US 6607784

I'll search for the specific patent number and any associated litigation.

Let me run a few more targeted searches to check for litigation or Federal Circuit activity.

Let me look specifically for the claim text and any litigation involving this patent.

Search summary

Scope of what I could verify. I ran web searches against indexed patent databases (Google Patents, FreePatentsOnline), secondary literature, and publicly indexed court filings, targeting the literal string 6607784 and combinations with "CAFC," "Federal Circuit," "2026," and "Baxter." I did not have direct API access to USPTO PatentCenter/PAIR or to the CAFC docket in this session, so my USPTO-side data comes from the patent document itself (Google Patents rendering, fetched 2026-09-30) plus corroborating third-party copies. I found no CAFC 2026 docket entry, appeal, or opinion referencing US 6,607,784, and no pending litigation tied to this specific number in the results returned. That is a negative search result, not proof of absence — a docket search on PACER/CM-ECF would be needed to confirm definitively.

I did not auto-correct any identifier. The number as searched and as returned is 6,607,784 (application 09/874,799).

Bibliographic data (US 6,607,784 B2)

Related family members (for context only, not asserted as identical): WO 2002/055059 A2, EP 1 347 747 B1, and later US patents in the same family such as US 6,869,617, US 6,957,086/US 6,977,085, US 7,037,528, and US 6,884,436.

Abstract (verbatim from the fetched full text)

"The present invention provides a method for preparing submicron sized particles of an organic compound, the solubility of which is greater in a water-miscible first solvent than in a second solvent which is aqueous, the process including the steps of (i) dissolving the organic compound in the water-miscible first solvent to form a solution, (ii) mixing the solution with the second solvent to define a pre-suspension; and (iii) adding energy to the pre-suspension to form particles having an average effective particle size of 400 nm to 2 microns."

Plain-language overview of the independent claims

Important caveat on verbatim accuracy: the full text I retrieved includes the abstract, specification, and Examples 1–12, but the numbered claim set was truncated and is not present in the fetched document. I therefore cannot quote claim 1 word-for-word with confidence. The following is a faithful plain-language reconstruction derived from the abstract, the "Summary of the Invention," and the detailed description; treat exact claim wording as unverified pending a look at the printed claims (USPTO PatentCenter or the granted patent PDF).

The patent is a method claim patent (not a composition claim). At its core, every independent claim covers a three-step process for making small drug/organic-compound particles:

1. Dissolve an organic compound (typically a poorly water-soluble drug) in a water-miscible first solvent (the specification's examples include N-methyl-2-pyrrolidinone/NMP, dimethyl sulfoxide, dimethylacetamide, ethanol, propylene glycol, PEGs, etc.).
2. Mix that solution with a second, aqueous solvent (water, optionally with buffers/surfactants) so the organic compound precipitates and forms a pre-suspension.
3. Add energy (high-shear mixing such as homogenization/sonication, and/or heat) to that pre-suspension to yield particles having an average effective particle size of about 400 nm to about 2 microns, suitable for parenteral (intravenous) delivery. The energy step is characterized as an "annealing" step that stabilizes the particle/surfactant interface and/or alters lattice structure.

The specification organizes the claimed subject matter into three process "categories," distinguished by the physical state of the compound before vs. after the energy step — these distinctions almost certainly map onto separate independent claims:

• Category 1: Before step 3 the compound is amorphous, semi-crystalline, or a supercooled liquid; after step 3 it is crystalline at essentially the same size.
• Category 2: Before step 3 the compound is already crystalline; after step 3 it remains crystalline at essentially the same size but with a reduced tendency to aggregate.
• Category 3: Before step 3 the compound is in a friable crystalline form (e.g., slender needles/thin plates, including crystals with lattice defects from rapid precipitation); after step 3 the crystals are smaller than in the pre-suspension and kinetically stabilized.

Each category also has two sub-embodiments reflected in the description ("Method A" and "Method B"), which differ in where the surfactant goes: Method A adds surfactant to the aqueous second solution; Method B adds the surfactant to the organic-compound-containing first solution. In Method B no polymer/amphiphile complex is pre-formed, which the patent distinguishes from U.S. Pat. No. 5,780,062 ('062).

Dependent claims (as described in the specification's supporting text) appear to add limitations such as: the energy-addition step being homogenization or sonication at specified pressures/frequencies; use of a piston-gap homogenizer (e.g., Avestin EmulsiFlex-C160 or C-50); the further step of removing the first solvent (e.g., by centrifugation/dialysis/diafiltration) and optionally replacing an excipient/surfactant with a different one; sterilization by filtration/heat; and recitation of specific classes of surface modifiers (anionic, cationic, nonionic surfactants, phospholipids, poloxamers, Solutol® HS 15, sodium deoxycholate, etc.).

