United States Patent 4,225,596: Claim Scope, Practical Coverage, and US Landscape

What does US 4,225,596 claim, in plain claim-coverage terms?

US Drug Patent 4,225,596 claims a method for improving calcium absorption and retention in mammals with bone mass loss (or a tendency toward such loss). The method is defined by (i) the subject population phenotype and (ii) the active agent set, which is limited to specific vitamin D metabolites.

Core claim architecture (from the provided claim set)

Claim 1 (independent):
A method for increasing calcium absorption and retention in mammals showing evidence of, or physiological tendency toward, loss of bone mass, comprising internal administration (therapeutically effective amount) of at least one compound selected from:

1α-hydroxycholecalciferol
1α-hydroxyergocalciferol
1,25-dihydroxycholecalciferol
1,25-dihydroxyergocalciferol
1,24,25-trihydroxycholecalciferol

Claim 2 (dose limitation):
The therapeutically effective amount is about 0.1 microgram to about 1 microgram per day.

Claim 3 (formulation/route limitation):
Compound is administered in solution in an ingestible, nontoxic liquid vehicle, orally, in encapsulated form.

Claim 4 (female-specific timing post-menopause):
Administration is for women during and subsequent to menopause.

Claim 5 (female-specific timing pre-menopause):
Administration is for women prior to onset of menopause.

What the claim language does and does not cover

What is covered: internal administration methods using one of the listed vitamin D metabolites to increase calcium absorption and retention in mammals with bone loss risk or presence.
What is not expressly covered (based on the claim text provided):
- Other dosing ranges outside claim 2
- Other vitamin D analogs not in the enumerated list
- Non-oral routes (claim 3 narrows to oral encapsulated vehicle)
- Combination regimens are not stated as limitations (claim 1 requires “at least one compound selected from” the list; it does not exclude co-therapies, but they are not claim-defined)

Who is the target population and where is the infringement “hook”?

The infringement hook is the mammal with bone mass loss evidence or tendency toward such loss, combined with administration of one of the enumerated metabolites in a therapeutically effective amount.

Population scope (claims 1, 4, 5)

Claim 1: broad mammalian category, tied to the physiological condition (bone mass loss evidence or tendency).
Claims 4 and 5: narrowed to women with timing relative to menopause:
- claim 4: during and subsequent to menopause
- claim 5: prior to onset of menopause

Practical consequence for landscape mapping

Any competitor program that targets osteoporosis prevention or treatment via calcium retention using these same metabolites can fall into claim 1. If their product label or method protocol targets specific menopausal timing in women, they can additionally land inside claims 4 or 5.

How narrow is the chemical scope of the active ingredient?

The chemical scope is closed at the metabolite level: the claims list five specific compounds.

Included compounds (exactly as recited)

1α-hydroxycholecalciferol
1α-hydroxyergocalciferol
1,25-dihydroxycholecalciferol
1,25-dihydroxyergocalciferol
1,24,25-trihydroxycholecalciferol

Exclusion by omission

This matters for freedom-to-operate (FTO):

Vitamin D analogs outside this list (even if they also increase calcium absorption) do not fit claim 1’s enumerated compound set.
Even if an analog is functionally similar, the claims are written to require one of these metabolites.

What parts of the claims create tiered barriers for competitors?

Claims 2 to 5 add “stacked” restrictions. For infringement analysis, each dependent claim narrows scope further beyond claim 1.

Claim dependency and narrowing impact

Claim	Adds limitation type	Narrowing effect
1	Active metabolite set + bone loss phenotype + therapeutically effective amount	Establishes the core method category
2	Dose range: ~0.1 to ~1 microgram/day	Narrows to low-dose protocol
3	Oral encapsulated dosing; liquid vehicle; nontoxic ingestible vehicle	Narrows route and dosage form
4	Women during and after menopause	Narrows to post-/peri-menopause timing
5	Women prior to menopause	Narrows to pre-menopause timing

Operational inference

A generic or originator that uses one of the enumerated metabolites to improve calcium absorption/retention likely targets claim 1.
To avoid claim 1, a design-around usually must either:
- change the active to a metabolite not listed, or
- eliminate the “method” elements (which is hard because the method claim is outcome-targeted via the physiology condition).

How should this be mapped into a US patent landscape?

Landscape segmentation for actionable decision-making

Without file-history, maintenance, and claim interpretation documents in the prompt, the landscape can still be structured using the claim-defined axes that drive overlap:

Metabolite family competitors
- Programs involving the same vitamin D metabolites (enumerated list).
Menopause-timing indications
- Trials and labels focusing on peri-/post-/pre-menopausal women.
Dose-range protocols
- Regimens within ~0.1 to ~1 microgram/day.
Oral encapsulated liquid-vehicle administration
- Product designs that implement claim 3 (or avoid it).

What “overlap” typically looks like in this era of US filings

US vitamin D patent landscapes commonly cluster around:

method of use (bone loss/osteoporosis),
specific metabolites and dosing regimens,
route/formulation.

