United States Patent 4,671,953 (Fentanyl Lollipop / Soluble Mucosal Matrix): Claim Scope and US Landscape
What does US 4,671,953 claim cover?
US 4,671,953 is directed to methods and compositions for systemic delivery of fentanyl through mucosal absorption in the mouth, using a soluble matrix formed as a lollipop (or equivalent “lollipop” form factor) that dissolves in the oral cavity. The claims combine: (i) a mucosa-absorbable soluble matrix, (ii) controlled dissolution rate (dose-to-effect), and (iii) patient-driven administration mechanics (sucking intensity, intermittent removal) to modulate drug uptake.
Claim set (as provided)
The claim set spans method claims (1-15) and composition claims (16-21). The core limitations appear across the independent claim species.
Independent method claim (Claim 1)
Claim 1 covers a method where the administration step is:
- Obtain soluble matrix material in lollipop form with fentanyl dispersed (“dispersed” substantially uniformly is stated in the composition claim; the method requires fentanyl “has been dispersed”).
- Matrix is soluble and releases fentanyl for absorption through mucosal tissue.
- Provide to patient so that matrix dissolves in mouth and fentanyl is absorbed through mucosal tissue, entering bloodstream.
- Administration is dose-to-effect.
- Control dissolution rate to obtain and maintain desired effect (sedative, analgesic, or anesthetic).
Dependent method claim cluster (Claims 2-8)
These narrow how fentanyl uptake is modulated:
- Claim 2: patient sucks initially for rapid dissolution (high quantities rapidly absorbed), then sucks only as needed.
- Claim 3 and 4: specify dose ratios vs IV injection
- Claim 3: 1 to 50 times IV dose
- Claim 4: 5 to 10 times IV dose
- Claim 5: fentanyl amount in matrix: 500 micrograms to 10 milligrams fentanyl equivalent
- Claim 6: matrix is carbohydrate mass
- Claim 7: intermittently remove lollipop to prevent excessive absorption
- Claim 8: after desired effect, maintain matrix passively to maintain effect
Analgesia-focused method claims (Claims 9-15)
Claims 9-15 mirror Claim 1 but expressly focus on analgesia and add patient-controlled dissolution linked to:
- “individual susceptibility” and “subjective experience of pain”
- Claims 12-15 add more detailed administration mechanics:
- Claim 12: continuous passive sucking for small continuous dosing, with increased suction aggressiveness in response to increasing pain
- Claims 13-14: the same IV ratio windows (1-50x, 5-10x)
- Claim 15: 500 micrograms to 10 milligrams fentanyl equivalent
- Claims 10-11: carbohydrate mass and intermittent removal
Composition claims (Claims 16-21)
Claim 16 is an apparatus/composition claim for systemic delivery:
- Effective dose fentanyl in a form capable of mucosal absorption and systemic sedative/analgesic/anesthetic effect
- Soluble matrix material with fentanyl dispersed substantially uniformly
- Holder means secured to the matrix, configured to permit insertion/removal from mouth
- Dependent claim narrowing:
- Claim 17: holder is a stick
- Claims 18-20: IV dose ratio windows and fentanyl dose range (1-50x, 5-10x, 500 µg to 10 mg)
- Claim 21: matrix is in the form of a lollipop
What are the key technical claim limitations (and what do they mean for infringement)?
For freedom-to-operate and landscape mapping, infringement risk tends to cluster around the following “hard” limitations:
1) Mucosal absorption route in the mouth
The claims require fentanyl release for absorption through mucosal tissue in a way that produces systemic sedation/analgesia/anesthesia. If an accused product uses:
- buccal/oral mucosal absorption, it stays closer to the claims
- intranasal, transdermal, GI, or injection delivery likely avoids the “mucosal dissolving in mouth” element
2) Soluble matrix that dissolves in the oral cavity
The method requires the matrix be dissolved in the patient’s mouth. The composition claims similarly require a soluble matrix that releases fentanyl as it dissolves.
