General Anesthetic Drug Class List

Drugs in Drug Class: General Anesthetic

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Abbvie	ULTANE	sevoflurane	LIQUID;INHALATION	020478-001	Jun 7, 1995	AN	RX	Yes	Yes
Baxter Hlthcare	SUPRANE	desflurane	LIQUID;INHALATION	020118-001	Sep 18, 1992		RX	Yes	Yes
Piramal Critical	SOJOURN	sevoflurane	LIQUID;INHALATION	077867-001	May 2, 2007	AN	RX	No	No

General Anesthetic market dynamics and patent landscape: What protects inhaled and IV anesthetics, when exclusivity ends, and where generic risks concentrate

Last updated: July 25, 2026

The general anesthetic category is dominated by off-patent small molecules with periodic “evergreening” around formulations, delivery systems, and combination products. Patent risk for generics is concentrated in (1) long-acting IV anesthetics with device-like delivery concepts, (2) inhalation products that have reformulated strength or delivery/packaging, and (3) adjuncts used to support anesthesia delivery (vasopressors, antiemetics, and analgesic components) that can sit in the same perioperative formulary. Most high-volume generic entry has already occurred; remaining exclusivity pockets typically come from formulation patents, method-of-use claims, or newer branded reformulations rather than the original drug substance.

Which general anesthetics drive demand and how does perioperative volume translate into IP value?

General anesthetics are used across inpatient surgery, outpatient surgery centers, emergency procedures, imaging requiring deep sedation, and pediatric and geriatric anesthesia protocols. Demand is tied to surgical case volume, reimbursement dynamics, and hospital formulary contracting.

Primary subsegments with different patent lifecycles

• Inhaled anesthetics: volatile agents delivered via vaporizers and breathing circuits. Many are older and largely generic. IP tends to cluster in specific pack/strength/indicator innovations and combination products, not the active ingredient.
• IV anesthetics: rapid onset and controllable depth via infusion or bolus. IP frequently includes formulation, concentration, and delivery concepts.
• Adjuncts that affect “anesthesia bundle” purchasing: opioids, neuromuscular blockers, antiemetics, and reversal agents. These are not always “general anesthetics” by strict labeling, but they drive perioperative procurement and can create practical IP overlap in litigation.

Commercial consequence for patent strategy

• Where the base molecule is off-patent, branded suppliers monetize through portfolio packaging, concentration differentiation, and patient safety positioning.
• Where a drug has relatively recent reformulation or is still within substance or use patent windows, exclusivity extensions matter more than class-wide volatility.

What patents protect common inhaled general anesthetics and who holds the estate?

Featured groups

• Sevoflurane
• Isoflurane
• Desflurane
• Nitrous oxide
• Older halogenated agents used in limited geographies

Typical protection pattern

• Drug substance patents are usually expired for most widely used volatile anesthetics.
• Remaining branded value often depends on:
  • Formulation/packaging patents (container materials, stabilizers, vaporizer compatibility constraints).
  • Method-of-use patents tied to specific administration protocols.
  • Improved delivery system claims tied to vaporizer models or anesthesia workflow.

Who commonly appears as patent holders

• Original NDA holders and their affiliates.
• Large inhalation-focused brands that historically maintained exclusive manufacturing, supply, and vaporizer systems.

Risk lens for generics

• For volatile agents, patentability often centers on whether a generic can be sold as the same strength and presentation without infringing narrow delivery/packaging claims.
• FDA requirements for inhalation products can allow straightforward copies if the claims landscape does not cover formulation or specific presentation.

What formulations are protected for propofol and other IV general anesthetics?

Propofol is the most visible IV anesthetic battleground because the market value sits in a branded-style administration experience: lipid emulsion characteristics, sterility assurance, and concentration.

Typical patent clusters for propofol-like IV anesthetics

• Lipid emulsion formulation patents
  • Particle size and stability control
  • Antioxidant and chelator selections
  • Emulsifier systems and osmolality targets
• Concentration and container patents
  • Strength-specific presentations
  • Container and stopper barrier properties for chemical stability
• Infusion workflow patents
  • Dedicated transfer sets, prefilled syringes, or light-protective packaging
• Method-of-use
  • Induction and maintenance protocols in specific patient populations

Generic entry reality

• Many jurisdictions have multiple generic propofol presentations. Remaining branded revenue is protected when formulation claims cover specific emulsion specs, or when patents cover the exact concentration and presentation that hospitals contract for.

When does exclusivity end for general anesthetics and how do you map substance vs formulation vs use patents?

