United States Patent 6,255,325 (D-threo methylphenidate once-daily bolus): scope of claims, likely covered subject matter, and US patent landscape

United States Patent 6,255,325 is directed to a once-daily, chronic-basis oral dosage form of D-threo methylphenidate (or a pharmaceutically effective salt) for treatment of a “nervous disorder” over substantially an entire day, via bolus administration. The single independent claim is drafted as a functional dosage regimen claim tied to an active ingredient identity (D-threo methylphenidate) and a pharmacologic use duration (“substantially an entire day”) rather than to a specific release mechanism. This claim construction can sweep broadly across immediate-release and modified-release architectures, provided the product is formulated and administered in a way that meets the once-daily bolus and duration limitations.

Because you provided only Claim 1, the analysis below focuses on claim-scope drivers (what the claim likely covers, what it does not) and then maps the typical US patent landscape around D-threo methylphenidate once-daily products in the Orange Book era, including formulation, method-of-use, and dosing-regimen claim families that usually affect freedom to operate.

What does US Patent 6,255,325 claim about once-daily bolus D-threo methylphenidate?

Short answer: It claims a dosage form and regimen for treating a nervous disorder on a chronic basis using D-threo methylphenidate (or a salt), administered as a once-daily bolus intended to provide treatment for substantially an entire day.

Key claim limitations (scope-defining elements)

Claim 1 has five operative elements:

Active ingredient identity
- “D-threo methylphenidate or a pharmaceutically effective salt thereof.”
- This anchors coverage to the enantiomeric form (D-threo) rather than racemic methylphenidate, and to salts that are “pharmaceutically effective.”
Dosage form (but not a specified release system in the excerpt)
- “A drug dosage form comprising…” indicates an oral product concept, but the excerpt does not include release-rate language (eg, “extended release,” “controlled release,” “immediate release,” “bead,” “polymer matrix”).
- If the specification includes a particular delivery system, the actual infringement analysis often turns on whether the claim construction imports structural features. The independent claim as quoted is functional and may not require a specific release mechanism.
Amount effective for once daily dosing
- “In an amount effective for once daily” fixes the dosing frequency, not necessarily the mg strength, but it does tether the dosage to schedules that are expected to be once daily in chronic use.
Bolus administration
- “Once daily, bolus administration” is a critical narrowing term.
- In patent litigation over modified-release vs immediate-release, “bolus” can become contested: whether the product is administered as a unit dose that is swallowed at once, versus whether the in vivo delivery profile must be “bolus-like.”
- If a product is a multiparticulated or layered modified-release that delivers drug over time, an accused infringer may argue it is not “bolus administration” in the pharmacokinetic sense. A patentee may argue that “bolus administration” describes the dosing act: a single unit dose given once daily rather than multiple administrations.
Functional treatment duration and chronic use
- “To engender treatment… for substantially an entire day on a chronic basis.”
- This injects a “result” limitation into a dosage regimen claim. It can broaden coverage to any product that, as formulated and administered, achieves therapeutic effect for essentially a full day, even if the drug release kinetics differ from those preferred in the patent’s embodiments.

What the claim likely covers (practical reading)

Claim 1 likely covers:

Oral D-threo methylphenidate (or qualifying salts) products dosed once daily as a swallowed unit dose.
Products whose therapeutic effect lasts “substantially an entire day” when used chronically for a nervous disorder (most commonly attention-deficit/hyperactivity disorder and related stimulant-responsive conditions, depending on how broadly “nervous disorder” is defined in the patent specification).

What the claim likely does NOT cover (based on the excerpt)

Products that use racemic methylphenidate (unless a court reads “comprising D-threo methylphenidate” to allow racemate as a component, which is unlikely).
Products not administered once daily or not administered as a bolus (if “bolus” is construed to require rapid/near-immediate delivery).
Products that do not provide treatment effect for “substantially an entire day” when used chronically.

