List of Excipients in Branded Drug BUSPIRONE HCL

Generic Drugs Containing BUSPIRONE HCL

Company	Ingredient	NDC	Excipient
Direct Rx	buspirone hcl	72189-235	ANHYDROUS LACTOSE
Direct Rx	buspirone hcl	72189-235	CELLULOSE, MICROCRYSTALLINE
Direct Rx	buspirone hcl	72189-235	MAGNESIUM STEARATE
Direct Rx	buspirone hcl	72189-235	SILICON DIOXIDE
Direct Rx	buspirone hcl	72189-235	SODIUM STARCH GLYCOLATE TYPE A POTATO

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

# Of NDCs	Excipient
1	ANHYDROUS LACTOSE
1	CELLULOSE, MICROCRYSTALLINE
1	MAGNESIUM STEARATE
1	SILICON DIOXIDE
1	SODIUM STARCH GLYCOLATE TYPE A POTATO

Buspirone HCl Excipient Strategy and Commercial Opportunities

Last updated: August 16, 2026

Buspirone hydrochloride is an off-patent, immediate-release anxiolytic with established generic competition and limited conventional patent protection. Commercial value is concentrated in formulation execution rather than active-ingredient exclusivity. The strongest opportunities are robust low-dose tablets, orally disintegrating or multiparticulate products, improved food-effect control, pediatric-friendly dosage forms, and reliable global supply.

What is the regulatory and commercial profile of buspirone HCl?

Buspirone hydrochloride is an oral azaspirodecanedione used primarily for the management of anxiety disorders. In the United States, the reference product was BuSpar, and generic buspirone hydrochloride tablets are marketed in several strengths.

Attribute	Buspirone HCl
Active ingredient	Buspirone hydrochloride
Drug class	Azapirone anxiolytic
Primary receptor activity	Partial agonist at 5-HT1A receptors
Dosage form	Immediate-release oral tablet
Common strengths	5 mg, 7.5 mg, 10 mg, 15 mg, 30 mg
Administration	Usually divided doses, with or without food
FDA pathway for standard generic	Abbreviated New Drug Application, or ANDA
Reference product	BuSpar
Current exclusivity profile	Legacy product; no meaningful current market exclusivity expected
Biosimilar relevance	None; buspirone is a small molecule
Main commercial constraint	Generic price competition

Buspirone has low and variable systemic exposure after oral administration because of extensive first-pass metabolism. Its absolute bioavailability is approximately 4%, according to U.S. prescribing information. Peak plasma concentrations generally occur within 40 to 90 minutes after administration.

The drug is metabolized mainly through CYP3A4. Formulation development must therefore avoid excipient choices that materially alter gastrointestinal transit, dissolution, intestinal permeability, or food-related exposure.

What excipient strategy is appropriate for buspirone HCl tablets?

The preferred strategy for a conventional generic is a simple, robust immediate-release formulation that meets dissolution, content-uniformity, stability, and bioequivalence requirements across all marketed strengths.

A typical platform may contain:

• Microcrystalline cellulose as a diluent and compression aid
• Lactose monohydrate or anhydrous lactose as a soluble filler
• Povidone or copovidone as a binder
• Croscarmellose sodium, sodium starch glycolate, or crospovidone as a disintegrant
• Colloidal silicon dioxide as a glidant
• Magnesium stearate or sodium stearyl fumarate as a lubricant
• Film-coating polymers such as hypromellose, polyethylene glycol, titanium dioxide, and approved colorants

The exact combination must be selected against the active pharmaceutical ingredient’s particle-size distribution, bulk density, flow, compressibility, hygroscopicity, and electrostatic behavior. Excipients listed in approved buspirone products vary by manufacturer and should be verified against current DailyMed labeling and FDA product records.[1,2]

How should the formulation address buspirone HCl solubility?

Buspirone hydrochloride is generally suitable for immediate-release oral dosage forms, but low dose strength creates manufacturing risks. At 5 mg, the active ingredient may represent a small fraction of total tablet weight. This increases the risk of blend segregation and content-uniformity failures.

The preferred controls are:

1. Geometric dilution or ordered blending. The active should be distributed through a controlled premix before final blending.
2. Narrow particle-size specifications. Excessively fine material may increase cohesion and segregation.
3. Granulation where needed. Wet granulation can improve content uniformity and flow but introduces moisture and drying variables.
4. Direct compression where justified. Direct compression reduces processing steps but requires strong flow and compactibility from the active-excipient blend.
5. Low-shear lubrication. Excessive magnesium stearate blending can slow dissolution and reduce tablet tensile strength.

