List of Excipients in Branded Drug GLYBURIDE AND METFORMIN HYDROCHLORIDE

Generic Drugs Containing GLYBURIDE AND METFORMIN HYDROCHLORIDE

Company	Ingredient	NDC	Excipient
Actavis Pharma Inc	glyburide and metformin hydrochloride	0228-2751	AMMONIO METHACRYLATE COPOLYMER TYPE B
Actavis Pharma Inc	glyburide and metformin hydrochloride	0228-2751	CELLULOSE, MICROCRYSTALLINE
Actavis Pharma Inc	glyburide and metformin hydrochloride	0228-2751	CROSCARMELLOSE SODIUM
Actavis Pharma Inc	glyburide and metformin hydrochloride	0228-2751	HYPROMELLOSES
Actavis Pharma Inc	glyburide and metformin hydrochloride	0228-2751	MAGNESIUM STEARATE

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

# Of NDCs	Excipient
1	AMMONIO METHACRYLATE COPOLYMER TYPE B
4	CALCIUM CARBONATE
33	CELLULOSE, MICROCRYSTALLINE
1	CI 77891
33	CROSCARMELLOSE SODIUM

Glyburide and Metformin Hydrochloride Excipient Strategy and Commercial Opportunities

Last updated: August 12, 2026

Glyburide/metformin hydrochloride is a mature fixed-dose combination for type 2 diabetes. Its commercial opportunity is primarily in generic supply, cost-efficient manufacturing, dose flexibility, improved tablet performance, and differentiated excipient systems rather than in new-molecule exclusivity. The formulation challenge is asymmetric: metformin hydrochloride is highly water soluble and high dose, while glyburide is poorly soluble and administered at a much lower dose. Excipients must therefore support high drug loading, uniform glyburide distribution, rapid and reproducible dissolution, tablet robustness, and tolerability.

What is glyburide and metformin hydrochloride?

Glyburide/metformin hydrochloride combines a sulfonylurea with a biguanide.

Component	Pharmacologic role	Formulation implication
Glyburide, also called glibenclamide	Stimulates pancreatic insulin release	Low dose, poorly soluble, content-uniformity and dissolution risk
Metformin hydrochloride	Reduces hepatic glucose production and improves insulin sensitivity	High dose, highly soluble, bitter, hygroscopic, and difficult to compress at high loading
Fixed-dose tablet	Reduces pill burden and supports combination therapy	Requires synchronized release and consistent dose delivery

The original branded product, Glucovance, was developed by Bristol-Myers Squibb and received FDA approval in 2000. FDA labeling covered glyburide/metformin hydrochloride tablets in multiple strengths, including 1.25 mg/250 mg, 2.5 mg/500 mg, and 5 mg/500 mg configurations. The product is used with diet and exercise for adults with type 2 diabetes when monotherapy is inadequate or when the patient is already receiving both components separately.[1]

The combination has a clinically important safety limitation. Glyburide can cause hypoglycemia, while metformin carries a lactic acidosis warning in patients with significant renal impairment or other risk factors. Excipient changes must not alter dose delivery, dissolution, gastrointestinal tolerability, or the ability to administer the product with meals.

What excipients are used in glyburide/metformin tablets?

There is no single universal excipient composition. Generic manufacturers can use different excipient systems if the finished product meets applicable quality, bioequivalence, stability, and labeling requirements.

Common excipient categories include:

Formulation function	Candidate excipients	Primary purpose
Diluent or filler	Microcrystalline cellulose, lactose, starch, dibasic calcium phosphate	Adds bulk and supports compression
Binder	Povidone, copovidone, pregelatinized starch, hydroxypropyl cellulose	Improves granule and tablet strength
Disintegrant	Croscarmellose sodium, crospovidone, sodium starch glycolate	Promotes tablet breakup and drug release
Lubricant	Magnesium stearate, sodium stearyl fumarate	Reduces sticking and ejection force
Glidant	Colloidal silicon dioxide	Improves powder flow
Coating	Hypromellose, polyethylene glycol, titanium dioxide, iron oxides	Improves swallowability, appearance, identification, and handling
Moisture control	Film coat, low-moisture excipients, high-barrier packaging	Protects metformin and preserves dissolution performance

Typical immediate-release formulations use microcrystalline cellulose, povidone, croscarmellose sodium, magnesium stearate, and a film-coating system. The precise composition varies by manufacturer and strength.[2]

Excipients should be selected against the drug substance properties, not copied from a reference product without development testing. Metformin hydrochloride can create high tablet mass and compression problems. Glyburide can create blend-uniformity and dissolution problems because of its low dose and low aqueous solubility.

