United States Patent 5,612,054: Claim Scope, Expiration, and Patent Landscape

U.S. Patent No. 5,612,054 covers pharmaceutical compositions combining simethicone with specified antidiarrheal agents, principally loperamide, bismuth subsalicylate, diphenoxylate, and polycarbophil. The claims reach both broad combination compositions and narrower dosage forms, including enteric-coated products and layered tablets. The patent’s statutory term has expired, so the claims no longer create an enforceable U.S. patent barrier to generic or competing products.

What does U.S. Patent 5,612,054 protect?

The patent protects compositions containing two therapeutic components:

An antidiarrheal compound selected from:
- Loperamide
- Bismuth subsalicylate
- Diphenoxylate
- Polycarbophil
- Pharmaceutically acceptable salts
- Mixtures of those compounds
Simethicone in an amount effective to reduce flatulence or gas.

The claims are composition claims rather than method-of-treatment claims. A product may infringe only if the accused formulation contains the required ingredients and satisfies the applicable dosage-form and concentration limitations.

The independent claims are Claims 1 and 16.

Claim	Principal subject matter	Scope
1	Antidiarrheal plus simethicone	Broad combination composition
2	Claim 1 with 20-125 mg simethicone	Dosage limitation
3	Claim 2 with 0.5-8.0 mg loperamide	Loperamide subgroup
4	Loperamide hydrochloride	Salt limitation
5	Enterically coated loperamide	Coating limitation
6	Solid dosage form	Tablet or other solid form
7	Two-layer solid dosage form	Loperamide in one layer, simethicone in another
8	120-1,200 mg bismuth subsalicylate	Bismuth subgroup
9	300 mg bismuth subsalicylate and 80 mg simethicone	Specific formulation
10	0.7-10 mg diphenoxylate	Diphenoxylate subgroup
11	Diphenoxylate hydrochloride	Salt limitation
12	150-2,000 mg polycarbophil	Polycarbophil subgroup
13	Calcium polycarbophil	Specific polycarbophil form
14	2 mg loperamide and 80 mg simethicone	Specific loperamide formulation
15	2 mg loperamide and 125 mg simethicone	Specific loperamide formulation
16	Enterically coated antidiarrheal plus enterically coated simethicone	Separate broad independent claim

How broad is Claim 1?

Claim 1 is the principal broad composition claim. It has four important characteristics.

It uses a Markush group

The antidiarrheal component can be any one of four named compounds, an acceptable salt of those compounds, or a mixture. A formulation containing loperamide and simethicone can therefore fall within Claim 1 without containing any of the other listed antidiarrheals.

The use of "selected from the group consisting of" normally limits the active antidiarrheal component to the listed members and their specified salts. Other antidiarrheals, such as racecadotril, rifaximin, or diphenoxylate-free opioid combinations, would not satisfy this limitation unless another claim construction or formulation feature brought them within the claim.

It uses "comprising"

"Comprising" is an open-ended transition. A competing product could contain additional active ingredients, excipients, coatings, flavors, or processing aids and still potentially satisfy Claim 1.

For example, the presence of an additional analgesic, antacid, electrolyte, or fiber ingredient would not by itself avoid the claim. The accused composition would still need to contain the required antidiarrheal and simethicone components.

The effective-amount limitations are functional

Claim 1 requires an effective amount of the antidiarrheal and an antiflatulent-effective amount of simethicone. These terms may require evidence concerning the formulation, labeling, dose, and intended use.

Claims 2 through 15 narrow the composition with numerical amounts. Those claims are less dependent on proving clinical effectiveness if the product’s labeled composition clearly falls within the stated ranges.

The human-treatment language limits the intended context

Claim 1 describes a composition for treating a human suffering from an intestinal disorder characterized by diarrhea and flatulence or gas. The claim is not a pure chemical composition claim. A product sold for a materially different use could present a different infringement analysis, although labeling and objective product characteristics would remain relevant.

What formulations are protected by Claims 2 through 15?

The dependent claims divide the patent into four formulation groups.

Loperamide and simethicone products

Claims 3 through 7 and Claims 14 and 15 address loperamide combinations.

