List of Excipients in Branded Drug BUSPIRONE HCL

Generic Drugs Containing BUSPIRONE HCL

Company	Ingredient	NDC	Excipient
Blenheim Pharmacal Inc	buspirone hydrochloride	10544-176	CELLULOSE, MICROCRYSTALLINE
Blenheim Pharmacal Inc	buspirone hydrochloride	10544-176	LACTOSE MONOHYDRATE
Blenheim Pharmacal Inc	buspirone hydrochloride	10544-176	MAGNESIUM STEARATE

What are the Most Frequently-Used Excipients in BUSPIRONE HCL?

# Of NDCs	Excipient
3	ANHYDROUS LACTOSE
26	CELLULOSE, MICROCRYSTALLINE
3	COLLOIDAL SILICON DIOXIDE

Buspirone HCl Excipient Strategy and Commercial Opportunities

Last updated: September 5, 2026

Buspirone hydrochloride is a mature, immediate-release anxiolytic with limited patent protection and a highly competitive generic market. The commercial opportunity is not based on exclusivity for the active ingredient. It depends on manufacturing cost, reliable supply, dosage-form differentiation, excipient control, packaging, and targeted regulatory positioning.

The strongest near-term strategy is a robust, low-cost tablet platform using conventional excipients. Higher-value opportunities include lactose-free tablets, orally disintegrating tablets, pediatric liquid formulations, and potentially modified-release or abuse-deterrent presentations. Each differentiated product would need a clear clinical or adherence benefit because buspirone tablets are already widely available as FDA-approved generics.

What is the FDA regulatory status of buspirone hydrochloride?

Buspirone hydrochloride is approved in the United States as an oral tablet for the management of anxiety disorders or short-term relief of anxiety symptoms. The reference product, BuSpar, was originally approved by Bristol-Myers Squibb in 1986. Generic buspirone hydrochloride tablets are approved through the abbreviated new drug application, or ANDA, pathway.

Key FDA and product facts

Attribute	Buspirone hydrochloride
Active ingredient	Buspirone hydrochloride
Drug class	Azaspirodecanedione anxiolytic
Approved dosage form	Immediate-release oral tablet
Common strengths	5 mg, 7.5 mg, 10 mg, 15 mg, 30 mg
Typical administration	Divided doses, taken consistently with or without food
FDA pathway for generics	ANDA
Reference product	BuSpar tablets
Original U.S. approval	1986
Biosimilar pathway	Not applicable
Primary metabolic pathway	CYP3A4
Major formulation issue	Dose flexibility and food-effect consistency

FDA labeling identifies buspirone as an oral drug with extensive first-pass metabolism. Food increases exposure, and patients are generally instructed to take the drug consistently either with or without food. The active metabolite 1-pyrimidinylpiperazine also contributes to pharmacology, although the parent drug is the commercial active ingredient (FDA, 2023a).

What excipients are used in buspirone hydrochloride tablets?

Commercial buspirone tablets commonly use a conventional direct-compression or wet-granulation excipient system. Product-specific formulations differ by manufacturer and strength.

Typical excipient architecture

Functional role	Common excipient options	Commercial rationale
Diluent	Lactose monohydrate, microcrystalline cellulose	Controls tablet weight and compressibility
Binder	Povidone, pregelatinized starch	Improves granule and tablet strength
Disintegrant	Sodium starch glycolate, crospovidone, croscarmellose sodium	Supports rapid tablet breakup
Glidant	Colloidal silicon dioxide	Improves powder flow
Lubricant	Magnesium stearate, sodium stearyl fumarate	Reduces sticking and ejection force
Film former	Hypromellose	Protects tablet surface and improves appearance
Opacifier	Titanium dioxide	Supports color and light protection
Plasticizer	Polyethylene glycol, triacetin	Improves coating flexibility
Colorant	FDA-permitted dyes or iron oxides	Strength identification and product differentiation

DailyMed-listed generic products commonly include combinations of lactose monohydrate, microcrystalline cellulose, sodium starch glycolate, colloidal silicon dioxide, and magnesium stearate. Film-coating systems vary between manufacturers (National Library of Medicine, 2024a, 2024b).

