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Patent landscape, scope, and claims: |
Executive summary
US Patent 4,735,805 is directed to a shaped, “bisectable” (split) drug tablet with a specific geometry: an elongated tablet body with top and bottom concavities (equal size; parallel major and minor axes), a longitudinally spanning smooth arcuate concavity, and a breaking groove located at an apex of the second concavity, arranged so the tablet fractures along the groove regardless of whether the groove faces up or down relative to a support surface. Claim 1 is the core breadth driver: it defines a tablet structure and fracture behavior as functional language tied to orientation. Claim 2 narrows to additional central-body geometry (finite uniform thickness; uninterrupted peripheral surface; frustoconical-like top/bottom parts) and groove depth that extends from the apex of one concavity to a top or bottom surface of the central body part. The landscape for this kind of technology typically clusters around (i) scored/bisectable tablet geometry, (ii) orientation-independent splitting behavior, and (iii) whether the groove depth and concavity shapes are structural limitations or functional outcomes.
Note: This analysis is confined to the claim text provided for US 4,735,805 and does not evaluate unprovided dependent claims, the specification’s detailed embodiments, file history, or any specific competitor patent numbers beyond what can be inferred from the claim language itself.
What is US 4,735,805 protecting: bisectable drug tablets with concavities and a orientation-independent breaking groove?
Answer (scope in one line): The patent protects a bisectable elongated tablet whose top and bottom are each shaped with concavities and whose fracture line is a breaking groove at the apex of one concavity, with geometry arranged to fracture along the groove whether the groove faces toward or away from the support surface.
Core structural elements in Claim 1
Claim 1 combines tablet form-factor and fracture control in one integrated limitation set:
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Elongated tablet body
- Length greater than width.
- Has top and bottom surfaces.
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Two concavities, one on each face, equal in size
- Each concavity has parallel major and minor axes.
- The concavities are equal in size.
- The concavity on the “first” side has a smooth uninterrupted arcuate surface that extends between opposite longitudinal ends.
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Thickness relationship at the concavity apexes
- The opposite longitudinal ends of the body are thicker than the thickness measured at apexes of the concavities.
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Breaking groove
- Formed in a second concavity (the opposite face from the first concavity).
- Extends laterally across the width of the tablet at an apex of the second cavity.
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Orientation-independent fracture functional requirement
- When downward pressure is applied to one face:
- the other face faces downward
- opposite longitudinal ends rest on a support surface
- Tablet fractures along the breaking groove.
- This fracture occurs irrespective of whether the breaking groove faces toward or away from the support surface.
How the orientation-independent language changes claim reach
Most score/groove tablet patents focus on splitting when the score is oriented in a certain way. Claim 1 makes the splitting outcome orientation-independent by specifying the fracture occurs regardless of groove orientation relative to the support. That affects:
- Claim construction pressure: courts and examiners often treat “irrespective of” functional results as an added limitation, not mere descriptive context.
- Design-around complexity: a competitor aiming to avoid infringement cannot rely solely on providing a lateral groove at some thickness transition; they must also control splitting mechanics so that the fracture follows the groove in both groove-up and groove-down orientations under the claimed supporting conditions.
What is arguably not explicitly required in Claim 1
Claim 1 does not specify:
- groove “V-shaped,” “rectangular,” or depth-to-thickness numeric ratios;
- excipients, drug identity, dose strength, or film coating;
- manufacturing method (compression, tooling, laser scoring);
- any specific material properties (brittleness, hardness, binder system).
So the protection, as written, is device/structure + fracture behavior, not a formulation-specific process.
How broad are Claim 1 limitations: are the concavities required to be mirror images, or just equal and parallel-axis?
Answer: Claim 1 requires each concavity to be equal in size, with parallel major and minor axes, but it does not require identical shapes for the two concavities except as implied by “first” being smooth uninterrupted arcuate and “second” containing the breaking groove at an apex.
Equal-size concavities and “parallel axes”
- “Equal in size” suggests geometric congruence in at least one dimension or overall volumetric/area sense.
- “Parallel major and minor axes” ties to an ellipse-like definition. That can matter in infringement if a competitor uses a concavity with different axis alignment.
First concavity smooth uninterrupted arcuate surface
- Claim 1 gives explicit detail for the first concavity: the surface is smooth and uninterrupted and arcuate, extending between opposite longitudinal ends.