Uncertainty and limitations

• Claim text not verified. The authoritative document I retrieved was cut off before the claims. I would not represent the paragraph above as the literal claim language, and the independent-claim count is inferred from the specification's stated "three categories" framework. A definitive answer requires the printed claims.
• No CAFC 2026 activity found. I found nothing indicating that US 6,607,784 was before the Federal Circuit in 2026, nor any 2026 litigation. I cannot rule out activity that is not indexed by general web search.
• Assignees. The record lists Baxter International Inc. as original and current assignee on the face of the document; later transfers (e.g., to a Baxter spinoff) are not evidenced in the material I retrieved and I make no assertion about them.
• Legal status. Google Patents shows "Expired – Lifetime" with an adjusted expiration of 2021-11-11. Google explicitly states legal status is an assumption and not a legal conclusion.
• Third-party copies agreed with the bibliographic data (FreePatentsOnline confirms title, inventors, application 09/874,799, filing 2001-06-05, publication 2003-08-19, and Baxter International as assignee), which increases confidence in the identify of the patent, though none of those sources provided claim text I can quote.

I'll research litigation involving US patent 6607784. Let me run several targeted searches.

Initial results didn't surface litigation. Let me search more specifically for the assignee/patent family and litigation databases.

Let me search litigation-specific databases and check related family members.

Answer: No litigation identified involving US 6,607,784

Bottom line: My searches did not surface any lawsuit, PTAB proceeding, ITC investigation, or other contested proceeding involving US Patent 6,607,784. To the best of the evidence available, no litigation is known.

Per your instruction not to auto-correct identifiers: I searched for the literal patent number 6,607,784 (and the digits "6607784") and excluded look-alike numbers.

Patent record (for identification only — not litigation)

Sourced from the authoritative full text at https://patents.google.com/patent/US6607784/en:

What the searches showed

• The Google Patents record (the authoritative source you supplied) contains no "Litigation" section, no PTAB/reexamination entries, and no adversary proceedings — only prosecution/assignment and international family events (WO 2002055059, EP 1347747, JP 4376518, CA 2431705, CN 100512798, RU 2272616, etc.).
• General web searches for the patent number return only academic citations and third-party patent documents citing the '784 patent as prior art — e.g., EP 2429493 B1 lists "US 6607784 B" among cited documents, and CN 101310011 A incorporates US 6,607,784 by reference. Citation as prior art is not litigation.
• Hits on "6607784" that are unrelated and must not be conflated with this patent: Japanese patent JP 6607784 B2 (a different, unrelated patent in the dempepimut/immunosuppressive Tat peptide family) and a Lithuanian business-registry notice number 6607784.
• Searches of Baxter's own annual-report litigation disclosures (2006, 2009, 2012 filings) list numerous Baxter patent suits (ADVATE, Sevoflurane, GAMMAGARD, Peritoneal Dialysis/Liberty Cycler, AlYX, the Baxter/DEKA v. Fresenius matter, etc.) but none asserting or defending US 6,607,784.

Important caveats (stated explicitly, not fabricated)

• I could not complete exhaustive queries of PACER, CourtListener, RPX Insight, or the Unified Patents litigation portal before my search budget was exhausted. Those dockets (and District Court complaints pre-dating ~2009 that were never digitized) are the most likely places a case, if any, would appear.
• A patent can be asserted in a case where only the case caption/product is indexed and the patent number is buried in an exhibit; my keyword searches would miss that.
• The '784 patent's family includes related Baxter patents in the same microprecipitation/nanoparticle technology (documents in the same family/portfolio cited by third parties include US 7,037,528, US 6,869,617, US 6,884,436, US 6,835,396, etc.). I did not verify litigation on those siblings, and any such litigation would not be litigation "involving US 6,607,784" unless that patent were actually asserted. I am not representing otherwise.

Conclusion: On the evidence gathered, the answer is that no known litigation involves US Patent 6,607,784. If you need a definitive negative, I recommend a direct docket check on PACER (Delaware, N.D. Illinois, E.D. Texas — Baxter's most common venues) and a Docket Navigator/Unified Patents litigation search on the exact number, since those proprietary tools will capture cases that public web search does not.

I'll start by verifying the structured data against what's publicly findable via web search.

Let me run more targeted searches to be sure nothing exists outside the ODP ingest.

Let me check the family patents' litigation history and whether any IPRs touched this family, plus the Unified Patents portal entry.

Proceedings overview

Zero AIA trial proceedings on file for US 6,607,784 — the ODP canonical list is empty (no IPR, no PGR, no CBM, no DER), and my independent web checks surfaced no petition, institution decision, FWD, or appeal captioned against this patent. Because there is no invalidating FWD and no institution denial to point to, the defensive posture is not "the patent is hardened by surviving IPRs" and not "the claims are dead" — it is the third case the framework doesn't anticipate: an untested, un-IPR'd patent that is now expired (adjusted expiration 2021-11-11), so the PTAB is not where this fight lives or ever lived.

Verification performed (so the null result is auditable)

Noise filter — do not conflate. Federated searches for "Baxter + Fresenius + patent invalid" return Fresenius USA, Inc. v. Baxter Int'l, Inc., 721 F.3d 1330 (Fed. Cir. 2013) and In re Baxter, 678 F.3d 1357 (Fed. Cir. 2012). Those concern Baxter's hemodialysis patents — U.S. 5,247,434; 6,284,131; 5,326,476; 5,744,027 — and the challenge vehicle was ex parte reexamination, not an AIA trial. Those are pre-AIA, CRU-track proceedings on an unrelated Baxter portfolio. Nothing in that saga touches US 6,607,784, and none of it is an IPR. If a vendor's litigation-history report blends them, it is wrong.

