US Patent 9,023,897: Claim Scope, Patent Strength, Expiration, and Drug-Delivery Landscape

US Patent 9,023,897 protects a biodegradable drug-delivery platform combining PLA-PEG-PLA triblock copolymers with methoxy-PEG-PLA diblock copolymers. The principal commercial value is in injectable, solvent-based depot formulations that form implants after administration. The patent does not claim a specific active pharmaceutical ingredient. Its coverage therefore extends across multiple drug classes, subject to the polymer architecture, molecular-weight ranges, polymer ratio, formulation characteristics, and process limitations recited in the claims.

The strongest protection is concentrated in claims 1, 2, 12, and 13. Claims 3 through 11 and 14 through 18 add formulation, concentration, solvent, dosage-form, and polymer-ratio limitations.

What does US Patent 9,023,897 protect?

The patent claims a drug-delivery composition containing two different biodegradable copolymers:

A PLA-PEG-PLA triblock copolymer.
A methoxy-PEG-PLA diblock copolymer.
At least one pharmaceutically active principle.

The composition must be insoluble in an aqueous environment. The claims cover injectable liquids that form implants in the body, small solid particles, rod implants, and other spatial formulations.

Claim element	Required limitation
Triblock polymer	PLA-v-PEG-w-PLA-x
Triblock PLA units	24 to 682 repeat units for each PLA block
Triblock PEG units	4 to 273 ethylene glycol repeat units
Triblock symmetry	v may equal x or may differ from x
Diblock polymer	methoxy-PEG-y-PLA-z
Diblock PEG units	3 to 45 ethylene glycol repeat units
Diblock PLA units	7 to 327 repeat units
Polymer ratio	Several claimed triblock-to-diblock ranges
Drug	At least one pharmaceutically active principle
Aqueous behavior	Composition is insoluble in an aqueous environment
Dosage forms	Injectable liquid, in situ implant, particles, rods, or spatial formulation

The claims are platform claims rather than molecule-specific claims. A formulation can potentially fall within the patent regardless of whether the active ingredient is an opioid, antipsychotic, hormone, peptide, protein, small molecule, or other therapeutic agent, provided the formulation satisfies the structural and compositional limitations.

How broad are the independent claims?

Claims 1 and 2 are composition claims. Claims 12 and 13 are manufacturing-method claims.

Claim 1: broad composition coverage

Claim 1 requires the presence of both polymer types and an active pharmaceutical ingredient. It does not impose the percentage ranges found in claim 2. It also does not limit the active ingredient, dosage strength, release period, or therapeutic indication.

The broadest practical limitations are:

Both the triblock and diblock copolymers must be present.
The copolymers must fall within the specified repeat-unit ranges.
The ratio must fall within at least one of the listed ratio bands.
The composition must be insoluble in water.
A pharmaceutical active must be included.

Claim 1 can potentially cover a wide range of polymer molecular weights because the repeat-unit ranges are extensive. The PEG segment in the triblock polymer can range from approximately 200 Da to 12 kDa under claim 5. The methoxy-PEG segment in the diblock polymer can range from approximately 100 Da to 2 kDa.

Claim 2: narrower quantitative composition

Claim 2 adds percentage limits:

Component	Claimed amount
Triblock copolymer	3.0% to 45% w/w
Diblock copolymer	8.0% to 50% w/w
Active pharmaceutical ingredient	1% to 20% w/w

Claim 2 may be commercially important because it maps more closely to a finished formulation than claim 1. A product outside these concentration ranges may still be captured by claim 1 if it satisfies the polymer structure, ratio, insolubility, and active-ingredient limitations.

What formulations are protected by US 9,023,897?

The patent covers formulations based on a mixed polymer system rather than a single polymer. The triblock and diblock components appear to perform different formulation functions.

The PLA segments provide biodegradability and hydrophobicity. PEG contributes hydrophilicity and affects polymer-water interactions, injectability, and degradation behavior. The methoxy-PEG-PLA diblock changes the balance between the triblock polymer and the surrounding solvent or biological environment.

The patent's formulation scope includes:

Injectable liquid depots.
In situ implants formed after injection.
Small solid particles.
Rod-shaped implants.
Spatial formulations.
Solvent-containing formulations.
Formulations using a pharmaceutically acceptable vehicle.

Claim 16 extends claim 1 to compositions containing specified organic solvents. Claim 17 does the same for claim 2. The listed solvents include benzyl alcohol, benzyl benzoate, dimethyl isosorbide, dimethyl sulfoxide, ethyl acetate, ethyl lactate, glycerol formal, N-methyl-2-pyrrolidone, triacetin, tributyrin, and related solvents.