3) Lollipop form factor and holder
Claim 1 explicitly uses “lollipop” language. Claim 16 requires “holder means” configured for insertion and removal, and Claim 17 specifies a stick holder. A product that uses a dissolvable wafer, film, chewable tablet, or gum base with no discrete holder may still be argued, but it is outside the claim’s most intuitive literal architecture unless it is functionally a “lollipop” or equivalent holder assembly.
4) Drug dispersed within the matrix
Method claims require fentanyl “has been dispersed” in the soluble matrix. Composition claim 16 tightens this to “dispersed substantially uniformly.” A product that uses surface coating rather than dispersion within the matrix could attempt to distinguish.
5) Dose-to-effect and controlled dissolution rate
The claims require administering in a dose-to-effect manner and controlling the rate of dissolution to obtain and maintain desired effect. The patient-driven mechanics matter (sucking intensity, intermittent removal, passively maintaining in mouth).
6) Dose windows (IV ratio and absolute range)
Dependent claims specify:
- 500 micrograms to 10 milligrams fentanyl equivalent (Claims 5 and 15; mirrored in Claims 20)
- 1 to 50 times IV dose (Claims 3 and 13; mirrored in Claim 18)
- 5 to 10 times IV dose (Claims 4 and 14; mirrored in Claim 19)
These provide structured claim “slices” that can be used for quick risk scoring:
- Products outside these ranges may avoid dependent claim coverage, but could still fall within independent method claim coverage if other limitations are met.
How broad is the scope? Where are the likely “in” and “out” boundaries?
The scope is broad on purpose (sedation, analgesia, anesthesia) and on administration outcome (systemic delivery) but narrower on mechanism (oral dissolving matrix in lollipop/holder format with mucosal absorption) and on patient-controlled dissolution/dosing behavior.
Likely within scope (conceptually)
- A “fentanyl lollipop” or similar stick-held dissolvable oral dosage that:
- dissolves in mouth,
- releases fentanyl in a way absorbed via oral mucosa, and
- uses patient-controlled suck rate and/or intermittent removal to tune dose-to-effect
Likely outside scope (conceptually)
- Fentanyl delivered by:
- injection,
- transdermal patch,
- intranasal spray,
- buccal film that is not dissolved from a lollipop-like holder assembly,
- ingestible oral tablets that disintegrate for GI absorption rather than mucosal absorption.
What does the claim structure imply for enforcement strategy?
The independent claims (1 and 9) and composition claim (16) allow a plaintiff to pursue infringement under multiple theories:
- Method infringement: centered on administration technique including patient behavior (suction intensity, intermittent removal, controlled dissolution)
- Composition infringement: centered on the product structure (soluble matrix with dispersed fentanyl + holder means, including stick/lollipop form)
Dependent claims then support narrower, product-specific positions:
- dose-range dependent claims (500 µg to 10 mg)
- IV ratio dependent claims (1-50x and 5-10x)
- matrix material dependent claims (carbohydrate mass)
- holder structure dependent claims (stick)
- patient technique dependent claims (intermittent removal; continuous passive with increased aggressiveness when pain increases)
What is the likely patent landscape around this concept in the US?
A full landscape typically requires bibliographic, legal status, and citation chain data from USPTO/Google Patents/PATENTSCOPE records for US 4,671,953 and its family and forward citations. The only information available here is the claim text and the US patent number; no prosecution history, priority data, examiner citations, or legal status is provided. Under the constraint that a complete and accurate response requires those facts, the landscape portion cannot be completed without risking incorrect identification of related US patents and successors.
If you are mapping freedom-to-operate, what screening rules apply using only this patent’s claim text?
Use these filters to score candidate products and R&D concepts against claim coverage:
Structural screen (fast exclusion)
- Does the product deliver fentanyl via oral mucosal dissolution from a soluble matrix?
- Is the dosage form a lollipop/holder that is inserted and removed (stick holder strongly matches Claim 17)?
- Is fentanyl dispersed in the matrix (not only a surface coating)?
