List of Excipients in Branded Drug ADEMPAS

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Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Bayer HealthCare Pharmaceuticals Inc	ADEMPAS	riociguat	50419-250	CELLULOSE, MICROCRYSTALLINE
Bayer HealthCare Pharmaceuticals Inc	ADEMPAS	riociguat	50419-250	CROSPOVIDONE
Bayer HealthCare Pharmaceuticals Inc	ADEMPAS	riociguat	50419-250	HYDROXYPROPYL CELLULOSE
Bayer HealthCare Pharmaceuticals Inc	ADEMPAS	riociguat	50419-250	HYPROMELLOSE

ADEMPAS Excipient Strategy and Commercial Opportunities

Last updated: October 6, 2026

Adempas, Bayer’s brand of riociguat, is an immediate-release oral tablet for chronic thromboembolic pulmonary hypertension and pulmonary arterial hypertension. Its excipient strategy prioritizes dose uniformity, rapid disintegration, tablet robustness, swallowability, and reliable color differentiation across five strengths. The largest commercial opportunities are generic substitution, lactose-free or low-lactose reformulation, orally disintegrating tablets, improved moisture protection, and cost-reduced manufacturing that preserves bioequivalence.

What is Adempas and how does its formulation work?

Adempas contains riociguat, a soluble guanylate cyclase stimulator. It is approved for:

• Persistent or recurrent chronic thromboembolic pulmonary hypertension after surgical treatment or inoperable disease.
• Pulmonary arterial hypertension, including selected functional classes and etiologies.

The U.S. product is supplied as immediate-release film-coated tablets in 0.5 mg, 1 mg, 1.5 mg, 2 mg, and 2.5 mg strengths. The recommended dose is titrated according to blood pressure and tolerability, generally up to 2.5 mg three times daily in adults [1].

Riociguat has dose-dependent pharmacokinetics and is administered repeatedly during the day. That dosing profile makes dose accuracy, rapid tablet disintegration, and low variability important formulation objectives.

What excipients are used in Adempas tablets?

The U.S. prescribing information identifies the following inactive ingredients for Adempas tablets:

Formulation component	Reported excipient or material	Primary function
Tablet core	Microcrystalline cellulose	Diluent and compression aid
Tablet core	Crospovidone	Superdisintegrant
Tablet core	Hypromellose	Binder and structural aid
Tablet core	Lactose monohydrate	Diluent
Tablet core	Magnesium stearate	Lubricant
Tablet core	Sodium lauryl sulfate	Wetting agent and dissolution aid
Film coat	Hypromellose	Film-forming polymer
Film coat	Propylene glycol	Plasticizer
Film coat	Titanium dioxide	Opacifier
Film coat	Talc	Anti-tacking and coating aid
Film coat	Iron oxides	Strength-specific colorant

The exact colorant composition varies by tablet strength. Strength-specific color coding reduces dispensing errors during titration and helps distinguish tablets in a multidose regimen [1].

How does the Adempas excipient strategy support commercial performance?

The formulation uses conventional, globally available excipients rather than a highly specialized delivery platform. That approach reduces manufacturing complexity and supports multiple contract manufacturing and generic development routes.

Immediate-release design

Crospovidone, sodium lauryl sulfate, and a soluble diluent system support rapid wetting and disintegration. The formulation does not rely on an extended-release matrix or gastroretentive technology. A generic developer therefore faces a comparatively accessible dosage-form target, although dissolution matching remains important because riociguat is administered at low doses and is titrated across several strengths.

Dose proportionality and manufacturing efficiency

The five-strength product line creates opportunities for a common-blend strategy. A manufacturer can use one or more master blends with controlled active concentration, followed by strength-specific compression and coating. This can reduce:

• Raw-material inventory.
• Blend-validation burden.
• Scale-up complexity.
• Changeover frequency.
• Content-uniformity risk.

The 0.5 mg and 1 mg strengths present the greatest low-dose uniformity challenge. Content uniformity can be affected by segregation, electrostatic behavior, particle-size differences, and inadequate active distribution. High-shear granulation, ordered mixing, or a controlled dry-granulation process may improve robustness, depending on the active pharmaceutical ingredient’s flow and compressibility.

Film coating and medication safety

The colored film coat is commercially important because Adempas is titrated and supplied in multiple strengths. A generic product that uses a different visual system may be legally permissible but could create pharmacy substitution and medication-error concerns. Matching the reference product’s color architecture can improve commercial acceptance.