The solvent list is open-ended in practical effect because the claims permit "mixtures thereof," although a formulation must still meet the other claim limitations.

What are the key dependent-claim limitations?

Claim	Added subject matter
3	Injectable liquid forming an implant, particles, rods, or spatial formulation
4	Specific polymer ratios of 1:1, 1:2, 1:3, 1:4, or 1:5
5	PEG and methoxy-PEG molecular-weight ranges
6	Pharmaceutically acceptable vehicle
7	Active ingredient at 1% to 20% w/w
8	Total copolymers at 20% to 50% w/w
9	Triblock polymer at 3.0% to 45% w/w
10	Diblock polymer at 8.0% to 50% w/w
11	PLA-to-ethylene oxide molar-ratio ranges
14	Specified organic solvents
15	Organic solvent at 40% to 74% w/w
16	Solvent-containing composition under claim 1
17	Solvent-containing composition under claim 2
18	Dosage forms under claim 17

Claim 4 is particularly relevant to infringement analysis because it narrows the ratio to discrete values. A formulation with a triblock-to-diblock ratio of 1:1 through 1:5 could face a stronger literal-infringement case than a formulation relying on a less conventional ratio interpretation.

How should the polymer ratios be interpreted?

The claims use several ratio ranges:

1:3 to 1:8.
1:1 to 1:19.
3:2 to 1:19.

The apparent ratio convention is triblock polymer:d iblock polymer. Under that convention, a 1:5 formulation contains one part triblock for every five parts diblock.

The third range, "3:2 to 1:19," creates a claim-construction issue because the endpoints move from a ratio greater than 1:1 to a ratio substantially below 1:1. It could be read as covering a broad progression of ratios, but the exact scope depends on the prosecution history and the interpretation adopted by a court.

The ratio limitations should be calculated on a consistent basis. Potential approaches include:

Weight ratio.
Molar ratio.
Polymer-mass ratio.
Ratio of polymer solids before solvent addition.

The claim language should be reviewed with the specification and prosecution history to determine the intended basis. A generic formulation label such as "polymer ratio 20:80" is not sufficient without confirming whether the ratio is measured by weight and whether it excludes solvent and active ingredient.

What manufacturing methods does US 9,023,897 cover?

Claims 12 and 13 protect preparation methods involving:

Dissolving the triblock and diblock copolymers in an organic solvent.
Maintaining the claimed polymer ratio.
Adding at least one pharmaceutical active.
Evaporating the solvent under claim 13.

The method claims are narrower than a general polymer-composition claim because they require the claimed preparation sequence. A competing manufacturer may avoid literal infringement if it uses:

A different solvent-removal sequence.
A solvent-free melt process.
Separate polymer solutions mixed immediately before administration.
A preformed implant manufactured without the claimed organic-solvent step.
A different order for introducing the active ingredient.

The doctrine of equivalents could remain relevant, particularly where the accused process performs substantially the same function in substantially the same way. The prosecution history would be important in assessing whether the patentee surrendered alternative manufacturing sequences.

When does US Patent 9,023,897 lose exclusivity?

US Patent 9,023,897 was granted on May 5, 2015. The expiration date is governed by the patent's earliest effective nonprovisional filing date, adjusted for any patent-term adjustment and any applicable patent-term extension. The grant date alone does not establish the expiration date.

The patent's expected term is generally 20 years from the relevant earliest nonprovisional filing date under 35 U.S.C. §154. Patent-term adjustment may move the expiration date later. Patent-term extension under 35 U.S.C. §156 is generally tied to regulatory review of an approved product and does not automatically apply to a platform patent.

Exclusivity item	Assessment
Patent grant	May 5, 2015
Patent type	Composition and manufacturing-method patent
Small-molecule regulatory exclusivity	Not established by the patent itself
Biologic exclusivity	Not applicable merely because the formulation may contain a biologic
Orange Book listing	Product-specific; not established by the patent claims
Patent expiration	Requires the recorded earliest effective filing date and PTA data
Patent-term extension	Requires a qualifying approved product and FDA determination

A formulation patent can remain relevant after a drug's active-ingredient patent expires. Conversely, an active-ingredient patent can expire while the formulation patent continues to restrict a particular depot or delivery system.

What is the Orange Book status of US Patent 9,023,897?

The patent is not inherently an Orange Book patent. The FDA Orange Book lists patents associated with specific approved drug products, not every patent that could theoretically cover a pharmaceutical formulation.[1]

For an Orange Book listing to matter, an approved product would normally need to:

Use the claimed PLA-PEG-PLA and methoxy-PEG-PLA polymer system.
Be associated with an approved drug application.
Have the patent submitted and accepted for listing under FDA rules.
Identify the relevant patent category, such as drug substance, drug product, or method of use.

