United States Patent 7,179,483: Scope, Claim Architecture, and US Patent Landscape for Oxybutynin Transdermal Methods Minimizing Anticholinergic Exposure
What does US 7,179,483 claim in one line?
US 7,179,483 claims a method of treating overactive bladder with transdermal oxybutynin while minimizing an anticholinergic/antimuscarinic adverse drug experience by targeting systemic exposure ratios between ox ybutynin and its primary metabolite (N-desethyloxybutynin), including specific AUC ratios, peak concentrations, and optional permeation enhancer selections, and also specifies R/S stereochemical variants.
Where is the claim scope concentrated: product form, exposure metrics, or stereochemistry?
The independent claim (claim 1) is built from three stacked gating elements:
- Route and dosage form
- Transdermal oxybutynin in one of two product classes:
- Topical formulations: ointments, lotions, gels, pastes, mousses, aerosols, skin creams
- Transdermal patches: adhesive matrix patches or liquid reservoir systems
- Pharmacokinetic exposure target
- An AUC ratio of ox ybutynin to oxybutynin metabolite of 0.5:1 to 5:1
- Outcome linkage
- The method is performed “while minimizing” an anticholinergic or antimuscarinic adverse drug experience associated with oxybutynin therapy
Dependent claims then add enforcement levers: tighter ratio windows, metabolite identity (N-desethyloxybutynin), stereochemistry, peak concentration thresholds, and permeation enhancer selection.
What is the independent claim 1: full scope break-down?
Claim 1 requires all of the following:
A. Indication and therapeutic purpose
- Treat a subject having overactive bladder
- With oxybutynin
- While minimizing an adverse drug experience described as:
- anticholinergic or antimuscarinic adverse drug experience associated with oxybutynin therapy
B. Key pharmacokinetic constraint (systemic ratio)
- Administer a transdermal formulation comprising oxybutynin
- Target exposure:
- AUC(ox ybutynin) / AUC(ox ybutynin metabolite) = 0.5:1 to 5:1
- The metabolite is not named in claim 1, but dependent claim 5 pins it to:
C. Optional permeation enhancer
- Formulation optionally includes a permeation enhancer
D. Allowed transdermal dosage form categories
The transdermal formulation is in one of the following:
- (a) Topical formulations selected from:
- ointments, lotions, gels, pastes, mousses, aerosols, skin creams
- (b) Transdermal patches selected from:
- adhesive matrix patches, liquid reservoir systems
E. Enforcement posture implied by the claim structure
Because claim 1 is written as a method with a measurable PK ratio and allows broad product forms, the claim’s practical boundary is (i) route and dosage form, and (ii) whether the resulting PK profile meets the ratio window.
How do dependent claims narrow the ratio scope?
The ratio-based elements are the central infringement test because they define the “minimizing” effect through exposure control.
AUC ratio tightening (claim set)
- Claim 2: AUC ratio 1:1 to 5:1
- Claim 3: AUC ratio 0.8:1 to 1.5:1
Metabolite identity (claim set)
- Claim 5: metabolite = N-desethyloxybutynin
- Claim 28: metabolite is N-desethyloxybutynin (depends on claim 9)
More ratio windows tied to N-desethyloxybutynin
- Claim 25: AUC ratio 0.5:1 to 4:1
- Claim 26: AUC ratio 1:1 to 5:1
- Claim 27: AUC ratio 0.8:1 to 2.5:1
Ratio windows incorporating stereochemistry of metabolite
- Claim 8: AUC ratio (R-N-desethyloxybutynin)/(R-oxybutynin) 0.4:1 to 1.6:1
- Claim 10: AUC ratio (R-N-desethyloxybutynin)/(S-N-desethyloxybutynin) 0.5:1 to 1.3:1
- Claim 7: AUC ratio (R-oxybutynin)/(S-oxybutynin) about 0.7:1
- Claim 9: AUC ratio (R-N-desethyloxybutynin)/(R-oxybutynin) about 1:1
- Claim 11: AUC ratio (R-N-desethyloxybutynin)/(S-N-desethyloxybutynin) about 0.9:1
Business implication: A competitor that matches transdermal oxybutynin delivery but shifts metabolic formation or clearance to fall outside these windows can attempt to avoid the ratio claims. Conversely, formulation developers that can tune PK toward higher parent exposure relative to metabolite face direct alignment risk with this patent.
How do claims constrain peak metabolite levels?
A second enforcement layer is metabolite Cmax windows.