A low-weight, aqueous hypromellose coating can maintain the immediate-release profile while limiting process time. Coating uniformity matters because color intensity and tablet identification are part of the product’s usability, not only its appearance.

What formulation patents protect Adempas?

Adempas protection is likely divided among active-ingredient patents, formulation or pharmaceutical-composition patents, manufacturing rights, and regulatory exclusivity. The core commercial risk for generic developers is not generally the excipient list itself. It is the combined interaction of:

• Riociguat composition-of-matter protection.
• Salt, polymorph, or solid-state claims, where applicable.
• Pharmaceutical-composition claims.
• Method-of-use claims covering pulmonary hypertension treatment.
• Patent-term adjustments or extensions.
• Orange Book listings and Paragraph IV litigation.

The FDA Orange Book is the controlling public source for current U.S. patent listings and regulatory exclusivity associated with approved Adempas products [2]. Patent status should be assessed by jurisdiction and claim scope rather than by the presence of excipients in the approved label.

Are Adempas excipients independently patentable?

Individual conventional excipients, such as microcrystalline cellulose, lactose, magnesium stearate, hypromellose, or crospovidone, generally provide weak standalone patent protection. Commercially meaningful formulation protection would more likely depend on:

• A defined excipient ratio.
• A specific dissolution profile.
• A low-dose content-uniformity process.
• A particle-size or solid-state limitation.
• A stability advantage.
• A coating system that preserves dose identification and release.
• A manufacturing process linked to critical quality attributes.

A generic developer can often design around a formulation patent by changing the disintegrant, binder, lubricant level, granulation process, coating composition, or tablet geometry, provided the resulting product remains pharmaceutically equivalent and bioequivalent.

When does Adempas lose exclusivity?

Adempas received U.S. approval in 2013. Its new chemical entity exclusivity period would ordinarily have ended five years after approval, subject to regulatory provisions and any pediatric exclusivity. The remaining market barrier is therefore primarily patent-based rather than NCE exclusivity-based [1, 2].

A precise generic-entry date depends on:

1. The expiration and enforceability of listed patents.
2. Any patent-term extension or adjustment.
3. Paragraph IV certifications.
4. Litigation outcomes.
5. Settlement terms.
6. Whether an ANDA applicant receives approval before commercial launch.
7. Regulatory exclusivity in non-U.S. markets.

What is the Orange Book status of Adempas?

The Orange Book identifies the patents and exclusivity information associated with FDA-approved Adempas products. A patent listed for a drug may cover the active ingredient, a formulation, or an approved method of use. An ANDA applicant must address applicable listed patents through certification or a statement that the patent is not relevant to the proposed product [2].

A Paragraph IV certification alleges that a listed patent is invalid, unenforceable, or will not be infringed. If the patent holder sues within the statutory period, FDA approval of the ANDA may be subject to a 30-month stay, subject to court and regulatory developments.

What generic entry risks exist for Adempas?

Adempas presents moderate formulation-development risk and potentially higher legal risk depending on the remaining patent estate.

Technical risk

The main technical risks are:

• Low-dose content uniformity.
• Matching dissolution across all five strengths.
• Strength-specific color matching.
• Stability of riociguat under heat and humidity.
• Lubricant sensitivity.
• Film-coating variability.
• Dose proportionality during scale-up.
• Drug-drug interaction effects in bioequivalence studies.

The use of sodium lauryl sulfate can improve wetting but may create sensitivity to concentration and mixing time. Excessive magnesium stearate can reduce tablet wettability and slow dissolution. Crospovidone level and distribution can affect disintegration and dissolution.

Regulatory risk

A generic riociguat product would generally be pursued through an ANDA in the United States if it can demonstrate pharmaceutical equivalence and bioequivalence to the reference listed drug. The applicant would need to address labeling, strength, dosage form, route of administration, inactive-ingredient suitability, and patent certifications.

FDA may scrutinize excipient differences when they affect:

• Absorption.
• Dissolution.
• Stability.
• Hypersensitivity risk.
• Pediatric use.
• Labeling of inactive ingredients.

A product that replaces lactose may improve access for patients with lactose intolerance, but the substitution still requires control of tablet performance and bioequivalence.

What commercial opportunities exist for Adempas excipient reformulation?

Lactose-free or low-lactose tablets

Adempas uses lactose monohydrate as a tablet diluent. A lactose-free formulation could use mannitol, anhydrous dibasic calcium phosphate, silicified microcrystalline cellulose, or a co-processed excipient system.