- That is not expressly said for the second concavity, though the second concavity contains the breaking groove, which would inherently introduce a discontinuity.
Second concavity has the breaking groove at its apex
- The groove is formed “in” the second concavity.
- The groove is at an apex: the apex is the highest/lowest point (depending on face orientation) of the concavity.
Where is the breaking groove located and how does it drive infringement risk?
Answer: The breaking groove must extend laterally across the width at the apex of the second concavity, and the groove’s placement must be linked to a fracture outcome that occurs independent of groove orientation relative to the support.
Location constraints
- Lateral across width: not merely a partial score or centered indentation; it spans across the tablet width.
- At the apex of the second cavity: a groove positioned away from the apex is outside the claim.
Fracture mechanics as a claim limiter
The fracture requirement is not generic “the tablet is bisectable.” It is conditional on:
- downward pressure applied to one face;
- the opposing face is down against a support with opposite longitudinal ends resting on the surface;
- fracture occurs along the groove regardless of whether the groove faces toward or away from the support.
This can narrow infringement to tablets that split in the required three-dimensional setup. The “irrespective of” clause reduces escape routes based purely on flipping.
What does Claim 2 add: finite-uniform-thickness central body with frustoconical-like parts and groove depth from apex to a surface?
Answer: Claim 2 restricts the tablet to a central uniform-thickness body with smooth continuous perimeter and adds frustoconical-like top and bottom regions that house the concavities, plus a groove depth that extends from the concavity apex to one of the central body surfaces.
New geometry features in Claim 2
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Central body part of finite and uniform thickness
- Not varying thickness through the central region, by the claim’s definition.
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Uninterrupted smooth perimetrical surface
- Extends parallel to a theoretical line through the geometric center.
- The theoretical line is perpendicular to the support surface when longitudinal ends rest on the support.
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Upstanding frustoconical-like parts on each face
- Each top and bottom surface of the central body part has an upstanding frustoconical-like part.
- Each concavity is provided in each frustoconical-like part.
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Concavity depth less than highest height dimension of the frustoconical parts
- Ensures concavities do not cut all the way through the raised conical-like geometry.
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Breaking groove depth extends from apex to one top/bottom surface of central body part
- Groove depth is directly tied to reaching the surface of the central body part (not merely near it).
Practical effect on scope
Claim 2 becomes a “narrower sub-variant” claim. A competitor copying Claim 1 geometry but using a groove that does not extend to the surface of the central body part could fall outside Claim 2 while still potentially infringing Claim 1, depending on whether other limitations are met.
How to read the claim language for claim construction in litigation: which terms are structural vs functional?
Answer: Claim 1 contains both structural and functional limitations; “fracture along said breaking groove irrespective of…” is functional but tied to structural geometry, making it a potential focal point for infringement analysis.
Likely structural terms (high fidelity)
- elongated body (length > width)
- top/bottom surfaces
- concavities with parallel major/minor axes
- smooth uninterrupted arcuate surface (first concavity)
- thicker longitudinal ends than thickness at concavity apexes
- breaking groove laterally across width at apex of second cavity
Likely functional terms (outcome-based)
- tablet fractures along breaking groove when pressed in the specified orientation-and-support setup
- fracture occurs irrespective of whether groove faces toward or away from support surface
Infringement framing
- For product infringement, the geometry can be measured or imaged; the fracture outcome may be validated by splitting tests aligned to the claim scenario.
- A defendant may argue the claim requires both fracture location and orientation independence, which depends on how the test is done.
What patent landscape surrounds split-tablet geometry like US 4,735,805?
Answer: The surrounding landscape generally falls into scored/bisectable tablets with controlled fracture lines, including patents on groove placement, depth profiling, tablet shape transitions, and orientation-independent splitting.
Common competitor claim themes (industry-wide patterns)
Without naming specific patents (not provided), the landscape for this technology tends to include:
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Score line geometry
groove depth, width, and profile (V, U, rectangular) to force fracture.
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Asymmetric grooves
grooves not centered on a single apex or not symmetrically placed, often to change splitting characteristics depending on orientation.
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Different concavity/topography approaches
use of embossments, channels, or stress concentrators rather than concavities with equal size and parallel axes.
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Process-driven approaches
scoring via mechanical tooling or laser, or using material properties to achieve reliable breakability.