How broad is the “once daily bolus for substantially an entire day” scope: immediate-release, extended-release, or both?

Short answer: The claim text you provided is compatible with broad coverage across dosage architectures because it does not expressly require a particular release technology. Scope disputes will center on the meaning of “bolus administration” and whether the dosage form’s in vivo profile achieves “substantially an entire day.”

Claim construction fault lines that decide infringement

1) “Bolus administration” meaning

Courts typically treat “bolus” as an administration mode term. Two competing constructions usually arise:

Act-of-dosing construction: the patient ingests/swallow a single unit once daily (bolus act), regardless of how the formulation releases drug afterward.
Pharmacokinetic construction: “bolus” implies drug enters systemic circulation quickly (no meaningful extended delivery).

If the patent’s specification teaches once-daily extended delivery, the patentee will argue the formulation still counts as bolus administration because it is taken as a single dose. The accused product manufacturer may argue the delivery is not “bolus” because plasma exposure is prolonged by design.

2) “Substantially an entire day” objective effect

This is a functional duration limitation. Practically:

A once-daily product with a typical dosing interval of about 24 hours and sustained efficacy will often meet the phrase.
Products designed with clearly shorter duration (eg, 8 to 12 hours) do not.

In litigation, duration can be supported by clinical endpoints, pharmacodynamic data, and labeling (if consistent with “substantially an entire day”).

3) “Dosage form comprising” without explicit release language

Where release mechanism is not claimed in the excerpt, claim scope can remain broad. However, if dependent claims (not provided) require particular release features, the independent claim can still be interpreted as broader than the dependent claims under standard claim differentiation principles.

What “nervous disorder” does US 6,255,325 likely cover? Is it limited to ADHD?

Short answer: The claim text says “a nervous disorder” with no explicit limitation in the excerpt. The operative question becomes how the patent defines “nervous disorder” in the specification and whether the disclosure ties the invention to stimulant-responsive conditions.

Typical nervous disorders covered in D-threo methylphenidate US patent families

In the US methylphenidate patent landscape, “nervous disorder” claims around D-threo methylphenidate most often map to:

Attention-deficit/hyperactivity disorder (ADHD) in children and adults
Other behavior disorders responsive to psychostimulants, depending on historical claim breadth

Because the claim language is not exclusive, infringement arguments generally focus on whether the accused product is marketed and prescribed for a condition that falls within the patent’s described therapeutic field.

What patents would typically overlap with US 6,255,325 in the US methylphenidate once-daily arena?

Short answer: In the US market, D-threo methylphenidate once-daily products typically face overlapping IP from at least three clusters: (1) enantiomer-specific composition claims, (2) once-daily dosing and method-of-use claims, and (3) dosage-form release technology claims (matrices, beads, multilayer pellets, osmotic systems, coatings). The claim in 6,255,325 is strongest against claims that do not require a specific release system but meet the once-daily bolus and duration functional limits.

How competitors structure their patent estates

Competitors commonly implement design-around by:

Using different enantiomer composition (unlikely in this category because the active ingredient is the target)
Changing dosing frequency (multiple daily doses)
Arguing lack of “bolus” under a pharmacokinetic construction
Arguing lack of “substantially an entire day” duration for the indicted use (labeling and clinical data)

Patent clusters most likely in same review universe

Without pulling the full prosecution record and Orange Book entries for the specific patented product, the most relevant US families around D-threo methylphenidate once-daily regimens usually include:

1) Enantiomer / salt / composition patents

Claims directed to D-threo methylphenidate and pharmaceutically effective salts
Claims addressing polymorphs/solvates (less likely to match the broad formulation claim but often present in later continuations)

2) Method-of-use and regimen patents

Claims covering chronic dosing, once-daily schedules, or duration of effect
Claims tied to “substantially an entire day” language or similar “about 24 hours” constructs

3) Dosage form release technology patents

Even if 6,255,325’s excerpt is not specific, competitors often protect the actual delivery platform:

Extended-release matrices
Layered pellets
Osmotic pumps
Bead-based time-release systems
Combination immediate + extended release profiles

In a freedom-to-operate assessment, these release technology patents may overlap on enforceability even if 6,255,325 is broad.

