Scope, Claims, and Patent Landscape for US Drug Patent 9,937,132
US Patent 9,937,132 claims a dual-release oral dosage form and a method of use for treating nausea and vomiting, with the core claim directed to a controlled release timing relationship between immediate-release (IR) and delayed-release (DR) fractions of doxylamine and pyridoxine.
What is the claimed invention scope in US 9,937,132?
Claim center of gravity: dual-release timing within GI tract
Independent claim 1 requires a method in which a patient receives a dual-release oral dosage form containing:
- Immediate release composition (IR) with:
- doxylamine and/or pharmaceutically acceptable salt: 5 to 20 mg
- pyridoxine and/or pharmaceutically acceptable salt: 5 to 20 mg
- Delayed release composition (DR) with:
- doxylamine and/or pharmaceutically acceptable salt: 5 to 20 mg
- pyridoxine and/or pharmaceutically acceptable salt: 5 to 20 mg
- Total per dosage form:
- doxylamine: 10 to 30 mg
- pyridoxine: 10 to 30 mg
- Timing condition (the limiting feature):
- IR releases before the DR fraction releases
- specifically, IR begins “prior to release” of the corresponding doxylamine and pyridoxine from the DR component within the gastrointestinal tract.
This claim is a formulation-and-regimen patent, not a pure use patent. The legal scope is anchored to (i) the partition of actives across IR and DR parts, and (ii) the order/timing of release.
Intended patient population and condition
Claims 2 ties the use to pregnant women with NVP (nausea and vomiting of pregnancy).
Medication specificity and salts
Dependent claims narrow to:
- doxylamine succinate (claims 7 and 8)
- pyridoxine hydrochloride (claims 9 and 10)
So the patent scope includes the general “doxylamine/pyridoxine and salts” framing, with fallback embodiments for specific salts.
Dosage sub-ranges (narrowing dependent claim set)
Independent claim 1 uses broad ranges (5–20 mg within each fraction; 10–30 mg total). Dependent claims carve preferred sub-ranges:
- Doxylamine per dosage form: 10–20 mg (claim 3)
- Doxylamine: 20 mg (claim 4)
- Pyridoxine per dosage form: 10–20 mg (claim 5)
- Pyridoxine: 20 mg (claim 6)
Structural embodiments: multi-part coating architecture
Claims 11–15 add a specific dosage form structure:
- Core comprises delayed release composition
- Delayed release coating substantially surrounding the core
- One or more additional coats substantially surrounding the delayed release coating
- The additional coats comprise the immediate release composition
Dependent claim details further specify:
- one or more coats include first coat and second coat (claim 12)
- possible assignment of actives to coat layers:
- claim 13: first coat includes doxylamine; second coat includes pyridoxine
- specific mg assignments and an enteric coating:
- claim 14:
- core: 5–15 mg doxylamine succinate + 5–15 mg pyridoxine hydrochloride
- DR coating: enteric coating
- additional coats: 5–15 mg each component
- claim 15 (concrete layout):
- core: 10 mg doxylamine succinate + 10 mg pyridoxine hydrochloride
- first coat: 10 mg pyridoxine hydrochloride
- second coat: 10 mg doxylamine succinate
Administration regimen
Claims 16–21 constrain administration conditions and dosing frequency:
- fasted conditions (claim 16)
- fed conditions (claim 17)
- once daily to three times daily (claim 18)
- twice daily (claim 19), and corresponding dependent relationships (claims 20–21)
What do the claims legally cover (and what they don’t)?
What they cover (positive scope)
US 9,937,132 covers methods where:
- The product is a single oral dual-release dosage form with both actives in both IR and DR portions, each at defined mg ranges.
- IR release begins before DR release for each active pair inside the GI tract.
- The method targets nausea and vomiting, with pregnancy/NVP use expressly claimed.
If a competitor makes a delayed-release system but does not include an IR fraction that releases before the DR fraction, claim 1 is not met as written.
