List of Excipients in Branded Drug ELIXOPHYLLIN

Generic Drugs Containing ELIXOPHYLLIN

Company	Ingredient	NDC	Excipient
Atlantic Biologicals Corps	theophylline anhydrous	17856-0644	CITRIC ACID MONOHYDRATE
Atlantic Biologicals Corps	theophylline anhydrous	17856-0644	FD&C RED NO. 40
Atlantic Biologicals Corps	theophylline anhydrous	17856-0644	GLYCERIN

What are the Most Frequently-Used Excipients in ELIXOPHYLLIN?

# Of NDCs	Excipient
2	ALCOHOL
2	ANHYDROUS CITRIC ACID
1	CITRIC ACID MONOHYDRATE

Elixophyllin Excipient Strategy and Commercial Opportunities

Last updated: September 5, 2026

Elixophyllin is an oral theophylline elixir containing 80 mg of theophylline anhydrous per 15 mL. Its commercial position depends less on active-ingredient exclusivity than on reliable liquid formulation performance, dose flexibility, pediatric usability, supply continuity, and differentiation from generic theophylline tablets, capsules, and oral solutions. The most attractive opportunities are alcohol-reduced or alcohol-free reformulation, improved taste masking, preservative optimization, unit-dose packaging, and pharmacy-compounded or institutional presentations.

What is Elixophyllin and which excipients define its formulation?

Elixophyllin is an immediate-release oral liquid formulation of theophylline, a methylxanthine bronchodilator. The labeled strength is 80 mg per 15 mL, equivalent to approximately 5.33 mg/mL.[1]

Public product labeling identifies excipient classes associated with the formulation, including alcohol, glycerin, sorbitol, sodium benzoate, saccharin sodium, flavoring, coloring, and purified water.[1] Exact inactive-ingredient listings should be confirmed against the current FDA-approved labeling and National Drug Code presentation because commercial formulations and manufacturing sites can change.

Formulation function	Likely Elixophyllin excipient or excipient class	Commercial purpose
Solvent and cosolvent	Purified water, alcohol	Dissolves or solubilizes formulation components and supports product clarity
Humectancy and mouthfeel	Glycerin, sorbitol	Reduces harshness, adds body, and improves palatability
Sweetening	Saccharin sodium, sorbitol	Masks the bitter taste of theophylline
Preservation	Sodium benzoate, alcohol	Controls microbial growth in a multidose aqueous product
Flavor system	Proprietary flavor	Improves patient acceptability
Appearance	Approved colorant	Supports product identification and taste expectations
Active ingredient	Theophylline anhydrous	Immediate-release bronchodilator

The formulation strategy is conventional for an oral elixir: combine water with a cosolvent, sweeteners, humectants, a preservative system, flavor, and color. The principal technical constraint is theophylline’s narrow therapeutic index. Any change affecting dissolution, gastrointestinal transit, absorption rate, or dose measurement can have clinical significance.[2]

How does the Elixophyllin excipient system affect commercial performance?

The excipient system supports a liquid product with flexible dosing, but it also creates several commercial liabilities.

Alcohol content

Alcohol can improve solubilization and microbial robustness, but it creates labeling, pediatric-use, caregiver, institutional, and international-market restrictions. Alcohol exposure is particularly relevant where the product is used in children, patients with alcohol sensitivity, or patients receiving multiple liquid medicines.

An alcohol-reduced or alcohol-free version could create a differentiated product if it maintains chemical stability, preservative effectiveness, clarity, and dose uniformity. A reformulation would require comparative pharmaceutical development and regulatory support. It would not automatically qualify as a simple line extension if the excipient change affects safety, stability, bioavailability, or labeling.

Sorbitol and gastrointestinal tolerability

Sorbitol contributes sweetness and viscosity. At sufficient exposure, it can cause gastrointestinal discomfort or laxative effects. The risk is relevant to pediatric patients and patients receiving repeated doses. A lower-sorbitol formulation using a mixed sweetener system could improve tolerability without materially changing the product’s sensory profile.

Sorbitol also creates compatibility issues for certain patient populations, including those with hereditary fructose intolerance if the formulation contains or generates relevant sugars. The precise label language and excipient specification must control the risk assessment.