When does US Patent 6,255,325 expire, and what exclusivity risk remains?

Short answer: Expiration depends on filing date, prosecution history, and any adjustments, and exclusivity may also exist via FDA regulatory exclusivity. The required facts (filing date, priority date, patent term adjustment) are not provided here, so a complete exclusivity timeline cannot be produced from the claim excerpt alone.

What Orange Book status and FDA labeling alignment usually drive infringement for regimen claims like this?

Short answer: For dosage regimen claims, alignment with FDA labeling matters. If a product is labeled for once-daily dosing and provides efficacy for an approximately 24-hour interval, it supports infringement arguments for “substantially an entire day.” For generic and Paragraph IV assessments, labeling and clinical trial duration become central evidence.

Evidence that typically matters in litigation

FDA-approved dosing instructions showing once-daily schedule
Clinical study endpoints demonstrating sustained effect over the day
Switching instructions for chronic use (consistent with the claim’s “chronic basis” language)

Generic risk mechanics

A generic challenger or petitioner for a substitute product will typically argue:

Different dosing frequency
Different in vivo delivery profile that is not “bolus” in the constructed sense
Insufficient day-long efficacy for the asserted indication

How strong is the patent estate for “once daily bolus D-threo methylphenidate” claims?

Short answer: As drafted in your excerpt, Claim 1 is relatively strong against competitors because it does not require a specific release architecture, but it is also vulnerable to interpretation disputes around “bolus administration” and “substantially an entire day.”

Strength drivers

Active ingredient specificity (D-threo methylphenidate + salts)
Frequency specificity (once daily)
Result/duration specificity (substantially an entire day on chronic basis)
Administration concept included (bolus)

Weakness drivers

Lack of explicit release mechanism in the excerpt can invite narrow construction or noninfringement theories, especially if “bolus” is construed pharmacokinetically.
Functional duration limitation requires proof that the accused regimen achieves day-long effect.

What generic entry risks exist for D-threo methylphenidate once-daily bolus products?

Short answer: The entry risk is driven by whether any generic applicant or authorized labeler can show noninfringement of the functional regimen limitations (bolus and substantially all-day efficacy) or invalidity of claim scope. In practice, these cases often hinge on how the claim is construed and on evidence from pharmacodynamic and clinical data.

Typical generic design-around pathways

Dosing interval change: move away from once-daily (often commercially unattractive)
Timing changes: shift dosing to achieve shorter exposure while retaining different labeling (rarely feasible)
Formulation changes: argue that prolonged release means the product is not “bolus administration” under the constructed meaning
Indication framing: if the patent is tied to a specific therapeutic frame in the specification, label the generic differently (this can be a regulatory and commercial risk trade-off)

How does US 6,255,325 compare with typical methylphenidate extended-release and immediate-release IP?

Short answer: Many methylphenidate dosage-form patents are built around release technology (matrices, pellets, coatings). Claim 1 in your excerpt is built around regimen outcomes rather than a specific delivery platform, so it can overlap multiple product architectures if they meet the regimen limitations.

Comparative positioning

Versus immediate-release patents: may still read if the product is dosed once daily and produces sustained “substantially an entire day” effect, which may be difficult with classic immediate-release.
Versus extended-release patents: strong overlap because extended-release products are commonly dosed once daily to cover much of the day, though defendants can argue “bolus” is not met.

What patent litigation would most likely affect enforceability of 6,255,325?

Short answer: The practical enforceability of regimen claims usually depends on claim construction rulings and whether courts treat “bolus” as a dosing-act or a delivery-profile limitation. Without the litigation docket, the specific case and outcome cannot be stated.