Peak metabolite thresholds (general)
- Claim 12: metabolite peak < 8 ng/mL
- Claim 13: metabolite peak < 5 ng/mL
Peak metabolite windows (N-desethyloxybutynin)
- Claim 20: N-desethyloxybutynin peak 0.5 to 8 ng/mL
- Claim 21: peak < 5 ng/mL
- Claim 22: peak 1.0 to 3 ng/mL
AUC-related gating on metabolite formation
- Claim 23: N-desethyloxybutynin AUC does not exceed oxybutynin AUC by more than 2:1
- Interpreting this as: AUC(metabolite) / AUC(parent) ≤ 2:1, or equivalently parent/metabolite ≥ 0.5:1 (consistent with the broad claim 1 ratio)
Specific peak level
- Claim 24: N-desethyloxybutynin peak about 3 ng/mL
Time-based concentration thresholds
- Claim 30: metabolite below 2.0 ng/mL at ~6 hours
- Claim 31: both parent and metabolite below 8 ng/mL at ~24 hours
- Claim 32: at steady state, both below 8 ng/mL for duration
- Claim 33: duration 24 to 96 hours
- Claim 34: administration duration 24 to 96 hours
- Claim 29: parent below 2.0 ng/mL at ~6 hours
Business implication: Even if a product meets the AUC ratio, failing peak constraints tied to metabolite identity and timepoints can leave the product outside narrower dependent claims.
How do the stereochemistry claims broaden or narrow the risk?
The patent recites stereochemical specificity in multiple claim branches. It covers:
A. Parent stereoisomer selection
- Claim 4: parent is (R), (S), or combination
- Claim 17: oxybutynin is mixture of R + S
- Claim 18: oxybutynin is R
- Claim 19: oxybutynin is S
B. Metabolite stereoisomer selection
- Claim 6: metabolite is N-desethyloxybutynin
- Claim 6 dependent on claim 5: N-desethyloxybutynin is (R), (S), or combination
C. Relative PK comparisons by stereoisomer
- Claim 35: at steady PK: peak and AUC for (R)-N-desethyloxybutynin are ≤ those for (S)-N-desethyloxybutynin
- Claim 36: peak and AUC for (R)-oxybutynin are approximately equal to those for (R)-N-desethyloxybutynin
D. Numeric windows involving R/S for parent and metabolite
- Claims 7-11, 8-11, 10-11: ratio windows for R vs S exposures, including fixed approximate ratios like 0.7:1 and 0.9:1.
E. Numeric metabolite R-form examples
- Claim 37: (R)-N-desethyloxybutynin peak < 4 ng/mL
- Claim 38: peak 0.25 to 4 ng/mL
- Claim 39: peak about 1.5 ng/mL
- Claim 42: R-metabolite below 1 ng/mL at ~6 hours
- Claim 43: R-metabolite below 2 ng/mL at ~24 hours
- Claim 40-41: R-metabolite AUC about 100 ng·hr/mL, or 30 to 170 ng·hr/mL
Business implication: A developer using an enantiopure formulation or optimizing to shift R/S balance can land inside or outside these dependent claim windows. If an investigational program uses racemate delivery, the stereochemical dependent claims still pose risk because claim 4 and claim 17 cover mixtures.
What permeation enhancer options are explicitly covered?
Claim 15 enumerates an enhancer class “essentially of” a defined list, and claims 16 and 44 single out specific members.
Permeation enhancer list (claim 15)
Member selected from essentially:
- fatty acids
- fatty acid esters
- fatty alcohols
- fatty acid esters of lactic acid or glycolic acid
- glycerol triesters
- glycerol diesters
- glycerol monoesters
- triacetin
- short chain alcohols
- urea
- mixtures thereof
Single-compound dependent claims
- Claim 16: permeation enhancer = triacetin
- Claim 44: permeation enhancer = urea
Business implication: If a competitor’s transdermal oxybutynin formulation uses a permeation enhancer outside this list, they may still be captured by claim 1 (which allows optional enhancer generally) but can reduce risk against the enhancer-specific dependent claims.
What adverse drug experience categories are recited?
Claim 14 defines adverse drug experience categories as:
- gastrointestinal/genitourinary
- nervous system
- cardiovascular
- dermatological
- ophthalmic
- or a combination
Business implication: This is broad, and it does not require a specific event label, which makes outcome-based differentiation harder for later designs.
Dosage duration scope (administration window)
- Claims 33-34: duration 24 to 96 hours
- Claim 32: at steady state, oxybutynin and metabolite below 8 ng/mL for duration (duration consistent with claim 33)
Business implication: The patent expects a longer-wear transdermal delivery profile rather than brief or single-dose exposure.