Exclusivity for anesthetics can come from different layers:

• Patent term for drug substance, composition/formulation, and method-of-use.
• Regulatory exclusivity (New Chemical Entity, New Therapeutic Biological Product, pediatric exclusivity) depending on the product’s approval history.
• Market exclusivity via litigation settlements for some branded products if generic entry is delayed through agreements.

Practical mapping approach for asset valuation

1. Identify the active ingredient(s) and list all Orange Book-listed patents for each NDA/ANDA.
2. Separate patents into:
   • composition/formulation
   • methods of treatment
   • manufacturing and process patents
   • device/delivery packaging patents
3. Identify which patents are “listed for protection of the drug product.”
4. For each remaining in-force patent, check whether the generic label is likely to be “carved out” by a settlement, or whether “design-around” is possible via presentation or formulation changes.

Timing driver

• Litigation and Paragraph IV actions usually cluster just before the earliest listed patent or earliest regulatory exclusivity date. For anesthetics, when the underlying substance is off-patent, the first generic risk often depends on whether formulation patents still have term left.

What is the Orange Book status of general anesthetics and where do listings concentrate?

Orange Book listings typically show:

• Multiple patents per NDA for:
  • composition and formulation
  • manufacturing processes
  • packaging
• Fewer substance patents when the active ingredient is old.

Concentration effect

• A single marketed NDA can have a high number of listed patents even when only a few are commercially critical. The critical list is the set that generics challenge or that trigger settlement-driven delay.

Featured “where listings concentrate”

• Sterility and stability improvements (composition and manufacturing)
• Emulsion quality for IV products
• Presentation-specific concentration and pack claims for hospital purchasing

How many patents cover leading general anesthetics and what does the estate strength usually look like?

General anesthetics typically show one of two estates:

• Old substance with narrow residual IP: the remaining patents are concentrated in specific presentation, formulation, and process. Estate strength is moderate unless there is a live method-of-use or composition claim broad enough to cover generics.
• Recent reformulation or platform delivery: estates are deeper, with multiple formulation, process, and device/delivery claims. Estate strength is higher for time-limited windows and for products where substitution is hard.

What drives “strong estate” in practice

• Independent claims on composition/formulation and manufacturing that are hard to design around.
• Continuation claims that align with the exact marketed product specs.
• Consistent infringement theories tied to exact ANDA formulation and facility process.

What Paragraph IV challenges are filed for general anesthetics and how do they shape generic entry timing?

Paragraph IV challenges are usually the mechanism for delayed exclusivity battles when:

• Orange Book patents are listed and in force, and
• the generic sponsor wants market entry before expiration.

Why Paragraph IV matters in anesthesia

• Hospital procurement is switching-cost heavy when the product is already in formulary with contracting terms.
• Generic timing is therefore often set not only by patent expiry but by whether settlements or injunction risks deter switching.

Litigation effect on entry

• Settlements frequently:
  • specify a “date certain” for entry (often aligned with a later-expiring patent),
  • require non-infringement design or labeling carve-outs,
  • restrict launch geography or packaging.

What patent litigation affects propofol, sevoflurane, and other major general anesthetics?

Patent litigation for anesthetics tends to focus on:

• infringement of formulation or method-of-use claims by ANDA products,
• process similarity arguments (manufacturing methods) when the same core specs are used,
• validity defenses targeting obviousness or lack of enablement.

Commercial outcome

• For generics, the core question is whether the claims cover the generic’s exact emulsion characteristics or presentation.
• For brands, the core question is whether the formulation and manufacturing process are sufficiently similar to maintain infringement positions.

Where outcomes typically favor brands

• When patents are clearly tied to specific formulation specs and the generic’s product is close in measurable attributes.
• When the brand’s claims include broad composition coverage.

Where outcomes typically favor generics

• When the remaining patents are narrow, and the generic can demonstrate different compositions, particle sizes, stabilizers, or concentrations.
• When the method-of-use claims are not practical to enforce against product label instructions.

How do biosimilars and biologics relate to “general anesthetic” competition?

Most general anesthetics are small molecules (inhaled volatile agents, nitrous oxide, propofol-like IV agents). Biosimilar competition is not a central driver for the anesthetic class.

However, biosimilar competition can matter indirectly:

• perioperative supply chains include biologics for supportive care,
• hospitals may reallocate procurement budgets, affecting formularies for anesthetic adjuncts.

What generic entry risks exist for inhaled volatile anesthetics?

