When do the patents on ALUMINUM HYDROXIDE AND MAGNESIUM TRISILICATE expire, and when will generic ALUMINUM HYDROXIDE AND MAGNESIUM TRISILICATE be available?

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Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Pennex	ALUMINUM HYDROXIDE AND MAGNESIUM TRISILICATE	aluminum hydroxide; magnesium trisilicate	TABLET, CHEWABLE;ORAL	089449-001	Nov 27, 1987		DISCN	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Exclusivity Expiration

Last updated: September 27, 2026

Aluminum hydroxide and magnesium trisilicate are mature, low-cost antacid ingredients used primarily in combination oral suspensions, chewable tablets, powders, and traditional gastrointestinal remedies. Their commercial outlook is stable but structurally limited by generic competition, low unit prices, extensive OTC substitution, and the absence of meaningful patent protection. Financial growth is driven more by private-label volume, geographic expansion, packaging, and retailer distribution than by clinical differentiation.

Ingredient-specific global revenue is not publicly reported with sufficient consistency. Sales are generally embedded in brand, private-label, or institutional antacid categories rather than disclosed separately for aluminum hydroxide or magnesium trisilicate.

What are aluminum hydroxide and magnesium trisilicate used for?

Aluminum hydroxide neutralizes gastric acid and can reduce pepsin activity. Magnesium trisilicate is a slowly reacting inorganic antacid that neutralizes gastric hydrochloric acid and may form colloidal silica during use. Both ingredients are used for short-term relief of:

Heartburn
Acid indigestion
Sour stomach
Dyspepsia
Episodic excess gastric acidity

The ingredients are often combined with other antacids or gastrointestinal agents. Aluminum salts tend to cause constipation, while magnesium salts can cause diarrhea. Combination products seek to balance these gastrointestinal effects.

In the United States, the principal commercial antacid market uses aluminum hydroxide with magnesium hydroxide, magnesium carbonate, or calcium carbonate more often than magnesium trisilicate. Magnesium trisilicate remains more visible in certain non-U.S. markets and traditional formulations.

What is the FDA regulatory status of aluminum hydroxide and magnesium trisilicate?

Aluminum hydroxide and magnesium trisilicate are regulated primarily through the U.S. OTC antacid monograph framework rather than through product-specific new drug approvals.

The FDA’s OTC antacid monograph establishes permitted active ingredients, dosage ranges, labeling conditions, and required warnings. Products that comply with the applicable monograph can be marketed without an individual approved New Drug Application, subject to current FDA requirements for OTC monograph drugs.[1]

FDA status by ingredient

Ingredient	U.S. OTC status	Primary use	Prescription drug role
Aluminum hydroxide	Permitted OTC antacid active ingredient under the antacid monograph	Acid neutralization	Limited and generally ancillary
Magnesium trisilicate	Recognized antacid ingredient in historical and international OTC use	Acid neutralization	Limited
Aluminum hydroxide plus magnesium trisilicate	Product-specific compliance depends on formulation, dose, labeling, and current monograph requirements	Combination antacid	Not a major prescription category

The FDA’s final OTC monograph rulemaking system under the CARES Act changed the procedural structure for OTC monograph products. Manufacturers must comply with the applicable final monograph and other FDA requirements, including current good manufacturing practices, labeling, adverse-event reporting, and facility obligations.[2]

What is the Orange Book status of aluminum hydroxide and magnesium trisilicate?

Neither ingredient has a meaningful Orange Book patent-exclusivity position for ordinary OTC antacid products.

The Orange Book primarily identifies approved prescription and certain approved nonprescription drug products, including therapeutic equivalence information and listed patents where applicable. Standard monograph-compliant antacid products based on aluminum hydroxide and magnesium trisilicate generally do not depend on Orange Book-listed patents for market access.[3]

Orange Book and exclusivity assessment

Issue	Assessment
Orange Book-listed core composition patent	Generally absent
New chemical entity exclusivity	None
Pediatric exclusivity	Not material to the mature OTC category
Orphan exclusivity	Not applicable
Reference-listed-drug dependence	Usually not the primary access route
Paragraph IV exposure	Low for legacy monograph products
Biosimilar exposure	None

What patents protect aluminum hydroxide and magnesium trisilicate products?