How should the excipient strategy address glyburide’s poor solubility?

Glyburide is the critical dissolution component. Conventional immediate-release products require sufficient wetting, particle dispersion, and disintegration to release the drug consistently.

Particle engineering

The first commercial formulation lever is glyburide particle size. Micronized or controlled-particle-size glyburide can improve surface area and reduce dissolution variability. Particle-size controls should cover:

• D10, D50, and D90 distribution;
• agglomeration;
• polymorphic form;
• specific surface area;
• blend segregation behavior; and
• dissolution profile across pH conditions.

Micronization can increase electrostatic charging and cohesion. A glidant such as colloidal silicon dioxide may improve flow, but excessive glidant can interfere with wetting or tablet strength. The formulation should use the lowest effective level.

Wetting and dispersion

Low levels of surfactant or wetting-promoting excipients may improve glyburide dispersion. Potential candidates include sodium lauryl sulfate or poloxamers, but these require careful evaluation because they can alter dissolution, gastrointestinal tolerability, and bioequivalence.

Crospovidone or croscarmellose sodium can accelerate tablet breakup. Crospovidone may be attractive where rapid wicking and low swelling are desired. Croscarmellose sodium may offer strong disintegration but can create sensitivity to compression force and storage humidity.

Solid-state and enabling systems

A more differentiated product could use:

• amorphous glyburide solid dispersions;
• spray-dried glyburide-polymer systems;
• co-processed excipients;
• lipid-based wetting systems; or
• nanocrystalline glyburide.

These approaches could improve dissolution, but they create a larger regulatory burden. Changes in crystallinity, supersaturation, precipitation, residual solvent, and physical stability must be characterized. For a mature generic product, such systems are most attractive when they solve a documented bioequivalence or manufacturing problem.

How should excipients address metformin hydrochloride’s high dose?

Metformin hydrochloride can account for most of the tablet mass. The formulation must balance dose loading with swallowability and mechanical strength.

Microcrystalline cellulose is commonly useful because it supports direct compression and tablet integrity. However, high levels can produce large tablets. Lactose may improve compactability but can create compatibility concerns for certain manufacturing platforms and may be unsuitable for products marketed to patients avoiding lactose.

Povidone or copovidone can improve granule strength in a wet-granulation process. Excessive binder can delay disintegration and slow glyburide release. Magnesium stearate should be optimized because over-lubrication can reduce tensile strength and impair dissolution.

A two-stage granulation approach may be commercially useful. Metformin can be granulated separately to manage high-dose compression behavior, while micronized glyburide is incorporated through a controlled blending step. This reduces the risk that glyburide will be trapped in dense metformin granules or segregate during downstream processing.

What formulation options are commercially attractive?

Immediate-release generic tablet

The lowest-risk opportunity is an immediate-release tablet matching the reference product’s release profile. The main competitive variables are:

• tablet size;
• robustness;
• dissolution consistency;
• manufacturing yield;
• cost of goods;
• packaging requirements;
• availability across all marketed strengths; and
• ability to secure a competitive ANDA approval.

This segment is likely to face substantial price pressure because the active ingredients are well established and multiple suppliers can manufacture the combination.

Strength-specific optimization

The 1.25 mg/250 mg, 2.5 mg/500 mg, and 5 mg/500 mg strengths present different formulation risks. The lowest glyburide strength has the greatest relative content-uniformity challenge. The highest glyburide strength raises dissolution and dose-related hypoglycemia concerns. A common excipient platform can reduce inventory and validation costs, but strength proportionality must be demonstrated rather than assumed.

Modified-release metformin component

A bilayer or modified-release product could create a more differentiated commercial position, but it would no longer be a simple substitution for an immediate-release combination. A prolonged-release metformin component may reduce gastrointestinal intolerance and dosing frequency, yet the combination would require a new formulation and potentially a different regulatory pathway.

The primary development risks would include:

• release synchronization between glyburide and metformin;
• food-effect behavior;
• dose dumping;
• altered glyburide exposure;
• clinical bridging requirements; and
• a more complex manufacturing process.

Sprinkle, orally disintegrating, or smaller-tablet formats

Alternative dosage forms could address swallowing difficulty and adherence. Their commercial value is uncertain because the high metformin dose can require substantial dosage-form mass. Orally disintegrating tablets may be impractical at 500 mg metformin strength unless the product is engineered as a multiparticulate or rapidly dispersible system.