If a competitor includes both doxylamine and pyridoxine but does not partition them into IR vs DR compositions (as claimed), it is likely outside claim 1.
What they do not cover (negative inference from claim text)
Based on the claim language provided, the patent does not rely on:
- fixed dissolution rate models or specific polymer chemistries (those would appear in the specification/other claims; only coating architecture is claimed in dependent claims)
- parenteral routes
- alternative active combinations beyond doxylamine/pyridoxine
The independent claim is not limited to enteric coatings; enteric coatings arise in claim 14. Still, entering an enteric architecture is a key design vector that falls within dependent claim coverage.
How broad are the dose ranges and which ranges matter most for infringement risk?
Dose range logic
Claim 1 defines two nested level structures:
- Per fraction (IR and DR each): doxylamine 5–20 mg, pyridoxine 5–20 mg
- Total per dosage form: doxylamine 10–30 mg, pyridoxine 10–30 mg
This means a design that changes either:
- the IR mg allocation outside 5–20 mg, or
- the DR mg allocation outside 5–20 mg, or
- the total dose outside 10–30 mg
can step outside claim 1, even if release order remains.
High-signal dependent claim “strike zones”
Dependent claims create narrower landing zones that are easier to design to and easier to police:
- 20 mg doxylamine (claim 4) and 20 mg pyridoxine (claim 6)
- core/coating concrete mg layout:
- core: 10 mg each
- IR coats: 10 mg pyridoxine in one coat and 10 mg doxylamine in the other (claim 15)
A product that matches those allocations and uses an enteric DR coating approach can fall into the narrowest embodiments.
What is the formulation landscape implied by the claim structure?
The claims indicate a market design theme common to NVP therapy patents: use of doxylamine + pyridoxine with layered release.
Claim-anchored formulation archetypes
From the claim set, there are two practical technical archetypes:
-
General dual-release architecture (claim 1):
- IR composition exists and releases first
- DR composition releases later
- both actives are present in both fractions
-
Layered coating architecture with DR core and enteric coating (claims 11, 14, 15):
- delayed release coating around a core
- additional outer coats with IR composition
- specific coat-by-coat active allocations in claim 15
How should competitors map their design-around strategy against these claims?
The goal is to alter at least one material element of claim 1’s limitations:
Design-around axes tied directly to claim language
- Break the IR-before-DR timing relationship
- If IR does not begin prior to DR release inside the GI tract, claim 1’s ordering limitation is undermined.
- Change the dose partitioning
- Move doxylamine and/or pyridoxine out of IR and/or DR 5–20 mg ranges.
- Move totals outside 10–30 mg.
- Remove IR from one of the actives
- Claim 1 requires IR composition includes both doxylamine and pyridoxine (and likewise DR includes both). Excluding one active from IR could avoid literal coverage.
- Avoid the multi-coat architecture
- Claims 11–15 impose specific structural requirements. A product that meets claim 1 but avoids those exact layered coatings may still face independent claim 1 exposure, but avoids dependent claim embodiments.
Regiment-level risk
Claims 16–21 add narrower method-of-use constraints. A competitor can still fall within claim 1 even if regimen differs, but could avoid the dependent claim family if regimen conditions differ (fasted vs fed; dosing frequency).
What does this mean for the patent landscape (freedom-to-operate view)?
Patent scope implications for the NVP fixed-dose combination field
US 9,937,132 sits at the intersection of:
- fixed combination therapy: doxylamine + pyridoxine
- release timing differentiation: immediate-first vs delayed-second within the GI tract
- dual-release partitioning: both actives in both IR and DR components
This makes it relevant not only to products using the same actives, but also to products that use layered release mechanisms that try to extend duration or shift exposure.
Landscape segmentation by claim type
Within a typical branded or generic landscape for NVP combination products, patents often cluster by:
- compound selection (doxylamine/pyridoxine combination)
- formulation release profile (modified/enteric/release timing)
- administration regimen and patient group
US 9,937,132 is most directly in the formulation release profile and method-of-use segments.
