MDI Propellant Patents: Who Leads, Where the Gaps Are 2026
- Filing has cooled from its 2021 peak. 35 records in 2021 fell to 16 by 2024, a 54% drop over three years, as the field moves from early HFO-propellant exploration toward consolidation.
- The top of the field is concentrated but not closed. The five leading assignees account for 48.0% of all 742 records in scope, and the ten leading assignees for 61.7% — leaving a long tail of single- and few-filing entrants.
- Device and packaging claims sit far behind formulation claims. A61M device claims cover 20.1% of records and B65D packaging claims only 5.7%, against 85.2% for A61K medicinal-preparation claims — device-side and canister-side space is comparatively open.
Filing growth compares 2021 (35 records) with 2024 (16) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 742 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This landscape tracks 742 published patent records filed between 2015 and mid-2026 that combine pressurized metered dose inhaler (pMDI) technology with the propellant transition away from high-global-warming-potential (GWP) hydrofluorocarbons. The scope spans formulation chemistry, valve metering, canister coatings, suspension and dose-uniformity claims, and the low-GWP propellant chemistries — chiefly hydrofluoroolefins (HFOs) — now displacing HFA-134a and HFA-227.
Because publication trails filing by roughly 18 months, the 2025 and 2026 counts in this dataset are still filling in and should not be read as a real decline. The 2021 peak and the subsequent fall to 2024 are the most reliable trend signal currently available.
Filing trends and technology composition
The record set spans 2015 through mid-2026 across six major receiving offices, with formulation chemistry dominating the IPC composition and device engineering a distant second.
A 2021 peak followed by a real pullback
Filings rose from 9 in 2017 to a peak of 35 in 2021, then fell to 16 by 2024 — a 54% decline over that three-year span. That pattern is consistent with an early wave of HFO-reformulation patents settling into a smaller group of active filers rather than a technology losing relevance.
Formulation chemistry dwarfs device and packaging claims
A61K medicinal-preparation claims appear in 85.2% of the 742 records in scope, with A61P therapeutic-activity claims at 42.7%. A61M device claims (20.1%), C07D heterocyclic-compound claims (9.3%), B65D packaging claims (5.7%), A61L sterilising claims (4.9%), A61J medicine-container claims (3.4%) and B01F mixing claims (2.0%) trail well behind, marking where claim density is comparatively light.
Shares are the percentage of the 742 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Metered Dose Inhalers and Low-GWP Propellants with Eureka
This page is one run against one query. Ask Eureka your own question about metered dose inhalers and low-gwp propellants and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative and most-cited filings
Albuterol aerosol suspension with high-amount HFO propellant, co-solvent-free
US12642779B1, filed by Amphastar Pharmaceuticals and published June 2026, claims a pressurized metered dose inhaler formulation combining pre-micronized albuterol sulfate with a high proportion of the green propellant HFO-1234ze(E) and a surfactant, while excluding any co-solvent such as ethanol, glycerol or propylene glycol.The co-solvent-free structure is the claim feature most likely to matter for freedom-to-operate: it narrows the formulation space this patent occupies but also signals a specific route others must design around.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | WO2001060420A1 | A medicinal aerosol formulation | 93 |
| 2 | WO2001026658A2 | Topical nasal treatment using desloratadine | 80 |
| 3 | WO2012051426A2 | Aggregate nanoparticulate medicament formulations, manufacture and use thereof | 79 |
| 4 | US20050056276A1 | Metered dose inhaler with lockout | 76 |
| 5 | US6551578B2 | Modulated release particles for aerosol delivery | 76 |
| 6 | US6585957B1 | Medicinal aerosol formulation | 72 |
| 7 | US20090208582A1 | Templated Open Flocs of Anisotropic Particles for Enhanced Pulmonary Delivery | 71 |
| 8 | US20070043030A1 | Pharmaceutical compositions for treating premature ejaculation by pulmonary inhalation | 69 |
| 9 | US20110182997A1 | Suspension formulations | 58 |
| 10 | US7905230B2 | Metered dose inhaler with lockout | 58 |
Citation counts reward older filings that have had more time to accumulate citers; treat them as a signal of influence within this corpus, not of current commercial importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers say about where this field stands
Three patterns stand out once the filing trend, the assignee concentration and the IPC composition are read together.
The wave has crested, not vanished
Filings dropped from 35 in 2021 to 16 in 2024. That is a real pullback on complete-year data, not an artifact of publication lag, and it suggests the initial rush to reformulate around HFO propellants is giving way to a smaller set of committed filers refining specific formulations.