Proceedings

None. There is no {PROCEEDING_NUMBER} to populate. No proceeding number can be listed without fabricating one, which the task forbids.

For completeness on the sub-fields that would otherwise be filled in:

• Type: N/A
• Filed: N/A — note the statutory window is closed regardless: the patent issued 2003-08-19, so IPR is the only available vehicle (PGR/CBM unavailable), and IPR was available from 2013-09-16 onward.
• Status: N/A
• Judge panel: N/A
• Petition grounds: N/A
• Institution decision: N/A
• Final Written Decision: N/A
• Settlement / termination: N/A
• Appeal: N/A — no PTAB decision exists to appeal
• Defensive value: Covered in the strategic summary; the short version is that the absence of any IPR here is explained by the patent's age and expiry, not by its strength.

Strategic summary

Claim status: entirely UNTESTED at the PTAB — not canceled, not sustained. No claim of US 6,607,784 has ever been adjudicated in an AIA trial, so there is no FWD to cite, no claim-level verdict, and no estoppel-creating record. I did not verify the claim set from the source text (the fetched Google Patents document truncates before the claims), so I am deliberately not asserting how many claims exist or quoting any claim number — treat any third-party claim chart that quotes "claim 1" etc. as unverified against the printed patent. For a defendant, that cuts both ways: there is no inter partes estoppel against you under § 315(e)(2), but there is also no ready-made invalidity roadmap from a prior petitioner and no public Board reasoning to borrow.

Estoppel landscape — practically nonexistent, but moot. Because no IPR was ever filed, no petitioner is estopped, no privies are estopped, and every § 102/§ 103 ground is still nominally available to a defendant today — nothing was "raised or reasonably could have been raised" by anyone. The binding limits are procedural and temporal, not estoppel-based: IPR remains legally available against an expired patent, but the practical value is near zero. The patent's adjusted expiration is 2021-11-11, so there are no prospective sales to enjoin and no ongoing royalty exposure. Only backward-looking damages survive, and they are being eaten by the § 286 six-year clock. Time-critical point: a complaint filed on 2026-09-30 reaches back only to 2020-09-30, so the recoverable window is already down to roughly 13 months of pre-expiry conduct (2020-09-30 → 2021-11-11). On 2027-11-11 that window closes entirely and the patent becomes assertion-proof as a damages matter. A sophisticated patent owner knows this; a demand letter arriving in 2026 is likely fishing for a cheap settlement on a shrinking claim, not building a case.

Pattern signals. No repeat-petitioner pattern, no patent-owner appeal pattern, no defensive-aggregator chain — because there is no proceeding at all. The genuinely notable pattern is on the enforcement side: this patent is one of a tightly related Baxter/Kipp-family group (US 6,869,617, US 7,037,528, US 6,884,436, US 6,835,396 are siblings/continuations, several of which are cited as incorporation-by-reference antecedents in later third-party patents). If you are facing a campaign rather than a single letter, check whether the assertion is actually being run through a later, unexpired family member — the '784 being expired and IPR-free does not tell you anything about the sibling that still has term.

Recommended next steps

1. Do not over-read the null. "No PTAB activity" here is explained by expiry (2021-11-11), not by the patent being a fortress that scared off challengers. Frame it that way internally; do not let a demand letter reframe the emptiness as strength.
2. Run the damages math before anything else. Compute the § 286 lookback from the actual complaint date. If you receive a letter in late 2026, the pre-expiry exposure band is roughly 2020-09-30 to 2021-11-11. Everything after 2021-11-11 is royalty-free as a matter of the patent term.
3. Verify the claim set yourself. Pull the printed patent from USPTO PatentCenter/Patent Public Search and confirm the claim numbering and count. Nothing in the PTAB record will help you here, and I did not independently confirm it.
4. Audit the family, not just this patent. Identify every unexpired member of the Kipp/Baxter microprecipitation family that remains enforceable. That is where IPR budget, if any, should go — an IPR on an expired patent buys you no injunction relief and competes with § 286's clock.
5. If you nonetheless want a Board record. An IPR against an expired patent is permissible, and an FWD canceling claims can be useful defensively in co-pending matters (compare Fresenius II's treatment of PTO cancellation in a still-nonfinal district-court judgment). But weigh that against the fact that no schedule-building estoppel exists against you and the damages tail is nearly gone — for most defendants in 2026, the economics point to a license-or-litigate decision on expiration timing, not to a petition.
6. Re-run the ODP check before filing anything. If a petition has been filed recently, the ODP ingest may lag. The correct query target is the PTAB E2E / PTAB Decisions systems for 6607784 and the application number 09/874,799.

Bottom line for a defendant: there is no PTAB proceeding to leverage and none to fear. The real defense on US 6,607,784 today is the calendar — the patent expired 2021-11-11, the § 286 recovery window is closing, and the absence of any IPR reflects an old, expiring asset rather than a validated one.

I'll research this systematically. Let me start with the assignment record and related sources.

Let me dig into post-issuance assignment records and Baxter's nanomedicine asset history.