The core active ingredients are old inorganic compounds and do not have meaningful composition-of-matter patent protection. Any commercially relevant IP is more likely to concern:

Suspension stability
Flavor masking
Particle-size control
Tablet compression
Effervescence
Packaging
Dosing systems
Co-formulation with alginate, simethicone, calcium carbonate, or other gastrointestinal actives
Manufacturing processes
Brand names and trade dress

Most such rights are narrow, expired, jurisdiction-specific, or commercially less important than manufacturing scale and retail distribution.

Patent-estate strength

Patent category	Commercial relevance	Expected strength
Core aluminum hydroxide composition	Very low	None or expired
Core magnesium trisilicate composition	Very low	None or expired
Combination formulation	Moderate in selected products	Low to moderate
Suspension or flavor system	Moderate	Low to moderate
Device or dispensing system	Limited	Product-specific
Trademark and packaging	High for branded products	Can remain durable
Manufacturing know-how	Moderate	Depends on process complexity

A branded product can retain commercial differentiation after its patent position disappears because consumers recognize its taste, packaging, dosing format, and retail placement. That protection is commercial rather than statutory exclusivity.

When do aluminum hydroxide and magnesium trisilicate products lose exclusivity?

For the active ingredients themselves, meaningful exclusivity was lost decades ago. The relevant commercial question is whether a particular branded formulation has enforceable patents, regulatory exclusivity, or trademark value.

A typical market-entry sequence is:

Period	Market event
Historical period	Ingredient and basic antacid use established
Patent expiry period	Basic composition and conventional formulation rights expire
Mature OTC period	Generic, private-label, and regional products expand
Current market	Competition centers on formulation, brand, distribution, and price
Future market	Growth depends on convenience formats, combination products, and emerging-market access

The category does not have a single patent expiration date because products are sold under multiple brands and formulations. A specific expiration date requires a product-specific patent and jurisdictional review.

How many patents cover aluminum hydroxide and magnesium trisilicate?

No single reliable patent count describes the global market. Patent records may include expired patents, formulation patents, foreign equivalents, abandoned applications, and patents covering combinations in which the ingredients are incidental.

A practical freedom-to-operate review should separate:

Patents claiming aluminum hydroxide or magnesium trisilicate as a broad active ingredient.
Patents claiming a specific ratio or dosage form.
Patents covering a co-active ingredient such as simethicone or alginate.
Patents covering suspension, coating, taste, or packaging technology.
Trademarks and trade dress that affect commercial launch risk.

For a conventional aluminum hydroxide and magnesium trisilicate antacid, the active-ingredient patent risk is generally low. The greater risk is infringement of a narrow formulation or delivery patent associated with a branded competitor.

What patent litigation affects the market?

There is no widely recognized, current U.S. patent litigation campaign centered on the basic aluminum hydroxide and magnesium trisilicate combination comparable to litigation in protected prescription-drug markets.

The litigation profile is typically limited to:

Brand-versus-generic disputes over product appearance or trade dress
Formulation claims involving suspension stability or taste
Labeling and advertising disputes
Manufacturing quality claims
Product-liability cases involving misuse, renal impairment, or drug interactions
Trademark disputes involving legacy antacid brands

Paragraph IV litigation is not a central market feature because many products are marketed under the OTC monograph pathway rather than through an abbreviated application referencing a patented prescription product.

What are the generic launch risks for aluminum hydroxide and magnesium trisilicate?

Generic launch risk is high for conventional products because the ingredients are inexpensive, widely available, and clinically familiar. A new entrant generally faces low technical barriers but substantial commercial pressure.