Key Takeaways

US Patent 6,255,325 Claim 1 is a regimen-and-dosage-form claim anchored to D-threo methylphenidate (or salts) and limited to once-daily bolus administration providing treatment for substantially an entire day during chronic use.
The claim excerpt does not specify a release mechanism, which increases potential coverage across dosage-form architectures, but the main infringement and design-around pressure points are the construction of “bolus administration” and proof of day-long efficacy.
The competitive and generic entry risk is determined by whether an accused product’s dosing and pharmacodynamic profile match the claim’s functional duration and administration requirements.

FAQs

Does a once-daily methylphenidate product with prolonged release infringe a “bolus administration” claim?
It depends on claim construction of “bolus administration” (dosing-act vs pharmacokinetic burst) and on whether “substantially an entire day” is met on the accused regimen.
Can a generic avoid infringement of Claim 1 by changing from once daily to twice daily dosing?
Yes, if dosing frequency is a strict claim limitation and the accused regimen does not satisfy “effective for once daily.”
If the product uses racemic methylphenidate instead of D-threo methylphenidate, is Claim 1 implicated?
The active ingredient limitation in the excerpt is enantiomer-specific, so racemate would generally not meet “comprising D-threo methylphenidate.”
How is “substantially an entire day” proven in litigation?
Through clinical efficacy duration evidence and alignment with chronic use dosing instructions that demonstrate benefit across the day interval.
Are Orange Book listings usually decisive for regimen claims like this?
They are influential in practice because FDA labeling and approved dosing schedules provide a strong evidentiary record for once-daily frequency and day-long effect.

References

United States Patent 6,255,325. (Claim 1 as provided by user: once-daily bolus dosing of D-threo methylphenidate for substantially an entire day on a chronic basis for a nervous disorder).

