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Patent landscape, scope, and claims: |
United States Patent 6,077,836: Scope, Claim Architecture, and Patent Landscape
What does US 6,077,836 cover?
US Patent 6,077,836 covers aqueous peritoneal dialysis compositions in which an osmotic agent is a specific water-soluble starch-hydrolysate glucose polymer mixture defined by molecular weight, composition of higher-DP glucose polymers, and (for composition claims) dialysate osmolality and optional electrolyte and additive ranges. The claims also include a separate composition claim to the glucose polymer mixture itself.
1) Core invention and claim strategy
US 6,077,836 is structured to capture (i) the dialysate product and (ii) the intermediate osmotic agent that drives osmotic performance.
Claim set overview
This creates a landscape where generic substitutes can be designed to avoid the literal glucose-polymer definition (DP profile and molecular weight band) while still aiming for similar tonicity in peritoneal dialysis.
2) Claim-by-claim scope (literal elements and practical design-around pressure)
Claims 1–2: the dialysate “open” anchor
Claim 1 (aqueous peritoneal dialysis composition)
Key required elements:
- Sterile and pyrogen-free
- Intended use: introduction into abdominal cavity for dialysis across peritoneal membrane
- Osmotic agent: water soluble glucose polymer mixture derived from starch hydrolysis
- At least 36.7% by weight of glucose polymers with D.P. > 12 glucose units
- Osmolality: about 265 to 378 mOsm/kg
- DP/MW banding not mandatory in Claim 1, but Claim 1 has the D.P. > 12 requirement and osmolality constraint.
- Claim 1 does reference DP > 12 as a composition threshold; Claim 2 adds explicit MW.
Claim 2 (aqueous peritoneal dialysis composition; tighter MW)
All elements of Claim 1, plus:
- Average molecular weight: 15,000 to 25,000
Practical implication for scope
- The decisive technical “gate” is not generic glucose polymers; it is the starch-hydrolysate-derived glucose polymer mixture with a minimum fraction of DP > 12 and, for Claim 2, an explicit average MW band.
- Osmolality 265–378 mOsm/kg narrows tonicity targets and blocks some otherwise similar osmotic agents if formulated outside that osmolality.
Claims 3–7: tightening the MW and DP weight fractions
- Claim 3: average molecular weight 18,000 to 22,000 (narrows Claim 1/2)
- Claim 4: glucose polymer mixture contains > 50% by weight of glucose polymers with D.P. > 12
- Claim 5: 50 to 90% by weight with D.P. > 12
- Claim 6: 75 to 100% by weight with D.P. > 12
- Claim 7: 90 to 100% by weight with D.P. > 12
Design-around pressure
- A substitute supplier can aim to lower the fraction of DP > 12 polymers below these thresholds, but the claims are arranged so multiple dependent positions still trap a broad center of “high-DP” mixtures:
- Minimum threshold is already 36.7% (Claim 1/2),
- Dependent claims push upper bands >50%, with ranges up to 90–100%.
Claims 8–12: dialysate concentration bands
- Claim 8: glucose polymer mixture 2 to 10% w/v
- Claim 9: 2 to 4% w/v
- Claim 11: 2 to 15% w/v
- Claim 12: 2 to 5% w/v
Interpretation for enforcement
- These claims bound the amount of osmotic agent in the dialysate.
- Even if a polymer mixture meets DP and MW requirements, formulation concentration outside these windows can avoid the dependent claim space (but not necessarily Claim 1/2 unless the dependent claim is asserted and Claim 1/2 are also avoided).
Claim 10: glucose impurity
- Claim 10: glucose polymer mixture contains less than 3% by weight of glucose
Implication
- This limits formulations where extensive dextrose formation occurs during hydrolysis.
- A designer can reduce “free glucose” content or select processing that changes the hydrolysis endpoint to remain below 3%.
Claim 13: starch linkage purity
- Claim 13: starch contains not more than 5% of 1,6-linkages
Implication
- This ties back to starting material starch chemistry (amylopectin branching via α-1,6 linkages).
