List of Excipients in Branded Drug GLYBURIDE AND METFORMIN

Generic Drugs Containing GLYBURIDE AND METFORMIN

Company	Ingredient	NDC	Excipient
Rebel Distributors Corp	glyburide and metformin	21695-568	CELLULOSE, MICROCRYSTALLINE
Rebel Distributors Corp	glyburide and metformin	21695-568	COPOVIDONE
Rebel Distributors Corp	glyburide and metformin	21695-568	CROSPOVIDONE

What are the Most Frequently-Used Excipients in GLYBURIDE AND METFORMIN?

# Of NDCs	Excipient
4	CELLULOSE, MICROCRYSTALLINE
3	COPOVIDONE
1	COPOVIDONE K25-31

Glyburide and Metformin Excipient Strategy and Commercial Opportunities

Last updated: August 3, 2026

Glyburide/metformin is a mature, genericized fixed-dose combination for type 2 diabetes. Commercial value is concentrated in manufacturing efficiency, supply reliability, differentiated dosage forms, patient tolerability, and market access rather than basic composition-of-matter exclusivity. The principal formulation challenge is combining poorly soluble glyburide with highly soluble metformin while controlling dose uniformity, dissolution, tablet size, stability, and gastrointestinal tolerability.

What is the regulatory and commercial status of glyburide/metformin?

Glyburide/metformin combines a sulfonylurea, glyburide, with the biguanide metformin hydrochloride. The branded product Glucovance was approved by the U.S. Food and Drug Administration in 2000 under NDA 021178. It was approved in immediate-release strengths of 1.25 mg/250 mg, 2.5 mg/500 mg, and 5 mg/500 mg glyburide/metformin hydrochloride tablets.[1]

Attribute	Glyburide/metformin
Therapeutic class	Oral antidiabetic combination
Active ingredients	Glyburide and metformin hydrochloride
Reference product	Glucovance
Original U.S. approval	2000
FDA pathway for generic products	ANDA under section 505(j)
Typical dosage form	Immediate-release film-coated tablet
Main generic risks	Bioequivalence, content uniformity, dissolution, hypoglycemia warnings, metformin gastrointestinal effects
Biosimilar exposure	None; both ingredients are small molecules
Current commercial position	Mature generic market with price and supply competition

The combination is generally used when monotherapy with metformin or a sulfonylurea does not provide adequate glycemic control, or when a patient is already receiving both agents as separate tablets. The fixed-dose product reduces pill burden but retains the clinical risks of both active ingredients, including hypoglycemia from glyburide and gastrointestinal adverse effects and lactic acidosis warnings associated with metformin.[1]

When does glyburide/metformin lose exclusivity?

Glyburide/metformin lost practical U.S. market exclusivity years ago. Generic manufacturers have marketed the combination through ANDAs, and the product is no longer protected by meaningful brand exclusivity.

FDA exclusivity timeline

Event	Approximate timing
Glucovance U.S. approval	2000
Generic entry	2000s
Current commercial status	Genericized
Biosimilar exclusivity	Not applicable
Remaining value of legacy patents	Primarily defensive or historical

The reference product's regulatory exclusivity period has expired. A current Orange Book review should distinguish between active listed patents, expired patents, patent-use codes, and discontinued or withdrawn products. For a mature small-molecule combination, the principal entry barriers are usually formulation know-how, manufacturing validation, ANDA execution, supplier qualification, and commercial scale rather than enforceable foundational patents.[2]

What patents protect glyburide/metformin products?

The original product may have been supported by formulation and combination patents, but the core active ingredients are long off-patent. A commercial patent review should examine the FDA Orange Book for NDA 021178 and related approved products, then compare each patent's expiration date, delisting status, and claim scope.[2]

Patent categories relevant to this combination

Patent category	Potential relevance	Commercial strength
Glyburide composition patents	Historical active-ingredient protection	Expired
Metformin composition patents	Historical active-ingredient protection	Expired
Fixed-dose combination claims	Combination ratio and dosage form	Generally weak if legacy claims have expired
Immediate-release tablet claims	Compression, disintegration, dissolution	Moderate only if technically narrow and unexpired
Modified-release claims	Metformin release control or glyburide release timing	Potentially stronger for differentiated products
Excipient composition claims	Specific polymer, binder, lubricant, or coating system	Stronger when linked to measured performance
Method-of-use claims	Glycemic control or patient subgroup use	Usually limited for generic launch under 505(j)
Manufacturing-process claims	Granulation, segregation control, coating, or scale-up	Can protect know-how but may be difficult to detect in litigation

No biosimilar patent strategy applies because glyburide and metformin are chemically defined small molecules. A new product using a novel release profile, lower-dose glyburide, or a redesigned delivery system could require a 505(b)(2) application rather than a conventional ANDA, depending on the extent of formulation and labeling changes.[3]

Which excipients are used in glyburide/metformin tablets?

