Injectable Depot Patents: Leaders, Trends & White Space 2026
- Filing activity peaked in 2023 at 17 families and has not returned to that level since, suggesting the current wave of depot-formulation filing has already crested rather than being early-stage.
- A61P therapeutic-activity claims sit in 127 of 240 families alongside the core A61K formulation claims, meaning most filings couple a delivery-vehicle claim to a specific indication rather than claiming the platform alone.
- The most-cited prior art dates to 1997–2004 with the top-cited record drawing 253 citations, so newer filings are building on formulation chemistry that is two decades old rather than displacing it.
What this landscape covers
This dataset tracks 240 patent families filed against a search built around long-acting injectable and depot formulation claims — PLGA microspheres, burst-release control, syringeability, degradation profile and sterilisation limitations — filtered to the medicinal-preparation and biodegradable-polymer IPC classes (A61K9, A61K47, C08G63). Coverage runs from 2015 through the mid-2026 data cut-off, with publication lag meaning the most recent 12-18 months are undercounted by definition.
The filing curve rose from a low base in 2017, reached its high point in 2023, and has since flattened. Read alongside a citation stack still anchored in filings from the late 1990s and early 2000s, this points to a field where the core delivery-vehicle chemistry is settled and current filing effort goes into indication-specific formulation claims rather than new release mechanisms.
Filing trend and technology composition
Two views of the same 240 families: how filing volume has moved year over year, and which IPC subclasses the claims actually sit in.
A flat-to-declining curve after a 2023 peak
Filings moved from 3 in 2017 to a peak of 17 in 2023, with the 2022 midpoint at 10. The 2026 figure of 2 is a partial year and should not be read as a collapse — but the plateau from 2022 to 2023 and the absence of a new high since then is a real signal, not an artefact of the cut-off.
Formulation claims dominate; indication claims are close behind
Every family in this set carries an A61K medicinal-preparation claim by construction of the search, but 127 of 240 also carry an A61P therapeutic-activity claim, and 54 touch C07D heterocyclic compound chemistry. Device claims (A61M), sterilisation (A61L) and polymer composition (C08L) each appear in single digits, marking those as thin, specific niches rather than crowded ground.
Shares are the percentage of the 240 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Injectable Depot and Long-Acting Formulations with Eureka
This page is one run against one query. Ask Eureka your own question about injectable depot and long-acting formulations and every answer comes back with the patent numbers behind it.
Try EurekaThe prior art everything else cites
Long Acting Injectable Compositions of Cariprazine or its Pharmaceutically Acceptable Salts
The present invention discloses to a long acting injectable composition comprising cariprazine or its pharmaceutically acceptable salts thereof and process to prepare the same. The present invention also discloses to use of the long acting injectable composition comprising cariprazine or its pharmaceutically acceptable salts thereof in the treatment of psychotic disorders.Filed by Cipla Limited, published 2024-05-23 — an indication-specific depot formulation claim layered on an established antipsychotic long-acting injectable pattern.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6174540B1 | Long acting injectable formulations containing hydrogenated caster oil | 253 |
| 2 | US6077843A | Aqueous suspensions of 9-hydroxyrisperidone fatty acid esters | 101 |
| 3 | WO2004006886A2 | Injectable depot formulation comprising crystals of iloperidone | 85 |
| 4 | US20040234616A1 | Long acting injectable insulin composition and methods of making and using thereof | 80 |
| 5 | WO1997044039A1 | Aqueous suspensions of 9-hydroxyrisperidone fatty acid esters | 78 |
| 6 | US20080220069A1 | Long Acting Injectable Crystal Formulations of Estradiol Metabolites and Methods of Using Same | 77 |
| 7 | WO1999027906A1 | Long acting injectable formulations containing hydrogenated castor oil | 70 |
| 8 | US20040146562A1 | Depot formulations in the form of a suspension | 57 |
| 9 | WO2009100441A2 | Depot formulations | 56 |
| 10 | EP0535734A1 | Long acting injectable formulations containing hydrogenated castor oil | 46 |
Citation counts inside a searched corpus favour older filings; treat this as a map of foundational chemistry, not of current competitive threat.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing decision
Three read-outs from the trend, the citation stack and the IPC split that matter more than the raw counts on their own.
The wave has crested, not started
Filing rose steadily from 2017 through a 2023 peak and has not set a new high since. Combined with publication lag, the 2026 figure understates true filing activity, but the 2022-2023 plateau at the top is a genuine signal that the easiest formulation claims have already been staked out.
Foundational chemistry is two decades old
The most-cited records in this corpus date to 1997-2004 and cover hydrogenated castor oil vehicles and 9-hydroxyrisperidone fatty acid ester suspensions. New filers are formulating around this chemistry rather than replacing it, which raises freedom-to-operate stakes for anyone claiming near the same excipient classes.
Formulation claims are rarely filed alone
Just over half of the families in this set pair the delivery-vehicle claim with a specific therapeutic indication under A61P, and 54 also touch C07D heterocyclic chemistry. A platform-only depot claim without an indication is the less common filing shape here.