Functional screen (fast hit)
- Does the system rely on patient-controlled dissolution rate to achieve a dose-to-effect sedative/analgesic/anesthetic response?
- Is administration described as:
- rapid initial sucking then intermittent/only-as-needed sucking (Claim 2/8), or
- continuous passive sucking with increased aggressiveness during pain spikes (Claim 12)
Dose screen (dependent claims)
If a candidate is close on form and mechanism, apply dose-range and IV ratio:
- 500 µg to 10 mg fentanyl equivalent (Claims 5/15/20)
- 1-50x IV dose (Claims 3/13/18)
- 5-10x IV dose (Claims 4/14/19)
What claim elements are most likely to be contested?
In disputes, the main factual/technical battlegrounds usually track claim construction issues:
1) What counts as “mucosal tissue” absorption
If evidence shows primary absorption occurs elsewhere (e.g., swallowing for GI absorption), the mucosal element weakens.
2) Whether the dosage is “in lollipop form” with the claimed holder logic
Products that use a dissolvable candy-like format without a stick holder may argue non-literal non-equivalence.
3) Whether fentanyl is “dispersed” in the soluble matrix
Coated films or reservoirs may dispute “dispersed substantially uniformly” versus coated layers.
4) Whether dosing is “dose-to-effect” with controlled dissolution
If clinical labeling does not require patient-controlled dissolution tuning, the “dose-to-effect” and “controlling rate of dissolution” limitations become central.
What actionable insights does this create for R&D and deal diligence?
- If your target concept is a fentanyl oral mucosal dissolving matrix in a stick-held lollipop format, this patent’s independent claims (1/9/16) define the conceptual envelope.
- If your concept differs, the cleanest separations are:
- delivery route not relying on oral mucosal dissolution,
- no lollipop/holder assembly,
- matrix not designed for dissolution in the mouth as the absorption trigger,
- dosing not relying on patient-controlled dissolution rate to achieve dose-to-effect.
- For product commercialization diligence, ensure claim mapping includes:
- dosage form architecture (holder + matrix + dispersion),
- administration instructions (suck intensity, intermittent removal, continuous/passive mechanics),
- dose values (absolute and IV ratio windows where dependent claims become relevant).
Key Takeaways
- US 4,671,953 claims a fentanyl delivery system that dissolves in the mouth from a soluble matrix formed as a lollipop/holder device, producing systemic sedation, analgesia, or anesthesia via mucosal absorption.
- The claim center of gravity is the combination of oral dissolving matrix + patient-controlled dissolution behavior (dose-to-effect) and, for composition claims, fentanyl uniformly dispersed in a soluble matrix secured to a holder (stick) for insertion/removal.
- Dependent claims narrow further by patient administration mechanics (rapid initial sucking, intermittent removal, continuous passive then increased suction) and dose ranges (500 µg to 10 mg; 1-50x IV; 5-10x IV) and matrix material (carbohydrate mass).
- A complete US patent landscape analysis requires bibliographic/legal-status/citation data beyond the claim text provided; that data is not included here.
FAQs
1) What is the main dosage form claimed in US 4,671,953?
A soluble lollipop-style matrix containing fentanyl that dissolves in the patient’s mouth for mucosal absorption.
2) Do the claims require patient-controlled administration?
Yes. The method claims require dose-to-effect use and controlling dissolution rate, with dependent claims specifying behaviors like sucking intensity and intermittent removal.
3) Are there specific fentanyl dose limits?
Dependent claims specify 500 micrograms to 10 milligrams fentanyl equivalent and IV-relative dose ratios of 1-50x and 5-10x.
4) Is the patent limited to analgesia only?
No. It covers sedation, analgesia, or anesthesia in independent method and composition claims, with separate claims focused on analgesia.
5) What structural element appears in the composition claims besides the matrix?
A holder means configured for mouth insertion/removal, including a stick holder in a dependent claim.
References
[1] US Patent 4,671,953 (claim set as provided in prompt).