Title:	Chronic, bolus administration of D-threo methylphenidate
Abstract:	Chronic bolus administration of D-threo methylphenidate is provided. The administration of the D-threo isomer eliminates adverse side effects associated with the DL racemate, and provides improved effectiveness. The compositions and methods of the invention are useful in treating nervous system disorders including attention deficit disorder, attention deficit hyperactivity disorder, and cognitive decline associated with systemic diseases such as acquired immunodeficiency syndrome.
Inventor(s):	Maghsoud M. Dariani, Andrew L. Zeitlin, Jerome B. Zeldis
Assignee:	Celgene Corp
Application Number:	US09/337,310
Patent Claim Types: see list of patent claims	Use; Compound; Dosage form;
Patent landscape, scope, and claims:	United States Patent 6,255,325 (D-threo methylphenidate once-daily bolus): scope of claims, likely covered subject matter, and US patent landscape United States Patent 6,255,325 is directed to a once-daily, chronic-basis oral dosage form of D-threo methylphenidate (or a pharmaceutically effective salt) for treatment of a “nervous disorder” over substantially an entire day, via bolus administration. The single independent claim is drafted as a functional dosage regimen claim tied to an active ingredient identity (D-threo methylphenidate) and a pharmacologic use duration (“substantially an entire day”) rather than to a specific release mechanism. This claim construction can sweep broadly across immediate-release and modified-release architectures, provided the product is formulated and administered in a way that meets the once-daily bolus and duration limitations. Because you provided only Claim 1, the analysis below focuses on claim-scope drivers (what the claim likely covers, what it does not) and then maps the typical US patent landscape around D-threo methylphenidate once-daily products in the Orange Book era, including formulation, method-of-use, and dosing-regimen claim families that usually affect freedom to operate. What does US Patent 6,255,325 claim about once-daily bolus D-threo methylphenidate? Short answer: It claims a dosage form and regimen for treating a nervous disorder on a chronic basis using D-threo methylphenidate (or a salt), administered as a once-daily bolus intended to provide treatment for substantially an entire day. Key claim limitations (scope-defining elements) Claim 1 has five operative elements: Active ingredient identity “D-threo methylphenidate or a pharmaceutically effective salt thereof.” This anchors coverage to the enantiomeric form (D-threo) rather than racemic methylphenidate, and to salts that are “pharmaceutically effective.” Dosage form (but not a specified release system in the excerpt) “A drug dosage form comprising…” indicates an oral product concept, but the excerpt does not include release-rate language (eg, “extended release,” “controlled release,” “immediate release,” “bead,” “polymer matrix”). If the specification includes a particular delivery system, the actual infringement analysis often turns on whether the claim construction imports structural features. The independent claim as quoted is functional and may not require a specific release mechanism. Amount effective for once daily dosing “In an amount effective for once daily” fixes the dosing frequency, not necessarily the mg strength, but it does tether the dosage to schedules that are expected to be once daily in chronic use. Bolus administration “Once daily, bolus administration” is a critical narrowing term. In patent litigation over modified-release vs immediate-release, “bolus” can become contested: whether the product is administered as a unit dose that is swallowed at once, versus whether the in vivo delivery profile must be “bolus-like.” If a product is a multiparticulated or layered modified-release that delivers drug over time, an accused infringer may argue it is not “bolus administration” in the pharmacokinetic sense. A patentee may argue that “bolus administration” describes the dosing act: a single unit dose given once daily rather than multiple administrations. Functional treatment duration and chronic use “To engender treatment… for substantially an entire day on a chronic basis.” This injects a “result” limitation into a dosage regimen claim. It can broaden coverage to any product that, as formulated and administered, achieves therapeutic effect for essentially a full day, even if the drug release kinetics differ from those preferred in the patent’s embodiments. What the claim likely covers (practical reading) Claim 1 likely covers: Oral D-threo methylphenidate (or qualifying salts) products dosed once daily as a swallowed unit dose. Products whose therapeutic effect lasts “substantially an entire day” when used chronically for a nervous disorder (most commonly attention-deficit/hyperactivity disorder and related stimulant-responsive conditions, depending on how broadly “nervous disorder” is defined in the patent specification). What the claim likely does NOT cover (based on the excerpt) Products that use racemic methylphenidate (unless a court reads “comprising D-threo methylphenidate” to allow racemate as a component, which is unlikely). Products not administered once daily or not administered as a bolus (if “bolus” is construed to require rapid/near-immediate delivery). Products that do not provide treatment effect for “substantially an entire day” when used chronically. How broad is the “once daily bolus for substantially an entire day” scope: immediate-release, extended-release, or both? Short answer: The claim text you provided is compatible with broad coverage across dosage architectures because it does not expressly require a particular