US Patent 8,153,149: Scope, Claim Construction, Expiration, and Bupivacaine Patent Landscape

US Patent 8,153,149 covers a narrowly defined sustained-release bupivacaine composition using sucrose acetate isobutyrate, or SAIB, as the principal liquid carrier and benzyl alcohol as a co-solvent. The independent claim requires an approximate 66:12:22 weight composition of SAIB, bupivacaine, and benzyl alcohol, together with release sufficient to provide local anesthesia for at least 24 hours. The patent is composition-focused and does not broadly cover all sustained-release bupivacaine products.

The claimed technology is associated with DURECT Corporation's SABER platform and its investigational POSIDUR or SABER-Bupivacaine products. No FDA-approved product appears to rely on this patent, and the patent is not an Orange Book patent for an approved reference drug. The principal commercial risks are formulation redesign, alternative sustained-release matrices, and regulatory entry through a 505(b)(2) application rather than a conventional ANDA.

What does US Patent 8,153,149 cover?

US Patent 8,153,149 covers a pharmaceutical composition containing three required components:

Component	Claimed amount by total composition weight	Technical role
Sucrose acetate isobutyrate, or SAIB	About 66%	Liquid carrier and sustained-release matrix
Bupivacaine	About 12%	Local anesthetic active ingredient
Benzyl alcohol, or BA	About 22%	Solvent, plasticizer, or release-modifying component
Total	Approximately 100%	Complete formulation

The composition must also release bupivacaine for at least 24 hours after administration in an amount sufficient to provide sustained local anesthesia. The claim is therefore limited by both composition and performance.

The patent does not claim bupivacaine generally, all injectable local anesthetics, or every SAIB-based delivery system. It requires the specified combination and a sustained-anesthesia result.

What is the commercial technology behind the patent?

SAIB is a highly viscous, hydrophobic liquid used in controlled-release drug delivery. In the claimed system, the carrier is administered with bupivacaine and benzyl alcohol. The formulation is intended to remain localized and release bupivacaine over an extended period.

The technology differs from:

Liposomal bupivacaine, such as EXPAREL;
Polymer microspheres;
Collagen implants;
In situ biodegradable polymer depots;
Bupivacaine combinations containing non-anesthetic active ingredients;
Conventional aqueous bupivacaine hydrochloride injections.

The patent is directed to the SAIB-based liquid formulation rather than to a liposome, implant, or biodegradable microsphere.

How should claim 1 of US 8,153,149 be construed?

Claim 1 is an open-ended composition claim because it uses "comprising." A product may contain additional excipients, stabilizers, preservatives, or processing agents and still fall within the claim, provided the required components and limitations are present.

The claim has five principal limitations:

A pharmaceutical composition;
About 66% SAIB by total composition weight;
About 12% bupivacaine by total composition weight;
About 22% benzyl alcohol by total composition weight;
Release of bupivacaine for at least 24 hours in an amount sufficient to provide sustained local anesthesia.

The "about" language creates a numerical scope that is broader than the exact 66%, 12%, and 22% formulation. The boundaries cannot be determined solely from the claim text. Courts typically assess the specification, prosecution history, technical meaning, and whether the numerical limitation provides a meaningful point of demarcation. A formulation containing 65.5% SAIB, 12.2% bupivacaine, and 22.3% benzyl alcohol could present a fact-specific infringement question rather than an automatic non-infringement result.

Does claim 1 require all three formulation components?

Yes. A formulation that omits SAIB, omits benzyl alcohol, or replaces bupivacaine with another anesthetic would not literally satisfy claim 1.

A formulation containing bupivacaine and SAIB but no benzyl alcohol would be outside the literal wording. A formulation containing bupivacaine, benzyl alcohol, and another carrier instead of SAIB would also be outside the literal claim.

The doctrine of equivalents could become relevant, but it would face limits where the patent specification or prosecution history treats the three-component composition as critical or where applying equivalents would effectively eliminate a claimed component.

What does the 24-hour release limitation require?

The formulation must release bupivacaine over at least 24 hours, and the released amount must be sufficient to provide sustained local anesthesia. This is more restrictive than a formulation that merely contains a viscous carrier or shows residual drug after 24 hours.

