List of Excipients in Branded Drug AMPHOTERICIN B LIPOSOME

Generic Drugs Containing AMPHOTERICIN B LIPOSOME

Company	Ingredient	NDC	Excipient
Mylan Institutional LLC	amphotericin b liposome	67457-926	.ALPHA.-TOCOPHEROL
Mylan Institutional LLC	amphotericin b liposome	67457-926	CHOLESTEROL
Mylan Institutional LLC	amphotericin b liposome	67457-926	HYDROCHLORIC ACID
Mylan Institutional LLC	amphotericin b liposome	67457-926	HYDROGENATED SOYBEAN PHOSPHATIDYLCHOLINE

What are the Most Frequently-Used Excipients in AMPHOTERICIN B LIPOSOME?

# Of NDCs	Excipient
1	.ALPHA.-TOCOPHEROL
1	CHOLESTEROL
1	HYDROCHLORIC ACID
1	HYDROGENATED SOYBEAN PHOSPHATIDYLCHOLINE

Amphotericin B Liposome Excipient Strategy and Commercial Opportunities

Last updated: August 19, 2026

Liposomal amphotericin B is a complex sterile nanomedicine in which excipient selection determines drug loading, particle size, release, nephrotoxicity, shelf life, and regulatory risk. The leading reference product, AmBisome, uses a defined phospholipid-cholesterol liposome with sucrose as a lyoprotectant. The strongest commercial opportunities are in qualified lipid supply, process-specific excipients, alternative liposomal amphotericin products, regional manufacturing, and improved presentations for global antifungal and leishmaniasis programs.

What excipients are used in liposomal amphotericin B?

The AmBisome formulation contains amphotericin B enclosed in liposomes composed primarily of hydrogenated soy phosphatidylcholine, distearoylphosphatidylglycerol, cholesterol, and alpha-tocopherol. Sucrose is used as a bulking agent and cryo- or lyoprotectant in the freeze-dried product. The vial is reconstituted with sterile water for injection before dilution and administration.[1]

Component	Functional role	Commercial relevance
Hydrogenated soy phosphatidylcholine	Primary structural phospholipid forming the bilayer	Requires high-purity, controlled oxidation and lot consistency
Distearoylphosphatidylglycerol	Anionic phospholipid that contributes surface charge and drug retention	Influences particle stability, biodistribution, and release
Cholesterol	Modifies membrane packing, permeability, and mechanical stability	Critical to liposome integrity and temperature tolerance
Alpha-tocopherol	Antioxidant protecting unsaturated or oxidation-sensitive lipid components	Supports chemical stability and shelf-life control
Sucrose	Lyoprotectant and bulking agent during freeze-drying	Affects cake structure, reconstitution, and particle recovery
Sterile water for injection	Reconstitution vehicle	Product-specific handling requirement
Dextrose solution	Diluent after reconstitution	Saline is generally incompatible with the liposomal product

The formulation is not interchangeable with conventional amphotericin B deoxycholate. The liposome is part of the active product performance, not a passive delivery vehicle. Changes in lipid identity, molar ratio, surface charge, particle size, encapsulation efficiency, or lyophilization cycle can alter efficacy and toxicity.

How does the AmBisome excipient system work?

The liposomal membrane packages amphotericin B and changes its distribution after intravenous administration. Compared with conventional amphotericin B, the liposomal system is associated with reduced renal toxicity and improved tolerability, while retaining broad antifungal activity.[2,3]

Phospholipid selection

Hydrogenated phosphatidylcholine provides a relatively rigid bilayer with improved oxidative stability compared with more unsaturated phospholipids. The high transition temperature of hydrogenated lipid supports membrane integrity during storage and administration.

Distearoylphosphatidylglycerol introduces negative surface charge. This affects:

• Amphotericin B association with the membrane
• Liposome aggregation behavior
• Interaction with plasma proteins
• Uptake by the reticuloendothelial system
• Drug release at sites of infection

The ratio between neutral and anionic phospholipid is a critical quality attribute. A supplier change that preserves chemical identity but shifts fatty-acid composition or residual impurity levels can affect product performance.

Cholesterol control

Cholesterol reduces membrane permeability and stabilizes the lipid bilayer. Excessive cholesterol can reduce drug release, while inadequate cholesterol can increase leakage during storage or after reconstitution.

For commercial development, cholesterol should be controlled for purity, oxidation products, residual solvents, heavy metals, and batch-to-batch physical properties. Pharmaceutical-grade cholesterol from animal or synthetic sources can create different regulatory and supply-chain profiles.