release technology. Scope disputes will center on the meaning of “bolus administration” and whether the dosage form’s in vivo profile achieves “substantially an entire day.” Claim construction fault lines that decide infringement 1) “Bolus administration” meaning Courts typically treat “bolus” as an administration mode term. Two competing constructions usually arise: Act-of-dosing construction: the patient ingests/swallow a single unit once daily (bolus act), regardless of how the formulation releases drug afterward. Pharmacokinetic construction: “bolus” implies drug enters systemic circulation quickly (no meaningful extended delivery). If the patent’s specification teaches once-daily extended delivery, the patentee will argue the formulation still counts as bolus administration because it is taken as a single dose. The accused product manufacturer may argue the delivery is not “bolus” because plasma exposure is prolonged by design. 2) “Substantially an entire day” objective effect This is a functional duration limitation. Practically: A once-daily product with a typical dosing interval of about 24 hours and sustained efficacy will often meet the phrase. Products designed with clearly shorter duration (eg, 8 to 12 hours) do not. In litigation, duration can be supported by clinical endpoints, pharmacodynamic data, and labeling (if consistent with “substantially an entire day”). 3) “Dosage form comprising” without explicit release language Where release mechanism is not claimed in the excerpt, claim scope can remain broad. However, if dependent claims (not provided) require particular release features, the independent claim can still be interpreted as broader than the dependent claims under standard claim differentiation principles. What “nervous disorder” does US 6,255,325 likely cover? Is it limited to ADHD? Short answer: The claim text says “a nervous disorder” with no explicit limitation in the excerpt. The operative question becomes how the patent defines “nervous disorder” in the specification and whether the disclosure ties the invention to stimulant-responsive conditions. Typical nervous disorders covered in D-threo methylphenidate US patent families In the US methylphenidate patent landscape, “nervous disorder” claims around D-threo methylphenidate most often map to: Attention-deficit/hyperactivity disorder (ADHD) in children and adults Other behavior disorders responsive to psychostimulants, depending on historical claim breadth Because the claim language is not exclusive, infringement arguments generally focus on whether the accused product is marketed and prescribed for a condition that falls within the patent’s described therapeutic field. What patents would typically overlap with US 6,255,325 in the US methylphenidate once-daily arena? Short answer: In the US market, D-threo methylphenidate once-daily products typically face overlapping IP from at least three clusters: (1) enantiomer-specific composition claims, (2) once-daily dosing and method-of-use claims, and (3) dosage-form release technology claims (matrices, beads, multilayer pellets, osmotic systems, coatings). The claim in 6,255,325 is strongest against claims that do not require a specific release system but meet the once-daily bolus and duration functional limits. How competitors structure their patent estates Competitors commonly implement design-around by: Using different enantiomer composition (unlikely in this category because the active ingredient is the target) Changing dosing frequency (multiple daily doses) Arguing lack of “bolus” under a pharmacokinetic construction Arguing lack of “substantially an entire day” duration for the indicted use (labeling and clinical data) Patent clusters most likely in same review universe Without pulling the full prosecution record and Orange Book entries for the specific patented product, the most relevant US families around D-threo methylphenidate once-daily regimens usually include: 1) Enantiomer / salt / composition patents Claims directed to D-threo methylphenidate and pharmaceutically effective salts Claims addressing polymorphs/solvates (less likely to match the broad formulation claim but often present in later continuations) 2) Method-of-use and regimen patents Claims covering chronic dosing, once-daily schedules, or duration of effect Claims tied to “substantially an entire day” language or similar “about 24 hours” constructs 3) Dosage form release technology patents Even if 6,255,325’s excerpt is not specific, competitors often protect the actual delivery platform: Extended-release matrices Layered pellets Osmotic pumps Bead-based time-release systems Combination immediate + extended release profiles In a freedom-to-operate assessment, these release technology patents may overlap on enforceability even if 6,255,325 is broad. When does US Patent 6,255,325 expire, and what exclusivity risk remains? Short answer: Expiration depends on filing date, prosecution history, and any adjustments, and exclusivity may also exist via FDA regulatory exclusivity. The required facts (filing date, priority date, patent term adjustment) are not provided here, so a complete exclusivity timeline cannot be produced from the claim excerpt alone. What Orange Book status and FDA labeling alignment usually drive infringement for regimen claims like this? Short answer: For dosage regimen claims, alignment with FDA labeling matters. If a product is labeled for once-daily dosing and provides efficacy for an approximately 24-hour interval, it supports infringement arguments for “substantially an entire day.” For generic and Paragraph IV assessments, labeling and clinical trial duration become central evidence. Evidence that typically matters in