Assignment & Ownership Reconstruction — US 6607784 B2

Scope note / evidentiary caveat (read first): I was able to retrieve the patent front matter, the Google Patents legal-events record, and prosecution-adjacent documents, but I could not directly pull the reel/frame entries from USPTO Assignment Center (assignmentcenter.uspto.gov) — the search tooling available to me returned no Assignment Center record view for this number. Everything below is grounded in the sources I did retrieve. Where the required reel/frame is not in hand, I say so rather than invent a number. Verify at Assignment Center and Google Patents legal events.

Inventors

All four residences (Wauconda, Gurnee, Grayslake, Algonquin) sit within commuting distance of Baxter's Deerfield, IL headquarters and its Round Lake, IL research/manufacturing campus; the inventors are jointly named as assignors to Baxter in the 2001-06-05 assignment. Employer = Baxter International Inc. is therefore supported, not merely inferred.

Unusual-pattern check: I found no evidence of a mass inventor departure or post-filing portfolio fire-sale connected to this patent. Note the opposite pattern instead — these inventors recur as a naming team on the whole Baxter nanosuspension family (e.g., US 6869617, US 7037528, US 6977085, US 7112340), which is the signature of a sustained in-house R&D group, not a one-off filing designed for later transfer. I could not determine separation dates for individual inventors from the sources I retrieved — unclear.

Original assignee

Baxter International Inc. (Deerfield, IL) — named on the face of the issued patent as assignee, and the current assignee of record per Google Patents (no later transferee shown).

• Line of business: global medical-products/pharmaceuticals company (renal care, IV/infusion systems, hospital products, and at the time a substantial parenteral drug-delivery R&D operation).
• Product embodying the claims: Yes, in development terms. Baxter developed an aqueous itraconazole nanosuspension for parenteral administration using this microprecipitation platform (referred to in the literature as Baxter's "Nanoedge" technology). I could not verify commercial launch of a specific product practicing the claims. Treat "shipped a product" as partially supported (development-stage platform, commercial status unverified).
• Current status: operating (publicly traded). No bankruptcy, dissolution, or Chapter 7/11 event touching this patent was found.
• Statutory status: Expired — lifetime; adjusted expiration 2021-11-11 (per the record). This is a dead patent; it cannot support a new assertion campaign.

Assignment timeline

Only one assignment appears in the record I could retrieve — the original inventor-to-company assignment. No post-issuance assignment surfaced.

• Executed 2001-06-05 / recorded 2001-06-05 — Reel/frame not retrieved (see caveat above; Google Patents' legal-events view exposes the event but not the reel/frame, and Assignment Center was not reachable via my tools)
  • Conveyance: Assignment of Assignors' Interest (original filing assignment)
  • Assignor: Kipp, James E.; Wong, Joseph Chung Tak; Doty, Mark J.; Rebbeck, Christine L. (all four inventors, jointly)
  • Assignee: Baxter International Inc., Deerfield, IL
  • Correspondent: not exposed in the sources retrieved. Related but NOT equivalent data point: on the sibling Baxter PCT (WO 03/026612, PCT/US02/31066) the agent of record is Buonauto, Mark J. et al., Baxter International Inc., One Baxter Parkway, Deerfield, IL 60015 — i.e., in-house Baxter patent counsel. That is a prosecution agent of record, not an assignment-recording correspondent, so I do not treat it as a recurrence finding.
  • Context: original in-house assignment from employee inventors to the corporate employer (not a fire-sale, reorg, or securitization).

No other recorded events — no change of name to a Baxter holding entity, no security agreement, no license recording, no transfer to an assertion vehicle, no defensive-aggregator acquisition. Per Google Patents, the assignee remained Baxter International Inc. throughout, and the patent expired on 2021-11-11.

Because the Assignment Center showed no records I could verify beyond the original assignment, the remaining mandated sections are reported in abbreviated form, consistent with your instruction to stop after the timeline where records are absent. I complete the NPE checklist and verdict below so the finding is explicit rather than implied.

Timeline diagram

timeline
    title Ownership of US 6607784
    2000 : Provisional 60258160 filed
    2001 : Inventors assign to Baxter International
         : Non-provisional 09874799 filed
    2003 : Patent issued to Baxter
    2021 : Patent term expires

NPE / troll-pattern signals

Inverse signal observed: the family was kept in-house and prosecuted as a platform (multiple continuations by the same inventor team), which is the opposite of the carve-out-and-sell pattern that precedes NPE assertion.

Verdict

Insufficient data — only the original assignment to the original operating company. The single retrievable record is the 2001-06-05 inventor-to-Baxter assignment (executed and recorded the same day), and the assignee of record remained Baxter International Inc. with no post-issuance transfer; the patent has since expired (adjusted expiration 2021-11-11). There is no shell-entity transfer, no known asserter, no cascading LLC chain, no pre-litigation transfer, and no defensive-aggregator terminus — so none of the NPE proxies can be scored, and the file reads as a clean operating-company ownership.

Caveat on confidence: my inability to open the Assignment Center record directly means I cannot exclude a recorded assignment that Google Patents' legal-events feed does not surface. If completeness matters, re-run the search at Assignment Center (search by patent number 6607784 or app 09/874,799) and confirm the reel/frame for the 2001-06-05 assignment before relying on the "no downstream transfers" conclusion.

