United States Patent 7,241,805: Bupropion Hydrobromide Patent Scope, Claims and Patent Landscape

U.S. Patent No. 7,241,805 protected a specific once-daily, controlled-release bupropion hydrobromide tablet with defined stability limits for the 3-CBZ degradation product. The patent did not broadly cover all bupropion hydrobromide products, all extended-release bupropion tablets, or the bupropion hydrobromide molecule itself. Its principal commercial relevance was Aplenzin, the bupropion hydrobromide extended-release product.

The patent issued July 10, 2007, from an application filed May 14, 2003. Its 20-year patent term ran to approximately May 14, 2023, subject to any applicable patent-term adjustment. The patent is therefore no longer a current U.S. exclusivity barrier based on ordinary patent term. [1][2]

What does U.S. Patent 7,241,805 cover?

The patent covers a modified-release bupropion hydrobromide tablet that satisfies both formulation and analytical stability requirements.

Claim 1: The principal composition claim

Claim 1 requires every one of the following elements:

Required element	Scope
Dosage form	Tablet suitable for oral administration
Active ingredient	Therapeutically effective amount of bupropion hydrobromide
Core excipients	A binder and a lubricant
Release system	A controlled-release polymeric coat surrounding the core
Degradation product	3-CBZ degradation product present in the tablet
Release profile	Controlled release over approximately 24 hours
Stability at 13 days	No more than approximately 0.070 percent increase in 3-CBZ relative to the amount present at formulation
Stability at 20 days	No more than approximately 0.098 percent increase in 3-CBZ relative to the amount present at formulation
Comparative performance	The bupropion hydrobromide tablet must show lower respective 3-CBZ increases than an otherwise identical bupropion hydrochloride tablet
Stress condition	Approximately 40°C and 75% relative humidity

The claim is cumulative. A product that has bupropion hydrobromide, a controlled-release coating and once-daily release would not infringe claim 1 unless it also met the specified stability and comparative-performance limitations.

The comparative limitation is important. The claim does not merely require a stability threshold. It requires the hydrobromide formulation to perform better than an otherwise identical hydrochloride comparator under the specified accelerated storage conditions.

What is the role of 3-CBZ?

3-CBZ is a specified bupropion degradation product used as the analytical stability marker in the patent. The claims use the change in the amount of that degradation product as a quantitative limitation.

The claim language measures the increase against the amount present at tablet formulation. The patent therefore targets a formulation-level stability result rather than merely the selection of the hydrobromide salt.

The specification and prosecution history would be relevant to determine:

The precise chemical identity assigned to “3-CBZ.”
The analytical method used to quantify it.
Whether “percent increase” means absolute percentage-point increase or relative percentage increase.
How the initial amount is measured.
Whether the hydrochloride comparator must be manufactured in the same batch or under identical process conditions.

Those issues would be central to claim construction in any infringement dispute.

How do claims 2 and 3 narrow the patent scope?

Claim 2: Core composition ranges

Claim 2 narrows claim 1 by specifying the dry-weight composition of the tablet core:

Component	Claimed range
Bupropion hydrobromide	Approximately 40% to 99%
Binder	Approximately 0.5% to 25%
Lubricant	Approximately 1% to 6%

A product may satisfy claim 1 without falling within claim 2. Claim 2 is narrower because it imposes quantitative excipient and active-content limitations.

The claim does not identify a single binder, lubricant or coating polymer. A formulation using different excipients could still fall within the claim if the amounts remain within the stated ranges and the other claim 1 limitations are met.

Claim 3: More demanding stability limits

Claim 3 narrows claim 1 by imposing lower 3-CBZ increases:

Test point	Claim 1 limit	Claim 3 limit
Approximately 13 days at 40°C/75% RH	No more than 0.070%	No more than 0.035%
Approximately 20 days at 40°C/75% RH	No more than 0.098%	No more than 0.046%

Claim 3 also retains the requirement that the hydrobromide product perform better than the otherwise identical hydrochloride comparator.

The practical consequence is that claim 3 is more difficult to meet than claim 1 but potentially more difficult to avoid if a competitor’s product demonstrates unusually strong stability.

What do claims 4 through 9 protect?