- It narrows the “derived from hydrolysis of starch” concept by constraining the starting starch phenotype, not just the endpoint polymer.
Claim 14: electrolyte composition constraints
- Sodium: 116 to 145 mEq/L
- Calcium: 0 to 6 mEq/L
- Chloride: 90 to 144 mEq/L
- Magnesium: 1 to 2 mEq/L
Enforcement impact
- This claim captures dialysates engineered with particular ionic strengths.
- A generic competitor could avoid Claim 14 while still meeting Claims 1–13, but that would not eliminate exposure under independent claims.
Claim 15: optional nitrogenous additives
- 0.5 to 25 g/L amino acid salts or protein hydrolyzates
Scope
- Captures nitrogen supplementation variants of the core osmotic dialysate.
3) Claims 16–22: independent coverage of the glucose polymer mixture
These claims isolate the osmotic agent as a standalone product.
Claim 16: mixture definition
A water soluble glucose polymer mixture with:
- average molecular weight 15,000 to 25,000
- derived from hydrolysis of starch
- contains at least 36.7% of glucose polymers with D.P. > 12
Claims 17–21: tighter MW and DP distribution
- Claim 17: MW 18,000 to 22,000
- Claim 18: >50% by weight with D.P. > 12
- Claim 19: 50 to 90%
- Claim 20: 75 to 100%
- Claim 21: 90 to 100%
Claim 22: linkage purity
- starch contains not more than 5% of 1,6-linkages
Why this matters for the landscape
- Even if a competitor reformulates electrolytes or dialysate osmolality, product-formulation circumvention can fail if they still buy or make a glucose polymer mixture that falls within Claims 16–22.
- This is the classic “intermediate capture” strategy: lock in the key upstream ingredient definition.
4) Scope map: what is captured vs what can be avoided
Literal capture (must-have elements)
For dialysate (Claims 1/2):
- peritoneal dialysis aqueous composition, sterile and pyrogen-free
- osmotic agent is a starch-hydrolysate-derived glucose polymer mixture
- minimum DP > 12 fraction: at least 36.7% by weight
- for Claim 1: osmolality about 265–378 mOsm/kg
- for Claim 2: average MW 15,000–25,000
For mixture (Claims 16–22):
- MW 15,000–25,000
- derived from starch hydrolysis
- at least 36.7% by weight DP > 12
- optionally narrowed further by MW and DP distribution (Claims 17–21)
- starch starting material has ≤5% 1,6-linkages (Claim 22)
Key avoidance levers (where design-around can occur)
The claim language points to clear “escape hatches”:
- reduce fraction of DP > 12 polymers below the threshold for the relevant claim (under Claim 1/16 at least 36.7% must hold)
- shift average molecular weight outside 15,000–25,000 (avoid Claim 2/16 and all dependent MW-banded claims)
- adjust dialysate osmolality outside 265–378 mOsm/kg (avoid Claim 1)
- alter starting starch chemistry (above 5% 1,6-linkages) to avoid Claim 13/22
- change free glucose content to >=3% (avoid Claim 10)
- reformulate electrolytes or omit nitrogenous additives to avoid dependent Claim 14/15
5) Patent landscape: risk assessment framework for US 6,077,836
Because only the claims were provided, this analysis cannot enumerate other specific US or WO families without external record retrieval. The landscape assessment below is therefore scoped to claim-driven competitive exposure patterns rather than named-citation mapping.
How competitors can be exposed
Exposure increases if a competitor:
- sells a starch-derived glucose polymer osmotic agent with high-DP (>12) fractions
- formulates dialysate in 265–378 mOsm/kg and uses the same polymer
- buys the polymer as an ingredient (intermediate capture via Claims 16–22)
How competitors can reduce exposure
- select alternative osmotic agents (e.g., other polymers, small molecules, or mixtures not meeting DP > 12 thresholds)
- use starch feedstocks or processing that produces a mixture outside the MW window and/or DP > 12 fraction
- formulate tonicity and ions to avoid dependent composition claims (while still potentially remaining outside Claim 1/2/16).