Glucovance labeling identifies common solid-dose excipients including microcrystalline cellulose, povidone, croscarmellose sodium, magnesium stearate, and coating components.[1] Generic labels vary by manufacturer and strength.

Functional excipient architecture

Excipient class	Typical examples	Primary function
Diluent	Microcrystalline cellulose, lactose, dibasic calcium phosphate	Controls tablet mass and compressibility
Binder	Povidone, pregelatinized starch, hydroxypropyl cellulose	Improves granule and tablet strength
Disintegrant	Croscarmellose sodium, crospovidone, sodium starch glycolate	Promotes tablet breakup
Lubricant	Magnesium stearate, sodium stearyl fumarate	Reduces sticking and ejection force
Glidant	Colloidal silicon dioxide	Improves powder flow
Coating polymer	Hypromellose, polyvinyl alcohol	Protects tablet and improves swallowability
Plasticizer	Polyethylene glycol	Improves coating flexibility
Opacifier or colorant	Titanium dioxide, iron oxides	Appearance and light protection

The formulation must manage two different drug substances. Metformin hydrochloride is highly water soluble and is commonly present at a high mass relative to glyburide. Glyburide has much lower aqueous solubility and is administered at a low dose. That imbalance creates risks of glyburide segregation, content-uniformity failures, and dissolution variability during blending and compression.

How should excipient selection address glyburide's poor solubility?

Glyburide's low solubility makes dissolution control a central technical issue. The preferred strategy is usually to improve wetting and dispersion without creating excessive tablet hardness or delaying release.

High-value formulation approaches

1. Particle-size control
   Micronized glyburide can improve surface area and dissolution. The manufacturer must control particle-size distribution, agglomeration, electrostatic charging, and blend uniformity.

2. Wetting enhancement
   Surfactants or hydrophilic polymers can improve contact between glyburide particles and dissolution media. Candidate systems include poloxamers, sodium lauryl sulfate at tightly controlled levels, and povidone-based wetting systems.

3. Solid dispersion or amorphous dispersion
   A polymeric dispersion can increase apparent solubility, but it introduces physical-stability, moisture-sensitivity, and scale-up risks. This approach may be more suitable for a differentiated 505(b)(2) product than for a low-cost ANDA.

4. Granulation control
   Wet granulation can reduce segregation and improve content uniformity. It can also cause glyburide redistribution, agglomeration, or altered dissolution if liquid addition and drying are not tightly controlled.

5. Surfactant-free design
   A simple microcrystalline-cellulose and disintegrant system may reduce regulatory and supply complexity. It can be commercially attractive if dissolution and bioequivalence remain robust.

The strongest intellectual-property position does not come from naming a conventional excipient. It comes from demonstrating that a defined excipient ratio, particle-size range, or process condition produces a reproducible dissolution and pharmacokinetic profile.

How should excipients manage metformin's high dose and gastrointestinal effects?

Metformin hydrochloride creates a tablet-size problem because the active dose is large. At the 500 mg level, the excipient system must provide sufficient compactibility without producing an excessively large tablet.

Relevant design choices

• High-functionality microcrystalline cellulose can improve tablet strength at lower excipient loading.
• Coprocessed excipients can improve flow and compression in direct-compression processes.
• Povidone or hydroxypropyl cellulose can support granule strength during wet granulation.
• Croscarmellose sodium or crospovidone can offset excessive hardness and maintain rapid disintegration.
• Film coating can improve swallowability and reduce powdering without materially delaying dissolution.
• Hydrophilic matrix polymers can support extended-release metformin, but this changes the product's regulatory and clinical profile.

Immediate-release glyburide/metformin should not be converted into an extended-release product through excipient substitution alone. A modified-release product would require a separate development program, comparative pharmacokinetic work, and potentially a different FDA regulatory pathway.

What formulation patents are commercially attractive?

A formulation patent is more defensible when it claims a measurable performance outcome and a narrow, reproducible composition. Broad claims covering ordinary tablet excipients are vulnerable to prior-art challenges.

More defensible claim concepts

• A defined glyburide particle-size distribution combined with a specified hydrophilic carrier.
• A tablet composition that achieves rapid glyburide dissolution while maintaining metformin release.
• A segregated or bilayer tablet that physically separates the two active ingredients.
• A low-dose glyburide granule embedded within a high-load metformin matrix.
• A coating system that protects glyburide from light or moisture without delaying release.
• A manufacturing process that reduces glyburide content variability across commercial-scale batches.
• A formulation with reduced tablet mass while maintaining dissolution and bioequivalence.
• A modified-release formulation that separates glyburide and metformin release profiles.