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Functional bisectability without the same structural anchors
claims that require “bisectable” and “fractures substantially along the score line” but may not include the explicit “irrespective of” orientation clause.
Where US 4,735,805 is a stronger reference
US 4,735,805’s combination of:
- equal-size concavities with parallel axes,
- an apex-anchored laterally spanning groove,
- plus the explicit orientation-independent fracture condition
makes it a more specific reference than broad “scored tablet” patents.
Where it may be vulnerable
If a later patent:
- keeps a groove but changes concavity architecture,
- removes or shifts apex alignment,
- alters thickness relationships at concavity apexes,
- or relies on orientation-dependent splitting
then it can create claim-space separation versus US 4,735,805.
Are there clear design-around vectors based on Claim 1 and Claim 2?
Answer: Yes. The limiting geometry and “irrespective” fracture behavior create multiple levers for noninfringing design.
Design-around vectors targeting Claim 1
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Move the groove away from the apex of the second concavity
- A groove not formed at the apex of the concavity likely misses a key locating limitation.
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Alter concavity “parallel axes” alignment or break “equal size”
- Using concavities of different size or different axis orientation can avoid the “equal in size” and “parallel major and minor axes” requirements.
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Remove the smooth uninterrupted arcuate surface on the first concavity
- Introducing interruptions or non-arcuate features on the first concavity can miss the explicit first-concavity limitation.
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Change the thickness relationship at concavity apexes
- If longitudinal ends are not thicker than thickness at concavity apexes, Claim 1 may not read.
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Make fracture orientation-dependent
- If splitting fails or fractures away from the groove when the groove is inverted relative to the support, the “irrespective of whether…” clause is not met.
Design-around vectors targeting Claim 2
- Avoid a uniform-thickness central body part with the claimed frustoconical-like regions.
- Alter groove depth so it does not extend from the apex of the second concavity to one of the central body surfaces.
What would an infringement claim analysis likely focus on for US 4,735,805?
Answer: A plaintiff’s infringement case would likely be built around (i) geometric mapping of concavities and groove placement and (ii) splitting tests performed under the specified pressure/support orientation.
Likely evidence categories
- Tablet cross-sections showing concavity geometry, apex location, and groove depth.
- Dimensional drawings or CT/microscopy images confirming:
- length greater than width,
- concavity axis parallelism,
- equal concavity size (as measurable),
- thickness at longitudinal ends vs concavity apexes.
- Controlled breakability testing matching the claim’s setup:
- downward pressure to one face,
- opposite face facing downward,
- opposite longitudinal ends resting on support surface,
- compare outcomes with groove facing toward vs away from support.
Likely defenses
- Dispute geometry mapping: apex identification, axis measurement, equal size criteria.
- Dispute the “fracture along said breaking groove” outcome under the claim setup.
- Argue the orientation-independent requirement is not met for the accused product.
Key Takeaways
- Claim 1 protects an elongated bisectable tablet defined by top and bottom concavities with equal size and parallel axes, plus an apex-anchored laterally spanning breaking groove that produces fracture along the groove regardless of groove orientation relative to the support surface.
- Claim 2 narrows to a uniform-thickness central body with uninterrupted perimeter, frustoconical-like raised portions containing concavities, and a groove depth that reaches from the apex to a central-body surface.
- Design-around paths are most direct where competitors can change: groove-to-apex alignment, concavity axis/size relationships, the smooth arcuate requirement, the thickness relationship at concavity apexes, and especially the orientation-independent fracture behavior.
- Landscape relevance: US 4,735,805 sits in the scored/bisectable tablet niche but is more specific than generic “scored tablet” patents because it anchors the mechanism in a tight geometry + orientation outcome.
FAQs
- What fracture standard does US 4,735,805 require, and how is “along said breaking groove” interpreted?
- Does Claim 1 require the two concavities to be mirror-image, or only equal size with parallel axes?
- Can a tablet with a groove spanning the width but not located at the concavity apex infringe Claim 1?
- How does Claim 2’s “groove depth extends from said apex… to one of said top and bottom surfaces” affect noninfringement strategy?
- What test setup best corresponds to the claim’s orientation-independent fracture limitation for enforcement or freedom-to-operate work?
References
- United States Patent 4,735,805, “Bisectable drug tablet,” claims 1-2 (text provided).
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