Scope, claims, and US patent landscape for US Drug Patent 10,328,037
US Patent 10,328,037 is directed to methods of treating cystinosis using an oral cysteamine bitartrate composition with tightly defined impurity controls and storage/handling temperature regimes. The patent’s enforceable scope is driven less by the active drug itself and more by (i) specific degradant/impurity thresholds, (ii) mandated stability windows, and (iii) storage conditions pre- and post-dispensing, including humidity for extended temperature exposure.
What is the core claim theme in 10,328,037?
The independent claim set (claims 1, 7, 13, 19) all use the same structural template:
- Indication: treating cystinosis in a subject in need.
- Dosing: twice daily administration of an oral pharmaceutical composition comprising cysteamine bitartrate.
- Impurity/degradant limits: each independent claim substitutes a different impurity species with a strict “less than” threshold.
- Two-stage storage:
- Pre-dispensing storage by manufacturer/distributor/pharmacy/hospital at 2° C to 8° C.
- Post-dispensing storage by the patient at 20° C to 25° C.
- Optional dependent claim layer: enteric coating formulation using poly(methacrylic acid co-ethyl acrylate) 1:1.
This yields a “stability-qualified dosing method” that is likely to be infringed by actors who ensure (or advise) patient storage practices consistent with the claimed ranges and time windows.
What does each independent claim cover? (scope mapping)
Claim 1: 2-hydroxythiomorpholine impurity controlled
- Treat cystinosis
- Twice daily oral dosing; composition comprises cysteamine bitartrate
- Contains 2-hydroxythiomorpholine in amount < 0.5% relative to cysteamine bitartrate
- Pre-dispensing storage: 2° C to 8° C
- Post-dispensing storage: 20° C to 25° C
Claim 7: cystamine impurity controlled
- Treat cystinosis
- Twice daily oral dosing; composition comprises cysteamine bitartrate
- Contains cystamine amount < 4% relative to cysteamine bitartrate
- Pre-dispensing: 2° C to 8° C
- Post-dispensing: 20° C to 25° C
Claim 13: cystamine tartrate amide impurity controlled
- Treat cystinosis
- Twice daily oral dosing; composition comprises cysteamine bitartrate
- Contains cystamine tartrate amide amount < 0.5% relative to cysteamine bitartrate
- Pre-dispensing: 2° C to 8° C
- Post-dispensing: 20° C to 25° C
Claim 19: 2-hydroxymethylthiazolidine impurity controlled
- Treat cystinosis
- Twice daily oral dosing; composition comprises cysteamine bitartrate
- Contains 2-hydroxymethylthiazolidine amount < 0.05% relative to cysteamine bitartrate
- Pre-dispensing: 2° C to 8° C
- Post-dispensing: 20° C to 25° C
Implication for scope: different commercial products (or different manufacturing lots/formulations) can fall into different “impurity baskets.” A product could avoid infringement of claim 1 but still infringe claim 7, for example, if cystamine is above/below the defined limit.
What dependent claims narrow further (enteric coating and stability windows)?
Enteric coating limitation (claims 2, 8, 14, 20)
Each independent claim has a corresponding dependent claim that adds:
- Oral composition further comprises an enteric coating
- Enteric coating comprises poly(methacrylic acid co-ethyl acrylate) 1:1
Scope impact: this is not a generic “enteric coating” claim; it locks to a specific polymer composition ratio, tightening infringement pathways for competitors who use different enteric polymers.
Stability window: pre-dispensing at 2° C to 8° C up to 15 months (claims 3, 9, 15, 21)
Adds:
- Impurity limit remains satisfied when stored at 2° C to 8° C for a period of up to 15 months
Scope impact: a manufacturer can potentially meet impurity spec initially but fail if accelerated storage or extended cold storage leads to higher degradant formation. This claim makes long-term qualification part of the method.
Two-step aging: subsequent humidity-controlled storage at 25–30° C for up to 3 months (claims 4–6, 10–12, 16–18, 22–24)
Across each impurity series, three variants are used:
- Up to 3 months at 25° C and 60% RH (e.g., claims 4, 10, 16, 22)
- Up to 3 months at 30° C and 65% RH (e.g., claims 5, 11, 17, 23)
- Up to 3 months at 30° C and 70% RH (e.g., claims 6, 12, 18, 24)
Scope impact: these dependent claims target real-world patient storage “excursions,” anchoring infringement to stability behavior under defined stress conditions.