US-centred but genuinely multi-jurisdictional
The United States receives the largest single share of filings, but Australia, Canada, WIPO and India each sit close together in the low twenties, indicating applicants are pursuing parallel protection across a fairly even spread of secondary markets rather than filing US-only.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to injectable depot and long-acting formulations, with the prior art for and against each one.
Who is active, and where the activity has gone quiet
Co-filing pairs point to joint development or licensing relationships; recent-year momentum shows which of the historically active names are still filing versus have gone dormant in the latest tracked year.
A small web of joint filings
Ten pairs of co-assignees share at least one family in this corpus, with the strongest pairings linking Merial and Merck-affiliated entities, and Novartis's Swiss and US filing arms. These pairings typically reflect corporate affiliate structures or licensing arrangements rather than open competition.
Historical leaders are not the current filers
Every one of the assignees showing the strongest co-filing history — Novartis, Farmazan, Janssen, Merial and the two Merck entities in this set — recorded zero filings in the latest tracked year. Whoever is filing now in this space is not the same group that built the citation base.
New entrants are filing indication-specific depot claims
Cipla's cariprazine long-acting injectable filing illustrates the current filing pattern: take an established depot delivery approach and file a fresh formulation claim tied to a specific active and indication, rather than a new release-mechanism platform.
| Assignee | Recent year | YoY |
|---|---|---|
| Novartis AG (Switzerland) | 0 | — |
| Farmazan | 0 | — |
| Janssen Pharmaceutica | 0 | — |
| Merial, LLC | 0 | — |
| Merck Sharp & Dohme Corp. | 0 | — |
| Merck & Co., Inc. (USA) | 0 | — |
| Yung Shin Pharmaceutical Industrial Co., Ltd. | 0 | — |
| ABON PHARMACEUTICALS LLC | 0 | — |
Where to take this analysis
The trend and assignee data point to specific next checks before committing to a filing strategy in this space.
Check freedom-to-operate against the citation core
The most-cited records in this corpus sit at the centre of excipient and vehicle chemistry still referenced by newer filings. Any formulation claim touching similar castor-oil or fatty-acid-ester vehicles should be checked against that older art directly.
Explore the cited prior art →Map the dormant assignees' portfolios before licensing
Several historically active co-filers show zero activity in the latest tracked year. Before assuming an opening, confirm whether that reflects genuine exit from the space or simply publication lag on filings not yet public.
Run an assignee portfolio check in Eureka →Test claim language in the under-claimed sub-areas
Sterilisation, device co-claims and non-PLGA polymer blends each show single-digit representation in this IPC set. Drafting a claim there and checking it against the full corpus is a faster way to find open space than reading the top-cited patents alone.
Draft and search a claim in Eureka →Common questions on injectable depot and long-acting formulation patents
The core classification is A61K9 for medicinal preparations characterised by their form, and A61K47 for formulations involving specific excipients or carriers such as PLGA. Biodegradable polymer chemistry used in depot vehicles often falls under C08G63 as well. In this dataset every one of the 240 families carries an A61K claim, with over half also carrying an A61P therapeutic-activity classification tied to a specific indication, so a full landscape search should not stop at A61K alone.
Co-filing analysis in this corpus shows a small cluster of related entities — Novartis's Swiss and US filing arms, Merial, and Merck-affiliated companies — sharing the strongest joint-filing pairs. However, all of these historically prominent names show zero filings in the latest tracked year, meaning the assignees with the deepest citation history are not necessarily the ones currently active. Anyone assessing current competitive pressure should weight recent-year filing activity over historical volume.
Filing rose from 3 families in 2017 to a peak of 17 in 2023 and has not exceeded that level since. This plateau, combined with a citation base still anchored in 1990s and early-2000s chemistry, suggests the core delivery-vehicle mechanisms — PLGA microspheres, castor-oil vehicles, fatty-acid ester suspensions — are largely settled, and current filers are claiming specific indication-formulation combinations rather than new platforms. Note that the 2026 figure is a partial year and understates true filing activity due to normal publication lag.
That filing, from Cipla Limited and published in May 2024, claims a long-acting injectable composition of cariprazine or its pharmaceutically acceptable salts together with a process for preparing it, for use in treating psychotic disorders. It is indication- and active-specific rather than a platform claim over depot delivery generally, so it does not block long-acting injectable work on other actives or other release mechanisms. Anyone working specifically with cariprazine depot formulations should review its claim scope and process steps directly before proceeding.
IPC composition in this corpus shows only single-digit representation for sterilisation processing (A61L), device-formulation co-claims (A61M), and non-PLGA polymer compositions (C08L), compared with 240 A61K and 127 A61P families. That imbalance points to under-claimed ground in sterile terminal processing for microspheres, prefilled syringeability engineering, and biodegradable polymer blends outside the standard PLGA chemistry. These are areas where claim density is genuinely thin rather than merely under-searched.
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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.