Why excipient selection matters

Buspirone has a relatively low dose per tablet, particularly at the 5 mg and 7.5 mg strengths. The excipient system therefore has a material effect on tablet weight, content uniformity, blend segregation, and compression performance.

A formulation must also support multiple strengths without creating unacceptable changes in dissolution, hardness, friability, or appearance. A common formulation platform across 5 mg, 7.5 mg, 10 mg, 15 mg, and 30 mg tablets can reduce validation and inventory complexity.

What is the best low-cost excipient strategy for generic buspirone?

The most defensible commodity strategy is a conventional immediate-release tablet using widely available compendial excipients.

Recommended base formulation approach

A low-cost formulation can use:

• Microcrystalline cellulose and lactose as primary diluents
• Sodium starch glycolate or crospovidone as the principal disintegrant
• Povidone if granulation or improved mechanical strength is required
• Colloidal silicon dioxide for flow control
• Magnesium stearate at a controlled concentration and lubrication time
• A simple hypromellose film coat for identification and handling

Direct compression offers lower processing cost, but the low drug load at the lower strengths can increase segregation risk. Wet granulation may improve blend uniformity and tablet robustness, but it adds process steps, equipment demand, and residual-moisture controls.

Critical quality attributes

The formulation development program should prioritize:

1. Assay and content uniformity across all strengths.
2. Rapid and reproducible disintegration.
3. Dissolution matching against the reference listed drug.
4. Low friability and acceptable tablet tensile strength.
5. Consistent score-line performance where scoring is claimed.
6. Stability under heat and humidity.
7. Low interaction between magnesium stearate and dissolution performance.
8. Color and imprint differentiation that minimizes medication errors.

A robust design should control lubricant concentration and blending time. Excess magnesium stearate can create a hydrophobic tablet surface and slow dissolution. Excess disintegrant can reduce tablet strength or increase variability during compression.

What formulation opportunities exist for buspirone hydrochloride?

Lactose-free buspirone tablets

Lactose-free tablets could target patients with lactose intolerance, dietary preferences, or excipient sensitivities. Microcrystalline cellulose, mannitol, dibasic calcium phosphate, and starch-based systems can replace lactose.

This opportunity is commercially practical but unlikely to support premium pricing by itself. The product would compete against multiple generic tablets and would need a clear pharmacy, institutional, or specialty-distributor strategy.

Orally disintegrating tablets

An orally disintegrating tablet could improve administration for patients with swallowing difficulty, psychiatric polypharmacy, or adherence problems. Mannitol, crospovidone, low-substituted hydroxypropyl cellulose, and a taste-masking system would be likely components.

Buspirone is not generally associated with severe bitterness comparable to some antibiotics, but taste evaluation remains necessary because an ODT exposes the formulation to the oral cavity. A 5 mg or 10 mg ODT could be more practical than developing every approved strength initially.

An ODT could be pursued through an ANDA if the product meets applicable sameness and bioequivalence requirements. A formulation that materially changes pharmacokinetics, administration conditions, or labeling could require a 505(b)(2) strategy rather than a conventional ANDA.

Oral liquid formulation

A ready-to-use oral solution or suspension could address pediatric, geriatric, and dysphagia markets. The main development issues are:

• Aqueous solubility and pH control
• Chemical stability
• Preservative efficacy
• Container compatibility
• Dose-measuring accuracy
• Flavor and taste masking
• Microbiological control
• In-use stability after opening

A liquid product could use a sugar-free vehicle based on sorbitol, glycerin, propylene glycol, or a combination of suspending and wetting agents. The regulatory value would depend on whether the proposed indication and population fit the approved labeling or require a supplemental clinical package.

Modified-release buspirone

Modified-release buspirone could reduce dosing frequency and improve adherence. The opportunity is technically more complex because buspirone has short apparent half-life, active metabolite exposure, extensive first-pass metabolism, and clinically relevant food effects.

Potential technologies include hydrophilic matrix tablets, multiparticulate pellets, coated beads, and osmotic systems. Development would require careful control of:

• Dose dumping
• Food effects
• Parent-drug and metabolite exposure
• Steady-state pharmacokinetics
• Interpatient CYP3A4 variability
• Conversion from divided immediate-release dosing

A modified-release product may qualify for a 505(b)(2) application if it relies on the established safety and efficacy of buspirone while introducing a new delivery system. The required clinical and pharmacokinetic package would be substantially more demanding than an ordinary ANDA.