What is the FDA regulatory status of glyburide/metformin?

Glyburide/metformin hydrochloride is regulated as a conventional small-molecule drug. A generic product generally requires an abbreviated new drug application demonstrating pharmaceutical equivalence and bioequivalence to the relevant reference-listed drug.

Key FDA requirements include:

• same active ingredients;
• same dosage form and route;
• equivalent strength;
• compliance with quality standards;
• acceptable dissolution;
• bioequivalence under applicable FDA guidance;
• stability through the proposed shelf life; and
• labeling consistent with the reference product, subject to permitted differences.

The FDA Orange Book identifies reference-listed drugs, therapeutic equivalence codes, patent information, and exclusivity information for approved products.[3] For this mature combination, the commercial relevance of Orange Book review is primarily identifying the current reference product, approved generic competitors, and any remaining listed patent or exclusivity information.

Is there current NCE or pediatric exclusivity?

The product is long past new chemical entity exclusivity. Any historical five-year NCE period and associated exclusivity would have expired decades ago. Pediatric exclusivity is not expected to create a current barrier for ordinary generic entry.

Are Paragraph IV challenges relevant?

Paragraph IV litigation risk is generally lower for a mature combination than for a recently launched branded product. A generic applicant must still evaluate any Orange Book-listed patents, method-of-use claims, formulation claims, and patent certifications. If no unexpired blocking patent remains listed, the principal barriers are regulatory approval, product development, manufacturing scale, and market economics rather than patent litigation.

What patents protect glyburide/metformin hydrochloride products?

The original combination was developed under an older branded product framework, and any historical composition or use patents associated with the original Glucovance product are unlikely to provide a current market exclusivity period. The commercial analysis should separate three patent categories:

Patent category	Relevance to a new entrant
Combination composition patents	Usually limited for a mature product unless a later patent remains enforceable
Formulation patents	Could cover particle size, solid dispersion, release profile, or excipient architecture
Method-of-use patents	Could cover treatment populations or dosing schedules, subject to labeling and carve-out analysis

A manufacturer pursuing a differentiated formulation could create a new patent estate around particle engineering, manufacturing controls, bilayer architecture, taste masking, stability, or modified release. Excipients themselves are rarely sufficient for strong exclusivity. Patentable value is more likely to arise from the interaction between the excipient system, process parameters, and measurable product performance.

A freedom-to-operate review should cover U.S. patents, continuations, reissues, terminal disclaimers, PCT filings, and major markets including Europe, Japan, Canada, China, Brazil, and Australia. Patent term should be calculated from the earliest effective nonprovisional filing date, with any applicable patent-term adjustment or extension assessed separately.

How strong is the patent estate for glyburide/metformin?

The legacy patent estate is commercially weak relative to protected branded combinations in newer therapeutic classes. The active ingredients are old, the combination has been marketed for many years, and the basic immediate-release concept is established.

A new entrant could still obtain narrower protection around:

• a defined glyburide particle-size distribution;
• a specified dissolution profile;
• a low-segregation blending process;
• a moisture-resistant excipient system;
• a bilayer tablet;
• a metformin extended-release matrix;
• a solid dispersion with defined polymer loading; or
• a formulation that reduces tablet mass while preserving bioequivalence.

The strength of these claims would depend on unexpected results, claim breadth, prior-art separation, reproducibility, and commercial relevance. A patent that protects only a minor excipient substitution would have limited blocking power.

What commercial opportunities exist for manufacturers?

Low-cost generic supply

The largest opportunity is efficient manufacturing of an approved immediate-release generic. Competitive advantage can come from high yield, low tablet weight, robust compression, and reduced analytical failure rates. The product may be attractive in price-sensitive markets with substantial use of metformin and sulfonylureas.

Emerging-market access

Glyburide/metformin may have continued relevance in markets where newer agents such as GLP-1 receptor agonists and SGLT2 inhibitors remain expensive or less accessible. Local manufacturing, regional registration, and tender participation can support volume even when U.S. pricing is compressed.

Contract manufacturing and licensing

Licensing opportunities are more likely to involve:

• an approved ANDA or equivalent national authorization;
• manufacturing capacity;
• regional distribution rights;
• a differentiated excipient platform; or
• a portfolio containing several diabetes products.

The absence of meaningful current compound exclusivity can make a product easier to license, but it also limits pricing power. The value of a transaction will depend on approval status, manufacturing site readiness, market access, supply reliability, and projected tender volume.