Inhaled anesthetics face a different IP and regulatory pattern:

• Generics must show sameness in active ingredient, strength, and conditions of use under applicable regulatory standards.
• Even when the active ingredient is generic, remaining risk can persist if:
  • Orange Book lists patents tied to packaging, stabilizers, or delivery compatibility, or
  • method-of-use claims include protocols that the generic label would adopt.

Key design-around levers

• Change presentation or container/packaging parameters if claims are presentation-specific.
• Use different stabilizers or production processes if composition patents cover measurable attributes.

How does the patent landscape differ between outpatient surgery centers and hospitals?

Contracting affects infringement economics:

• Hospitals have more inertia and deeper contracts with branded suppliers.
• Outpatient centers often have faster substitution cycles but may rely on fewer SKUs.

Strategic consequence for brands

• If patents are narrow, brands can rely on formulary and supply agreements to hold volume until the last relevant patent expires.
• If patents are broad and enforceable, generic entry timing can be delayed materially, preserving share during critical budget cycles.

Which companies have the largest exposure across general anesthetics?

Exposure is best understood as:

• share of revenue tied to a single anesthetic molecule or a small set,
• dependence on proprietary formulations/concentrations,
• sensitivity to hospital contract duration and switching risk.

Typical exposure profile

• Brands with multiple presentations of the same anesthetic have higher switching friction and greater value of formulation or packaging claims.
• Brands with a single product and generic supply pressure are more exposed to near-term exclusivity erosion if there are only a few remaining patents.

What licensing and settlement agreements commonly appear in anesthetic patent disputes?

Common settlement constructs for small-molecule and inhalation products:

• Date-based entry tied to the expiration of the last litigated listed patent.
• Narrow design carve-outs where generic changes composition/presentation to avoid infringement.
• Non-challenge covenants restricting further patent challenges during a window.

How to use this in commercial planning

• Settlement dates often become de facto launch milestones.
• Even if other patents expire earlier, settlement can delay entry to a later “floor” date.

Which manufacturing/IP barriers can stop generic launches even after patent expiry?

For anesthetics, launch friction can come from:

• scale-up and validated manufacturing that hits the same stability specs,
• sterility assurance and container compatibility,
• vaporizer and inhalation device integration where product compatibility affects usability.

Even when patent expiry occurs, practical barriers can delay broad rollout, letting branded products sustain volume through conversion lead times.

Key Patent Estate Patterns by General Anesthetic Modality

Inhaled volatile agents

• Dominant active ingredients are old and off-patent.
• Residual IP concentrates in:
  • presentation and packaging,
  • stabilizer systems and manufacturing controls,
  • specific administration protocols.

IV emulsion anesthetics (ex: propofol class)

• Residual IP concentrates in:
  • emulsion formulation stability and particle attributes,
  • concentration-specific compositions,
  • container and light-protective packaging,
  • manufacturing process validation.

“Newer platform” anesthetic delivery

• If reformulated with dedicated containers or patient-specific delivery workflows:
  • more patents remain in force,
  • more design-around constraints,
  • more settlement leverage.

Key Takeaways

• General anesthetics are mostly off-patent at the drug-substance level; remaining IP value is concentrated in formulations, presentations, packaging, and method-of-use claims.
• Patent risk for generics is highly product-specific. The key variable is which Orange Book-listed patents are still in force at the time of Paragraph IV filing.
• Litigation and settlements are frequently used to delay generic entry beyond the earliest expiration date, aligning market entry to the last enforceable listed patent.
• Commercial dynamics favor brands when switching is contractually and operationally expensive, which magnifies the economic value of narrow but enforceable formulation or presentation patents.

FAQs

1) What types of patents most often block generic entry for inhaled anesthetics?
Presentation and packaging patents, formulation/stabilizer claims, and narrow method-of-use claims that align with label-administration protocols.

2) Do general anesthetics typically have many Orange Book patents or just a few critical ones?
Often many patents appear on paper, but only a subset are commercially critical because they map to the generic’s intended strength, container, and formulation specs.

3) Can generics launch after “patent expiry” but still face enforcement risk?
Yes, if other listed patents remain in force or if settlement terms delay entry to a later date.

4) Are biosimilars a significant competitive threat in general anesthesia?
Not usually. Competition is mostly driven by small-molecule generics and reformulations; biosimilars affect perioperative budgets indirectly via hospital procurement.

5) What determines whether a brand’s formulation patent is design-aroundable?
Whether claims are tied to measurable formulation attributes and whether the generic can change composition, particle attributes, stabilizer systems, or presentation without losing bioequivalence and label consistency.

References

No sources cited.