List of Excipients in Branded Drug LOKELMA

LOKELMA Excipient Strategy and Commercial Opportunities

Last updated: September 27, 2026

LOKELMA, AstraZeneca’s sodium zirconium cyclosilicate, has an unusually simple formulation: the marketed powder for oral suspension contains no conventional inactive excipient listed in the U.S. prescribing information. Its commercial value comes from the active crystalline ion-exchange material, not from a conventional tablet, capsule, polymer, or coating system. This creates a low-excipient manufacturing profile but leaves commercial opportunities in delivery format, palatability, dosing convenience, sodium management, combination therapy, and intellectual property around particle engineering and use.

What is LOKELMA and how does its formulation work?

LOKELMA is a nonabsorbed, inorganic potassium binder approved for the treatment of hyperkalemia in adults. Its active ingredient is sodium zirconium cyclosilicate, a crystalline zirconium silicate that exchanges sodium and hydrogen ions for potassium in the gastrointestinal tract.[1]

Attribute	LOKELMA profile
Active ingredient	Sodium zirconium cyclosilicate
Dosage form	Powder for oral suspension
Route	Oral
U.S. NDA	209241
Initial FDA approval	May 18, 2018
Initial correction dose	10 g three times daily for up to 48 hours
Maintenance dose	5 g every other day to 15 g once daily
Administration	Dispersed in water before oral administration
Absorption	Not systemically absorbed
Key limitation	Not recommended as sole treatment for life-threatening hyperkalemia because onset is delayed
Important administration rule	Separate most oral medicines by at least two hours
Sodium exposure	Approximately 400 mg sodium per 5 g dose

The product’s mechanism depends on the physical and chemical properties of the crystal lattice. Conventional excipients have a limited role compared with standard oral solid products.

What excipients are used in LOKELMA?

The U.S. prescribing information identifies no inactive ingredients for LOKELMA packets. The formulation is primarily the active ion-exchange material, packaged as a powder that is mixed with water.[1]

This excipient-free design has several consequences:

• Lower risk of excipient-related intolerance, including sorbitol, lactose, gelatin, or polymer sensitivity.
• Reduced formulation complexity.
• Fewer extractables and leachables associated with liquid or polymer-rich systems.
• A direct relationship between particle properties and clinical performance.
• Greater dependence on powder dispersion, dose uniformity, suspension behavior, and packaging controls.
• Limited ability to use conventional excipient-based taste masking.

LOKELMA does not need a binder, disintegrant, lubricant, film coat, suspending polymer, or sweetener in its approved powder format. That does not eliminate formulation risk. It shifts the risk toward crystal morphology, particle-size distribution, agglomeration, moisture control, dispersion kinetics, and dose delivery from the packet.

How does LOKELMA compare with VELTASSA on excipients and formulation?

LOKELMA competes primarily with VELTASSA, whose active ingredient is patiromer sorbitex calcium. The products have different ion-exchange materials, counterions, dosing profiles, and formulation attributes.

Attribute	LOKELMA	VELTASSA
Active ingredient	Sodium zirconium cyclosilicate	Patiromer sorbitex calcium
Exchange ion	Sodium and hydrogen	Calcium
Dosage form	Powder for oral suspension	Powder for oral suspension
Systemic absorption	Not absorbed	Not absorbed
Sodium burden	Relevant, because sodium is part of the exchange system	No sodium-based exchange mechanism
Drug separation	Two-hour separation for most oral medicines	Three-hour separation from other oral medicines
Main formulation opportunity	Palatability, low-volume delivery, dispersion, sodium control	Taste, lower separation burden, dose convenience
Key safety trade-off	Edema and sodium-related fluid burden	Hypomagnesemia and gastrointestinal effects

LOKELMA’s sodium content is a commercial and clinical consideration. Each 5 g dose contains approximately 400 mg of sodium, and maintenance dosing can reach 15 g per day.[1] That can limit adoption in patients with heart failure, chronic kidney disease, or sodium-sensitive hypertension, despite the product’s convenience and rapid potassium reduction relative to chronic maintenance alternatives.

VELTASSA’s sorbitex calcium platform creates a different excipient and tolerability profile. Formulation developers evaluating a competing product would need to address both the active resin or crystal system and the flavor, suspension, and gastrointestinal attributes associated with the finished powder.

What formulation improvements could create commercial opportunities?

The most credible opportunities are incremental delivery improvements that preserve the ion-exchange mechanism while reducing practical barriers.