I'll search for the specific patent and its cited prior art references.

Let me gather the complete list of cited references and their details.

Let me retrieve the complete front-page reference list from the patent record.

Verification of the Target Patent

Before any analysis, confirming the identifier as searched:

Sources: https://patents.google.com/patent/US6607784/en and https://www.freepatentsonline.com/[6607784](/patent/6607784).html.

I have not substituted any similar number. Note that US 6,869,617, US 7,037,528 and US 6,884,436 are different patents in the same Baxter family — they are not US 6,607,784 and are treated here only as family context.

Important Scope Caveat (read before the §102 analysis)

Two transparency points, per the instruction not to fabricate:

1. Claim text. The authoritative full text I retrieved includes the abstract, summary, description and examples, but not the verbatim granted claim set. The §102 mapping below therefore uses the claimed elements as they are recited in the specification/abstract, namely a three‑step process:

   • (i) dissolving an organic compound in a water‑miscible first solvent → first solution;
   • (ii) mixing that solution with a second, aqueous solvent to precipitate the compound and define a pre‑suspension; and
   • (iii) adding energy to the pre‑suspension to form particles of 400 nm – 2 µm (with dependent aspects: amorphous/semi‑crystalline/supercooled → crystalline; crystalline → less aggregation; friable crystalline → smaller crystalline; anionic/cationic/nonionic surface modifiers; pH 3–11; sterilization; solvent removal).
     Verify the actual claim numbering against the granted patent before relying on any single‑claim §102 call.

2. Reference completeness. The front‑page "U.S. Patent References" list could not be retrieved in full in this session. I can confirm the items shown below; the Background Art references are quoted verbatim from the patent's own text and are therefore the most reliably supported. Any reference I could not confirm is flagged.

A note to prevent a common error: WO 02/055059 appears in the family data — that is the applicant's own PCT publication of this same application (PCT/US2001/049737), not prior art.

The Prior Art — Reference by Reference

Group A — References cited and discussed by the applicant in the Background Art (verbatim from US 6,607,784)

Group B — Front‑page U.S. patent references (from freepatentsonline.com/6607784.html; list may be incomplete)

(Date confirmations for A2, A3, A4 are from the citation table at https://patents.google.com/patent/US20050009908; the others are as listed by the patent records but should be verified.)

§102 Anticipation Analysis

Analytical frame

Anticipation under 35 U.S.C. § 102 requires that a single reference disclose every element of a claim, arranged as in the claim. Given the three‑step claim architecture above, the decisive element that separates this patent from almost all of the cited art is step (iii): adding energy (cavitation/shear/impact — homogenization or sonication) to a pre‑suspension that was formed by aqueous precipitation to drive particle size/annealing into the 400 nm–2 µm window. A reference that precipitates or that homogenizes/mills, but not both in sequence, cannot anticipate the independent method claim.

Reference‑level treatment

US 4,826,689 (A2) — Potentially anticipates only a claim from which the energy‑addition step is absent. It discloses solvent/antisolvent precipitation of water‑insoluble organics into particles and even the use of surface‑active agents, but it is directed to trapping the drug in a metastable state and does not disclose an energy‑addition/annealing step. Against the patent's independent claim (which requires step (iii)), it is not anticipatory; it is a strong §103 reference. It could anticipate a dependent claim limited to precipitation + surface modifier if one exists.

US 4,997,454 (A3) — Same conclusion, and weaker: it discourages the crystalline state that the patent's step (iii) produces, so it cannot anticipate the crystalline‑product claims.

US 5,118,528 (A4) — Cannot anticipate. It expressly teaches that high‑energy equipment (sonicators/homogenizers) is undesirable — i.e., it teaches away from the claimed energy‑addition step. This is the patent's principal §103 counter‑reference and the reason the Examiner allowed over the art.

US 5,145,684 (A5) — Cannot anticipate the method claims. It is a milling process (no precipitation/pre‑suspension step). Relevant to obviousness and to any claim reciting a surface‑modified particle <400 nm.

US 5,605,785 (A6) — Cannot anticipate. Emulsification‑based; no solvent/antisolvent precipitation‑to‑pre‑suspension sequence.

US 5,780,062 (A7) — Cannot anticipate. The patent in suit expressly distinguishes it: '062 requires formation of a polymer/amphiphile complex prior to precipitation, and discloses no energy‑addition step. Methods A and B of the patent in suit are defined by the absence of that complex. The comparative Table 1 (Method A, 18.7/10.7/12.1 µm vs. Method B, ~0.18 µm) is the applicant's evidentiary rebuttal.

US 5,858,410 (A8) — Cannot anticipate. It discloses homogenization of a solid drug but its Examples jet‑mill prior to homogenization; there is no aqueous microprecipitation step creating a pre‑suspension. Relevant to obviousness only.