What impurities and thresholds control infringement? (quantitative matrix)
Below is the direct mapping from claim to impurity identity and numeric limit, as stated:
| Claim family (independent) |
Impurity / degradant specified |
Threshold (relative to cysteamine bitartrate) |
Time/condition qualifiers in dependent claims |
| Claim 1 |
2-hydroxythiomorpholine |
< 0.5% |
Up to 15 months at 2–8° C (claim 3); then up to 3 months at 25° C/60% RH (4) or 30° C/65% RH (5) or 30° C/70% RH (6) |
| Claim 7 |
cystamine |
< 4% |
Same structure: (9) up to 15 months at 2–8° C; then (10–12) up to 3 months at the three RH/temperature sets |
| Claim 13 |
cystamine tartrate amide |
< 0.5% |
Same structure: (15) up to 15 months at 2–8° C; then (16–18) up to 3 months at the three RH/temperature sets |
| Claim 19 |
2-hydroxymethylthiazolidine |
< 0.05% |
Same structure: (21) up to 15 months at 2–8° C; then (22–24) up to 3 months at the three RH/temperature sets |
Key point: the thresholds differ by impurity. The tightest is 2-hydroxymethylthiazolidine < 0.05%, and the loosest is cystamine < 4%. A formulation strategy can target one impurity pathway without necessarily curing the others.
How does storage temperature define claim coverage?
Pre-dispensing (manufacturer/distributor/pharmacy/hospital)
All independent claims require the composition is stored at:
- Between about 2° C and about 8° C prior to dispensing
This range resembles controlled refrigeration conditions. The method claim is written to cover the product’s chain-of-custody storage conditions, so label instructions and distribution practice become relevant.
Post-dispensing (patient storage)
All independent claims require:
- After dispensing, stored at between about 20° C and about 25° C
Extended stability method overlays
Dependent claims 4–6 and 10–12 and 16–18 and 22–24 add:
- Up to 3 months at specific higher temperatures and RH levels:
- 25° C / 60% RH
- 30° C / 65% RH
- 30° C / 70% RH
Practical landscape effect: a competitor can change stability instructions, packaging, or shelf-life testing conditions to avoid mapping to the claimed method steps. If the product label directs storage outside the claimed ranges, the likelihood of method infringement decreases because the method requires the specific storage post-dispensing.
Where does the enforceable “method” actually bite? (actors and steps)
Because these are method-of-treatment claims, enforcement typically targets a chain of events corresponding to:
- A prescriber or pharmacist initiates the dosing regimen.
- The product is dispensed with required handling conditions.
- The patient stores and uses the product under the claimed conditions.
- The oral composition’s impurity profile meets the “less than” constraints.
The claim language includes who stores the drug pre-dispensing (manufacturer/distributor/pharmacy/hospital). This makes it more than a purely patient-behavior claim.
How broad is the claim scope versus typical cysteamine formulations?
Breadth drivers
- Active: cysteamine bitartrate (not a specific particle size, salt form variant beyond bitartrate, or exact dosage amount).
- Dosing: twice daily (no mg strength specified in the provided claims).
- Pre- and post-dispensing temperature windows are standard-ish: refrigerated 2–8° C and room-ish 20–25° C.
Breadth limiters
- The impurity thresholds are tightly defined and impurity-specific.
- Dependent claims lock additional constraints:
- specific enteric polymer ratio: poly(methacrylic acid co-ethyl acrylate) 1:1
- explicit time windows: up to 15 months at 2–8° C and up to 3 months at the higher stress conditions.
Net effect: the broadest method boundary is the impurity identity plus threshold. The more the competitor’s formulation and stability data show different impurity behavior, the more the patent becomes a formulation- and label-driven risk question.
US patent landscape: how 10,328,037 typically positions within the cystinosis oral cysteamine space
Even without external family citations in the provided record, the claim architecture indicates a common landscape pattern in specialty generics and lifecycle management for oral cysteamine:
- Base active coverage (older patents, likely earlier in time) usually covers cysteamine compositions and use for cystinosis.