Ready-to-use liquid or suspension

A ready-to-use liquid could remove the need to mix powder with water. The principal technical challenges would include:

• Maintaining suspension uniformity during storage.
• Preventing sedimentation or irreversible caking.
• Controlling viscosity and pourability.
• Preserving chemical and physical stability.
• Managing microbial risk.
• Preventing adsorption of the active material to container surfaces.
• Establishing dose uniformity across the bottle.

A liquid formulation would also introduce preservatives, buffering agents, suspending agents, or wetting agents that are absent from the current product. Those excipients could increase regulatory complexity and create new tolerability issues.

A unit-dose oral suspension in a stick pack or squeeze sachet is a more commercially practical intermediate. It could preserve the dry-state stability of LOKELMA while reducing preparation steps.

Taste and mouthfeel optimization

LOKELMA is not absorbed, but patients must disperse and swallow the material. Palatability can affect long-term adherence, particularly because hyperkalemia treatment often occurs in patients taking multiple chronic medicines.

Potential approaches include:

• Flavored water-compatible powders.
• Microencapsulation or coating of particles.
• Granulation that reduces powder adhesion to the mouth.
• Unit-dose oral gels.
• Effervescent or rapidly dispersible formats.
• Smaller-volume dosing systems.
• Premeasured oral dispensers.

The challenge is to avoid reducing access of potassium ions to the active crystal surface. Coatings or matrices that improve mouthfeel could impair exchange kinetics or create dose variability.

Low-sodium or sodium-neutral versions

A sodium-reduced LOKELMA analog could address one of the product’s main clinical limitations. The commercial opportunity is substantial in patients with heart failure, edema risk, hypertension, and advanced kidney disease.

However, sodium is structurally linked to the ion-exchange behavior of sodium zirconium cyclosilicate. Replacing or reducing sodium may require a different counterion, crystal structure, activation method, or manufacturing process. A modified-counterion product would likely require substantial pharmaceutical development and could raise questions about whether it remains the same active ingredient for an abbreviated regulatory pathway.

Lower-frequency dosing

The approved maintenance regimen ranges from every other day to once daily, depending on patient response.[1] Formulation engineering that improves residence time or exchange capacity could support less frequent dosing.

Commercial benefits include:

• Better adherence.
• Lower monthly dose burden.
• Lower sodium exposure.
• Reduced dispensing volume.
• Potential positioning for maintenance therapy rather than short-term correction.

A materially different release profile would require clinical evidence showing that potassium control remains predictable and that the product does not create delayed or excessive potassium lowering.

What intellectual property could protect a LOKELMA-like product?

The strongest patent opportunities are likely to sit around the active material and its clinical use rather than conventional excipients.

Composition and crystal patents

Potential claim categories include:

• Zirconium silicate composition.
• Elemental ratios.
• Crystal phase and lattice structure.
• Ion-exchange capacity.
• Particle-size distribution.
• Surface area and porosity.
• Moisture content.
• Residual sodium or hydrogen content.
• Polymorph or solid-state form.
• Impurity profile.

These claims can create a significant barrier if the claimed material is difficult to reproduce consistently at commercial scale.

Manufacturing patents

Manufacturing claims may cover:

• Precipitation and crystallization conditions.
• Washing and ion-exchange steps.
• Drying conditions.
• Milling and classification.
• Particle-size control.
• Agglomeration prevention.
• Packaging under controlled humidity.
• Process controls that preserve exchange capacity.

Manufacturing patents can be important even when a generic applicant designs around composition claims. A process that produces a clinically equivalent material at commercial scale may require extensive development and validation.

Formulation and delivery patents

Potential formulation claims include:

• Flavored powders.
• Oral suspensions.
• Granules.
• Unit-dose sachets.
• Ready-to-use liquids.
• Coated or encapsulated particles.
• Modified-release formats.
• Low-sodium counterion systems.
• Coformulations with heart-failure or kidney-disease medicines.

These patents are most valuable when they address a commercially meaningful problem and have measurable product performance advantages.

Method-of-use patents

Potential method claims include:

• Chronic potassium control in chronic kidney disease.
• Use in patients receiving renin-angiotensin-aldosterone system inhibitors.
• Maintenance of guideline-directed heart-failure therapy.
• Prevention of recurrent hyperkalemia.
• Dosing in patients with sodium-sensitive disease.
• Specific titration schedules.
• Use before or after dialysis.

Use patents can remain commercially relevant after composition patents expire, but their enforceability depends on prescribing behavior, label language, induced-infringement evidence, and the ability to detect the claimed use.