Alpha-tocopherol and oxidation management

Alpha-tocopherol limits lipid oxidation. Oxidative degradation can change membrane fluidity, generate reactive impurities, and reduce product shelf life. The antioxidant system must be evaluated with:

• Peroxide value
• Anisidine value
• Individual lipid oxidation products
• Headspace oxygen
• Container closure integrity
• Light exposure
• Freeze-thaw stress

The excipient strategy should pair alpha-tocopherol with low-oxygen manufacturing, nitrogen overlay, low-peroxide raw materials, and validated storage conditions.

Sucrose and lyophilization

Sucrose protects the liposomal structure during freezing and drying by replacing water at the lipid interface. Its concentration, residual moisture, and crystallization behavior affect reconstitution time and particle-size recovery.

A strong formulation program evaluates the product before and after lyophilization. Critical measurements include:

• Mean particle diameter
• Polydispersity index
• Zeta potential
• Encapsulation or association of amphotericin B
• Free amphotericin B
• Reconstitution time
• Residual moisture
• Drug potency
• Lipid degradation
• Visible and subvisible particles

What formulation patents protect liposomal amphotericin B?

The original intellectual-property value in liposomal amphotericin B was concentrated in composition, lipid ratios, drug-loading methods, manufacturing conditions, and therapeutic use. The earliest AmBisome-related U.S. composition patents have generally reached the end of their ordinary patent terms, based on filing dates in the 1990s and standard 20-year patent terms, subject to patent-term adjustment, terminal disclaimers, and jurisdiction-specific rules.

The commercial barrier is now less likely to be a basic excipient claim and more likely to involve product-specific know-how. Relevant protection categories include:

Protection category	Typical subject matter	Current strategic value
Composition patents	Amphotericin B with defined phospholipid and sterol combinations	Historically important; many early claims have expired
Process patents	Loading, homogenization, solvent removal, aseptic processing, and lyophilization	Can remain relevant if later-filed
Product-by-process claims	Liposomes defined by size, drug association, or manufacturing outcome	Potentially relevant in complex-product litigation
Method-of-use patents	Treatment of fungal infections, leishmaniasis, or selected patient groups	Narrower value where clinical use is established
Trade secrets	Mixing energy, temperature profiles, lipid hydration, filtration, and drying cycles	Often the most durable practical barrier
Regulatory exclusivity	Clinical-data or pediatric exclusivity	Time-limited and separate from patent protection

The FDA Orange Book controls the current listed-patent position for an approved small-molecule drug product. AmBisome is a complex liposomal product, so the absence of a broad active composition patent would not eliminate development risk. A competing applicant still must demonstrate pharmaceutical equivalence and bioequivalence or comparable performance through an FDA-accepted pathway.[4]

When does liposomal amphotericin B lose exclusivity?

AmBisome received U.S. approval in 1997. Its early composition and formulation patents were filed during the 1990s and would ordinarily have expired during the 2010s, although exact expiration dates depend on each patent family and any patent-term adjustment.

Milestone	Approximate timing
Original liposomal amphotericin B development	Early to mid-1990s
AmBisome U.S. approval	1997
Likely expiration period for earliest U.S. composition patents	Mid-2010s
Current commercial barrier	Complex-product development, manufacturing know-how, regulatory comparability
Regulatory route for a conventional generic	Abbreviated application where FDA requirements can be met
Biosimilar pathway	Not applicable because amphotericin B is a chemically synthesized small molecule

The key commercial question is therefore not whether the original formulation patent has expired. It is whether a challenger can reproduce the reference product’s critical quality attributes at commercial scale and obtain regulatory approval without infringing later process or use claims.

Are there generic or biosimilar challenges to AmBisome?

A biosimilar application is not the appropriate pathway for amphotericin B. Biosimilars apply to biological products. Liposomal amphotericin B is a complex drug-device-like formulation of a small-molecule active ingredient.

A generic or hybrid application may be possible, but conventional chemical sameness is insufficient. A challenger must address the liposome as a functional delivery system. The principal development issues are:

• Matching amphotericin B content
• Matching lipid identity and composition
• Demonstrating comparable particle-size distribution
• Establishing equivalent drug association with the liposome
• Controlling free amphotericin B
• Matching release and leakage behavior
• Demonstrating equivalent pharmacokinetics where required
• Addressing infusion reactions and renal safety
• Showing stability after reconstitution and dilution

A Paragraph IV certification could challenge any unexpired listed patent. The litigation risk would depend on the Orange Book entries in force at filing, the scope of asserted claims, and whether the challenger’s process uses different lipid hydration, loading, filtration, or drying conditions.

What manufacturing and excipient barriers affect market entry?

Manufacturing is the principal barrier for a competing liposomal amphotericin B product.