Buspirone HCl may be formulated without complex solubilization technology for a standard tablet. Cyclodextrins, surfactants, lipid systems, and amorphous solid dispersions would add regulatory and manufacturing complexity without a clear commercial benefit unless the developer is pursuing a new dosage form or a pharmacokinetic advantage.

Which excipients create the greatest technical risk?

The principal formulation risks are dissolution delay, dose nonuniformity, excessive friability, and variability caused by food or gastrointestinal conditions.

Risk	Likely cause	Development response
Low-dose content variability	Segregation or inadequate premixing	Control particle size, use geometric dilution, validate blend uniformity
Slow dissolution	Excess lubricant, over-compression, hydrophobic coating	Optimize lubricant level, compression force, and coating weight
Capping or lamination	Poor compaction, excess fines, inadequate dwell time	Adjust granulation, tooling, and compression parameters
High friability	Weak binder system or insufficient compression	Optimize binder and tablet hardness
Food-related exposure variability	Rapid dissolution combined with buspirone’s high first-pass metabolism	Match reference dissolution and assess fed/fasted behavior
Moisture instability	Hygroscopic excipients or moisture-sensitive blend	Use controlled humidity, desiccant packaging, and accelerated stability testing
Color or appearance inconsistency	Multi-strength coating or pigment variation	Use standardized coating systems and in-process controls

Magnesium stearate is commercially convenient but should be tightly controlled. Buspirone formulations depend on rapid and consistent release, so over-lubrication can create avoidable dissolution risk. Sodium stearyl fumarate may be considered when the development team needs lower hydrophobicity, although its cost and compaction behavior must be assessed.

What formulations are protected or commercially differentiated?

Conventional buspirone HCl tablets are difficult to differentiate through formulation alone because the reference product and generic market establish a low-cost immediate-release standard. Commercial differentiation requires a measurable benefit in administration, adherence, supply reliability, or patient usability.

Orally disintegrating tablets

An orally disintegrating tablet could target patients who have difficulty swallowing, patients receiving outpatient psychiatric care, or settings where water is unavailable. The formulation would require:

• Efficient superdisintegrants
• Low tablet friability
• Acceptable mouthfeel
• Taste masking
• Rapid wetting and dispersion
• Packaging protection against moisture

Buspirone may have a bitter or otherwise objectionable taste profile. Taste masking could use ion-exchange resins, polymer coatings, flavor systems, or lipid barriers. Each approach creates additional dissolution and bioequivalence work.

A novel orally disintegrating dosage form would likely require a regulatory strategy beyond a straightforward ANDA if the dosage form or inactive-ingredient profile materially differs from the approved reference product. Depending on the claims and formulation changes, a 505(b)(2) application may be more appropriate than an ANDA.[3]

Multiparticulates and sprinkle formulations

Mini-tablets or coated multiparticulates could support administration to patients with swallowing difficulties. A sprinkle product could have value in institutional care, home health, or selected pediatric populations.

The main development barriers are:

• Uniform distribution of a low-dose active
• Taste masking after opening or sprinkling
• Stability after container opening
• Demonstration that the dosage is not chewed or crushed
• Compatibility with soft foods
• Appropriate labeling for administration

Modified-release formulations

A sustained-release buspirone product could reduce the need for multiple daily doses. It would also face substantial development risk. Buspirone’s short effective exposure profile, CYP3A4 metabolism, food effect, and dose-titration requirements make modified release pharmacologically nontrivial.

A modified-release product may require a new clinical and pharmacokinetic rationale. A release profile that reduces peak concentrations could alter therapeutic response or tolerability. Extended-release technology therefore offers a larger potential market distinction but also the highest regulatory and formulation risk.

Liquid and pediatric-friendly products

An oral solution or suspension could address patients who cannot use tablets. This opportunity is technically attractive but requires careful control of:

• Chemical stability in aqueous media
• pH
• Preservative effectiveness
• Container-closure compatibility
• Dose uniformity
• Palatability
• Microbial limits

A liquid formulation may also increase the risk of dosing errors. Unit-dose packaging, calibrated oral syringes, or concentrated presentations could improve commercial usability.

When does buspirone lose exclusivity, and what is the Orange Book status?

Buspirone is an established generic product. The original innovator exclusivity period has long expired, and generic manufacturers compete through ANDAs.