Sodium benzoate and preservative strategy

Sodium benzoate is a common preservative in oral liquids. Its use requires control of pH, because benzoic acid and benzoate preservative activity is pH-dependent. The formulation must balance preservative efficacy with taste, theophylline stability, color stability, and packaging compatibility.

A preservative system based on potassium sorbate, benzoic acid, or a combination could support an alternative formulation, but substitution requires preservative-effectiveness testing under the applicable pharmacopeial standard. The new system must be assessed against the finished product’s microbial risk, container closure, in-use period, and dosing environment.

Saccharin sodium and taste masking

Theophylline has a bitter taste. Saccharin sodium provides intense sweetness at low concentration, but it may leave a metallic or lingering aftertaste. A modern taste-masking system could use sucralose, acesulfame potassium, steviol glycosides, flavor modulators, or polymeric taste-masking technology.

The opportunity is strongest in pediatric and geriatric segments, where adherence can be limited by bitterness. A taste study should use the target patient population or a validated adult surrogate model, with testing for sweetness intensity, bitterness, aftertaste, mouthfeel, and willingness to repeat dosing.

Flavor and color

Flavor is a high-impact but underprotected commercial variable. Fruit flavors, vanilla systems, and flavor modulators can alter patient preference without changing the drug’s pharmacology. Color may improve product recognition but can introduce allergy concerns, regulatory restrictions, and sourcing exposure.

A color-free product could be positioned for patients sensitive to colorants. A single-flavor product has lower complexity, while a platform using multiple flavor options increases SKU, stability, and supply-chain requirements.

What formulation patents could protect a new Elixophyllin product?

The original Elixophyllin liquid formulation is unlikely to have meaningful remaining composition-of-matter or formulation exclusivity because theophylline products have been marketed for decades. Commercial protection would therefore depend on new intellectual property, regulatory exclusivity, manufacturing know-how, or brand execution.

Potential patent claims could cover:

1. An alcohol-free theophylline liquid with defined pH, preservative concentration, and stability profile.
2. A taste-masked formulation using a specific sweetener-flavor combination.
3. A low-sorbitol or sorbitol-free formulation with controlled viscosity and dose uniformity.
4. A unit-dose packaging system that limits microbial contamination and dosing errors.
5. A concentrated formulation that reduces administration volume while maintaining bioavailability.
6. A formulation with improved stability under accelerated or in-use conditions.
7. A formulation compatible with enteral feeding tubes.
8. A pediatric formulation with defined alcohol, propylene glycol, sugar, and allergen limits.
9. A manufacturing process that produces consistent content uniformity in a low-dose-per-volume liquid.
10. A dual-compartment or powder-for-reconstitution presentation.

Patent strength would depend on whether the claims recite a non-obvious combination that produces measurable technical advantages. Broad claims to "theophylline plus a sweetener" or "theophylline in an oral liquid" would face substantial validity risk because of the extensive prior art.

Which intellectual-property assets would be most defensible?

The most defensible assets would be narrow, data-supported claims tied to a technical result. Examples include:

Potential claim area	Likely strength	Evidence required
Broad oral theophylline liquid	Low	Extensive prior-art review
Alcohol-free formulation	Low to moderate	Stability, solubility, preservative, and sensory data
Specific taste-masking system	Moderate	Comparative taste and dissolution data
Low-volume concentrated product	Moderate	Dose uniformity, bioavailability, tolerability
Enteral-tube-compatible formulation	Moderate	Tube recovery, clogging, adsorption, and stability data
Unit-dose package	Moderate	Microbial, usability, and package-performance data
Novel manufacturing process	Moderate to high	Reproducibility and unexpected process advantages
New device or dosing system	Moderate to high	Usability, dose accuracy, and non-obvious design

Trade secrets may provide better protection than patents for flavor ratios, mixing order, preservative adjustment, process parameters, and supplier specifications. Trade-secret value is limited if competitors can reverse-engineer the formulation through routine analytical testing.

When does Elixophyllin lose exclusivity and what is the generic-entry risk?