Claims 4 through 9 are method-of-treatment claims directed to administration of the claimed stable bupropion hydrobromide modified-release tablet.

Claims	Subject matter
4	Once-daily treatment of a depressive condition using the claim 1 tablet
5	Once-daily treatment using the claim 2 tablet
6	Once-daily treatment using the claim 3 tablet
7	Treatment of a diagnosed depressive condition using the claim 1 tablet
8	Treatment of a diagnosed depressive condition using the claim 3 tablet
9	Once-daily treatment using the claim 3 tablet

Claims 4 through 6 and claim 9 expressly require once-daily administration. Claims 7 and 8 do not expressly include the once-daily limitation, but they incorporate the underlying tablet limitations through dependency.

These claims are narrower than a general method claim covering administration of bupropion for depression. They require use of the patented hydrobromide modified-release tablet.

How strong is the patent estate for U.S. Patent 7,241,805?

The patent was technically narrow but commercially relevant.

Strengths

Specific product architecture
The claim combines the bupropion hydrobromide salt, a coated core and approximately 24-hour release.
Quantitative stability limitations
The 3-CBZ thresholds provide objective claim boundaries.
Comparative salt limitation
A competing product must be evaluated against an otherwise identical bupropion hydrochloride formulation. This makes the claim more specific than a standard extended-release formulation claim.
Commercial alignment
The claim language corresponds to the stability and release characteristics associated with bupropion hydrobromide extended-release tablets marketed as Aplenzin.

Weaknesses

Multiple limitations must be satisfied
Failure of any one element defeats literal infringement.
Potential measurement disputes
The meaning of “increase,” the identity of 3-CBZ, and the testing protocol could create material claim-construction issues.
Comparator requirement
The need to establish performance against an otherwise identical hydrochloride tablet adds evidentiary complexity.
Narrow dosage-form coverage
The independent claim is directed to a tablet with a controlled-release polymeric coat. Capsules, multiparticulates, matrix tablets without the claimed coat, liquid systems and other delivery systems may fall outside the literal scope.
Expired term
Whatever litigation leverage the patent provided during its term ended when the patent term expired in 2023.

What patents protected Aplenzin and bupropion extended-release products?

Aplenzin contains bupropion hydrobromide and is an extended-release product. U.S. Patent 7,241,805 was the principal patent associated with the stable bupropion hydrobromide formulation described in the claims supplied by the user.

The broader bupropion patent landscape also included earlier patents directed to bupropion hydrochloride sustained-release and extended-release formulations, including U.S. Patent No. 5,427,798. Those patents were associated with the Wellbutrin and Wellbutrin XL product lineage and expired before U.S. Patent 7,241,805. [3]

The distinction between the salt forms matters:

A patent directed specifically to bupropion hydrochloride does not automatically block bupropion hydrobromide.
A claim directed to a broad controlled-release bupropion formulation could potentially cover both salts, depending on its language.
U.S. Patent 7,241,805 is narrower because it expressly requires bupropion hydrobromide and the 3-CBZ stability comparison.

What was the Orange Book status of U.S. Patent 7,241,805?

The patent was listed in the FDA Orange Book in connection with bupropion hydrobromide extended-release tablets marketed under the Aplenzin product franchise. Orange Book listings are product-specific and depend on the relevant NDA holder and dosage strengths. [4]

The Orange Book listing did not mean that every bupropion product was covered. It indicated that the NDA holder identified the patent as claiming the approved drug or an approved method of using the drug.

After patent expiration:

The patent no longer supplied a live Orange Book patent barrier.
A new ANDA applicant would no longer need to defeat the patent through a Paragraph IV certification for a future launch date based solely on this patent.
Any litigation based only on future infringement of the expired patent would generally lack ongoing injunctive value, although historical damages issues could remain relevant for conduct occurring before expiration.

When did U.S. Patent 7,241,805 lose exclusivity?

The patent’s ordinary expiration date was approximately May 14, 2023.