Commercial advantages could include:

• Broader use among patients avoiding lactose.
• A differentiated generic or authorized-generic product.
• Improved positioning in selected international markets.
• Reduced dependence on lactose supply and moisture specifications.

The main development issue is preserving tablet tensile strength, disintegration, and dissolution at the 0.5 mg strength.

Orally disintegrating tablets

An orally disintegrating tablet could address patients with pulmonary hypertension who have difficulty swallowing or who need dosing during travel and acute symptom periods. Mannitol, crospovidone, low-substituted hydroxypropyl cellulose, and taste-masking systems could support this format.

The commercial case is stronger if the product demonstrates:

• Rapid in-mouth dispersion.
• Acceptable taste.
• Low friability.
• Moisture stability.
• No clinically meaningful change in exposure.
• Convenient packaging.

An ODT would not automatically replace the standard tablet because Adempas dosing is titrated and may require several strength options.

Sprinkle or dispersible dosage forms

A dispersible tablet or capsule-based product could address patients with swallowing limitations. The formulation would need to control dose recovery, uniformity after dispersion, and compatibility with soft food or liquid vehicles.

This opportunity is more complex than a conventional generic because the label would need clear administration instructions and stability data after dispersion.

Moisture-protective packaging

A packaging innovation may offer commercial value without changing the tablet formulation. Options include:

• High-barrier aluminum blister packaging.
• Desiccant-containing bottles.
• Unit-dose adherence packs.
• Calendarized titration packs.
• Child-resistant, senior-friendly packaging.

A titration pack could improve the transition from starting dose to maintenance dose. It would require careful alignment with prescribing instructions and regional dispensing rules.

Excipient simplification

A manufacturer could seek to eliminate sodium lauryl sulfate or reduce coating complexity. The objective would be lower cost, improved tolerability, or a simpler global regulatory package.

The tradeoff is that a simplified formula may lose wetting performance or create dissolution differences. Such a strategy is commercially viable only if the revised formulation maintains bioequivalence and adequate stability.

How does Adempas compare with competing pulmonary hypertension drugs?

Adempas competes with phosphodiesterase-5 inhibitors, endothelin receptor antagonists, prostacyclin-pathway products, and combination regimens. The excipient opportunity differs by dosage form and therapeutic use.

Product class	Representative products	Typical dosage form	Excipient opportunity
Soluble guanylate cyclase stimulator	Riociguat, Adempas	Immediate-release tablet	Generic tablets, ODT, lactose-free formula, titration packaging
PDE-5 inhibitor	Sildenafil, tadalafil	Tablet, oral suspension for some products	Low-cost generics, dispersible formats, pediatric liquids
Endothelin receptor antagonist	Macitentan, ambrisentan	Tablet	Formulation and combination-product opportunities
Prostacyclin pathway	Selexipag and inhaled or infused products	Tablet, inhalation, infusion	Device compatibility, stability, adherence packaging
Combination therapy	Various combinations	Oral or device-based	Fixed-dose combinations and synchronized packaging

Adempas has a distinct position because riociguat is not interchangeable with PDE-5 inhibitors and is contraindicated with them due to hypotension risk. The differentiation of the product is therefore clinical and regulatory, not only formulation-based [1].

Which companies are challenging Adempas?

Generic competition is expected to come from established ANDA manufacturers and specialty generic companies with experience in low-dose oral solids. Potential competitors would likely include companies with capabilities in:

• Complex immediate-release tablets.
• Paragraph IV litigation.
• Pulmonary hypertension distribution.
• Multi-strength manufacturing.
• Global bioequivalence programs.

A reliable list of active challengers requires current FDA ANDA data, Orange Book review, court dockets, and company disclosures. The commercial assessment should distinguish between a filed ANDA, tentative approval, final approval, and actual launch.

What patent litigation affects Adempas?

Adempas litigation risk can arise from:

• Paragraph IV challenges to listed patents.
• Hatch-Waxman infringement actions.
• Patent-term disputes.
• Label-carve-out disputes involving pulmonary hypertension methods.
• Declaratory judgment actions.
• Settlement agreements that establish an authorized or licensed entry date.

A method-of-use patent can create a launch problem if the generic label includes a patented indication. A carve-out may be possible only if the remaining label omits the protected use without making the product unsuitable for the non-protected indications.