A platform patent may therefore affect a product's commercial freedom to operate without appearing in the Orange Book. The absence of an Orange Book listing would not, by itself, eliminate infringement risk.

What generic entry risks exist?

The principal entry risk is formulation-specific rather than a conventional active-ingredient generic risk.

A generic or follow-on manufacturer could face infringement exposure if its product uses:

Both required polymer architectures.
The claimed PLA and PEG repeat-unit ranges.
A covered polymer ratio.
A water-insoluble formulation.
A covered solvent system.
An injectable in situ depot or related dosage form.

A product may reduce risk by changing one or more of the following:

Design-around variable	Potential effect
Replace PLA with PLGA or another polyester	May avoid the literal PLA limitation
Use only a diblock or only a triblock polymer	Removes the required two-polymer combination
Use a different PEG end group	May avoid methoxy-PEG limitation
Change polymer ratio	May move outside the claimed ratio bands
Use a preformed microsphere system	May avoid an injectable liquid depot claim
Use a non-listed solvent	May avoid narrower solvent claims, but not necessarily claim 1
Alter polymer molecular weight	May move outside the repeat-unit ranges
Use an aqueous or otherwise non-insoluble system	May avoid the insolubility limitation

These changes can affect release kinetics, injectability, implant formation, stability, sterilization, and regulatory comparability. A design-around that avoids the patent may create a new regulatory-development burden.

How strong is the patent estate?

The patent's strength is mixed.

Strengths

Claims both composition and manufacturing methods.
Covers a combination of two polymer classes rather than a single narrow polymer.
Does not limit the active ingredient to one drug.
Includes broad molecular-weight and repeat-unit ranges.
Covers injectable depots, particles, rods, and spatial formulations.
Includes specific solvent and concentration fallbacks.

Vulnerabilities

PLA-PEG-PLA and methoxy-PEG-PLA polymers were established biodegradable delivery materials before the patent's filing.
Injectable depot formulations using organic solvents were also known in the field.
The inventive distinction may depend heavily on the selected polymer ratio, insolubility, concentration, and demonstrated release or implant properties.
Broad repeat-unit ranges may create written-description or enablement questions if the specification does not support the full claimed genus.
The ratio language contains drafting ambiguity.
Claims 12 and 13 may face process-infringement limitations where the accused manufacturer uses a different sequence.

The most important validity question is whether the claimed combination produced an unexpected technical result over prior formulations containing PLA-PEG-PLA, PEG-PLA, or related block copolymers. Evidence on depot formation, burst release, sustained release, injectability, degradation, and drug loading would materially affect an obviousness analysis under 35 U.S.C. §103.[2]

Which companies may compete with this technology?

The relevant competitive field includes companies developing long-acting injectables, biodegradable depots, microspheres, in situ implants, and polymeric drug-delivery systems. Commercially relevant competitors can include:

MedinCell, through long-acting injectable delivery platforms.
Tolmar and related ATRIGEL-based depot products.
Alkermes, through microsphere and long-acting injectable technologies.
Luye Pharma and other companies developing sustained-release injectable systems.
Specialty injectable manufacturers using PLGA microspheres or in situ forming depots.
Generic manufacturers developing alternative depot architectures.

The competitive comparison is technology-specific:

Technology	Typical polymer approach	Main distinction
US 9,023,897 platform	PLA-PEG-PLA plus methoxy-PEG-PLA	Solvent-based mixed-polymer depot
PLGA microspheres	Preformed PLGA particles	Microsphere manufacturing and injection
In situ PLGA depot	PLGA in organic solvent	Implant forms after administration
MedinCell-type depot	Proprietary polymer and delivery system	Long-acting injectable platform
Conventional implant	Preformed rod or solid implant	No in-body phase transition required

The existence of competing platform patents does not establish freedom to operate. Patent families may overlap at the level of polymer chemistry, solvent systems, depot formation, or therapeutic use.

What patent litigation or Paragraph IV challenges affect this patent?

The claims provided do not identify litigation, inter partes review, post-grant review, Paragraph IV notices, or settlement agreements. Paragraph IV certification applies to an ANDA applicant challenging listed patents for an approved drug product. It does not automatically apply to a stand-alone platform patent that is not listed against an FDA-approved drug application.[3]

A relevant challenge could arise through:

ANDA litigation under the Hatch-Waxman Act.
Declaratory-judgment litigation by a prospective entrant.
Patent-eligibility, anticipation, or obviousness defenses.
Inter partes review at the Patent Trial and Appeal Board.
Contract or license disputes involving a platform license.