Fixed-dose combination portfolio strategy

A manufacturer may use glyburide/metformin as part of a broader diabetes portfolio that includes metformin monotherapy, glyburide monotherapy, glimepiride/metformin, sitagliptin/metformin, dapagliflozin/metformin, or empagliflozin/metformin. The combination can use shared excipient technologies, common packaging operations, and common distribution channels.

What generic launch risks exist?

The main launch risks are operational and clinical rather than patent-based.

Risk	Commercial effect	Mitigation
Glyburide content nonuniformity	Batch rejection or bioequivalence failure	Controlled micronization and staged blending
Slow or variable glyburide dissolution	Exposure variability and regulatory failure	Particle engineering, disintegrant optimization, dissolution mapping
Large tablet size	Poor adherence and lower acceptance	High-load compression, co-processed excipients, size optimization
Metformin gastrointestinal intolerance	Discontinuation and reduced demand	Smooth tablet disintegration and consistent release
Moisture sensitivity	Shelf-life failure	Barrier packaging and low-moisture manufacturing
Price erosion	Low return on investment	Multi-market registration and efficient scale
Hypoglycemia concerns	Lower prescribing relative to newer agents	Clear labeling and targeted use in cost-sensitive settings

How does glyburide/metformin compare with newer diabetes combinations?

Glyburide/metformin has a lower expected development and manufacturing cost than newer combinations, but it also has weaker clinical differentiation and greater safety concerns.

Attribute	Glyburide/metformin	Newer metformin combinations
Active ingredient maturity	Very high	Often lower
Patent barrier	Generally limited	Frequently significant
Tablet cost	Potentially low	Often higher
Hypoglycemia risk	Higher because of glyburide	Varies by partner drug
Weight effect	Glyburide may promote weight gain	Some newer agents support weight loss
Cardiovascular or renal differentiation	Limited	Stronger for selected SGLT2 and GLP-1 therapies
Best commercial markets	Price-sensitive and access-driven	Premium and outcome-focused markets

The product is therefore best positioned as a cost-efficient generic or regional-access product, not as a premium innovation competing directly with patented incretin or SGLT2 therapies.

Key Takeaways

• Glyburide/metformin hydrochloride is a mature fixed-dose combination with limited current compound-level exclusivity.
• The primary formulation challenge is combining high-dose, highly soluble metformin hydrochloride with low-dose, poorly soluble glyburide.
• Micronized glyburide, controlled blending, rapid disintegration, and moisture management are central excipient and process priorities.
• Microcrystalline cellulose, povidone, croscarmellose sodium, crospovidone, magnesium stearate, and film-coating polymers are practical starting points, subject to product-specific development.
• The strongest near-term opportunity is a low-cost immediate-release generic with reliable dissolution and efficient manufacturing.
• Modified-release, bilayer, solid-dispersion, and smaller-tablet concepts could create differentiation but carry higher regulatory and development costs.
• New patents are more likely to protect formulation architecture or manufacturing controls than the basic active-ingredient combination.
• Commercial returns will depend on manufacturing scale, geographic coverage, tender access, and portfolio integration.

FAQs

Can lactose be used in glyburide/metformin tablets?

Yes. Lactose can function as a diluent or compression aid, but its suitability depends on compatibility, moisture behavior, patient labeling considerations, and the selected manufacturing process.

Which excipient is most important for glyburide dissolution?

No single excipient controls performance. Glyburide particle size, wetting, disintegrant selection, compression force, and blend uniformity usually have a greater combined effect than any one excipient.

Is a glyburide/metformin combination eligible for a 505(b)(2) strategy?

A conventional generic is generally pursued through the ANDA pathway. A 505(b)(2) strategy could be relevant for a materially changed dosage form, release profile, route, or formulation that cannot rely solely on ordinary generic equivalence.

Can a new formulation patent block generic glyburide/metformin entry?

A valid, enforceable patent with claims covering the proposed product or its use could create litigation or launch risk. Narrow excipient claims usually provide less practical exclusion than claims tied to a defined product performance or enabling technology.

Does glyburide/metformin have biosimilar competition?

No. Glyburide and metformin hydrochloride are chemically synthesized small molecules, not biologics. Competition proceeds through generic-drug pathways rather than biosimilar applications.

References

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

2. DailyMed. (n.d.). Glyburide and metformin hydrochloride tablets: Inactive ingredients and prescribing information. National Library of Medicine.

3. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book. FDA.

4. U.S. Food and Drug Administration. (2015). Metformin hydrochloride; glyburide tablets: Product-specific guidance for industry. FDA.