Settlement agreements may permit an earlier entry date, but their economic value depends on whether the settlement includes a license, supply arrangement, authorized-generic commitment, or restrictions on formulation and indication.

How strong is the Adempas patent estate?

The patent estate should be assessed as a layered portfolio rather than as a single expiration date.

Layer	Strategic value	Generic vulnerability
Riociguat composition claims	Highest value if enforceable	Depends on expiration, validity, and claim construction
Solid-state or salt claims	Can delay alternative API sourcing	Vulnerable to non-infringing solid forms
Formulation claims	Protect specific excipient or release systems	Often design-around possible
Method-of-use claims	Can protect selected indications	Carve-outs may reduce exposure
Manufacturing claims	Can restrict certain processes	Alternative process development may avoid claims
Regulatory exclusivity	Delays approval independently of patents	Fixed statutory duration

The conventional excipient profile is less difficult to design around than a modified-release or device-linked product. The stronger protection is likely to come from the active ingredient and approved-use claims rather than from routine tablet excipients.

What is the revenue exposure from generic Adempas entry?

Adempas revenue exposure depends on:

• Bayer’s sales by region.
• The timing of first generic launch.
• The number of approved competitors.
• Generic price erosion.
• Payer substitution.
• Continued demand for branded supply in specialist centers.
• The ability to retain patients through titration support and distribution channels.

A single first entrant may produce limited initial erosion if supply is constrained or if payer substitution is gradual. Multiple entrants usually accelerate price decline. Specialty products can retain a larger branded share than mass-market drugs when prescriber control, reimbursement complexity, and titration management remain significant.

Bayer reports Adempas sales in its annual and quarterly financial disclosures. Those reports should be used to quantify current revenue concentration and geographic exposure [3].

Key Takeaways

• Adempas is an immediate-release riociguat tablet with five strengths and a conventional excipient system.
• The core formulation uses microcrystalline cellulose, crospovidone, hypromellose, lactose monohydrate, magnesium stearate, and sodium lauryl sulfate.
• Strength-specific color coding is commercially relevant because patients are titrated across multiple doses.
• Low-dose content uniformity and dissolution matching are the main formulation-development risks.
• The strongest generic opportunities are lactose-free tablets, ODTs, dispersible products, titration packs, and moisture-protective packaging.
• Conventional excipients provide limited standalone patent strength. Active-ingredient, method-of-use, solid-state, and listed formulation patents are more important.
• Adempas has no biosimilar pathway because riociguat is a small-molecule drug.
• Generic entry will depend on current Orange Book listings, Paragraph IV certifications, litigation, settlements, and approval timing.
• A generic developer can likely design around routine excipient claims, but low-dose bioequivalence and regulatory execution remain material barriers.

FAQs

Can a generic Adempas use different excipients?

Yes. A generic may use different inactive ingredients if the formulation meets FDA requirements, remains pharmaceutically equivalent where applicable, and demonstrates bioequivalence. Differences must not create unacceptable safety, stability, or performance risks.

Is Adempas lactose-free?

The U.S. Adempas tablet formulation contains lactose monohydrate. A lactose-free generic could use another diluent, but the replacement would require formulation and regulatory validation.

Is there a commercial opportunity for a generic riociguat oral suspension?

Potentially. An oral suspension could serve patients who cannot swallow tablets, but riociguat’s low dose, content uniformity, settling behavior, stability, taste, and dose-measurement requirements make development more complex than a standard tablet.

Does Adempas have biosimilar competition?

No. Adempas contains riociguat, a small-molecule active ingredient. Competition would proceed through generic-drug pathways, principally an ANDA in the United States, rather than through a biosimilar application.

Which excipient is most important for Adempas dissolution?

Sodium lauryl sulfate and crospovidone are likely important contributors to wetting and disintegration, while the diluent and lubricant system also affects dissolution. The commercial formulation cannot be evaluated by a single excipient because performance depends on concentration, particle size, mixing, compression, and coating conditions.

References

1. U.S. Food and Drug Administration. (2023). Adempas (riociguat) prescribing information. Bayer HealthCare Pharmaceuticals Inc.

2. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/

3. Bayer AG. (2024). Annual report 2023. Bayer AG.

4. European Medicines Agency. (n.d.). Adempas: European public assessment report and product information. https://www.ema.europa.eu/

5. U.S. Food and Drug Administration. (n.d.). Guidance for industry: Bioequivalence studies with pharmacokinetic endpoints for drugs submitted under an ANDA. https://www.fda.gov/###