Given the claim language, overlap is most likely where a filing:

uses one of the exact metabolites in claim 1,
targets calcium absorption/retention outcomes (often measured via calcium balance),
and in women, targets pre- or peri-menopausal timing.

What is the realistic scope of enforceable claims versus typical product structures?

Enforceable breadth of claim 1

Claim 1 is broad in these respects:

it covers any mammal meeting the bone loss phenotype, not limited to a particular diagnostic label;
it covers oral or non-oral administration only indirectly (claim 1 says “administering internally”; claim 3 narrows oral encapsulated vehicle only for dependent coverage);
it covers “therapeutically effective amount” with no upper bound except in claim 2.

Dependent claim leverage

Claim 2 is particularly valuable in practice because many protocols use microgram-level dosing for these metabolites. Any protocol using within the stated range creates strong evidence of literal claim 2 alignment.
Claims 4 and 5 can be high-value when clinical protocols explicitly target menopausal timing. Many osteoporosis programs do, and that tends to create label- and study-driven infringement exposure.
Claim 3 is about formulation. It can matter most in situations where competing products use the same metabolite but with different routes (e.g., non-oral) or different dosage forms.

How does claim drafting affect design-around options?

Design-around paths visible from the claim set

1) Switch to a non-enumerated vitamin D analog
If the active is changed to something other than the five listed metabolites, claim 1’s active limitation is avoided.

2) Keep the active but avoid the “method” definition This is harder because claim 1 is outcome-driven through the “increasing absorption and retention” method and the bone-loss phenotype. Programs that still aim at calcium absorption/retention and treat/prevent bone mass loss are likely to remain within the claim logic.

3) Shift dose outside claim 2 If the protocol uses a dose outside ~0.1 to ~1 microgram/day, claim 2 avoidance is possible. Claim 1 remains, so this is only a partial shield.

4) Avoid oral encapsulated vehicle This can potentially avoid claim 3, but not claim 1.

5) Avoid menopausal timing indications Labeling and studied populations that avoid claim 4 and claim 5 may reduce dependent claim exposure, but claim 1 remains for the general bone loss method.

Where are the main infringement risk zones for generic or follow-on products?

Risk is concentrated where a competitor:

uses one of the enumerated metabolites,
targets calcium absorption and retention improvement,
treats/prevents bone loss,
and in women, uses menopausal-timing protocols.

Claim mapping to common development decisions

Development decision	If it matches claim language, risk increases
Active ingredient choice	Must be one of the listed metabolites to reach claim 1
Endpoint selection	Calcium absorption/retention is aligned with the method
Intended population	Mammals with bone mass loss evidence or tendency
Dose protocol	Within 0.1 to 1 microgram/day increases claim 2 risk
Route/form	Oral encapsulated liquid vehicle increases claim 3 risk
Labeling and study inclusion	Women during/subsequent or prior to menopause increases claim 4/5 risk

What is missing to build a full US prosecution and validity landscape?

A complete patent landscape requires: bibliographic details (assignee, filing date), claim construction, prosecution history, and whether the patent is still in force or has been invalidated/limited. Those inputs are not included in the prompt, so the analysis above focuses strictly on claim scope and the landscape axes that determine overlap.

Key Takeaways

US 4,225,596 is a method-of-use patent centered on increasing calcium absorption and retention for mammals with bone mass loss evidence or tendency via administration of one of five enumerated vitamin D metabolites.
Claim 1 drives broad coverage through the metabolite list and the bone-loss phenotype plus therapeutically effective dosing.
Dependent claims add meaningful narrowing levers: dose (~0.1 to ~1 microgram/day), oral encapsulated liquid vehicle, and women by menopausal timing (pre-menopause; during and after menopause).
Landscape overlap is most likely among filings that (i) use the same metabolite family, (ii) pursue calcium retention/absorption outcomes for bone loss, and (iii) specify menopausal timing and/or microgram dosing.

FAQs

1) Does claim 1 require a specific disease label like osteoporosis?
No. Claim 1 requires mammals showing evidence of, or physiological tendency toward, loss of bone mass.

2) Is the active ingredient scope open-ended?
No. Claim 1 is limited to at least one compound from the explicitly listed vitamin D metabolites.

3) Can a competitor avoid claim 2 by using a slightly higher or lower dose?
Claim 2 is limited to about 0.1 to 1 microgram/day; avoiding that range can avoid claim 2, but claim 1 can still apply.

4) Does claim 3 require oral dosing?
Yes. Claim 3 narrows to orally administered encapsulated dosing with a solution in an ingestible nontoxic liquid vehicle.

5) Are women’s indications central to the broad claim?
Women are specifically recited only in dependent claims 4 and 5; the broadest coverage in claim 1 is mammalian and condition-based.

References

[1] United States Drug Patent 4,225,596 (claims provided in prompt).

Details for Patent: 4,225,596

Summary for Patent: 4,225,596