Sterile lipid handling

The product requires sterile or controlled-bioburden lipid processing, aseptic manufacture, and validated removal of process-related impurities. Lipids must meet tight limits for oxidation, hydrolysis, residual solvents, endotoxins, and microbial contamination.

Liposome formation

Commercial processes may use thin-film hydration, solvent injection, high-pressure homogenization, microfluidic mixing, or related methods. Each approach can produce different particle-size distributions and encapsulation profiles.

Scale-up risks include:

• Increased batch-to-batch particle-size variation
• Nonuniform drug loading
• Heat generation during homogenization
• Filter adsorption
• Lipid oxidation
• Longer aseptic hold times
• Reduced recovery after sterile filtration

Freeze-drying

Lyophilization requires a cycle that protects both amphotericin B and the liposome. A product that meets potency specifications but fails to recover its particle-size profile after reconstitution may not be clinically comparable.

Packaging and distribution

The finished product is a sterile powder for reconstitution. Commercial packaging must protect against moisture, oxygen, light, and mechanical stress. The supply chain must also support controlled storage and reliable access to sterile water and compatible dextrose diluent.

What commercial opportunities exist in excipients and lipid supply?

Qualified phospholipid manufacturing

High-purity hydrogenated phosphatidylcholine and distearoylphosphatidylglycerol are attractive specialty-excipient products. Suppliers can compete through:

• GMP production
• Low-peroxide specifications
• Tighter fatty-acid distribution
• Consistent transition-temperature profiles
• Regional inventory
• Multi-site qualification
• Regulatory support packages

The strongest opportunity is not commodity phospholipid volume. It is dependable supply of injectable-grade material with a complete regulatory file.

Synthetic or non-soy lipid systems

A developer could investigate synthetic phosphatidylcholine, alternative anionic phospholipids, or non-soy lipid sources. These options may reduce allergen, agricultural, or supply-chain exposure. They also create comparability and regulatory burdens because the lipid system is central to the product’s performance.

Improved lyoprotectants

Sucrose is established and inexpensive. Commercial differentiation may come from mixed protectant systems using trehalose, mannitol, or other excipients, but such changes must preserve liposome size, drug retention, reconstitution, and stability. Mannitol can improve cake structure but may crystallize and reduce interfacial protection if poorly controlled.

Ready-to-use presentations

A ready-to-use or shorter-reconstitution presentation could have value in hospitals and resource-limited settings. The technical challenge is maintaining stability in an aqueous formulation without increasing leakage, aggregation, hydrolysis, or free amphotericin B.

Regional production

Demand is strongest where invasive fungal infections, HIV-associated cryptococcal meningitis, hematologic malignancies, transplantation, and visceral leishmaniasis create recurring use. Regional fill-finish, lipid production, or technology transfer could reduce lead times and improve public-sector procurement.

What regulatory status and indications support demand?

AmBisome is FDA-approved for several serious fungal indications, including empirical treatment of presumed fungal infection in febrile neutropenic patients, cryptococcal meningitis in patients with HIV, and selected systemic fungal infections. It also has an indication for visceral leishmaniasis in the U.S. label.[1]

The product is used in settings where renal toxicity, prior intolerance, or treatment complexity makes conventional amphotericin B less suitable. WHO guidance and global health procurement have supported liposomal amphotericin B access for cryptococcal disease and visceral leishmaniasis.[5,6]

The principal commercial demand drivers are:

• Hospital antifungal protocols
• Oncology and transplant populations
• HIV-associated cryptococcal meningitis
• Visceral leishmaniasis programs
• Resistant or refractory fungal infections
• Public-sector tenders
• National treatment guidelines

Product demand can be volatile because much of the global opportunity is procurement-driven rather than retail-driven.

How does AmBisome compare with other amphotericin B products?

Product	Lipid platform	Key commercial characteristic
AmBisome	Small unilamellar liposome	Strong clinical adoption and established regulatory history
Abelcet	Amphotericin B lipid complex	Different particle structure and pharmacokinetic behavior
Amphocil or Amphotec	Amphotericin B colloidal dispersion	Distinct excipient and particle system; availability varies by market
Conventional amphotericin B deoxycholate	No lipid carrier	Lower acquisition cost but greater infusion and renal-toxicity burden
Regional liposomal products	Varies by manufacturer	May compete on price, local supply, or public-sector access

These products cannot be treated as formulation substitutes solely because they contain the same active ingredient. Their lipid architecture, dosing, safety profiles, administration requirements, and clinical evidence differ.

What is the patent strength and generic entry risk?