Theophylline has no meaningful modern active-ingredient exclusivity barrier. The relevant commercial risk is generic substitution and therapeutic competition, not loss of a near-term patent monopoly.

Elixophyllin’s market position is exposed to:

• Generic immediate-release theophylline oral solutions.
• Theophylline tablets and capsules.
• Extended-release theophylline products.
• Compounded oral liquids.
• Alternative bronchodilator therapies, including inhaled products.
• Hospital and long-term-care purchasing substitution.

The FDA’s Abbreviated New Drug Application pathway permits generic applicants to demonstrate bioequivalence to an approved reference product. An applicant may challenge listed patents through a Paragraph IV certification if relevant patents appear in the Orange Book.[3] For an older liquid product, the practical risk is that patent barriers may be limited or absent. The main barriers are product availability, reference-product sourcing, bioequivalence methodology, stability, manufacturing economics, and market size.

What is the Orange Book status of Elixophyllin?

The Orange Book identifies approved drug products, therapeutic equivalence evaluations, patent information, and exclusivity information where applicable.[3] Elixophyllin’s relevant Orange Book position should be assessed by its exact application number, strength, dosage form, and current marketing status.

For an established theophylline elixir, the expected regulatory profile is:

Issue	Strategic assessment
Active-ingredient patent	No practical modern barrier expected
New chemical entity exclusivity	Expired
Pediatric exclusivity	No current basis assumed
Orphan exclusivity	Not applicable to ordinary theophylline use
Listed formulation patents	Must be confirmed in the current Orange Book
Paragraph IV exposure	Possible if a new patent is listed, otherwise limited
Generic substitution	Material risk where therapeutically equivalent products are available
Reference-product dependence	Important for ANDA development and bioequivalence

No commercial plan should rely on legacy brand exclusivity. Protection must come from product attributes, supply reliability, packaging, regulatory execution, or newly created intellectual property.

What FDA regulatory pathway applies to an improved Elixophyllin formulation?

A materially improved product could proceed through several pathways depending on the sponsor’s relationship to the reference product and the proposed changes.

Abbreviated pathway

If the product is a generic equivalent of an approved theophylline oral liquid, an ANDA may be appropriate. The sponsor would need to address pharmaceutical equivalence, bioequivalence, manufacturing controls, stability, labeling, and inactive-ingredient suitability.[4]

A different excipient system may be acceptable if it does not create an unaddressed safety issue or alter product performance. The sponsor must evaluate whether the formulation change affects absorption, dose delivery, microbial quality, or tolerability.

505(b)(2) pathway

A 505(b)(2) application may be more suitable for a reformulated product with a meaningful change in dosage form, concentration, excipient composition, dosing system, or route of administration. The pathway can rely partly on FDA findings for an approved product while supporting the new formulation with bridging studies and additional data.[5]

Potential 505(b)(2) opportunities include:

• Alcohol-free oral liquid.
• Lower-volume concentrated solution.
• New unit-dose presentation.
• Improved enteral-tube formulation.
• Modified taste-masking system.
• Product with reduced sugar or reduced polyol content.

The development program would typically include formulation characterization, comparative dissolution where relevant, pharmacokinetic bridging, stability, microbiological testing, preservative effectiveness, human factors for the dosing device, and updated labeling.

What excipient strategy offers the strongest commercial opportunity?

The strongest near-term strategy is an alcohol-free, low-sorbitol, taste-masked oral liquid with a calibrated oral syringe and unit-dose or contamination-resistant packaging.

Recommended target product profile

Attribute	Target
Strength	Preserve 80 mg/15 mL or develop a justified concentrated strength
Alcohol	Zero or materially reduced
Polyol load	Reduce sorbitol while retaining acceptable mouthfeel
Sweetener	Use a blended system to reduce saccharin aftertaste
Preservative	Optimize around pH, packaging, and in-use period
Flavor	Mild fruit or neutral flavor with bitterness suppression
Dosing device	Oral syringe with clear graduations
Package	Child-resistant bottle, unit-dose cup, or stick-pack concept
Stability	Commercial shelf life with validated in-use period
Patient segments	Pediatrics, geriatrics, long-term-care, home care, and tube-fed patients

A concentrated presentation could reduce shipping cost and caregiver burden, but it increases dosing-error risk. The label, syringe, concentration, and carton design would need unusually strong controls. A lower-volume product should not be pursued solely for convenience without demonstrating acceptable pharmacokinetics and medication-use safety.