Event	Date
Earliest priority date	May 14, 2002
U.S. nonprovisional filing	May 14, 2003
Publication	November 18, 2004
Issue	July 10, 2007
Approximate ordinary expiration	May 14, 2023

A provisional application priority date generally does not reduce the 20-year term calculated from the nonprovisional filing date. Patent-term adjustment, if any, would need to be confirmed in the USPTO patent record. The public patent records identify the patent as a 2023-expiring right. [1][2]

Were Paragraph IV challenges relevant?

Paragraph IV challenges were commercially relevant before the patent expired because an ANDA applicant seeking approval for a generic bupropion hydrobromide extended-release product could have certified that the patent was invalid, unenforceable or would not be infringed.

The principal challenge routes were:

Paragraph III certification: Approval deferred until patent expiration.
Paragraph IV certification: Applicant asserts invalidity, unenforceability or noninfringement.
Section viii statement: Applicant omits a patented method of use where applicable.

For this patent, a Paragraph IV defense would likely have focused on:

Whether the accused tablet used a controlled-release polymeric coat surrounding a core.
Whether the product released bupropion hydrobromide over approximately 24 hours.
Whether 3-CBZ was present and increased within the claimed ranges.
Whether the required bupropion hydrochloride comparator was properly constructed.
Whether the claim limitations were anticipated or obvious in view of bupropion hydrochloride and hydrobromide formulation technology.

Because the patent expired in 2023, its Paragraph IV significance is now historical rather than a continuing obstacle to generic approval.

What generic entry risks existed?

Before expiration, generic entry risk depended on whether an applicant could design around the stability and coating limitations or prevail in a patent challenge.

Design-around options

A competitor could attempt to avoid the claims by using:

A different dosage form, such as a capsule or multiparticulate system.
A matrix-based extended-release tablet without a separate surrounding polymeric coat.
A formulation that does not satisfy the approximately 24-hour release limitation.
A composition outside the claim 2 active, binder or lubricant ranges.
A product that exceeds the claim 1 or claim 3 3-CBZ limits.
A formulation for which the comparative hydrochloride condition is not satisfied.

Design-around analysis would still require attention to equivalents, because a minor change in coating composition or manufacturing process would not necessarily eliminate infringement.

Generic launch scenarios

Scenario	Pre-expiration result
ANDA with Paragraph III certification	Launch after patent expiration
ANDA with Paragraph IV certification and successful challenge	Potential early launch
ANDA with noninfringing formulation	Potential launch after FDA approval, subject to other listed rights
Product outside the approved method-of-use claims	Possible section viii strategy
Post-expiration ANDA	Patent 7,241,805 no longer blocks launch

The main remaining commercial issues after expiration are FDA approval, formulation development, bioequivalence, manufacturing scale-up, supply reliability and any separate unexpired patents.

Does biosimilar risk apply to bupropion hydrobromide?

No. Bupropion hydrobromide is a small-molecule active pharmaceutical ingredient, not a biologic. The relevant competitive pathway is an ANDA for a generic drug, not a biosimilar application under the Public Health Service Act.

The relevant barriers are therefore:

Pharmaceutical equivalence.
Bioequivalence.
Chemistry, manufacturing and controls.
Stability data.
Labeling and exclusivity.
Orange Book patents.
State substitution and commercial distribution.

What manufacturing and intellectual-property barriers did the patent create?

The patent’s manufacturing relevance arose from the interaction between salt selection, tablet-core composition, coating technology and degradation control.

A manufacturer seeking to reproduce the product would need to control:

Bupropion hydrobromide particle and salt characteristics.
Core compression and excipient compatibility.
Binder and lubricant concentration.
Polymer-coat uniformity.
Moisture exposure.
Storage conditions.
3-CBZ formation over time.
Release performance across the tablet’s shelf-life.

The patent did not claim a particular manufacturing process in the claims supplied. It therefore operated principally as a product and method-of-treatment patent. Manufacturing steps could still create infringement risk if they produced a tablet meeting the claimed product limitations.

How does the patent compare with bupropion hydrochloride patents?