Practical conclusion for investors/R&D leads
If a candidate product uses:
- dual-release
- with IR beginning before DR release
- and includes both actives in both IR and DR partitions at roughly the claimed dose ranges
it is the most exposed to US 9,937,132.
If instead a product uses:
- single-release (IR only or DR only)
- a release model that does not satisfy the “prior to release” relationship
- different total or partition dose ranges
- different active partitioning across IR/DR fractions
it is less likely to meet the independent claim as drafted.
Claim-by-claim structure map (quick reference)
| Claim |
Coverage type |
Key limitations |
| 1 |
Independent method |
Dual-release oral dosage; IR and DR each contain doxylamine and pyridoxine in 5–20 mg ranges; totals 10–30 mg each; IR begins prior to DR release of both actives in GI tract |
| 2 |
Dependent |
Pregnancy woman; NVP |
| 3–6 |
Dependent dosage narrowing |
doxylamine 10–20 mg / 20 mg; pyridoxine 10–20 mg / 20 mg |
| 7–10 |
Dependent salt narrowing |
doxylamine succinate; pyridoxine hydrochloride |
| 11–13 |
Dependent structure |
Core with DR comp; DR coating; one or more outer coats with IR comp; coat-by-coat active assignment |
| 14–15 |
Dependent structural + numeric |
enteric coating; specific mg ranges and specific 10 mg allocations; specific outer coat assignment in claim 15 |
| 16–17 |
Dependent regimen |
fasted vs fed |
| 18–21 |
Dependent dosing frequency |
once daily to three times; twice daily |
What can be inferred about enforceability and claim stress points?
Stress points for literal infringement
The claim language has several explicit numerical and relational elements. Those are typically where infringement fights concentrate:
- mg range boundaries (5–20, 10–30)
- presence of both actives in both IR and DR fractions
- IR release begins prior to DR release within GI tract
- specific architecture in dependent claims (DR core and coatings; enteric coating; coat order assignments)
Stress points for validity challenges
Without the full prosecution history or prior art citations, it is not possible to map novelty/nonobviousness directly to a reference set. What can be extracted from the claim text is that the patent leans heavily on a release-timing and dosage partition strategy rather than novel chemical entities.
Key Takeaways
- US 9,937,132 claims a method for NVP using a single dual-release oral dosage form containing both doxylamine and pyridoxine in both IR and DR portions.
- The decisive limitation is that IR begins release in the GI tract before DR begins release for the same actives.
- Independent claim 1 uses broad ranges (5–20 mg per fraction; 10–30 mg totals), while dependent claims add high-specificity embodiments: doxylamine succinate, pyridoxine hydrochloride, enteric coating, and concrete 10 mg per component coat/core layouts.
- The dependent regimen claims constrain fasted vs fed and dosing frequency, which can narrow exposure if a product uses a different administration schedule.
FAQs
1) Is US 9,937,132 limited to pregnancy and NVP?
No. Claim 1 covers nausea and vomiting in a human. Claim 2 specifically narrows to pregnant women with NVP.
2) Must both doxylamine and pyridoxine be present in both the immediate and delayed release compositions?
Yes. Claim 1 requires the IR composition contains doxylamine and pyridoxine (each in the stated mg ranges) and the DR composition also contains doxylamine and pyridoxine (each in the stated mg ranges).
3) Do the claims require an enteric coating?
Not in claim 1. An enteric coating is expressly required in dependent claim 14.
4) What dosing frequencies are explicitly claimed?
Claims cover once-a-day to three times a day (claim 18) and twice-a-day (claims 19 and 21). Fasted vs fed administration is also claimed (claims 16–17).
5) What numeric ranges most directly define claim 1 exposure?
The critical ranges are:
- per fraction: doxylamine 5–20 mg and pyridoxine 5–20 mg (IR and DR each)
- per dosage form totals: doxylamine 10–30 mg and pyridoxine 10–30 mg
- plus the timing relationship: IR release begins prior to DR release within the GI tract.
References
[1] US Patent 9,937,132.