The limitation introduces two related issues:

Duration: release must continue for at least 24 hours.
Functional effect: the released bupivacaine must provide sustained local anesthesia.

A release profile showing detectable bupivacaine at 24 hours may not be enough if the amount is clinically ineffective. Conversely, a product could face risk if its release profile differs from the claimed formulation but still provides the required anesthetic effect.

What do dependent claims 2 through 4 add?

Claim	Added limitation	Scope effect
2	Bupivacaine is in free-base form	Excludes formulations using only bupivacaine salts, subject to claim construction and conversion during formulation
3	Suitable for topical, systemic, or parenteral administration	Broadens administration suitability across multiple routes
4	Suitable for injection, pouring, spraying, dipping, aerosolizing, or coating-applicator delivery	Adds a broad set of administration or application formats

What is the significance of claim 2?

Claim 2 narrows the composition to free-base bupivacaine. Bupivacaine hydrochloride is the conventional form used in many approved injectable products. A product using bupivacaine hydrochloride would not automatically meet the express free-base limitation of claim 2.

Claim 1 itself, however, does not expressly require free-base bupivacaine. A salt-based formulation could therefore require analysis under claim 1 even if it falls outside claim 2.

How broad are claims 3 and 4?

Claims 3 and 4 are unusually broad in route language. Claim 3 reaches compositions suitable for topical, systemic, or parenteral administration. Claim 4 identifies multiple delivery formats, including injection, pouring, spraying, dipping, aerosolizing, and coating application.

These claims do not necessarily require that every listed route be used. The ordinary reading is that a composition suitable for one of the identified routes may satisfy the limitation. The specification and prosecution history would control whether "or" is interpreted disjunctively.

The practical value of these claims depends on whether the formulation can actually be manufactured and delivered through the stated route while retaining the claimed sustained-release performance.

What patents protect SAIB-based sustained-release bupivacaine?

US Patent 8,153,149 is the key patent identified by the supplied claims. It is generally associated with DURECT Corporation and the SABER delivery platform.

Patent	Subject matter based on supplied claims	Applicant or owner associated with technology	Practical relevance
US 8,153,149	SAIB, bupivacaine, and benzyl alcohol composition with at least 24-hour sustained local anesthesia	DURECT Corporation	Core formulation claim
Related patent-family filings	Potentially overlapping sustained-release local anesthetic formulations, methods, or platform claims	DURECT and related entities	Must be reviewed separately for continuation or divisional scope
Competitor patents	Liposomal, collagen, polymeric, or combination bupivacaine products	Pacira, Innocoll, Heron and others	Alternative technologies, not necessarily overlapping claim 1

A complete freedom-to-operate review cannot rely on US 8,153,149 alone. Continuations, foreign counterparts, terminal disclaimers, prosecution amendments, and patent-family members may contain claims directed to methods of treatment, release profiles, manufacturing processes, or broader excipient combinations.

When does US Patent 8,153,149 lose exclusivity?

The patent's base statutory term is generally measured from the earliest effective nonprovisional or international filing date, not from the April 10, 2012 grant date. Public patent-family information associates the technology with a 2006 filing period, producing a base term that runs into December 2026, subject to patent-term adjustment, terminal disclaimers, and any applicable term calculations. The exact enforceable expiration date requires review of the USPTO Patent Examination Data System and the patent-term adjustment certificate.

Event	Date or period
Relevant filing period	December 2006-era priority and international filing history
US patent grant	April 10, 2012
Base 20-year term	Expected to extend into December 2026
Possible adjustment	Patent-term adjustment may modify the date
Regulatory exclusivity	None established for an approved product
Orange Book status	No approved NDA listing identified for this patent

The grant date does not create a 17-year term under current US law. Patent applications filed after the Uruguay Round Agreements Act generally receive a term of 20 years from the earliest effective nonprovisional filing date, subject to adjustments.

What is the FDA and Orange Book status of US Patent 8,153,149?

US Patent 8,153,149 does not appear to be an Orange Book-listed patent for an FDA-approved bupivacaine product. The patent is linked to an investigational sustained-release product rather than an approved reference listed drug.