Weaker claim concepts

• Use of microcrystalline cellulose without a defined technical result.
• Conventional magnesium stearate lubrication.
• Generic film coating compositions.
• Broad claims covering any glyburide/metformin ratio already disclosed in the reference product.
• Excipient substitutions that do not produce a clinically or analytically measurable advantage.

For a generic product, process know-how may have greater value than patenting. A manufacturer can protect blending order, screen size, granulation endpoint, lubricant-mixing time, coating parameters, and in-process controls as trade secrets.

What FDA pathway applies to new glyburide/metformin products?

A product that matches the reference product in active ingredients, strength, dosage form, route, and labeling can generally pursue an ANDA under section 505(j). The applicant must demonstrate pharmaceutical equivalence and bioequivalence and satisfy chemistry, manufacturing, and controls requirements.[3]

A 505(b)(2) strategy may be appropriate for:

• Extended-release metformin with immediate-release or modified-release glyburide.
• A lower-hypoglycemia formulation using a reduced glyburide dose.
• A bilayer or multilayer delivery system.
• A product with a novel excipient not previously used in the relevant route or dosage form.
• A formulation with a new indication, dosing schedule, or patient population.
• A product supported by a clinical tolerability advantage.

The regulatory value of a novel excipient depends on whether the ingredient is already accepted for oral solid dosage forms, the proposed level, prior human exposure, and the quality of the supporting toxicology package. A conventional excipient strategy minimizes development risk but provides less differentiation.

Which commercial opportunities exist for excipient suppliers?

Excipient suppliers can target this product class through performance, not simple ingredient replacement.

Opportunity 1: High-load direct compression

A co-processed filler-binder that improves flow, tensile strength, and disintegration can reduce granulation steps and manufacturing cost. The commercial proposition is strongest for manufacturers producing multiple metformin combinations on shared equipment.

Opportunity 2: Glyburide content-uniformity platforms

Low-dose glyburide creates a high-value application for engineered carrier particles, ordered mixing, surface-treated excipients, and controlled agglomeration. Suppliers that provide both excipient and process-support data can differentiate from commodity vendors.

Opportunity 3: Dissolution-control systems

A tailored wetting and dispersion platform can address glyburide's dissolution while preserving rapid metformin release. Supporting data should include dissolution across pH conditions, discriminatory methods, stability, and scale-up performance.

Opportunity 4: Low-moisture formulations

Moisture-sensitive processes can benefit from anhydrous excipients, low-water granulation systems, or dry coating technologies. The value is higher where the formulation has long distribution routes or limited environmental control.

Opportunity 5: Taste and swallowability improvements

Film coatings, tablet-size reduction, and lower-friction surfaces can improve adherence. These features are commercial enhancements rather than regulatory exclusivity unless linked to a protected composition or process.

Opportunity 6: Emerging-market fixed-dose combinations

Glyburide/metformin remains relevant in price-sensitive markets where newer agents have limited reimbursement. Opportunities include local manufacture, robust room-temperature stability, lower-cost packaging, and region-specific excipient sourcing.

How does glyburide/metformin compare with newer diabetes combinations?

Glyburide/metformin has a lower acquisition cost than newer combinations but faces clinical and commercial pressure from therapies with lower hypoglycemia risk, weight benefit, cardiovascular outcomes data, or once-weekly dosing.

Product class	Main advantage	Main disadvantage versus glyburide/metformin
Metformin plus sulfonylurea	Low cost and established use	Hypoglycemia and weight gain risk
Metformin plus DPP-4 inhibitor	Lower hypoglycemia risk	Higher cost; less weight benefit
Metformin plus SGLT2 inhibitor	Cardiovascular, renal, and weight benefits for selected patients	Higher cost and infection-related adverse effects
Metformin plus GLP-1 receptor agonist	Weight loss and potent glucose lowering	Injectable or higher-cost oral products
Metformin extended release	Improved gastrointestinal tolerability for some patients	Does not provide sulfonylurea activity
Glyburide/metformin generic	Low price and two-drug convenience	Mature product with limited differentiation

The strongest commercial niche is cost-sensitive treatment where prescribers and health systems prioritize low acquisition cost and established supply. The weakest niche is premium chronic-care formularies that favor newer agents with outcome data.

What generic entry risks exist?