US 5,922,355 (A9) — ⚠️ The most dangerous §102 reference in the set. It is the only cited reference that discloses both precipitation/recrystallization and sonication/homogenization for making submicron particles with surface modifiers + phospholipid. If the granted independent claim is drafted broadly (precipitate a poorly soluble organic compound, then apply energy to reach 400 nm–2 µm), the '355 Patent is the closest candidate for anticipation. However:

• The patent in suit states the '355 Patent contains "no disclosure of changing process conditions to make crystals in a more friable form." Thus the '355 Patent likely cannot anticipate the third‑process‑category (friable‑crystal) claims, which are among the more commercially important claims (prednisolone, carbamazepine, nabumetone examples).
• Whether it anticipates the broad claim depends on whether '355 discloses the specific two‑solvent precipitation + energy sequence and the recited size window — verify against the '355 specification.
  This is the reference to check first.

US 2,745,785 (A1) — Cannot anticipate. Its final sizing step yields 5–20 µm crystals (air‑blast micronization), outside the claimed 400 nm–2 µm range, and it uses formamide/water recrystallization without the claimed energy‑addition annealing.

US 5,091,187 / 5,091,188 / 4,725,442 (A10) — Cannot anticipate. They are coating/emulsion approaches, not precipitation + energy.

US 5,720,551 (A11) — Cannot anticipate. It is an emulsification apparatus incorporated by reference to perform the claimed energy‑addition step; an apparatus cannot disclose the claimed process. It is relevant only as enablement/support for the homogenization equipment.

Group B references (B1–B11) — These are nanoparticulate/microparticulate formulation and processing patents. On the record retrieved, none is shown to disclose the specific three‑step precipitation → pre‑suspension → energy‑addition sequence to 400 nm–2 µm. The most pertinent are:

• B1 (US 6,337,092, Khan et al.) and B2 (US 6,299,906, Bausch et al.) — both address microparticle/submicron preparation and deserve element‑by‑element checking, including their filing dates for §102(e) purposes, because their publication dates (2002, 2001) are close to the critical date.
• B6 (US 6,267,989, Liversidge) — bears directly on the claimed "reduced tendency to aggregate" aspect of the second/third process categories, and (with B4, US 6,270,806) on the claimed surface‑modifier/surfactant limitations.
• B3, B5, B7, B8, B9, B10, B11 — background art on nanoparticulate carriers and parenteral microparticles; §103 context rather than §102 anticipation.

None of B1–B11, on the information retrieved, supplies the missing energy‑addition‑to‑a‑precipitated‑pre‑suspension element in a single reference sufficient to anticipate the independent claim.

Bottom Line

• No reference in the cited set clearly anticipates the independent claim as I understand its elements, because the combination of (a) aqueous microprecipitation forming a pre‑suspension and (b) a subsequent energy‑addition/annealing step to 400 nm–2 µm is not disclosed by any single one of them — the closest, US 5,118,528 (A4), actually disparages the energy step.
• The reference to examine most closely for §102 is US 5,922,355 (A9), because it alone recites precipitation plus sonication/homogenization; the distinguishing limitation to test is the friable‑crystal / morphology‑control feature, which the patent states '355 lacks, and which supports the third‑process‑category claims.
• The §103 picture is where most of these references matter: '689, '454, '528, '684, '410 and '062 together describe precipitation, surface modification and homogenization generically, but '528's express teaching away from high‑energy equipment and the applicant's Table 1 data (Method B ≈ 0.18 µm vs. Method A ≈ 10–19 µm) are the key rebuttals.
• Disclaimer: my §102 conclusions addressing "claim 1" and dependent claims are based on the claim architecture described in the specification, not verbatim claim text, which I could not retrieve. Confirm claim numbering and exact language against the granted patent; the grant‑date and filing‑date fields for A1, A6–A11 and B1/B2/B11 should likewise be verified before any legal reliance.

I'll ground this analysis in the cited prior art and verify the references before building the §103 combinations.

Let me verify the actual claim language and a couple more references.

Obviousness Analysis — U.S. Patent No. 6,607,784 (35 U.S.C. § 103)

Patent: US 6,607,784 B2, "Microprecipitation method for preparing submicron suspensions"
Inventors: Kipp, Wong, Doty, Rebbeck — Assignee: Baxter International Inc.
Priority: Dec. 22, 2000 (prov. 60/258,160); Filed: Jun. 5, 2001; Granted: Aug. 19, 2003
Source: https://patents.google.com/patent/US6607784/en

Evidentiary caveat up front. The fetched Google Patents record for US 6,607,784 includes the Abstract, Summary, Detailed Description and Examples, but the granted claim set is not reproduced in the text I was given. Accordingly, I analyze the independent claim as it is reflected in the Abstract and the "Summary of the Invention," which recite the same three-step process. Where a dependent claim adds a specific limitation (e.g., surfactant in the first solvent, pH 3–11, the three "process categories"), I flag that the analysis would change. I have not fabricated claim language.

I. The claimed subject matter (as disclosed)

The Abstract and Summary track a three-step process:

1. Dissolving the organic compound in a water-miscible first solvent (solubility greater in the first solvent than in the second);
2. Mixing the first solution with an aqueous second solvent to define a pre-suspension; and
3. Adding energy to the pre-suspension to form particles having an average effective particle size of about 400 nm to about 2 µm.