litigation FDA-approved dosing instructions showing once-daily schedule Clinical study endpoints demonstrating sustained effect over the day Switching instructions for chronic use (consistent with the claim’s “chronic basis” language) Generic risk mechanics A generic challenger or petitioner for a substitute product will typically argue: Different dosing frequency Different in vivo delivery profile that is not “bolus” in the constructed sense Insufficient day-long efficacy for the asserted indication How strong is the patent estate for “once daily bolus D-threo methylphenidate” claims? Short answer: As drafted in your excerpt, Claim 1 is relatively strong against competitors because it does not require a specific release architecture, but it is also vulnerable to interpretation disputes around “bolus administration” and “substantially an entire day.” Strength drivers Active ingredient specificity (D-threo methylphenidate + salts) Frequency specificity (once daily) Result/duration specificity (substantially an entire day on chronic basis) Administration concept included (bolus) Weakness drivers Lack of explicit release mechanism in the excerpt can invite narrow construction or noninfringement theories, especially if “bolus” is construed pharmacokinetically. Functional duration limitation requires proof that the accused regimen achieves day-long effect. What generic entry risks exist for D-threo methylphenidate once-daily bolus products? Short answer: The entry risk is driven by whether any generic applicant or authorized labeler can show noninfringement of the functional regimen limitations (bolus and substantially all-day efficacy) or invalidity of claim scope. In practice, these cases often hinge on how the claim is construed and on evidence from pharmacodynamic and clinical data. Typical generic design-around pathways Dosing interval change: move away from once-daily (often commercially unattractive) Timing changes: shift dosing to achieve shorter exposure while retaining different labeling (rarely feasible) Formulation changes: argue that prolonged release means the product is not “bolus administration” under the constructed meaning Indication framing: if the patent is tied to a specific therapeutic frame in the specification, label the generic differently (this can be a regulatory and commercial risk trade-off) How does US 6,255,325 compare with typical methylphenidate extended-release and immediate-release IP? Short answer: Many methylphenidate dosage-form patents are built around release technology (matrices, pellets, coatings). Claim 1 in your excerpt is built around regimen outcomes rather than a specific delivery platform, so it can overlap multiple product architectures if they meet the regimen limitations. Comparative positioning Versus immediate-release patents: may still read if the product is dosed once daily and produces sustained “substantially an entire day” effect, which may be difficult with classic immediate-release. Versus extended-release patents: strong overlap because extended-release products are commonly dosed once daily to cover much of the day, though defendants can argue “bolus” is not met. What patent litigation would most likely affect enforceability of 6,255,325? Short answer: The practical enforceability of regimen claims usually depends on claim construction rulings and whether courts treat “bolus” as a dosing-act or a delivery-profile limitation. Without the litigation docket, the specific case and outcome cannot be stated. Key Takeaways US Patent 6,255,325 Claim 1 is a regimen-and-dosage-form claim anchored to D-threo methylphenidate (or salts) and limited to once-daily bolus administration providing treatment for substantially an entire day during chronic use. The claim excerpt does not specify a release mechanism, which increases potential coverage across dosage-form architectures, but the main infringement and design-around pressure points are the construction of “bolus administration” and proof of day-long efficacy. The competitive and generic entry risk is determined by whether an accused product’s dosing and pharmacodynamic profile match the claim’s functional duration and administration requirements. FAQs Does a once-daily methylphenidate product with prolonged release infringe a “bolus administration” claim? It depends on claim construction of “bolus administration” (dosing-act vs pharmacokinetic burst) and on whether “substantially an entire day” is met on the accused regimen. Can a generic avoid infringement of Claim 1 by changing from once daily to twice daily dosing? Yes, if dosing frequency is a strict claim limitation and the accused regimen does not satisfy “effective for once daily.” If the product uses racemic methylphenidate instead of D-threo methylphenidate, is Claim 1 implicated? The active ingredient limitation in the excerpt is enantiomer-specific, so racemate would generally not meet “comprising D-threo methylphenidate.” How is “substantially an entire day” proven in litigation? Through clinical efficacy duration evidence and alignment with chronic use dosing instructions that demonstrate benefit across the day interval. Are Orange Book listings usually decisive for regimen claims like this? They are influential in practice because FDA labeling and approved dosing schedules provide a strong evidentiary record for once-daily frequency and day-long effect. References United States Patent 6,255,325. (Claim 1 as provided by user: once-daily bolus dosing of D-threo methylphenidate for substantially an entire day on a chronic basis for a nervous disorder). More… ↓ ⤷ Start Trial

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Details for Patent: 6,255,325

Summary for Patent: 6,255,325