Five assignees hold half the field
The five leading assignees account for 48.0% of all 742 records in scope, rising to 61.7% for the ten leading assignees. That leaves roughly two-fifths of filings spread across a long tail of smaller entrants, generics manufacturers and academic assignees.
Formulation chemistry is the crowded lane
A61K medicinal-preparation claims touch 85.2% of records, far ahead of A61M device claims at 20.1% and B65D packaging claims at 5.7%. New formulation chemistry entrants face dense prior art; device, canister-coating and packaging claims sit on comparatively open ground.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to metered dose inhalers and low-gwp propellants, with the prior art for and against each one.
Who is filing, and where the activity has slowed
A handful of pharmaceutical formulators lead the ranking, but recent-year filing counts across even the top names have dropped to zero or near-zero, consistent with the post-2021 pullback seen in the overall trend.
A clear leader, but momentum has cooled
The leading assignee holds 132 records, well ahead of the fifth-place assignee at 37 and the tenth at 16. Even so, recent-year momentum data shows several of the most active historical filers, including the leader, recording zero filings in the latest tracked year.
Concentration flattens quickly past tenth place
The top ten assignees combine for 61.7% of all 742 records, meaning the remaining 90 ranked assignees share the other 38.3% between them — a long tail of single- and few-filing entrants, including generics manufacturers and university systems.
Co-filing is rare and concentrated
Only ten co-assignee pairs appear across the dataset, and the strongest pairing links a device specialist with a biopharmaceutical partner. Most filings in this space are filed by a single assignee rather than through joint development.
| Assignee | Recent year | YoY |
|---|---|---|
| Cipla Ltd | 1 | -83% |
| Chiesi Farmaceutici S.p.A. | 0 | — |
| Vectura Ltd | 0 | — |
| Aerophaam Technology Incorporated | 0 | — |
| Board of Regents of The University of Texas System | 0 | — |
| Pulmatrix Operating Co Inc | 0 | — |
| Proveris Scientific Corporation | 0 | — |
| Teva Branded Pharmaceutical Products R&D, Inc. | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, licensing, or R&D prioritisation.
Run a freedom-to-operate check on device claims
With A61M device claims at only 20.1% of records against 85.2% for formulation chemistry, valve metering and canister coating are comparatively open. A targeted search before committing to a device design can confirm the gap holds for a specific mechanism.
Search device claims in EurekaTrack the leading assignees' next filings
Several top assignees show zero filings in the latest tracked year despite historically large portfolios. Watching for their next publications will show whether the pullback is temporary or a genuine step back from this space.
Set up assignee tracking in EurekaMap co-solvent-free formulation claims
The most recent representative filing narrows its claim to a co-solvent-free HFO suspension. Mapping adjacent surfactant and stabilizer claims against it clarifies how much formulation space remains open around that specific approach.
Explore formulation claims in EurekaCommon questions about this landscape
Complete-year data shows filings falling from a peak of 35 in 2021 to 16 in 2024, a 54% decline. This lines up with an initial wave of patents built around reformulating existing drugs for HFO propellants, followed by a smaller group of assignees continuing to refine specific formulations rather than a broad rush of new entrants. It should not be read as the technology losing relevance; the underlying regulatory pressure to phase out high-GWP HFA propellants has not reversed.
The ranking covers 100 assignees across 742 records, with the leading assignee holding 132 records and the fifth-place assignee holding 37. The five leading assignees together account for 48.0% of all records in scope, and the ten leading assignees for 61.7%, leaving a long tail of smaller filers including generics manufacturers, device specialists and university systems.
A61K medicinal-preparation claims appear in 85.2% of the 742 records, making formulation chemistry the densest claim area by a wide margin. A61P therapeutic-activity claims follow at 42.7%. Device claims under A61M sit at only 20.1% and packaging claims under B65D at 5.7%, indicating that device engineering and canister packaging carry comparatively less claim density than the drug formulation itself.
No. High filing density in A61K formulation claims means that particular claim space is occupied, not that the underlying technology has stopped developing. Recent representative filings, such as a 2026 co-solvent-free HFO suspension patent, show formulators still working out specific surfactant and stabilizer combinations within the propellant transition, so mature filing volume and active innovation are coexisting here.
The IPC composition points to device and packaging claims as comparatively under-claimed relative to formulation chemistry: A61M device claims cover 20.1% of records, B65D packaging 5.7%, A61L sterilising 4.9%, and B01F mixing just 2.0% of the 742 records in scope. Valve metering mechanisms, canister internal coating chemistry, and plume geometry control are specific sub-areas within those classes worth a closer freedom-to-operate look before committing to a device design.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.