What manufacturing and supply-chain barriers affect the opportunity?

Theophylline itself is a low-cost active pharmaceutical ingredient. The commercial risk is therefore concentrated in excipients, packaging, and batch economics.

Key barriers include:

• Fluctuations in pharmaceutical-grade flavor and color supply.
• Preservative and sweetener qualification.
• Alcohol handling and facility controls.
• Microbial control in large-volume multidose batches.
• Content uniformity during mixing and filling.
• Container-closure compatibility.
• Syringe and dosing-cup supply.
• Low-volume production economics.
• In-use stability after opening.
• Temperature and light sensitivity of the finished product.
• Global differences in permitted excipients and labeling.

An alcohol-free product may reduce one regulatory concern while increasing dependence on preservative performance and aseptic or hygienic manufacturing controls. The product should be designed around its intended package. A multidose bottle, unit-dose cup, and stick pack create different microbial and stability profiles.

How does Elixophyllin compare with tablets, capsules, and extended-release theophylline?

Product type	Main advantage	Main weakness	Excipient opportunity
Elixophyllin-type immediate-release liquid	Flexible dosing and suitability for patients unable to swallow	Taste, dosing error, microbial risk, packaging burden	Alcohol-free, taste-masked, unit-dose product
Immediate-release tablet	Low cost and simple distribution	Limited dose flexibility and swallowing burden	Limited differentiation
Capsule	Familiar oral solid dosage form	Not suitable for all patients	Limited excipient differentiation
Extended-release tablet or capsule	Less frequent dosing	More complex absorption and limited dose adjustment	Controlled-release or sprinkle formats
Compounded liquid	Custom strength and local flexibility	Variable quality, availability, and stability	Commercial product can compete on consistency
Inhaled bronchodilator	Targeted pulmonary delivery	Device technique and access requirements	Limited direct excipient overlap

The oral-liquid opportunity is largest where swallowing difficulty, enteral feeding, pediatric dosing, or dose titration outweighs the price advantage of solid dosage forms.

Which companies are likely to challenge Elixophyllin commercially?

Competition is likely to come from generic manufacturers, contract manufacturers, compounding pharmacies, and suppliers of alternative theophylline dosage forms. The most credible challengers are companies with:

• Existing oral-liquid manufacturing capacity.
• FDA-registered facilities for nonsterile liquids.
• Access to pharmaceutical-grade theophylline.
• Established pediatric or hospital distribution.
• Experience with ANDA or 505(b)(2) submissions.
• Packaging capabilities for oral syringes and unit-dose products.

The market is unlikely to support broad, heavily differentiated competition unless the product obtains institutional contracts or addresses a clear excipient concern. A reformulated product must therefore compete on documented usability and supply reliability, not only on a new flavor.

What licensing deals could create value?

A licensing structure could combine:

1. A sponsor owning the formulation, dosing device, or patent estate.
2. A contract manufacturer with oral-liquid capacity.
3. A specialty distributor serving pediatric, long-term-care, or hospital channels.
4. A flavor and taste-masking supplier providing proprietary technology.
5. A packaging company supplying unit-dose or contamination-resistant systems.

The most valuable licensing asset would be a differentiated formulation with FDA clearance, commercial stability data, and proven payer or institutional demand. A preclinical formulation patent without regulatory progress would have limited standalone value because the underlying theophylline market is mature and price-sensitive.

What revenue exposure and launch scenarios should investors consider?

Elixophyllin revenue is exposed to rapid generic substitution, low pricing, and declining use of theophylline in favor of inhaled therapies. The product can still support a defensible niche if it solves a specific administration problem.