What patents protect buspirone hydrochloride products?

The original BuSpar composition and use patents are long expired. Buspirone is a small-molecule generic drug with no biosimilar exclusivity and no meaningful composition-of-matter patent barrier in the United States.

Orange Book and patent position

Issue	Assessment
Original product exclusivity	Expired
Composition-of-matter protection	Expired
Generic pathway	ANDA
Active brand patent moat	None identified for ordinary buspirone tablets
Formulation patents	Possible only for later, product-specific technologies
Method-of-use patents	No practical barrier for the established anxiety indication
Paragraph IV exposure	Possible against future formulation patents, not the legacy molecule
Biosimilar risk	Not applicable

The FDA Orange Book identifies approved products, reference products, and listed patent information. Ordinary buspirone hydrochloride tablets are marketed as generic products rather than protected branded products with a current patent barrier (FDA, 2024).

A new ODT, liquid, depot, or modified-release system could generate formulation or method-of-use claims. Those claims would protect the new presentation, not the underlying buspirone molecule. Claim scope would depend on the specific excipient ratios, release profile, manufacturing process, patient population, or pharmacokinetic characteristics.

When does buspirone lose exclusivity?

Buspirone lost practical market exclusivity decades ago. Generic competition followed the expiration of the original BuSpar patents and regulatory exclusivity. Current commercial competition is therefore based on price, availability, wholesaler access, product quality, and formulation differentiation.

The legacy product has no meaningful 180-day generic exclusivity issue. A future Paragraph IV challenge would be relevant only if a company obtained patents for a new formulation or delivery system and listed those patents in the Orange Book.

Which companies compete in the buspirone market?

The U.S. market includes multiple generic manufacturers and marketers. Product availability can change because companies discontinue products, consolidate portfolios, or adjust production. The competitive field generally includes:

• Large generic manufacturers with national wholesaler contracts
• Contract manufacturers supplying private-label products
• Specialty companies targeting institutional or shortage-sensitive channels
• Distributors marketing products under private labels

The strongest commercial advantages are usually low cost of goods, reliable active pharmaceutical ingredient supply, multiple approved strengths, and the ability to maintain inventory through generic price pressure.

What generic entry risks exist for a new buspirone formulation?

A new entrant faces five primary risks.

Regulatory risk

An ODT, liquid, or modified-release product may not qualify for a simple ANDA if the dosage form changes the route, release profile, inactive ingredients, or labeling requirements. The 505(b)(2) pathway may be required for certain differentiated presentations.

Bioequivalence risk

Buspirone exposure is sensitive to food and metabolism. A formulation that changes absorption rate or extent may produce difficult-to-interpret pharmacokinetic results. Both parent buspirone and relevant metabolite data may affect development decisions.

Commercial substitution risk

Pharmacies often substitute among therapeutically equivalent generic tablets. A new conventional tablet has limited pricing power unless it solves a supply, excipient, or packaging problem.

Manufacturing risk

Buspirone tablets require consistent low-dose blending across several strengths. API particle-size variation, electrostatic behavior, lubricant sensitivity, and blend segregation can produce batch failures.

Patent risk

A differentiated product may be patentable, but patents covering only routine excipient substitutions may have limited strength. Stronger protection would require a defined technical effect, such as a reproducible release profile, improved stability, reduced food effect, or clinically relevant adherence benefit.

How strong is the buspirone patent estate?

The legacy patent estate is weak because the active ingredient and conventional tablet technology are old and widely available. A new estate could be moderate if it combines narrow formulation claims with process, composition, and pharmacokinetic claims.

Stronger patent claim categories

• Defined controlled-release matrices
• Multiparticulate systems with specified coating architecture
• Food-effect reduction
• Improved stability under accelerated conditions
• ODT formulations with defined disintegration and dissolution limits
• Taste-masking compositions with measurable performance
• Pediatric formulations with dose accuracy and in-use stability
• Manufacturing processes that resolve content-uniformity problems

Broad claims covering buspirone with standard lactose, cellulose, and magnesium stearate would face substantial validity and obviousness pressure. Narrow claims tied to a demonstrated technical benefit would be more defensible.