Main launch risks

Risk	Effect on entrant
Low ingredient cost	Limits pricing power
Retailer private labels	Compresses margins
Established brands	Raises marketing costs
Taste and texture differences	Can affect repeat purchase
Suspension separation	Creates quality and consumer complaints
Aluminum and magnesium tolerability	Requires appropriate warnings
Renal impairment concerns	Increases labeling and pharmacovigilance burden
Retail concentration	Can restrict shelf access
Slow-moving inventory	Raises working-capital risk

A conventional liquid or chewable product can usually be replicated without advanced technology. The strongest launch proposition is often a differentiated delivery format, improved palatability, smaller package, institutional contract, or combination product.

What formulations are protected by patents or know-how?

The most commercially defensible formulations are not the simple active-ingredient combinations. They are products that solve practical problems in use.

Relevant formulation areas

Oral suspensions

Suspensions may require control of sedimentation, viscosity, redispersibility, particle size, and preservative performance. These attributes can be protected through formulation patents or retained as trade secrets.

Chewable tablets

Chewable products depend on compressibility, mouthfeel, flavor, active loading, friability, and dissolution. A successful formulation may use excipients and processing conditions that are difficult to reproduce economically even without a live patent.

Effervescent products

Effervescent formulations use acid-base reactions to improve dispersion or consumer experience. Moisture control and packaging integrity are key manufacturing barriers.

Combination products

Products combining aluminum hydroxide or magnesium trisilicate with simethicone, alginate, calcium carbonate, or other agents may have a more complex regulatory and patent profile. The combination can create additional claims around dose, ratio, administration, or indication.

How does the market compare with other antacid ingredients?

Aluminum hydroxide and magnesium trisilicate compete with a broad group of antacid and acid-control products.

Product category	Typical commercial position	Competitive pressure
Aluminum hydroxide and magnesium trisilicate	Traditional antacid, often regional or legacy	High
Aluminum hydroxide and magnesium hydroxide	Broad OTC use, liquid and tablet formats	Very high
Calcium carbonate	Low-cost, high-volume chewable antacid	Very high
Sodium bicarbonate	Rapid-acting, limited by sodium and formulation concerns	High
Alginate combinations	Reflux-focused differentiation	Moderate to high
H2 blockers	Longer acid suppression, distinct therapeutic positioning	High
Proton-pump inhibitors	Stronger and longer acid suppression	High

The principal competitive threat comes from calcium carbonate and aluminum hydroxide-magnesium hydroxide products in the basic antacid segment. In reflux-oriented products, alginate combinations and acid-suppression therapies compete more directly.

What is the financial trajectory for aluminum hydroxide and magnesium trisilicate?

The financial trajectory is mature and volume-driven. Revenue growth is unlikely to come from major price increases or new chemical-entity innovation.

Revenue drivers

Population growth and rising self-medication
Expansion of modern retail and pharmacy distribution
Private-label adoption
Liquid-to-chewable or single-dose format migration
Combination products with simethicone or alginate
Growth in emerging markets
Institutional and hospital supply contracts
E-commerce distribution

Margin pressures

Commodity-like active ingredients
Retailer bargaining power
Brand substitution
Promotional discounting
Packaging and freight costs
Quality-control requirements for suspensions
Regulatory compliance costs
Low switching costs for consumers

The most attractive financial opportunities are likely to sit downstream from the ingredients: branded formulations, convenient dosing systems, export registrations, contract manufacturing, and private-label supply. Bulk active-ingredient sales generally have weaker margins and limited differentiation.