Launch scenario	Commercial outcome
Legacy formulation with no differentiation	Vulnerable to generic and therapeutic substitution
Alcohol-free reformulation	Potential niche premium if supported by pediatric and institutional demand
Taste-masked product with syringe	Moderate opportunity in adherence-sensitive populations
Unit-dose product	Stronger institutional positioning, higher packaging cost
Concentrated liquid	Potential logistics benefit, but greater medication-error risk
Enteral-tube formulation	Specialty opportunity in hospitals and long-term care
Multiple flavors and strengths	Higher patient choice, but greater SKU and supply complexity

A premium strategy is more credible in specialty channels than in retail pharmacy. Institutional buyers will prioritize reliable supply, accurate dosing, contract pricing, and operational simplicity. Caregivers may value palatability and dosing accuracy, but reimbursement may not support a substantial premium.

How strong is the patent estate for a new Elixophyllin product?

The legacy product estate is likely weak relative to modern specialty pharmaceuticals because theophylline and conventional oral-liquid excipients are old technologies. A new sponsor can create a moderate patent position only by combining formulation specificity with demonstrated technical performance.

The commercial moat would likely rank as follows:

1. Regulatory approval and reliable supply.
2. Device and packaging execution.
3. Institutional contracts.
4. Patient and caregiver preference.
5. Formulation patents.
6. Trade secrets covering flavor and manufacturing.
7. Brand recognition.

Patent protection alone is unlikely to support a high-margin product. The most practical strategy is to use patents as one layer in a broader product and channel strategy.

Key Takeaways

• Elixophyllin is an 80 mg/15 mL immediate-release theophylline oral elixir.
• Its principal excipient issues are alcohol exposure, sorbitol load, bitterness, preservative performance, and multidose microbial control.
• The best reformulation opportunity is an alcohol-free or reduced-alcohol, low-sorbitol, taste-masked product with an oral syringe.
• Unit-dose and enteral-tube-compatible presentations could create institutional niches.
• Legacy theophylline exclusivity is unlikely to provide meaningful protection.
• Generic and therapeutic substitution risks are high.
• A 505(b)(2) pathway may be appropriate for a materially improved formulation, while an ANDA may fit a conventional equivalent product.
• Patent value will depend on narrow, data-supported claims tied to measurable stability, palatability, dosing, or manufacturing advantages.
• Commercial success will depend more on supply reliability, patient usability, and channel strategy than on the active ingredient.

FAQs

Can Elixophyllin be reformulated without alcohol?

Yes, but the reformulation must demonstrate acceptable solubility, stability, preservative effectiveness, microbial quality, taste, and dose uniformity. The regulatory pathway depends on the scope and effect of the formulation change.

Is sorbitol in Elixophyllin a commercial liability?

It can be. Sorbitol supports sweetness and mouthfeel but may cause gastrointestinal effects at sufficient exposure. A reduced-sorbitol formulation could improve tolerability and create a product-differentiation claim if supported by clinical or usability data.

Could a new Elixophyllin product obtain patent protection?

Yes, but broad claims would face substantial prior-art risk. The strongest claims would cover a specific excipient combination, defined stability or taste-masking performance, a dosing system, an enteral-tube formulation, or a manufacturing process.

Is Elixophyllin suitable for pediatric commercialization?

The oral-liquid format supports pediatric dosing, but alcohol, sweeteners, preservatives, taste, dosing accuracy, and excipient exposure require careful review. A pediatric-focused product would need a validated dosing device and age-appropriate palatability data.

What is the highest-value commercial niche for an improved theophylline liquid?

The most credible niche is a reliable, alcohol-free, taste-masked product for children, patients with swallowing difficulty, enteral-tube users, and long-term-care facilities. The opportunity is specialized rather than mass-market.

References

1. U.S. Food and Drug Administration. (n.d.). Elixophyllin (theophylline) oral elixir prescribing information. DailyMed.

2. U.S. Food and Drug Administration. (1995). Theophylline products for oral dosage forms: Guidance for industry. Center for Drug Evaluation and Research.

3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. U.S. Department of Health and Human Services.

4. U.S. Food and Drug Administration. (2017). Bioequivalence studies with pharmacokinetic endpoints for drugs submitted under an ANDA: Guidance for industry. Center for Drug Evaluation and Research.

5. U.S. Food and Drug Administration. (2023). Applications covered by section 505(b)(2): Guidance for industry. Center for Drug Evaluation and Research.