulatory status of this combination?

The two active ingredients are established OTC ingredients, but a combination product must satisfy the requirements applicable to each ingredient and the combination’s labeling, dosage and directions.

FDA’s OTC framework has moved from traditional monographs toward administrative orders under the CARES Act. Sponsors must assess the current status of the applicable analgesic/antipyretic and nighttime sleep-aid requirements rather than rely only on historical monograph language. [2] Naproxen sodium is addressed within the OTC internal analgesic framework, while diphenhydramine is used in OTC nighttime sleep-aid products under conditions governing indications, warnings and directions. [3]

The product’s regulatory pathway depends on the precise formulation, claims, strength, labeling and market history. A new combination or materially different presentation may require an FDA submission even when each active ingredient is well established.

What is the Orange Book status of naproxen sodium and diphenhydramine HCl?

The Orange Book is primarily relevant to approved prescription and certain approved nonprescription drug applications. A product marketed under the OTC monograph system generally does not have the same Orange Book patent-listing structure as an NDA product.

The active-ingredient names alone do not establish an Orange Book patent listing or a blocking patent. A sponsor should not assume that the absence of an Orange Book listing means the product is free of all patent risk. Patent exposure can arise from:

• Formulation patents.
• Coating and bilayer-tablet patents.
• Packaging patents.
• Manufacturing-process patents.
• Method-of-use patents.
• Trade dress and trademark rights.
• Contractual restrictions involving API or contract-manufacturing supply.

For a conventional immediate-release tablet using known excipients, the likely patent position is weaker than for an extended-release, liquid-gel, transdermal or multiparticulate formulation.

How many patents cover the combination?

No definitive patent count can be assigned from the ingredient names alone. Patent scope depends on the specific product, jurisdiction, dosage form and formulation features.

The active ingredients are old chemical entities, so new composition-of-matter protection for naproxen sodium or diphenhydramine HCl is not the expected commercial barrier. The more relevant patent categories are secondary rights covering:

Patent category	Relevance to a conventional tablet
Combination composition	Potentially limited if claims broadly cover known actives
Immediate-release formulation	Moderate risk if specific excipient ratios or dissolution profiles are claimed
Bilayer or multilayer tablet	Higher risk if the product uses physical separation
Modified release	Relevant only if release is intentionally altered
Film coating	Usually narrow and design-around possible
Packaging	Usually product-specific and avoidable
Method of use	Relevant to particular nighttime pain indications
Manufacturing process	Relevant when process parameters are essential to product performance

A patent search should cover the exact salt form, strength, dosage form and intended claims in the United States, European Union, Canada, Australia and major emerging markets. The USPTO Patent Center and WIPO PATENTSCOPE are the primary public search systems for this work. [4,5]

When does this product lose exclusivity?

There is no single exclusivity date for the ingredient combination.

Naproxen and diphenhydramine have long-established histories. The commercial exclusivity of a new product would instead depend on:

• Any newly granted formulation patent.
• Any method-of-use patent.
• FDA regulatory exclusivity, if applicable.
• Trademark duration and renewal.
• Market adoption and retailer contracts.
• Manufacturing scale and cost position.

For a conventional OTC product with no enforceable formulation patent, competitive entry can occur once the entrant has completed regulatory, quality and commercial requirements. Paragraph IV certification is generally associated with an ANDA referencing an approved drug application and listed patents. It is not the central pathway for a product marketed solely under the OTC monograph system. [6]

What commercial opportunities exist?

Private-label and store-brand products

Retailers can position the product as a lower-cost alternative to branded nighttime pain relievers. The formula is suitable for national pharmacy, grocery, club and e-commerce channels. The principal advantages are low formulation complexity, broad consumer familiarity and access to existing tablet manufacturing capacity.

Regional brand launches

A regional brand can differentiate through:

• Smaller tablets.
• Easy-open packaging.
• Unit-dose blister packs.
• Clear nighttime labeling.
• Spanish-language and multilingual packaging.
• Travel-size packs.
• Retailer-exclusive packaging.
• Lower tablet count and lower upfront price.

Contract-manufacturing platform

A manufacturer with validated naproxen and diphenhydramine processes can offer multiple configurations from one core blend. Potential variants include bottle, blister, caplet, coated tablet and retailer-specific pack sizes. The best economies arise from shared raw-material specifications, common tooling and a single validated manufacturing process.

International markets

The opportunity is strongest where nighttime analgesic products are established and OTC pharmacy distribution is developed. Geographic expansion requires separate review of:

• Permitted salt forms.
• Maximum daily doses.
• Sedating antihistamine rules.
• NSAID warnings.
• Combination-product registration.
• Local language requirements.
• Advertising restrictions.
• Pharmacist-only or prescription classifications.

A product compliant in the United States may require a different dose, label or regulatory pathway elsewhere.

Which companies are challenging the branded market?