The principal numerical ranges are:

Simethicone: approximately 20-125 mg
Loperamide: approximately 0.5-8.0 mg
Specific combinations:
- 2 mg loperamide with 80 mg simethicone
- 2 mg loperamide with 125 mg simethicone

Claim 4 specifies loperamide hydrochloride. This is commercially important because loperamide is commonly formulated as loperamide hydrochloride rather than as the free base.

Claim 5 requires enterically coated loperamide. Claim 6 requires a solid dosage form. Claim 7 requires at least two layers, with the enterically coated loperamide in a first layer and simethicone in a second layer.

A conventional single-layer tablet containing 2 mg loperamide hydrochloride and 125 mg simethicone could implicate Claims 2, 3, 4, and 15, but not Claim 7 unless it has the required multilayer structure.

Bismuth subsalicylate and simethicone products

Claims 8 and 9 cover bismuth subsalicylate combinations.

The relevant amounts are:

Bismuth subsalicylate: approximately 120-1,200 mg
Simethicone: approximately 20-125 mg under Claim 2
Specific combination under Claim 9:
- 300 mg bismuth subsalicylate
- 80 mg simethicone

Claim 9 is narrower than Claim 8 because it requires the exact stated amounts. It may be relevant to chewable tablets, caplets, or liquid products depending on how the amounts are measured and distributed.

Diphenoxylate and simethicone products

Claims 10 and 11 address diphenoxylate combinations.

The relevant amount is approximately 0.7-10 mg diphenoxylate. Claim 11 narrows the compound to diphenoxylate hydrochloride.

The claim set does not require atropine in the expressly quoted claims. A product containing diphenoxylate hydrochloride and simethicone could therefore require analysis of whether additional ingredients affect infringement under the open "comprising" language.

Polycarbophil and simethicone products

Claims 12 and 13 address polycarbophil combinations.

The relevant range is approximately 150-2,000 mg polycarbophil. Claim 13 narrows the ingredient to calcium polycarbophil.

This branch is technically distinct from the loperamide branch because polycarbophil is a polymeric bulk-forming ingredient rather than an opioid antidiarrheal. Product classification, labeling, and dosing could affect whether the composition satisfies the claimed "antidiarrheal" function.

What does Claim 16 add?

Claim 16 is an independent claim requiring:

An enterically coated antidiarrheal compound from the listed Markush group; and
Enterically coated simethicone.

Unlike Claims 5 through 7, Claim 16 is not limited to loperamide. It can cover enterically coated formulations using bismuth subsalicylate, diphenoxylate, polycarbophil, loperamide, their acceptable salts, or mixtures.

The claim does not include the numerical simethicone range of Claim 2. A formulation could therefore fall within Claim 16 without containing 20-125 mg simethicone, provided the coating and functional limitations are met.

The coating requirement is central. A formulation in which only loperamide is enterically coated would not satisfy the express requirement that simethicone also be enterically coated. Conversely, a product with an enteric coating applied to a complete dosage form may raise questions about whether both components are properly characterized as enterically coated.

How many patents cover the claimed loperamide-simethicone combination?

The quoted patent is one identified U.S. patent covering the loperamide-simethicone combination. Its claim set covers both:

Broad combination compositions; and
Specific dosage strengths associated with commercial antidiarrheal and antiflatulent products.

The patent does not establish that it was the only U.S. patent relevant to the product. Separate patents could have addressed:

Tablet manufacture
Coating materials
Layered-tablet architecture
Taste masking
Controlled release
Packaging
Manufacturing processes
Product labeling or other commercial formulations

Those rights would need to be evaluated separately by searching continuation applications, related patent families, and patents assigned to the product manufacturer.

When did U.S. Patent 5,612,054 lose exclusivity?

The patent was granted on March 18, 1997. Its term was governed by the post-June 8, 1995 patent-term framework, generally providing 20 years from the earliest effective U.S. nonprovisional filing date, subject to patent-term adjustment and any applicable patent-term extension. The patent’s enforceable term ended no later than the March 2014 period indicated by its filing chronology, absent a specific term adjustment.

The patent is therefore expired. Expiration eliminates the right to enforce the claims against later products. It does not invalidate the historical patent, but it removes the principal exclusionary value of the claims.