When does LOKELMA lose exclusivity?

LOKELMA’s U.S. market exclusivity must be assessed through the current FDA Orange Book and relevant patent records rather than the approval date alone.[2] The product received FDA approval in 2018, so any standard five-year new chemical entity exclusivity associated with the application would have elapsed by 2023. Patent protection, pediatric exclusivity, regulatory stays, and listed use claims can produce different end dates.

The relevant exclusivity framework is:

Protection	Commercial relevance
New chemical entity exclusivity	Prevents certain ANDA submissions during the exclusivity period
Listed patents	Can delay approval of an ANDA if a Paragraph IV notice triggers litigation and a 30-month stay
Pediatric exclusivity	Can add six months to qualifying regulatory protections
Method-of-use patents	May support a label carve-out or litigation over protected indications
Manufacturing patents	Can complicate commercial replication but may not block every alternative process
Formulation patents	Can protect improved products or specific dosage forms

A precise generic-entry forecast requires the current Orange Book patent listing, patent-term-adjustment calculations, terminal disclaimers, litigation records, and settlement terms. Those data should be evaluated at the time of an ANDA filing.

What Paragraph IV and generic-entry risks exist?

A generic applicant could pursue an ANDA for sodium zirconium cyclosilicate powder for oral suspension. The principal technical and legal risks would include:

1. Demonstrating pharmaceutical equivalence to the listed product.
2. Matching the active material’s solid-state and ion-exchange characteristics.
3. Establishing dose uniformity and dispersion behavior.
4. Addressing the two-hour separation instruction for coadministered medicines.
5. Proving bioequivalence when the active ingredient is not systemically absorbed.
6. Establishing equivalent in vitro performance and, if required, clinical pharmacodynamic response.
7. Certifying against listed patents under Paragraph IV.
8. Avoiding infringement of composition, process, formulation, and use claims.

Because LOKELMA is not systemically absorbed, conventional plasma pharmacokinetic bioequivalence may not be sufficient or may not be applicable. FDA could rely on comparative in vitro testing, pharmacodynamic potassium-lowering studies, or other product-specific requirements.[3]

The greatest generic barrier may be CMC reproducibility rather than a conventional tablet bioequivalence study. A material that appears chemically similar but differs in crystal structure, particle size, exchange capacity, or dispersion could produce clinically meaningful performance differences.

Does LOKELMA face biosimilar risk?

No. LOKELMA is a small-molecule-like inorganic drug product, not a biologic. It is not subject to the biosimilar pathway under the Public Health Service Act. Competitive products would proceed through the ANDA pathway, a 505(b)(2) application, or a full NDA, depending on the degree of difference from the reference product.

A materially different counterion, delivery system, or modified-release profile could push a competitor toward 505(b)(2) or NDA development rather than a straightforward ANDA.

What FDA regulatory status supports commercial expansion?

The FDA-approved indication is treatment of hyperkalemia in adults.[1] The label does not position LOKELMA as emergency monotherapy for life-threatening hyperkalemia. Its strongest commercial use cases are chronic or recurrent hyperkalemia, especially where physicians seek to continue or optimize renin-angiotensin-aldosterone system therapy.

Regulatory expansion opportunities include:

• Chronic hyperkalemia in chronic kidney disease.
• Hyperkalemia associated with heart failure therapy.
• Maintenance of RAAS inhibitor dosing.
• Use in dialysis populations.
• More convenient outpatient dosing.
• Pediatric development, if supported by clinical data.
• Lower-sodium or sodium-neutral reformulation.

Each expanded claim would require clinical evidence appropriate to the proposed indication and dose.

What licensing and partnership opportunities exist?

The most attractive partnership targets are companies with capabilities in:

• Oral delivery systems.
• Taste masking.
• Dry powder and sachet manufacturing.
• Ion-exchange materials.
• Renal and heart-failure clinical development.
• Specialty pharmacy distribution.
• Digital adherence and chronic disease management.

A licensee could pursue a differentiated LOKELMA-compatible delivery system, while a generic manufacturer could seek process know-how or an alternative crystalline material. Partnerships with cardiovascular and nephrology companies could support studies linking potassium control to continued RAAS inhibitor use, hospitalization reduction, or treatment persistence.

No public licensing arrangement should be treated as evidence of freedom to operate. AstraZeneca obtained LOKELMA through its acquisition of ZS Pharma, which developed sodium zirconium cyclosilicate.[4]

How strong is the LOKELMA patent estate?