The regulatory consequences are material:

There is no established Orange Book patent certification pathway directed specifically to this patent.
A generic applicant cannot ordinarily file an ANDA against an unapproved SAIB-bupivacaine product.
An applicant developing a comparable sustained-release product would more likely consider a 505(b)(2) application or, depending on the product and reference, another NDA pathway.
FDA approval of conventional bupivacaine hydrochloride products does not establish approval of the claimed SAIB formulation.

The lack of Orange Book listing does not eliminate patent risk. A patent owner can assert a non-Orange Book patent against a commercial product, but the applicant would not receive the same automatic 30-month stay mechanism associated with a timely Paragraph IV certification against an Orange Book-listed patent.

Are there Paragraph IV challenges or patent litigation involving this patent?

No material public Paragraph IV litigation is associated with US 8,153,149 in the supplied record. That result is consistent with the absence of an approved NDA and Orange Book listing for the claimed formulation.

A Paragraph IV challenge is generally relevant when:

An ANDA applicant identifies a reference listed drug;
The Orange Book lists the patent for that drug;
The applicant certifies that the patent is invalid, unenforceable, or will not be infringed.

Those conditions do not naturally apply to an investigational SAIB-bupivacaine formulation. A future 505(b)(2) applicant could face ordinary patent litigation, an offer-to-sell claim, or a declaratory judgment dispute even without an Orange Book certification.

Are there settlement agreements?

No publicly established patent settlement agreement involving US 8,153,149 and an ANDA challenger is identified. DURECT's licensing and development arrangements for POSIDUR are commercially relevant, but a development or licensing agreement is not equivalent to a Paragraph IV settlement.

What formulations are protected by the patent?

The strongest literal-risk profile is a product with the following characteristics:

Bupivacaine as the anesthetic;
SAIB at approximately 66% of total weight;
Benzyl alcohol at approximately 22%;
Bupivacaine at approximately 12%;
Liquid or flowable formulation;
Local administration;
Release lasting at least 24 hours;
Free-base bupivacaine, for claim 2;
Injection or another listed application route, for claims 3 and 4.

Formulations with greater design-around distance include:

Design approach	Likely claim-avoidance rationale
Liposomal bupivacaine	No SAIB or benzyl alcohol combination
Polymer microsphere bupivacaine	Different carrier architecture
Collagen implant	Solid implant rather than SAIB liquid carrier
Bupivacaine plus meloxicam	Different active-ingredient and formulation system
Bupivacaine hydrochloride in an aqueous depot	Does not match the claimed SAIB/BA composition
SAIB formulation with materially different excipient ratios	May avoid the numerical limitations, subject to "about" construction
Alternative co-solvent replacing benzyl alcohol	Removes an express claim element

Changing only the administration route is unlikely to avoid claim 1 if the composition and release limitations remain satisfied. Changing the bupivacaine concentration or SAIB-to-BA ratio may provide a stronger design-around, but the acceptable distance depends on the construction of "about."

How does this patent compare with competing bupivacaine estates?

Product or technology	Company	Delivery system	Regulatory position	Relationship to US 8,153,149
SABER-Bupivacaine or POSIDUR	DURECT	SAIB-based liquid depot	Investigational	Directly associated technology
EXPAREL	Pacira	Liposomal bupivacaine	FDA approved	Different formulation platform
XARACOLL	Innocoll	Bupivacaine collagen matrix	FDA approved	Different dosage form
ZYNRELEF	Heron Therapeutics	Bupivacaine and meloxicam extended-release system	FDA approved	Different active-ingredient combination and delivery technology
Conventional bupivacaine injection	Multiple manufacturers	Aqueous solution, usually bupivacaine hydrochloride	FDA approved	Generally outside the claimed SAIB formulation

EXPAREL, XARACOLL, and ZYNRELEF demonstrate that sustained local anesthesia can be protected through different formulation architectures. Their patent estates may create competitive barriers, but their products do not automatically infringe US 8,153,149.

What generic entry risks exist?

The immediate ANDA risk is limited because the claimed formulation lacks an approved reference product. The more significant risk would arise if a sponsor develops a clinically effective SAIB-bupivacaine product and seeks approval through a 505(b)(2) pathway.