No conclusion about a specific litigation or settlement should be drawn from the claim text alone.

What licensing deals and commercial rights are relevant?

A patent's commercial value depends on ownership, exclusive licenses, field-of-use restrictions, territory, sublicensing rights, and rights to continuations or divisionals. The claims do not identify those arrangements.

A diligence review should distinguish:

Assignment of the patent.
Exclusive license to the polymer platform.
Product-specific sublicense.
Territory-limited rights.
Rights to improvements.
Manufacturing rights.
Royalty obligations.
Milestone payments.
Change-of-control provisions.

Platform patents are often licensed separately from patents covering an active ingredient or approved product. A drug company may need licenses to both the formulation platform and the drug substance, method of use, device, or manufacturing process.

Key Takeaways

US 9,023,897 is a platform patent covering a mixed PLA-PEG-PLA and methoxy-PEG-PLA biodegradable delivery system.
Claims 1 and 2 are the principal composition claims.
Claims 12 and 13 cover solvent-based preparation methods, including solvent evaporation.
The patent is not limited to a specific active ingredient or therapeutic indication.
Injectable liquids that form in situ implants are a central commercial embodiment.
The most important infringement variables are polymer architecture, repeat-unit ranges, polymer ratio, insolubility, solvent, and concentration.
The patent's expiration date cannot be established from the grant date alone; it depends on the effective filing date and patent-term adjustment.
Orange Book relevance is product-specific and does not arise automatically from the patent.
Generic entry risk is highest for formulations using the same two-polymer combination and solvent-based depot design.
Validity may turn on prior art involving known PLA-PEG and PEG-PLA polymers, the claimed ratios, and evidence of unexpected formulation performance.
No litigation, Paragraph IV challenge, or settlement can be established from the supplied claims.

FAQs About US Patent 9,023,897

Does US 9,023,897 cover all PLA-based injectable depots?

No. The claims require both a PLA-PEG-PLA triblock polymer and a methoxy-PEG-PLA diblock polymer, along with specified structural ranges, ratios, and an insoluble composition.

Can a formulation avoid the patent by using PLGA instead of PLA?

Potentially. Replacing PLA with PLGA may avoid literal infringement of the PLA limitations, but the complete formulation and any related patent families must be evaluated.

Does the patent cover a drug substance by itself?

No. The claims require a drug-delivery composition containing the specified copolymer system. They do not claim an active pharmaceutical ingredient independently.

Can a preformed microsphere product infringe the patent?

Yes, potentially. Claim 3 expressly includes small solid particles, although infringement would still require satisfaction of the remaining claim limitations.

Is an FDA-approved product automatically protected by this patent?

No. FDA approval does not establish patent coverage. Patent protection depends on whether the approved formulation and manufacturing process satisfy the issued claims.

Sources

U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. Center for Drug Evaluation and Research.
United States Code. (2023). 35 U.S.C. §§ 102, 103, 112, 154, and 156.
U.S. Food and Drug Administration. (2024). Abbreviated new drug application submissions: Patent certification and exclusivity provisions. Center for Drug Evaluation and Research.
U.S. Patent No. 9,023,897. (2015). Biodegradable drug delivery composition. United States Patent and Trademark Office.
United States Patent and Trademark Office. (2024). Manual of Patent Examining Procedure. U.S. Department of Commerce.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Teva	UZEDY	risperidone	SUSPENSION, EXTENDED RELEASE;SUBCUTANEOUS	213586-001	Apr 28, 2023		RX	Yes	Yes	9,023,897	⤷ Start Trial	Y				⤷ Start Trial
Teva	UZEDY	risperidone	SUSPENSION, EXTENDED RELEASE;SUBCUTANEOUS	213586-002	Apr 28, 2023		RX	Yes	Yes	9,023,897	⤷ Start Trial	Y				⤷ Start Trial
Teva	UZEDY	risperidone	SUSPENSION, EXTENDED RELEASE;SUBCUTANEOUS	213586-003	Apr 28, 2023		RX	Yes	Yes	9,023,897	⤷ Start Trial	Y				⤷ Start Trial
Teva	UZEDY	risperidone	SUSPENSION, EXTENDED RELEASE;SUBCUTANEOUS	213586-004	Apr 28, 2023		RX	Yes	Yes	9,023,897	⤷ Start Trial	Y				⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2011350898	⤷ Start Trial
Brazil	112013016662	⤷ Start Trial
Canada	2822854	⤷ Start Trial
Chile	2013001942	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 9,023,897

Which drugs does patent 9,023,897 protect, and when does it expire?

Summary for Patent: 9,023,897