What licensing deals could create value?

Buspirone has limited value as a standalone licensing asset in its conventional tablet form. Licensing opportunities are more credible in three areas:

1. A proprietary ODT or taste-masking platform that can be applied to other CNS drugs.
2. A controlled-release technology with demonstrated buspirone pharmacokinetic performance.
3. A contract manufacturing agreement that guarantees supply of multiple strengths and alternate excipient configurations.

A platform license can create more value than a molecule-specific license because the formulation technology may support additional anxiolytics, antidepressants, antipsychotics, or sleep products.

What commercial strategy is most attractive?

Base case: conventional generic tablet

This strategy has the lowest technical and regulatory risk but the highest price pressure. It is suitable for a manufacturer with efficient compression, coating, packaging, and supply-chain operations.

Moderate-value case: lactose-free or excipient-controlled tablet

This approach has limited development complexity and can address institutional formularies, private-label customers, and patients seeking specific excipient profiles. It should be supported by transparent inactive-ingredient labeling and stable supply.

Higher-value case: ODT or oral liquid

These products can reach underserved administration segments and may command better contract pricing. Their value depends on demonstrated adherence or administration benefits, not the buspirone molecule itself.

Highest-risk case: modified-release formulation

Modified release offers the greatest potential differentiation but carries the highest bioequivalence, food-effect, clinical, and patent-development costs. It is more suitable for a company with CNS pharmacokinetic expertise and an established 505(b)(2) platform.

Key Takeaways

• Buspirone hydrochloride is a mature generic small-molecule drug with no biosimilar issue.
• Conventional immediate-release tablets have low regulatory risk but severe price competition.
• A common excipient platform across 5 mg through 30 mg strengths can reduce manufacturing complexity.
• Lactose-free tablets offer a practical, modest differentiation strategy.
• ODT and oral liquid products provide clearer administration-based opportunities.
• Modified-release buspirone has higher value potential but substantial pharmacokinetic and regulatory risk.
• The original BuSpar patent estate no longer creates a meaningful barrier to generic entry.
• New patent value must come from formulation, delivery, manufacturing, or clinically relevant performance claims.
• Commercial success depends more on supply reliability and channel strategy than on legacy molecule exclusivity.

FAQs

Is buspirone hydrochloride a high-value generic drug?

It is generally a low-margin generic opportunity in standard tablet form. Value improves when the product solves a specific problem involving excipients, swallowing, pediatric dosing, supply reliability, or dosing frequency.

Can a lactose-free buspirone tablet receive FDA approval?

Yes. A lactose-free product can be developed as an ANDA if it satisfies applicable sameness, quality, dissolution, and bioequivalence requirements. The inactive-ingredient change must remain acceptable for the proposed dosage form and route.

Is buspirone suitable for an orally disintegrating tablet?

Yes, but taste, dose uniformity, mechanical strength, disintegration time, and bioequivalence require focused development. A 5 mg or 10 mg ODT may be the most practical initial strength.

Does buspirone have biosimilar competition?

No. Biosimilars apply to biological products. Buspirone is a chemically synthesized small molecule and competes through generic-drug regulation.

Can a new buspirone formulation receive patent protection?

Yes, if the formulation has patentable technical features and satisfies novelty, nonobviousness, written-description, and enablement requirements. Protection would generally cover the new dosage form or manufacturing method rather than buspirone itself.

References

1. DailyMed. (2024a). Buspirone hydrochloride tablet: Product labeling. U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/

2. DailyMed. (2024b). Buspirone hydrochloride tablet, film coated: Product labeling. U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/

3. U.S. Food and Drug Administration. (2023a). Buspirone hydrochloride prescribing information. FDA. https://www.accessdata.fda.gov/

4. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, Orange Book. FDA. https://www.accessdata.fda.gov/scripts/cder/ob/

5. U.S. Food and Drug Administration. (2024). Inactive ingredient database. FDA. https://www.accessdata.fda.gov/scripts/cder/iig/index.cfm