The Orange Book should be used to verify current listed patents, exclusivity, reference-product status, and therapeutic-equivalence codes. For a legacy product such as buspirone hydrochloride tablets, the principal commercial expectation is that no active composition-of-matter or basic formulation patent blocks routine generic entry. Any current patent listing would need to be reviewed at the specific strength and dosage-form level.[4]

Exclusivity issue	Buspirone HCl assessment
New chemical entity exclusivity	Expired
Original product patent protection	Expired or commercially irrelevant
Current generic pathway	ANDA for pharmaceutically equivalent immediate-release tablets
Biosimilar pathway	Not applicable
Paragraph IV significance	Limited for basic legacy tablets unless a current listed patent exists
Formulation patent risk	Relevant only for specific novel dosage forms or manufacturing processes
Regulatory exclusivity opportunity	Possible only through a qualifying new formulation, pediatric program, or other statutory pathway

How do Paragraph IV challenges affect buspirone generic entry?

A Paragraph IV certification is relevant when an ANDA applicant challenges a patent listed in the Orange Book. For ordinary buspirone HCl tablets, the commercial importance of Paragraph IV litigation is likely lower than for newer branded products because the original product is long off-patent.

The main scenarios are:

1. Routine ANDA entry. The applicant certifies that no relevant patent is listed or uses a non-infringement or invalidity position against any listed patent.
2. Novel dosage-form challenge. A new orally disintegrating, sprinkle, liquid, or modified-release product may have formulation patents that create a separate patent landscape.
3. Manufacturing-process challenge. Process patents may affect a specific supplier or product but generally do not block all buspirone tablet competition.
4. Settlement risk. Settlement agreements matter only if a listed patent remains enforceable and the parties negotiate a delayed entry date.

No biosimilar challenge is relevant because buspirone is a chemically synthesized small molecule rather than a biologic.

What manufacturing and intellectual-property barriers exist?

The largest barriers are operational rather than patent-based.

Manufacturing barriers

Buspirone products require reliable control of low-dose blending, tablet compression, dissolution, and packaging. Manufacturers with established oral-solid-dose infrastructure have an advantage in:

• Low-dose content uniformity
• Multi-strength scale-up
• High-speed compression
• Stability testing
• Cost-efficient packaging
• Regulatory maintenance across multiple markets

A supplier change for the active ingredient can alter particle size, polymorphic form, flow, and dissolution. Any change should be assessed through comparative characterization, process validation, and regulatory change-control procedures.

Intellectual-property barriers

Potentially relevant rights may cover:

• Orally disintegrating tablets
• Taste-masked buspirone particles
• Multiparticulate systems
• Modified-release matrices
• Liquid formulations
• Packaging or dispensing systems
• Specific manufacturing processes

These rights would not normally prevent competition in standard immediate-release tablets unless they are necessary to produce the marketed product. Freedom-to-operate analysis should distinguish product claims from optional process or delivery-system claims.

Which companies are competing in buspirone HCl?

Competition is fragmented across generic pharmaceutical companies and contract manufacturers. Market participants have historically included large generic suppliers, regional manufacturers, and authorized distributors. The relevant competitive variables are:

• FDA-approved product availability
• Supply continuity
• Wholesale acquisition cost
• Contract pricing
• Number of strengths
• Bottle and unit-dose packaging
• Backorder history
• DMF and API sourcing
• State and institutional formulary access

A company entering the standard tablet market is unlikely to win through premium pricing. It must compete through dependable supply, complete strength coverage, efficient packaging, or a differentiated dosage form.

Current manufacturer rankings, market share, and revenue exposure require live IQVIA, Symphony Health, FDA shortage, wholesaler, and company-disclosure data. They should not be inferred from approval counts alone.

What are the commercial opportunities for buspirone excipients?

The most credible opportunities are listed below.

Opportunity	Commercial rationale	Relative risk
Low-cost standard tablets	Large established market and straightforward ANDA pathway	Low
Full-strength portfolio	Supports pharmacy and institutional contracting	Low
Moisture-robust formulation	Reduces stability and packaging failures	Low to moderate
Orally disintegrating tablet	Patient convenience and adherence positioning	Moderate to high
Taste-masked sprinkle product	Swallowing-difficulty and pediatric potential	High
Oral solution or suspension	Administration flexibility	Moderate to high
Modified-release tablet	Potential dosing convenience	High
Coated multiparticulates	Flexible administration and taste control	High
Excipient platform licensing	Can support multiple low-dose CNS products	Moderate

The best near-term opportunity is a robust immediate-release platform with strong low-dose uniformity and rapid dissolution. The best differentiated opportunity is an orally disintegrating or taste-masked product, provided the developer can support a defensible regulatory pathway and demonstrate commercial demand.