Event	Date or period
Earliest priority or filing chronology reflected in the patent record	1993-1994 period
U.S. patent grant	March 18, 1997
Ordinary 20-year term endpoint	March 2014 period
Current enforceability	Expired

Patent expiration should be confirmed against the USPTO Patent Center record if a transaction, launch, or litigation opinion depends on the precise terminal date and any patent-term adjustment.

What is the Orange Book status of U.S. Patent 5,612,054?

The patent should not be treated as an Orange Book-listed patent merely because it covers a drug combination.

FDA Orange Book listing is tied to approved drug products, applicable New Drug Applications, and patents submitted for listing under the governing FDA regulations. Many over-the-counter products are marketed under monographs rather than through an NDA-based approval structure that produces an Orange Book patent listing.

Loperamide and simethicone products have historically been associated with OTC regulatory frameworks. A patent covering an OTC composition may therefore have no Orange Book listing, particularly where the product is marketed under an OTC monograph rather than an NDA.

The practical consequences are:

An Orange Book Paragraph IV certification may not have been the relevant challenge mechanism.
Generic manufacturers may not have faced a 30-month stay based on this patent.
Expiration of the patent independently removes any current patent obstacle.
OTC monograph compliance, labeling, active-ingredient status, and product quality remain separate regulatory issues.

The FDA’s OTC monograph system and the Orange Book address different regulatory pathways. Patent status cannot be inferred solely from product availability or Orange Book searches.

Were there Paragraph IV challenges or patent litigation?

The quoted patent claims do not establish a Paragraph IV certification, ANDA filing, infringement action, settlement, or license.

Because the patent is expired, a current Paragraph IV challenge would have no practical purpose against these claims. Any historical ANDA litigation would have needed to occur before expiration and would depend on the existence of an approved reference product, an ANDA, and an Orange Book-listed patent or other litigation trigger.

The commercially relevant litigation questions are therefore historical:

Whether an ANDA applicant challenged the patent before expiration.
Whether the patent owner asserted Claims 1, 2, 3, 14, or 15 against a loperamide-simethicone product.
Whether a settlement included a launch date, license, supply arrangement, or admission.
Whether related patents, rather than Patent 5,612,054, controlled the commercial launch date.

No litigation or settlement terms can be derived from the claims alone. The patent number should be searched in PACER, district court dockets, Federal Circuit decisions, and FDA litigation records before relying on a litigation conclusion.

How strong was the patent estate?

The patent had meaningful historical scope but limited structural depth.

Strengths

Claim 1 covered a broad combination of simethicone with four antidiarrheal categories.
"Comprising" allowed additional formulation ingredients.
The Markush structure covered salts and mixtures.
Claims 14 and 15 targeted commercially intuitive loperamide strengths.
Claim 16 addressed enterically coated versions of both components.
The claims covered multiple active-ingredient branches rather than a single commercial product.

Weaknesses

The claim set is composition-focused and does not independently protect manufacturing processes.
Numerical claims could be avoided by changing dosage strengths outside the stated ranges.
Claim 7 could be avoided through a single-layer dosage form.
Claim 16 could be avoided through a formulation in which one or both components are not enterically coated.
The broad functional language could have created validity questions concerning anticipation, obviousness, written description, enablement, and claim construction.
Expiration eliminates present enforcement value.

The strongest historical claims were likely the specific commercial formulations in Claims 14 and 15, provided the accused product matched the required active ingredients and amounts. The broadest claim, Claim 1, offered wider coverage but presented greater potential validity and construction exposure.

What generic entry risks exist today?

There is no current patent-based entry risk from U.S. Patent 5,612,054 because the patent has expired.

A generic or private-label manufacturer can develop a loperamide-simethicone product without obtaining a license under this patent. Current barriers may instead include:

FDA OTC monograph compliance
Active-ingredient specifications
Bioavailability or equivalence requirements, if an NDA or abbreviated pathway applies
Tablet compression and coating technology
Product stability
Taste and mouthfeel
Trademark and trade-dress restrictions
Supplier qualifications for simethicone and loperamide hydrochloride
Other unexpired formulation, process, or packaging patents

The expired patent may still be relevant as prior art against later patent applications claiming the same combination, dosage strengths, or enteric-coating concept.