Consolidated claim scope map (what must be true for infringement)
| Claim element |
Scope driver |
Typical “must show” in analysis |
| Indication |
Overactive bladder |
Clinical target population |
| Route/dosage form |
Transdermal: topical or patch, includes adhesive matrix and liquid reservoir |
Product class and administration route |
| PK ratio target |
AUC(parent)/AUC(metabolite) in ranges |
PK study demonstrating ratio in claimed window |
| Metabolite identity |
N-desethyloxybutynin (dependent claims) |
Metabolite quantitation and identity confirmation |
| Peak targets |
Cmax(parent and/or metabolite) thresholds and windows |
Cmax and timing after dosing |
| Stereochemistry |
R/S composition and relative PK comparisons |
Enantiomer-resolved PK if using stereochemical dependent claims |
| Enhancer |
Optional enhancer; dependent list includes triacetin/urea |
Formulation excipients and their identity |
| Outcome language |
Minimizing anticholinergic/antimuscarinic adverse experience |
Clinical tolerability linkage (but claims mainly anchor on PK constraints) |
| Duration |
24-96 hours |
Dosing schedule and steady-state timepoint alignment |
US patent landscape: where this patent sits relative to formulation and PK-targeting strategies
US 7,179,483 is a method claim built around formulation administration and PK outcomes rather than a purely composition claim. In the US landscape, this tends to cluster with the following adjacent patent families and design-around tracks:
1) Transdermal oxybutynin dosage form patents (patch and topical)
These typically claim:
- adhesive matrix patch compositions
- reservoir patch compositions
- manufacturing and adhesive layer structures
- skin permeation engineering
This patent’s differentiator is that even if another patent owns the patch structure, 7,179,483 can attach if the administered transdermal product yields the claimed AUC ratio and metabolite peak constraints.
2) PK-optimized “parent over metabolite” concepts
Across oxybutynin transdermal development, a recurring strategy is to increase parent exposure relative to the metabolite that is linked to tolerability burden. US 7,179,483 hard-codes:
- AUC(parent)/AUC(metabolite) windows
- metabolite Cmax ceilings and windows
- timepoint concentration ceilings
This makes it a PK-defined enforcement patent rather than an excipient-defined patent only.
3) Enantiomer and stereochemistry-specific PK tuning
Because oxybutynin has stereochemical forms and metabolism can differ by stereospecific exposure, later development often explores:
- racemic vs single-enantiomer formulations
- enantiomer-resolved PK targets
US 7,179,483 explicitly covers:
- R-only, S-only, and combinations
- R vs S parent and metabolite AUC and Cmax relationships
This increases the probability of coverage against later “single isomer” strategies, at least where they hit the ratio and metabolite thresholds.
4) Permeation enhancer excipient families
Transdermal permeation enhancers are often patented:
- fatty acids and esters
- urea and related enhancers
- triacetin and glycolate/lactate esters
US 7,179,483 explicitly lists many enhancer types and has dependent claims for triacetin and urea, making it an additional layer over excipient and patch-structure patents.
Practical freedom-to-operate reading: what is the most litigable boundary?
The most litigable boundary is PK endpoints. For business diligence, you map competitor and internal candidates to these measurable claims:
- Does the transdermal product produce AUC(parent)/AUC(metabolite) in 0.5:1 to 5:1?
- If metabolite is N-desethyloxybutynin, does it meet the metabolite peak thresholds (<8 ng/mL, <5 ng/mL, or 1-3 ng/mL windows)?
- If the program is stereochemically defined, does the R/S enantiomer PK pattern match the dependent windows?
- If using triacetin or urea, does it meet the enhancer-dependent dependent claims?
- Are dosing duration and timing consistent with 24-96 hours and the timepoint concentration limits?
Key Takeaways
- US 7,179,483 is a transdermal oxybutynin method patent that anchors infringement on measurable PK outcomes: an AUC(parent)/AUC(metabolite) target and metabolite peak concentration ceilings/windows.
- The claim set covers topical formulations and transdermal patches (adhesive matrix and liquid reservoir systems).
- Dependent claims add tight ratio ranges, explicit metabolite identity (N-desethyloxybutynin), R/S stereochemistry gates, and specific permeation enhancers (triacetin, urea).
- Landscape-wise, this patent overlaps formulation categories (patch/topical) but shifts the core enforcement hook to PK-based tolerability minimization via metabolite exposure control.
FAQs
1) Is the metabolite required to be N-desethyloxybutynin in the independent claim?
No. Claim 1 uses “oxybutynin metabolite” without naming it; N-desethyloxybutynin is specified in dependent claim 5.
2) Does the patent require a particular patch structure?
No. Claim 1 allows both adhesive matrix patches and liquid reservoir systems, and also topical formulations (ointment, gel, cream, aerosol, etc.).
3) What is the broadest AUC ratio range in the claims?
The independent claim 1 range is 0.5:1 to 5:1 for oxybutynin AUC relative to oxybutynin metabolite AUC.
4) Are triacetin and urea required to be used?
No. They are optional via the “optionally includes a permeation enhancer” language in claim 1, and they appear in dependent claims (triacetin in claim 16; urea in claim 44).
5) What dose duration is contemplated by the patent?
Dependent claims tie administration duration to about 24 to about 96 hours.
References
- United States Patent 7,179,483 (provided claims text by user).