Potential launch scenarios are:

A non-overlapping formulation using a different carrier, such as liposomes or biodegradable polymers.
A SAIB formulation with materially different component ratios.
A product using bupivacaine hydrochloride rather than free-base bupivacaine.
A product with a release profile shorter than 24 hours, if clinically adequate.
A product launched after patent expiration, subject to any valid related patents.
A licensed product using the DURECT platform or patent family.

Manufacturing risk also matters. Even if a formulation avoids the exact percentages, it may still implicate related platform patents covering SAIB processing, depot formation, solvent systems, or local anesthetic release.

How strong is the patent estate?

The individual patent claim is narrow in composition but potentially meaningful against an exact or near-exact formulation. Its strengths are:

Three-component definition;
Functional release limitation;
Coverage of multiple delivery routes through dependent claims;
Potentially broad interpretation of "comprising";
Relevance to a differentiated sustained-release product.

Its limitations are:

Exact or near-exact numerical requirements;
Dependence on a specific SAIB and benzyl alcohol system;
No approved product supporting Orange Book leverage;
Availability of alternative delivery technologies;
Possible difficulty proving the claimed clinical anesthesia result in a competitor's product;
Potential expiration in or around December 2026 before a new product reaches market.

The patent is therefore more important as a formulation-specific barrier than as a broad bupivacaine exclusivity right.

Key Takeaways

US 8,153,149 claims a SAIB-based sustained-release bupivacaine formulation.
Claim 1 requires approximately 66% SAIB, 12% bupivacaine, and 22% benzyl alcohol by weight.
The formulation must release bupivacaine for at least 24 hours in an amount sufficient to provide sustained local anesthesia.
Claim 2 specifically addresses free-base bupivacaine.
Claims 3 and 4 extend coverage across multiple administration routes and application formats.
The patent is associated with DURECT's SABER or POSIDUR technology.
No Orange Book listing or conventional Paragraph IV pathway has been established for this investigational formulation.
The base patent term appears to extend into December 2026, subject to USPTO term adjustment and related-file review.
Liposomal, collagen, polymeric, and combination bupivacaine products use different formulation architectures.
The highest infringement risk applies to a near-identical SAIB-bupivacaine-benzyl alcohol formulation, not to bupivacaine products generally.

FAQs about US Patent 8,153,149

Can bupivacaine hydrochloride infringe US Patent 8,153,149?

It may avoid claim 2 because that claim requires free-base bupivacaine. Claim 1 does not expressly require the free-base form, so the salt form should be assessed against the full composition and release limitations.

Does a 24-hour release profile automatically infringe the patent?

No. The product must also contain the claimed SAIB, bupivacaine, and benzyl alcohol amounts. The release must provide sufficient local anesthesia, not merely show detectable drug release.

Is EXPAREL covered by US Patent 8,153,149?

EXPAREL uses a liposomal bupivacaine delivery system rather than the claimed SAIB and benzyl alcohol formulation. It is not covered by the supplied claims solely because it contains bupivacaine.

Can a formulation with 65% SAIB avoid the patent?

Not automatically. The claim uses "about 66%," so a court would assess the technical and prosecution-history meaning of "about." The numerical difference must be evaluated with the remaining formulation and evidence of equivalence.

Does patent expiration eliminate all SABER-bupivacaine risk?

No. Expiration of US 8,153,149 would not eliminate separate risks from continuation patents, foreign patents, manufacturing patents, trade secrets, regulatory exclusivity, or other claims covering the same product or platform.

References

DURECT Corporation. (2012). United States Patent No. 8,153,149, sustained-release local anesthetic composition. U.S. Patent and Trademark Office.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
U.S. Food and Drug Administration. (2024). Approved drug products and FDA regulatory pathways. FDA.
Pacira BioSciences, Inc. (2024). EXPAREL prescribing information. U.S. Food and Drug Administration.
Innocoll Pharmaceuticals, Inc. (2024). XARACOLL prescribing information. U.S. Food and Drug Administration.
Heron Therapeutics, Inc. (2024). ZYNRELEF prescribing information. U.S. Food and Drug Administration.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	E537844	⤷ Start Trial
Australia	2005287175	⤷ Start Trial
Brazil	PI0515372	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 8,153,149

Summary for Patent: 8,153,149