The three "process categories" are distinguished only by what the solid looks like before vs. after the energy step (amorphous/semi-crystalline/supercooled → crystalline at essentially the same size; crystalline → crystalline but less aggregating; friable crystalline → smaller crystalline). Method A puts surfactant only in the aqueous diluent; Method B puts the surfactant in the first (organic) solvent.

So the inventive core, for §103 purposes, is the combination of (a) a solvent/non-solvent microprecipitation step with (b) a post-precipitation energy (high-shear) step, yielding 400 nm–2 µm particles.

II. The prior art of record (the patent's own Background Art section)

All of these predate the Dec. 22, 2000 priority date and are §102(b)/§103(a) art.

III. The §103 framework

Under Graham v. John Deere, 383 U.S. 1 (1966), and KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), I ask whether the differences between the claim and the art are such that the subject matter as a whole would have been obvious to a POSA, considering (1) scope/content of the art, (2) differences, (3) PHOSITA level, and (4) secondary considerations. For a combination, the question is whether there was an apparent reason to combine with a reasonable expectation of success (In re Keller, 642 F.2d 413; In re Merck, 800 F.2d 1091), and a teaching away defeats obviousness only if it would not have been "reasonably expected to be followed" (In re Gurley, 27 F.3d 551).

PHOSITA here: a formulation scientist with an advanced degree and several years' experience in parenteral suspensions of poorly water-soluble drugs — familiar with both antisolvent precipitation and high-pressure homogenization/milling.

IV. Combinations that render the claims obvious

Combination 1 (primary): US 5,780,062 + US 5,858,410

This is the cleanest prima facie case.

• '062 supplies every element of steps (1) and (2), including the identical claim preamble — "an organic compound, the solubility of which is greater in a water-miscible first solvent than in a second solvent which is aqueous." Its claim 1 is the same three-part (i)–(iii) recitation, minus the energy step. The '784 specification itself concedes this: "Methods A and B are further distinguished from the process of the '062 patent by the absence of a step of forming a polymer-amphiphile complex."
• '410 supplies step (3) in the same technological field: subjecting a dispersed solid drug "to high pressure homogenization in a piston-gap homogenizer," by "cavitation or shearing and impact forces with introduction of a high amount of energy," to reach a defined sub-micron size — see '410 claims 35–38 (process claims expressly reciting piston-gap homogenization and cavitation/shear-impact forces).
• Motivation to combine: Both references target the same problem — parenteral delivery of water-insoluble drugs as a stable particle dispersion. The '062 process is expressly described as producing aggregates (see '062's claims and EP 0 788 350 B1, ¶¶[0008]–[0010], col. 4–5), and aggregation/particle growth is the acknowledged raison d'être of the '410 homogenization step. A POSA seeking smaller, non-aggregated particles would routinely reach for the art's best-known disaggregation tool (high-pressure homogenization) and apply it to the '062 precipitate.
• Reasonable expectation of success: '410 expressly teaches that its homogenization works on solid drug "without prior conversion into a melt," and its Examples disclose jet-milling (i.e., a dry size-reduction step) before homogenization — confirming that homogenization is a post-particulate-formation finishing step, exactly as claimed.
• Result-effective variable: The claimed 400 nm–2 µm window is a routine optimization of homogenization pressure/cycles (In re Aller; In re Boesch).

Combination 2: US 5,780,062 + US 5,145,684 (or US 5,922,355)

Substituting '684 or '355 for '410 does not change the outcome. '684 discloses the same parenteral nano-suspension objective with <400 nm particles and a surface modifier that "prevents agglomeration into larger particles" — a direct teaching of the stated benefit of the '784 energy step. '355 is even more on point: it expressly discloses surface modifiers + phospholipid with subsequent "sonication, homogenization, milling, microfluidization, precipitation or recrystallization" — a single reference that teaches combining a precipitation-type formation step with an energy/particle-size-reduction step and even recites the size range. '355 alone evidences that the combination was known as an integrated process.

Combination 3: US 4,826,689 (or 4,997,454) + US 5,858,410 (or 5,922,355)

• '689 supplies steps (1) and (2) (dissolve in water-miscible organic solvent → infuse aqueous precipitating liquid → non-aggregated particles), plus the express teaching to add crystallization inhibitors (PVP) and surface-active agents (e.g., poly(oxyethylene)-co-oxypropylene) to keep the precipitate stable — which is the same excipient strategy as the '784 surface modifiers (e.g., poloxamer 188).
• '689 also discloses trapping the compound in a metastable state whose free energy lies between solution and stable crystal — the functional equivalent of the '784 "first process category" (amorphous/semi-crystalline/supercooled → crystalline). See also '454, FIG. 1 free-energy diagram.
• Adding the '410/'355 energy step to stabilize and size the metastable precipitate is the natural next step; '689 itself notes the metastable state "eventually converts to a more stable crystalline state," i.e., the very stabilization the '784 annealing step achieves.

Combination 4: US 2,745,785 + US 5,145,684 / US 5,858,410

Even the oldest reference is a microprecipitation-plus-energy template: '785 teaches recrystallizing penicillin G by adding water to reduce solubility, coating the particles with wetting agents/lecithin/sorbitan esters, and then micronizing with a pressured air blast. A POSA substituting modern high-shear homogenization for the 1956 air-blast micronizer — the '410 technique — arrives at the claimed process. This combination is weaker on the "same size range" point but strong on motivation (both are parenteral suspensions of a poorly soluble antibiotic).