The competitive field includes the branded manufacturer, national generic and private-label OTC companies, contract manufacturers and retailers with store brands. The product is not dependent on a proprietary delivery system, so competition is likely to focus on procurement, shelf placement, packaging, consumer trust and price.

The most credible entrants are companies that already manufacture:

• Naproxen sodium tablets.
• Diphenhydramine tablets or capsules.
• OTC combination analgesics.
• Film-coated immediate-release products.
• Blister-packed pharmacy products.

No major biosimilar issue applies. Naproxen sodium and diphenhydramine HCl are small-molecule ingredients, not biologics.

What generic launch risks exist?

The primary launch risks are regulatory and operational rather than scientific.

Risk	Business impact	Mitigation
Diphenhydramine content-uniformity failure	Batch rejection or delay	Ordered blending and low-dose assay controls
Slow dissolution	Regulatory deficiency or recall	Control lubricant level and compression force
API supply disruption	Lost retailer supply	Dual-source qualified APIs
Labeling error	FDA action and product withdrawal	Salt-equivalence and warning review
Excessive tablet size	Lower consumer acceptance	High-density excipients and tooling optimization
Moisture instability	Reduced shelf life	Barrier packaging and accelerated stability testing
Patent or trade-dress conflict	Injunction or redesign cost	Freedom-to-operate and packaging review
Sedation-related complaints	Reputation and retailer pressure	Prominent nighttime-use warnings

How strong is the patent estate?

The likely patent estate for a standard immediate-release naproxen sodium/diphenhydramine HCl tablet is weak to moderate, depending on the specific formulation and jurisdiction. Broad protection based only on the two known active ingredients is vulnerable to prior-art challenges. Narrow claims directed to a defined dissolution profile, excipient ratio, tablet architecture or manufacturing process may be more defensible but are easier to design around.

Commercial defensibility is therefore more likely to come from:

• Reliable supply.
• Lower cost per dose.
• Retail distribution.
• Brand recognition.
• Packaging differentiation.
• Manufacturing quality.
• Consumer reviews and repeat purchase.

Key Takeaways

• Naproxen sodium plus diphenhydramine HCl is a low-complexity OTC combination with a conventional immediate-release tablet opportunity.
• Direct compression is the preferred initial manufacturing strategy; dry granulation is the main fallback.
• Content uniformity, salt equivalence, dissolution and moisture control are the core technical issues.
• The branded benchmark Aleve PM uses diphenhydramine citrate, so HCl-based products require careful dose-equivalence and labeling control.
• Patent risk is more likely to arise from formulation, process, packaging or method-of-use claims than from the active ingredients.
• Orange Book analysis may not provide a complete freedom-to-operate assessment for an OTC monograph product.
• The strongest commercial routes are private label, regional OTC brands and contract-manufacturing platforms.
• No biosimilar pathway applies because the product contains small-molecule active ingredients.

FAQs

Is naproxen sodium with diphenhydramine HCl the same as Aleve PM?

No. Aleve PM is commonly labeled with naproxen sodium and diphenhydramine citrate. A product using diphenhydramine HCl uses a different salt and must calculate and label the diphenhydramine active-equivalent amount correctly. [1]

Can naproxen sodium and diphenhydramine HCl be formulated in one tablet?

Yes. A conventional immediate-release, film-coated tablet is technically feasible. The main development issue is achieving uniform distribution of the lower-dose diphenhydramine component throughout the higher-load naproxen blend.

Is an extended-release version commercially attractive?

It may offer differentiation, but it adds formulation, patent and regulatory risk. The nighttime product concept generally favors rapid release of both actives rather than a complex extended-release profile.

Does an OTC combination require a Paragraph IV certification?

Not necessarily. Paragraph IV certification is generally tied to an ANDA referencing an approved application with listed patents. A product proceeding under the OTC monograph system may follow a different regulatory route. [6]

Which excipient creates the greatest dissolution risk?

Magnesium stearate is a common risk when used at excessive levels or blended for too long. Over-compression and high hydrophobic-lubricant loading can reduce tablet wetting and slow immediate release.

References

1. DailyMed. (n.d.). Aleve PM: Naproxen sodium and diphenhydramine citrate tablet, film coated. U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/

2. U.S. Food and Drug Administration. (2022). Over-the-counter monograph drug products. https://www.fda.gov/drugs/over-counter-otc-nonprescription-medicines

3. U.S. Food and Drug Administration. (n.d.). OTC monograph M009: Nighttime sleep-aid drug products. https://www.accessdata.fda.gov/

4. United States Patent and Trademark Office. (n.d.). Patent Center. https://patentcenter.uspto.gov/

5. World Intellectual Property Organization. (n.d.). PATENTSCOPE. https://patentscope.wipo.int/

6. U.S. Food and Drug Administration. (n.d.). Paragraph IV patent certifications. https://www.fda.gov/drugs/abbreviated-new-drug-application-anda/paragraph-iv-certifications