Issue	U.S. 7,241,805	Earlier bupropion hydrochloride patents
Salt	Bupropion hydrobromide	Generally bupropion hydrochloride
Dosage form	Modified-release tablet	Sustained- or extended-release formulations
Stability marker	3-CBZ	Depends on patent
Comparative test	Requires lower degradation than HCl comparator	Generally not the same comparative limitation
Release period	Approximately 24 hours	Varies
Treatment claims	Depression and related depressive conditions	Varies
Current term	Expired around May 14, 2023	Earlier patents generally expired
Biosimilar relevance	None	None

The patent’s commercial differentiation was the use of the hydrobromide salt as a stability-enhancing alternative to bupropion hydrochloride in a once-daily controlled-release tablet.

What litigation or settlement issues affected the patent?

The patent could have supported Hatch-Waxman litigation after a Paragraph IV certification, but the supplied information does not establish a specific lawsuit, settlement agreement, consent judgment or authorized-generic arrangement. No litigation or settlement conclusion should be attributed to U.S. Patent 7,241,805 without a docket-specific review.

The patent’s current legal effect is principally historical because its ordinary term ended in 2023.

Key Takeaways

U.S. Patent 7,241,805 claimed a stable, once-daily bupropion hydrobromide controlled-release tablet.
Claim 1 required a coated core, approximately 24-hour release, 3-CBZ stability thresholds and superior stability versus an otherwise identical bupropion hydrochloride tablet.
Claim 2 added quantitative ranges for bupropion hydrobromide, binder and lubricant.
Claim 3 imposed tighter 3-CBZ limits than claim 1.
Claims 4 through 9 covered treatment of depressive conditions using the claimed tablet.
The patent was relevant to Aplenzin and the bupropion hydrobromide extended-release product category.
It was a narrow formulation patent, not a broad patent on bupropion, bupropion hydrobromide or all extended-release products.
The patent’s ordinary U.S. term expired around May 14, 2023.
Bupropion is a small molecule, so generic ANDA competition, not biosimilar competition, applies.
Current generic entry is not blocked by this expired patent alone.

FAQs

What drug was associated with U.S. Patent 7,241,805?

The patent was associated with bupropion hydrobromide extended-release tablets marketed as Aplenzin.

Does U.S. Patent 7,241,805 cover bupropion hydrochloride?

No. The independent claims require bupropion hydrobromide. The bupropion hydrochloride formulation appears as a required comparator for the stability limitation.

Is U.S. Patent 7,241,805 still enforceable?

The patent’s ordinary term expired around May 14, 2023. It is not a current patent-term barrier based on the standard expiration calculation.

Can a generic manufacturer use a different bupropion hydrobromide formulation?

Yes, subject to FDA approval and any other enforceable intellectual-property rights. A formulation that does not meet all limitations of the expired claims would not be blocked by this patent.

Is Aplenzin protected by a biosimilar framework?

No. Aplenzin contains the small-molecule drug bupropion hydrobromide. Generic competition proceeds through the ANDA pathway rather than the biosimilar pathway.

References

United States Patent and Trademark Office. (2007). U.S. Patent No. 7,241,805, stable formulations of bupropion hydrobromide. https://patents.google.com/patent/US7241805B2/en
Google Patents. (n.d.). US7241805B2: Stable formulations of bupropion hydrobromide. https://patents.google.com/patent/US7241805B2/en
United States Patent and Trademark Office. (1995). U.S. Patent No. 5,427,798, sustained release formulations of bupropion hydrochloride. https://patents.google.com/patent/US5427798A/en
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Bausch	APLENZIN	bupropion hydrobromide	TABLET, EXTENDED RELEASE;ORAL	022108-001	Apr 23, 2008		RX	Yes	No	⤷ Start Trial	⤷ Start Trial	Y				⤷ Start Trial
Bausch	APLENZIN	bupropion hydrobromide	TABLET, EXTENDED RELEASE;ORAL	022108-002	Apr 23, 2008		RX	Yes	No	⤷ Start Trial	⤷ Start Trial	Y				⤷ Start Trial
Bausch	APLENZIN	bupropion hydrobromide	TABLET, EXTENDED RELEASE;ORAL	022108-003	Apr 23, 2008		RX	Yes	Yes	⤷ Start Trial	⤷ 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	2006261788	⤷ Start Trial
Australia	2008285660	⤷ Start Trial
Australia	2008320915	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,241,805

Which drugs does patent 7,241,805 protect, and when does it expire?

Summary for Patent: 7,241,805