V. Motivation, and the objective evidence in the specification

The specification's own data are comparative evidence of the problem the energy step solves, which is itself the motivation:

• Example 1, Suspension A vs. B: the unhomogenized pre-suspension flocculated within 12 hours and grew plate-like crystals >10 µm; the homogenized suspension was stable at 2–8 °C for 1 month with no change in morphology or size. That is a classic "recognized problem → known solution" fact pattern.
• Comparative Example (Table 1): Method A (polymer + amphiphile co-present in the diluent, per '062) gave 18.7/10.7/12.1 µm that collapsed to ~2 µm only upon sonication — diagnostic of aggregation; Method B gave 0.194 µm unaffected by sonication. This shows the '062-style process needs the energy/stabilization step.

A POSA reading '062 (aggregates), '689 (metastable, needs stabilizers), and '410 ('410's own stated purpose is producing stable nanosuspensions by cavitation/shear energy) would have had every reason to combine them and a reasonable expectation that the particles would be smaller and more stable.

VI. The counterarguments (non-obviousness positions to test)

A rigorous analysis must flag where the patent can defend itself:

1. Teaching away — US 5,118,528. '528 expressly states it produces <500 nm particles "without the supply of energy" and that "it is undesirable to use high energy equipment such as sonicators and homogenizers." Under In re Gurley, a reference that criticizes, discredits, or otherwise discourages the claimed route can defeat a prima facie case. But this cuts only against combinations that rely on '528 as the primary reference. Where the primary reference is '062 or '689 (neither of which disparages homogenization), a single discouraging statement in a different reference is generally insufficient to overcome the strong contrary teaching in '355 and '410 — both of which embrace sonication/homogenization. The §103 combination should therefore be built on '062/'689 + '355/'410, not on '528.

2. US 4,997,454's caution against crystalline particles. '454 discourages a crystalline state because dissolution/recrystallization during precipitation broadens the size distribution. This is a caution, not a teaching away from the claimed order of operations (precipitate first, then energize), and it is expressly rebutted by the '784 data showing an amorphous pre-suspension converting to crystalline particles of essentially the same size after annealing.

3. Possible unexpected results. The strongest non-obviousness argument is the "annealing" finding: an amorphous/supercooled pre-suspension is converted by homogenization to a crystalline form of essentially the same average particle size, with the X-ray diffractograms before and after homogenization being "essentially identical, yet … significantly different … as compared with the starting raw material" (Example 5, FIG. 5). If the applicant can show that a POSA would have expected homogenization to shrink the particles or destroy crystallinity, the "same-size amorphous→crystalline" outcome could qualify as unexpected (In re Soni). This is an evidentiary question, not a legal one, and the record here contains no declaration evidence on the point.

4. The "friable crystal" third category (Examples 6–12). The '784 specification argues that precipitation in the presence of a surface modifier (glycodeoxycholic acid) yields very slender, thin needles (FIG. 6) whose cleavage force is ~1/1000 that of the raw-material crystals (the Eq. 1 derivation in Example 8). The Background Art section expressly notes that "'355 discloses … no … changing process conditions to make crystals in a more friable form." If a claim is limited to the third category (making the pre-suspension crystals friable, then breaking them), the '355 and '410 references are less directly anticipatory of that purposeful morphology selection, and this is the most defensible claim scope.

5. Method B limitation. If a claim requires the surfactant to be dissolved in the first organic solvent (Method B), that is a genuine structural difference from '062, which requires the polymer/amphiphile complex in the aqueous phase. The specification frames this as the inventive distinction ("Methods A and B are further distinguished from the process of the '062 patent by the absence of a step of forming a polymer-amphiphile complex"). '689, however, discloses surfactant/crystallization-inhibitor use broadly, and '355 discloses surface modifiers generally, so a POSA could still find the Method B arrangement an obvious alternative — but this is a closer question and would benefit from the Table 1 data (0.194 µm vs 18.7 µm).

VII. Bottom line

Conclusion: On the record of the patent's own Background Art section, the independent claim — a three-step precipitation-then-energy process yielding 400 nm–2 µm particles — would likely have been obvious under §103 over US 5,780,062 in view of US 5,858,410 (and, independently, over US 4,826,689 in view of US 5,922,355), with the motivation supplied by the well-known aggregation/particle-growth instability of micro-precipitated suspensions and by the express purpose of the '410 homogenization step. The principal non-obviousness defenses would be (a) the '528 teaching away from high-energy equipment, (b) unexpected "annealing" results (amorphous→crystalline at constant size), and (c) any claim limitation that captures the friable-crystal third category or the Method B (surfactant-in-organic-phase) arrangement — each of which is a factual/evidentiary question that the patent's own examples only partially support.

If you can supply the granted claim set (or confirm that claim 1 reads as the Abstract does), I will re-run the element-by-element mapping against the specific claims, including any dependent claims reciting pH 3–11, the enumerated surfactant classes, the 400 nm–2 µm range as a standalone limitation, and the solvent-free/surfactant-replacement steps.