The historical composition patent estate is weaker than it was during AmBisome’s protected period because early patents have largely aged out. The practical barrier remains moderate to high for a fully substitutable generic because liposomal amphotericin B is a complex sterile product.

Risk factor	Assessment
Basic active ingredient patent risk	Low; amphotericin B is an old molecule
Early composition patent risk	Generally reduced by expiration
Later process patent risk	Product- and jurisdiction-specific
Formulation replication risk	High
Bioequivalence risk	High compared with conventional tablets or injections
Manufacturing scale-up risk	High
Regulatory review risk	High
Price competition after approval	Potentially significant
Biosimilar risk	Not applicable
Supply-chain opportunity	High for qualified lipid and fill-finish suppliers

A generic launch would most likely begin in price-sensitive tenders, hospital systems, and countries with established local regulatory pathways. U.S. substitution would require stronger evidence of equivalence and reliable commercial supply.

What litigation and settlement issues affect the product?

The central litigation issues for a future challenger would be:

1. Whether any unexpired Orange Book patent remains listed.
2. Whether the challenger’s lipid ratios or process fall within an asserted claim.
3. Whether product-by-process claims reach a product made by a different process.
4. Whether a method-of-use claim covers the proposed label.
5. Whether the challenger can establish noninfringement or invalidity under a Paragraph IV notice.
6. Whether a settlement delays launch or permits an agreed entry date.

Publicly disclosed product-level revenue and settlement economics for AmBisome are limited. Gilead’s broader financial reporting does not consistently separate AmBisome revenue from other products, so product-specific revenue exposure cannot be reliably inferred from consolidated filings.[7]

Key Takeaways

• AmBisome relies on hydrogenated phosphatidylcholine, distearoylphosphatidylglycerol, cholesterol, alpha-tocopherol, and sucrose.
• The liposome is a functional component of the product and drives regulatory comparability risk.
• Early composition patents have generally expired or reached the end of their ordinary terms.
• Manufacturing know-how, lipid quality, lyophilization, and sterile processing remain meaningful barriers.
• A biosimilar pathway does not apply; a generic or hybrid pathway is the relevant route.
• The most attractive excipient opportunities are GMP-grade phospholipids, anionic lipids, cholesterol, oxidation-control systems, and regional supply.
• Commercial demand is concentrated in invasive fungal disease, cryptococcal meningitis, visceral leishmaniasis, oncology, transplantation, and public-health procurement.
• A competing product can achieve differentiation through lower cost, regional availability, simplified reconstitution, or improved stability, but formulation changes increase regulatory risk.

FAQs About Liposomal Amphotericin B Excipients and Market Entry

Which excipient is most important in AmBisome?

The phospholipid system is most important because it determines liposome formation, drug association, membrane stability, biodistribution, and release. Sucrose is also important for maintaining the liposome during lyophilization.

Can a company replace soy phosphatidylcholine in liposomal amphotericin B?

Yes, a developer can investigate alternative phospholipid sources, but the change would require extensive comparability data. The replacement must preserve particle size, drug association, stability, release, and clinical performance.

Why is liposomal amphotericin B difficult to genericize?

It combines a complex lipid carrier, a sterile injectable dosage form, a freeze-drying process, and clinically relevant particle attributes. Matching the active ingredient alone does not establish equivalence.

Is cholesterol in liposomal amphotericin B an active ingredient?

No. Cholesterol is an excipient that stabilizes and modifies the liposomal membrane. Its concentration and quality can still materially affect product performance.

What is the strongest commercial opportunity around amphotericin B liposomes?

The strongest opportunities are qualified injectable-lipid supply, regional fill-finish, lower-cost public-sector products, and process technologies that improve reconstitution, stability, or manufacturing yield without changing the clinical profile.

References

1. U.S. Food and Drug Administration. (2023). AmBisome (amphotericin B) liposome for injection: Prescribing information.

2. Adler-Moore, J. P., & Proffitt, R. T. (2002). AmBisome: Liposomal formulation, structure, and mechanism of action. Journal of Antimicrobial Chemotherapy, 49(Suppl. 1), 21-30.

3. Stone, N. R. H., Bicanic, T., Salim, R., & Hope, W. (2016). Liposomal amphotericin B: A review of the current clinical evidence. Journal of Antimicrobial Chemotherapy, 71(Suppl. 2), ii5-ii19.

4. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.

5. World Health Organization. (2022). Guidelines for diagnosing, preventing and managing cryptococcal disease among adults, adolescents and children living with HIV.

6. World Health Organization. (2022). WHO guideline for the treatment of visceral leishmaniasis in HIV coinfected patients in East Africa and South-East Asia.

7. Gilead Sciences, Inc. (2024). Form 10-K annual report.