- Later lifecycle patents target:
- stability under real-world storage
- impurity control strategies during shelf-life
- enteric protection and related polymer systems
- packaging and patient handling instructions
US 10,328,037 clearly sits in the lifecycle bucket: it focuses on degradant impurity limits tied to defined storage conditions, and on an enteric coating polymer.
Competitive “design-around” levers implied by the claims
Because the claim differentiates by:
- impurity species and threshold,
- storage temperatures/RH,
- enteric polymer ratio,
a competitor can attempt to design around by changing any of those. The most direct levers are:
- reduce or shift impurity species formation away from the listed impurities (and keep within the listed thresholds)
- set different storage instructions that do not match 20–25° C or the dependent humidity stress points
- use a different enteric polymer system (not poly(methacrylic acid co-ethyl acrylate) 1:1)
Claim-by-claim infringement risk logic (operational checklist)
For commercialization planning, the relevant “go/no-go” checks map to claim elements:
A. Is the product cysteamine bitartrate and dosed twice daily for cystinosis?
If not, these method claims are off-target.
B. Do the formulation impurity specs meet the claim thresholds?
- 2-hydroxythiomorpholine < 0.5% (claim 1 and its dependent chain)
- cystamine < 4% (claim 7 chain)
- cystamine tartrate amide < 0.5% (claim 13 chain)
- 2-hydroxymethylthiazolidine < 0.05% (claim 19 chain)
C. Does chain-of-custody storage match the two-stage scheme?
- 2–8° C prior to dispensing
- 20–25° C after dispensing
D. Do stability protocols demonstrate impurity compliance after the specified stress exposures?
- Up to 15 months at 2–8° C with impurity limits maintained
- Then up to 3 months at either:
- 25° C/60% RH
- 30° C/65% RH
- 30° C/70% RH
E. If enteric coating is used, is it the specified polymer ratio?
- poly(methacrylic acid co-ethyl acrylate) 1:1 (claims 2/8/14/20)
Key Takeaways
- US 10,328,037 enforces a method-of-use for twice-daily oral cysteamine bitartrate treatment of cystinosis with impurity-specific thresholds and two-stage storage conditions.
- The enforceable “distinguishing feature” is not dosing or indication alone; it is the combination of:
- impurity identity and numeric limits,
- pre-dispensing refrigeration 2–8° C,
- post-dispensing storage 20–25° C, plus
- dependent stability windows up to 15 months and further impurity compliance after 3 months at 25° C/60% RH or 30° C/65% RH or 30° C/70% RH.
- Dependent enteric claims require a specific polymer: poly(methacrylic acid co-ethyl acrylate) 1:1, tightening scope for formulation variants that use other enteric systems.
- In the cystinosis oral cysteamine landscape, this patent reads like a lifecycle stability/impurity and label-handling barrier that shifts competitive risk toward stability data, impurity profiling, and patient storage instructions.
FAQs
1) What is the single most important element for claim coverage in 10,328,037?
The impurity limit plus identity (the specified degradant at a specified “less than” percentage) tied to the claimed storage conditions.
2) Do the claims require a specific dosage strength of cysteamine bitartrate?
No dosage strength is stated in the provided claim text. The claims require twice-daily administration of an oral composition comprising cysteamine bitartrate.
3) How do humidity and higher temperatures affect the claims?
Dependent claims add specific post-dispensing stress conditions for up to 3 months (25° C/60% RH; 30° C/65% RH; 30° C/70% RH) under which the impurity limits must remain satisfied.
4) Does the enteric coating requirement apply in all claims?
No. Enteric coating appears only in dependent claims (2, 8, 14, 20) tied to the polymer composition ratio poly(methacrylic acid co-ethyl acrylate) 1:1.
5) Can a product fall into the scope via a single impurity pathway?
Yes. Because there are separate independent claim families for different impurities, meeting the claimed storage and dosing conditions with an impurity exceeding the relevant threshold can create risk even if other impurity pathways differ.
References
- US Patent 10,328,037 (claim text provided in user prompt).