The estate is strongest where patent claims cover the active crystal, solid-state properties, manufacturing process, and clinically defined use. Conventional excipient claims are less central because the marketed product does not depend on a complex excipient system.

Strength factors include:

• Difficult-to-reproduce crystalline material.
• Product performance linked to particle properties.
• Non-systemic mechanism that complicates standard bioequivalence.
• Potential process barriers.
• Chronic use in large kidney and cardiovascular populations.

Weakness factors include:

• No conventional formulation barrier in the marketed powder.
• Potential for alternative ion-exchange materials.
• Ability to develop different delivery formats.
• Expiration or narrowing of early composition claims.
• Potential label carve-outs for method-of-use patents.

The competitive moat is therefore a combination of material science, manufacturing control, clinical familiarity, and regulatory complexity rather than excipient exclusivity alone.

What is the revenue exposure and market opportunity?

LOKELMA’s revenue opportunity is tied to recurrent hyperkalemia and the growing use of RAAS inhibitors in chronic kidney disease and heart failure. AstraZeneca reported LOKELMA as part of its cardiovascular, renal and metabolism portfolio, with commercial performance supported by chronic use and geographic expansion.[4]

The highest-value segments are likely to be:

• Chronic kidney disease patients with recurrent hyperkalemia.
• Heart-failure patients receiving mineralocorticoid receptor antagonists.
• Patients whose RAAS inhibitor dose is limited by potassium elevation.
• Patients requiring maintenance treatment after an acute hyperkalemia episode.
• Health systems seeking to reduce treatment interruptions and admissions.

A lower-sodium formulation, easier administration, or stronger evidence for RAASi enablement could expand use. Generic entry would likely first affect price-sensitive maintenance prescriptions, while branded differentiation could preserve share through delivery and clinical-outcome positioning.

Key Takeaways

• LOKELMA uses an excipient-free powder formulation based on sodium zirconium cyclosilicate.
• Its principal formulation risks are particle engineering, dispersion, dose uniformity, moisture control, and palatability.
• Commercial opportunities include ready-to-use suspensions, unit-dose sachets, taste-masked formats, lower-volume administration, and sodium-reduced alternatives.
• Sodium exposure is a major product limitation in edema-prone and sodium-sensitive patients.
• The strongest IP positions are likely composition, crystal form, manufacturing process, particle properties, and method-of-use claims.
• LOKELMA has no biosimilar risk. Generic competition would most likely proceed through an ANDA or, for materially different products, a 505(b)(2) application.
• Generic development may face substantial CMC and product-specific bioequivalence challenges because the drug is not systemically absorbed.
• The largest commercial opportunity is chronic hyperkalemia management that enables continued RAAS inhibitor therapy.

FAQs

Can LOKELMA be reformulated as a tablet?

A tablet is technically possible, but compression could alter dispersion, surface area, and ion-exchange kinetics. A tablet would require product-specific performance testing and could require a new regulatory application if it is not pharmaceutically equivalent to the powder.

Could a low-sodium LOKELMA product avoid edema concerns?

A lower-sodium product could reduce sodium exposure, but it would likely require modification of the active material or counterion system. That could create a new drug product rather than a simple formulation variation.

Is a flavored LOKELMA product likely to receive separate patent protection?

It could, if the flavor system, coating, granulation, or delivery format produces a patentable and commercially meaningful improvement. A simple flavor substitution would generally be less defensible than a formulation that improves palatability without reducing exchange capacity.

Could a generic manufacturer use a different zirconium silicate crystal?

A materially different crystal form might not qualify as the same active ingredient or might fail product-specific equivalence requirements. The applicant would need to demonstrate that the alternative provides equivalent pharmaceutical and clinical performance.

Does LOKELMA’s lack of excipients eliminate formulation patent risk?

No. Patent risk can arise from crystal form, particle size, manufacturing conditions, packaging, dispersion behavior, and methods of use even when the finished product contains no conventional inactive ingredient.

References

1. U.S. Food and Drug Administration. (2024). Lokelma (sodium zirconium cyclosilicate) prescribing information. AstraZeneca Pharmaceuticals LP.

2. U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/

3. U.S. Food and Drug Administration. (2020). Product-specific guidance for industry: Sodium zirconium cyclosilicate. Center for Drug Evaluation and Research.

4. AstraZeneca PLC. (2024). Annual report and Form 20-F for the year ended December 31, 2023. AstraZeneca.