How does buspirone compare with competing anxiolytics?

Buspirone competes with generic selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, benzodiazepines, hydroxyzine, and other treatments used for anxiety. Its formulation opportunity is shaped by its non-controlled status and absence of the dependence concerns associated with benzodiazepines.

Product category	Formulation advantage	Commercial limitation
Buspirone tablets	Low cost, non-controlled, established use	Multiple daily dosing and delayed clinical effect
Benzodiazepines	Rapid symptomatic relief	Controlled-substance restrictions and dependence risk
SSRIs/SNRIs	Broad psychiatric use and once-daily options	Delayed onset and tolerability concerns
Hydroxyzine	Multiple dosage forms	Sedation and anticholinergic effects
Buspirone ODT or liquid	Administration flexibility	Requires new development and possible 505(b)(2) strategy

Buspirone’s most defensible commercial position is a low-cost, non-controlled anxiolytic with improved administration rather than a premium tablet that offers no patient-facing benefit.

What is the likely generic launch scenario?

For standard buspirone HCl tablets, the likely launch model is immediate commercial entry after ANDA approval, subject to manufacturing capacity, market pricing, and any applicable supply or patent issue.

A successful launch should prioritize:

1. The 5 mg and 10 mg strengths, which support titration and broad prescribing.
2. The 15 mg and 30 mg strengths, which support higher-dose regimens and lower pill burden.
3. A tablet design that supports dose flexibility where permitted by scoring and labeling.
4. Rapid dissolution under multiple pH conditions.
5. Stable supply of API from more than one qualified source.
6. Bottle and unit-dose packaging for retail and institutional channels.

The standard tablet segment is likely to be price sensitive. A differentiated product must justify its development expense through improved adherence, expanded patient access, institutional demand, or a licensing strategy that covers more than buspirone alone.

Key Takeaways

• Buspirone HCl is an established, off-patent small-molecule anxiolytic with no biosimilar issue.
• Standard immediate-release tablets are the lowest-risk commercial opportunity.
• Low-dose blend uniformity, lubricant control, rapid dissolution, and moisture management are the main technical priorities.
• A simple excipient system based on diluents, binders, superdisintegrants, glidants, and controlled lubrication is generally appropriate.
• Orally disintegrating, taste-masked, liquid, sprinkle, and modified-release products offer greater differentiation but may require a 505(b)(2) strategy.
• Current Orange Book listings, patent records, and exclusivity status must be checked at the specific product and dosage-form level.
• Manufacturing reliability is likely to create more commercial value than patent ownership in the conventional tablet market.
• A full-strength product portfolio and dependable API supply are critical for generic contracting.
• The strongest formulation opportunity is a patient-friendly product that improves administration without creating unacceptable food-effect or bioequivalence risk.

FAQs

Is buspirone HCl suitable for an orally disintegrating tablet?

Yes. An orally disintegrating tablet is technically feasible, but taste masking, friability, moisture protection, and bioequivalence are the central development issues.

Which superdisintegrant is best for buspirone tablets?

Crospovidone, croscarmellose sodium, and sodium starch glycolate are reasonable candidates. The choice depends on tablet porosity, compression force, dissolution performance, and stability rather than on a universally preferred excipient.

Does buspirone HCl require a solubility-enhancement system?

Usually not for a conventional immediate-release tablet. Solubilizers or advanced dispersion systems may be justified for a novel dosage form but would increase formulation and regulatory complexity.

Can buspirone be developed as a pediatric liquid?

Yes, but aqueous stability, taste, preservative efficacy, dosing accuracy, and container compatibility require full development and regulatory evaluation.

Is there a viable licensing opportunity around buspirone excipients?

The strongest licensing opportunity is a platform covering taste masking, orally disintegrating delivery, multiparticulates, or low-dose content-uniformity technology that can be applied to buspirone and other central nervous system products.

References

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

2. U.S. Food and Drug Administration. (n.d.). Drugs@FDA: FDA-approved drugs database. https://www.accessdata.fda.gov/scripts/cder/daf/

3. U.S. Food and Drug Administration. (2023). Applications covered by section 505(b)(2). https://www.fda.gov/

4. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.fda.gov/drugsatfda.