Generic entry is already established, so the strategic question is competitive erosion rather than first entry. Key risks include:

• Price compression from multiple ANDA holders.
• Substitution among equivalent strengths.
• Shortage exposure if few suppliers produce low-volume strengths.
• Variability in excipient supply and source qualification.
• Manufacturing failures caused by glyburide segregation.
• Dissolution differences after scale-up or site transfer.
• Labeling constraints related to renal function, hypoglycemia, and lactic acidosis.
• Low reimbursement margins that limit investment in differentiated formulations.

The 1.25 mg/250 mg strength may offer less volume but can provide a supply-continuity niche if competitors focus on the higher-volume 2.5 mg/500 mg and 5 mg/500 mg strengths.

What licensing opportunities exist?

Licensing opportunities are more likely to involve formulation technology, manufacturing platforms, or regional commercialization rights than the underlying drug combination.

Potential deal structures

Asset	Likely transaction
Direct-compression platform	Nonexclusive excipient or technology license
Glyburide uniformity process	Know-how license with technical transfer
Extended-release combination	Exclusive development or territory license
Regional generic registration	Distribution or marketing authorization transfer
Coated tablet platform	Supply agreement with formulation support
Combination product dossier	ANDA or dossier acquisition

A formulation licensor should seek claims or trade secrets that are difficult to design around and should tie royalties to measurable value, such as reduced manufacturing cost, fewer rejected batches, shorter development time, or premium pricing.

What is the patent strength of the glyburide/metformin estate?

The legacy estate is weak as a barrier to ordinary immediate-release generic competition because the active ingredients and reference dosage form are mature. Patent strength is higher for a genuinely differentiated formulation that demonstrates:

• A non-obvious technical problem.
• A defined composition or process.
• Reproducible dissolution or pharmacokinetic performance.
• Stability across commercial storage conditions.
• A clinically relevant benefit or manufacturing advantage.
• Limited design-around options.

The practical protection hierarchy is usually:

1. Approved product exclusivity, where available.
2. Narrow formulation patents with validated performance.
3. Method-of-use patents with enforceable, differentiated labeling.
4. Manufacturing-process patents.
5. Trade secrets covering scale-up and quality controls.
6. Conventional excipient substitutions.

Key Takeaways

• Glyburide/metformin is a mature generic fixed-dose combination with no biosimilar exposure.
• The main formulation problem is balancing low-dose, poorly soluble glyburide with high-dose, highly soluble metformin.
• Excipient value lies in content uniformity, dissolution, compressibility, tablet-size reduction, stability, and manufacturing yield.
• Conventional immediate-release products generally fit the ANDA pathway.
• Extended-release, bilayer, lower-glyburide, or clinically differentiated products may require a 505(b)(2) strategy.
• The strongest commercial opportunities are engineered excipients, low-cost high-load compression, glyburide dispersion systems, and supply-reliable regional products.
• Legacy patent protection is unlikely to prevent ordinary generic competition. New protection must rest on narrow composition, process, or performance claims.
• No biosimilar strategy applies because both active ingredients are small molecules.
• Revenue opportunity is volume-driven and concentrated in price-sensitive markets, contract manufacturing, and differentiated formulation platforms.

FAQs

Can glyburide and metformin be combined in a bilayer tablet?

Yes. A bilayer tablet can separate the low-dose glyburide fraction from the high-load metformin fraction and improve control of dose uniformity or release. It would require comparative dissolution, stability, mechanical-strength, and bioequivalence evidence.

Which excipient is most important for glyburide dissolution?

No single excipient is universally optimal. Particle-size control, wetting agents, hydrophilic binders, disintegrants, and granulation conditions must be evaluated as an integrated system.

Is glyburide/metformin suitable for an extended-release product?

It can be technically developed, but extended release changes the pharmacokinetic profile and regulatory requirements. The product would need a new formulation strategy rather than a simple excipient substitution.

Can an excipient supplier obtain patent protection for a glyburide/metformin formulation?

Yes, if the formulation contains a novel and non-obvious composition or process tied to a measurable performance result. A patent covering only conventional excipients at routine levels is less likely to provide durable protection.

Does a generic glyburide/metformin product face biosimilar competition?

No. Biosimilars apply to biological products. Glyburide and metformin are small-molecule active ingredients, so competition occurs through generic-drug pathways such as ANDAs.

References

1. U.S. Food and Drug Administration. (2000). Glucovance (glyburide and metformin hydrochloride) tablets: Prescribing information. FDA.

2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.

3. U.S. Food and Drug Administration. (2022). Abbreviated new drug application process under section 505(j) of the Federal Food, Drug, and Cosmetic Act. FDA.

4. U.S. Food and Drug Administration. (2024). Inactive ingredient database. FDA.

5. U.S. Pharmacopeial Convention. (2024). United States Pharmacopeia and National Formulary. USP.