Financial outlook by segment

Segment	Near-term outlook	Margin outlook
Bulk aluminum hydroxide	Stable demand, commodity pricing	Low
Bulk magnesium trisilicate	Stable but narrower demand base	Low
Standard liquid antacid	Mature volume, intense competition	Low to moderate
Chewable tablets	Stable demand, packaging and flavor differentiation	Moderate
Combination products	Better differentiation	Moderate
Private-label manufacturing	Volume opportunity, buyer price pressure	Low to moderate
Premium branded products	Stronger pricing, higher marketing cost	Moderate
Specialty delivery systems	Potentially higher margin	Product-dependent

Public companies typically report gastrointestinal or consumer-health sales at a broader category level. They generally do not disclose revenue attributable specifically to aluminum hydroxide and magnesium trisilicate. Any ingredient-level market-size estimate should therefore be treated as a modeled allocation, not reported financial data.

Which companies are challenging the market?

Competition is fragmented across branded consumer-health companies, generic manufacturers, regional pharmaceutical companies, contract manufacturers, and retailers.

Relevant competitor groups include:

Branded OTC manufacturers
Store-brand and private-label suppliers
Regional antacid producers
Generic drug companies
Consumer-health subsidiaries of multinational pharmaceutical groups
Contract development and manufacturing organizations
Pharmaceutical distributors and pharmacy chains

The competitive advantage is usually based on distribution and manufacturing economics. No company has a durable monopoly over the basic active ingredients.

What manufacturing and IP barriers exist?

Manufacturing barriers are moderate for liquid and combination products but low for simple tablets and powders.

Manufacturing considerations

Raw-material identity and purity
Particle-size consistency
Heavy-metal and elemental-impurity control
Microbial control in aqueous suspensions
Viscosity and settling behavior
Container-closure compatibility
Dose uniformity
Stability under heat and humidity
Taste and mouthfeel
Packaging leakage and dispensing accuracy

Aluminum hydroxide products may require careful control of gel structure and particle behavior. Magnesium trisilicate can create formulation and sedimentation issues depending on particle size and excipient selection.

Manufacturing know-how may provide a practical barrier even where patent protection is weak. That barrier is usually replicable by a capable OTC manufacturer and does not support long-term exclusivity comparable to a patented prescription product.

What geographic markets are most relevant?

The United States has a highly developed OTC antacid market, but magnesium trisilicate is more prominent in some non-U.S. formulations. Regulatory treatment varies by jurisdiction.

Region	Market characteristics
United States	OTC monograph framework, strong private-label competition, high retail concentration
United Kingdom	Traditional antacid mixtures and reflux products, pharmacy and supermarket distribution
European Union	National and mutual-recognition regulatory considerations, varied product histories
Latin America	Strong self-medication markets and regional brands
Asia-Pacific	Population growth, pharmacy expansion, and increasing OTC access
Middle East and Africa	Import dependence in some markets, local registration and distribution barriers

Geographic growth is more likely to come from registration, distribution, and local pricing than from patent exclusivity.

What settlement agreements and licensing deals affect the market?

No major, market-defining patent settlement agreement is generally associated with the basic aluminum hydroxide and magnesium trisilicate combination.

Licensing activity is more likely to involve:

Brand licensing
Private-label supply agreements
Regional distribution rights
Contract manufacturing
Combination-product technology
Trademark licensing
Retailer-exclusive packaging

These arrangements are commercial rather than patent-driven. Their terms are usually confidential, and financial disclosures rarely isolate the contribution of these antacid ingredients.

What generic entry scenarios should investors consider?

Scenario 1: Standard private-label entry

A retailer launches a conventional suspension or chewable tablet sourced from an established manufacturer. Price competition increases, while branded products retain share through recognition and shelf placement.

Scenario 2: Combination-product expansion

A manufacturer adds simethicone, alginate, calcium carbonate, or a reflux-oriented claim. Regulatory and formulation complexity rise, but the product may command a higher price.

Scenario 3: Premium delivery format

A single-dose sachet, portable chewable, or improved-flavor product targets convenience and adherence. The product has better differentiation but requires marketing investment.