How does this patent compare with a modern formulation patent?

Patent 5,612,054 is primarily an early combination-composition patent. A modern formulation patent would more likely rely on narrower technical features, such as:

Specific particle-size distributions
Defined polymer coating compositions
Release profiles
Layer separation and manufacturing parameters
Stability limits
Dissolution specifications
Taste-masking systems
Process controls
Quantified pharmacokinetic or performance data

The older patent has broader ingredient-level coverage but less apparent process and performance detail in the quoted claims. A later patent with narrow but technically specific claims could retain enforceable value after Patent 5,612,054 expired.

What licensing deals are associated with the patent?

The claims do not identify a license, assignment, co-development transaction, or royalty arrangement. Patent ownership and licensing must be distinguished:

The patent’s named assignee may not be the current owner.
A commercial product license may cover trademarks or distribution without licensing the patent.
A patent assignment may transfer ownership without transferring product rights.
A settlement may include an implied or express license.

No licensing conclusion should be drawn from the patent claims alone.

Key Takeaways

U.S. Patent 5,612,054 covers combinations of simethicone with loperamide, bismuth subsalicylate, diphenoxylate, polycarbophil, their acceptable salts, or mixtures.
Claim 1 is the broadest composition claim.
Claims 14 and 15 specifically cover 2 mg loperamide combined with 80 mg or 125 mg simethicone.
Claim 7 targets a multilayer solid dosage form with enterically coated loperamide separated from simethicone.
Claim 16 separately requires enteric coating of both the antidiarrheal and simethicone.
The patent’s statutory term expired in the March 2014 period.
The patent does not create a current U.S. generic-entry barrier.
Orange Book status cannot be inferred from the patent and may be inapplicable to an OTC-monograph product.
Any current freedom-to-operate review should focus on later patents covering coatings, manufacturing, controlled release, packaging, trademarks, or other product-specific technology.
The patent remains relevant as prior art even though its claims are no longer enforceable.

FAQs About U.S. Patent 5,612,054

Does U.S. Patent 5,612,054 cover Imodium Multi-Symptom Relief?

The claims are consistent with a loperamide-simethicone product, including formulations containing 2 mg loperamide and either 80 mg or 125 mg simethicone. The patent claims alone do not prove a particular product’s ownership, branding, or historical commercial use.

Can a company now sell loperamide and simethicone in the claimed amounts?

Yes, the patent has expired. A company must still satisfy applicable FDA requirements and avoid unexpired patents, trademarks, and trade dress.

Does a liquid product avoid the patent?

Not necessarily. Claim 1 is not limited to tablets or solid dosage forms. Claims 6 and 7 are limited to solid dosage forms, but Claim 1 could reach a liquid composition containing the required ingredients and functional amounts.

Does changing 125 mg of simethicone to 130 mg avoid all claims?

It may avoid the numerical limitation in Claim 2 and claims depending from it, but it would not automatically avoid Claim 1, which does not state a numerical simethicone range. The patent’s expired status makes the distinction commercially unnecessary for present enforcement, but it remains relevant to historical infringement analysis.

Does the patent cover a product containing simethicone alone?

No. The quoted claims require simethicone together with at least one listed antidiarrheal compound or qualifying mixture. A simethicone-only product does not satisfy the combination requirement.

References

United States Patent and Trademark Office. (1997). U.S. Patent No. 5,612,054. Washington, DC: U.S. Department of Commerce.
United States Code. (2023). 35 U.S.C. § 154: Contents and term of patent; provisional rights. Washington, DC: Office of the Law Revision Counsel.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. Silver Spring, MD: U.S. Department of Health and Human Services.
U.S. Food and Drug Administration. (2024). Over-the-counter monograph drugs. Silver Spring, MD: U.S. Department of Health and Human Services.
Electronic Code of Federal Regulations. (2024). 21 C.F.R. Parts 331, 332, and 335. Washington, DC: U.S. Government Publishing Office.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	0428296	⤷ Start Trial	SPC/GB98/013	United Kingdom	⤷ Start Trial
European Patent Office	0428296	⤷ Start Trial	99C0029	Belgium	⤷ Start Trial
Austria	106737	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 5,612,054

Summary for Patent: 5,612,054