Enforceability pressure points
- This patent ties to measurable polymer attributes (MW distribution, DP distribution by weight, free glucose %, and starch 1,6-linkage content).
- These are testable by standard polymer characterization approaches, making literal infringement evaluation feasible when analytical methods match the claim metrics.
6) Freedom-to-operate implications by segment
(A) Osmotic agent manufacturers
Most exposed if their product is:
- starch hydrolysate-derived glucose polymer mixture
- MW 15k–25k
- with ≥36.7% by weight of DP > 12
If they also have:
- starch feedstocks with ≤5% 1,6-linkages
they face direct exposure to Claims 16 and 22 even without final dialysate formulation.
(B) Dialysate formulators
Exposure depends on whether they buy polymers that fall into Claims 16–22 and whether the dialysate product aligns with Claim 1/2 constraints:
- osmolality 265–378 mOsm/kg (Claim 1)
- polymer MW 15,000–25,000 (Claim 2)
Dialysate formulators can reduce exposure by changing polymer selection or tonicity formulation, but intermediate capture claims create leverage against upstream supply.
(C) Product variants (electrolytes and nitrogen additives)
- Variants adding amino acid salts/protein hydrolyzates (0.5–25 g/L) can trigger Claim 15 if other elements align.
- Electrolyte tuning to the specified mEq/L ranges can trigger Claim 14.
7) Decision-grade conclusions on claim breadth
Breadth highlights
- The independent dialysate claims hinge on:
- DP > 12 fraction threshold (≥36.7% by weight)
- and, for Claim 1, osmolality (265–378 mOsm/kg)
- and, for Claim 2, average molecular weight (15,000–25,000)
Breadth limits
- The starch-derived origin is not fully open-ended: it is anchored to the starch-hydrolysis endpoint definition, plus dependent constraints:
- ≤5% 1,6-linkages of the starting starch (Claim 13/22)
- free glucose <3% (Claim 10)
- specific concentration windows of the polymer mixture (Claims 8–9/11–12)
Overall, the patent is moderately broad on polymer DP distribution, and narrower on MW/osmolality and starting-material linkage characteristics via dependent claims.
Key Takeaways
- US 6,077,836 claims starch-hydrolysate-derived glucose polymer mixtures with ≥36.7% by weight of glucose polymers having D.P. > 12, used as the osmotic agent in peritoneal dialysis.
- The independent dialysate claims require either osmolality (Claim 1) and/or average molecular weight 15,000–25,000 (Claim 2), in addition to the DP > 12 threshold.
- The patent also claims the glucose polymer mixture itself (Claims 16–22), enabling enforcement against upstream ingredient supply even when end-formulation differs.
- Dependent claims tighten the scope with MW 18,000–22,000, DP > 12 weight fractions (up to 90–100%), polymer concentration ranges, free glucose <3%, ≤5% 1,6-linkages in starch, and specified electrolyte and nitrogen additive ranges.
FAQs
1) What is the central technical requirement in US 6,077,836?
A glucose polymer mixture derived from starch hydrolysis with at least 36.7% by weight of glucose polymers having D.P. > 12.
2) Does the patent cover only dialysate products?
No. It also covers the glucose polymer mixture itself (Claims 16–22), including MW and DP distribution criteria.
3) Which claims are most relevant for dialysate tonicity?
- Claim 1 includes osmolality about 265–378 mOsm/kg.
- Claims 8–9 and 11–12 set polymer concentration ranges in the dialysate.
4) How can a competitor reduce infringement risk?
The clearest levers are to reformulate polymer selection or processing so the product is outside the claimed MW and/or the DP > 12 weight fraction thresholds, or to formulate tonicity outside Claim 1’s osmolality window.
5) What starting material characteristic is claimed?
Dependent claims constrain the starch feedstock: starch contains not more than 5% of 1,6-linkages (Claims 13 and 22).
References
- United States Patent US 6,077,836. Claims as provided in prompt.
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