Scenario 4: Institutional supply

A supplier wins pharmacy, hospital, or long-term-care contracts. Volumes are predictable, but margins are compressed and procurement pricing is aggressive.

Scenario 5: Regional market expansion

A manufacturer enters markets with limited modern antacid penetration. Growth can be attractive, but local registration, import controls, currency exposure, and distributor dependence increase execution risk.

How strong is the patent estate for aluminum hydroxide and magnesium trisilicate?

The patent estate for the basic ingredients is weak. The commercial estate is stronger when it includes trademarks, formulation know-how, distribution, and retailer relationships.

Asset	Strategic value
Active-ingredient patent	Minimal
Basic combination patent	Minimal to low
Formulation patent	Low to moderate
Manufacturing know-how	Moderate
Trademark	Moderate to high
Distribution agreement	High for local market access
Retail placement	High
Consumer loyalty	Moderate

The category is therefore unattractive for patent-driven pharmaceutical investment but potentially viable for efficient OTC manufacturing and consumer-health commercialization.

Key Takeaways

Aluminum hydroxide and magnesium trisilicate are mature OTC antacid ingredients with limited differentiation.
The FDA regulatory pathway is primarily monograph-based rather than NDA-driven.
Standard products generally have no meaningful Orange Book or active composition-patent protection.
Paragraph IV litigation, biosimilar risk, and major patent settlements are not central to the category.
Financial performance depends on volume, private-label supply, packaging, distribution, and combination products.
Bulk active ingredients have low margins and weak pricing power.
Formulation know-how, trademarks, and retailer access are more valuable than core patent rights.
The strongest growth opportunities are in emerging markets, convenient dosage forms, and differentiated reflux or gastrointestinal combinations.
Ingredient-specific revenue cannot be reliably separated from broader antacid and consumer-health sales disclosures.
Generic entry risk is high, but manufacturing, quality, registration, and distribution still create practical barriers.

FAQs

Is magnesium trisilicate still used in modern antacid products?

Yes. It remains used in selected traditional and international antacid formulations, although aluminum hydroxide-magnesium hydroxide and calcium carbonate products are more prominent in many major retail markets.

Can a company patent a new aluminum hydroxide and magnesium trisilicate product?

A company is unlikely to obtain a broad patent over the old active ingredients. It may obtain narrower protection for a novel ratio, delivery system, suspension, flavor system, manufacturing process, or combination with another active ingredient.

Are aluminum hydroxide and magnesium trisilicate products prescription drugs?

Most conventional products are OTC products. Prescription status depends on the specific formulation, strength, labeling, jurisdiction, and regulatory pathway.

Do aluminum hydroxide and magnesium trisilicate products create biosimilar risk?

No. These are inorganic small-molecule antacid ingredients, not biologic medicines. Biosimilar competition does not apply.

What is the biggest commercial risk for a new entrant?

The largest risk is weak pricing power in a crowded OTC market. Retailer private labels, established antacid brands, and low switching costs can prevent a new product from recovering formulation, registration, and marketing costs.

References

U.S. Food and Drug Administration. (2023). Antacid products for over-the-counter human use: Final administrative order. 21 C.F.R. Part 331.
U.S. Food and Drug Administration. (2022). Over-the-counter monograph drug user fee program and OTC monograph order requests. https://www.fda.gov
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book-data-files
U.S. Food and Drug Administration. (2023). Drug products marketed without an approved application. U.S. Department of Health and Human Services. https://www.fda.gov/drugs
Code of Federal Regulations. (2024). 21 C.F.R. Part 331: Antacid products for over-the-counter human use. U.S. Government Publishing Office. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-D/part-331

US Patents:	0
Applicants:	1
NDAs:	1
Raw Ingredient (Bulk) Api Vendors:	4
Patent Applications:	103
DailyMed Link:	ALUMINUM HYDROXIDE AND MAGNESIUM TRISILICATE at DailyMed

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