List of Excipients in Branded Drug BUSPIRONE

Generic Drugs Containing BUSPIRONE

Company	Ingredient	NDC	Excipient
STAT RX USA LLC	buspirone hydrochloride	16590-600	CELLULOSE, MICROCRYSTALLINE
STAT RX USA LLC	buspirone hydrochloride	16590-600	LACTOSE MONOHYDRATE
STAT RX USA LLC	buspirone hydrochloride	16590-600	MAGNESIUM STEARATE
STAT RX USA LLC	buspirone hydrochloride	16590-600	SILICON DIOXIDE
Direct Rx	buspirone hcl	72189-235	ANHYDROUS LACTOSE
Direct Rx	buspirone hcl	72189-235	CELLULOSE, MICROCRYSTALLINE

What are the Most Frequently-Used Excipients in BUSPIRONE?

# Of NDCs	Excipient
1	CELLULOSE, MICROCRYSTALLINE
1	LACTOSE MONOHYDRATE
1	MAGNESIUM STEARATE
1	SILICON DIOXIDE

Buspirone Excipient Strategy and Commercial Opportunities

Last updated: September 5, 2026

Buspirone is an off-patent, immediate-release anxiolytic with a mature generic market and limited differentiation in conventional tablets. The strongest commercial opportunities are formulation-led: orally disintegrating tablets, oral liquids, adherence-focused products, and modified-delivery systems that reduce dosing frequency. Excipient selection must account for buspirone hydrochloride’s extensive first-pass metabolism, short elimination half-life, food effect, moisture sensitivity, taste, and CYP3A4-mediated drug interactions.

What is the current formulation profile of buspirone?

Buspirone hydrochloride is marketed primarily as an immediate-release oral tablet. U.S. labeling includes 5 mg, 7.5 mg, 10 mg, 15 mg, and 30 mg strengths, with scored tablets supporting dose titration.[1]

Attribute	Buspirone formulation profile
Active ingredient	Buspirone hydrochloride
Therapeutic class	Azaspirodecanedione anxiolytic
Main U.S. indication	Management of anxiety disorders or short-term relief of anxiety symptoms
Approved dosage form	Immediate-release tablet
Common strengths	5 mg, 7.5 mg, 10 mg, 15 mg, 30 mg
Typical administration	Divided oral doses, usually two or three times daily
Elimination half-life	Approximately 2 to 3 hours
Metabolism	Primarily CYP3A4
Food effect	Food increases exposure substantially
Controlled-substance status	Not a controlled substance under the U.S. Controlled Substances Act
Pediatric status	Safety and effectiveness are not established for routine pediatric use in U.S. labeling

Buspirone tablets generally use conventional excipients such as lactose monohydrate, microcrystalline cellulose, colloidal silicon dioxide, sodium starch glycolate, and magnesium stearate. Exact qualitative and quantitative compositions differ by manufacturer and strength.[1,2]

The immediate-release dosage form is technically simple. Its commercial weakness is the need for repeated daily dosing and the absence of a strong delivery-system franchise.

What excipient properties matter most for buspirone?

The excipient strategy should prioritize rapid disintegration, dose uniformity, manufacturability, moisture control, and acceptable taste. Buspirone is administered at relatively low milligram strengths, so blend uniformity and segregation control are more important than bulk drug loading.

Solubility and dissolution

Buspirone hydrochloride is a salt form intended for oral administration. Immediate-release products should achieve rapid dissolution across relevant gastrointestinal pH conditions. Superdisintegrants such as crospovidone, croscarmellose sodium, or sodium starch glycolate can support rapid tablet breakup.

A high-disintegrant formulation should be balanced against:

• Tablet friability
• Lubricant sensitivity
• Compression force
• Moisture uptake
• Gelling or delayed disintegration
• Stability during high-speed tableting

Crospovidone may be attractive for orally disintegrating tablets because it promotes wicking without forming a viscous gel. Croscarmellose sodium can provide strong swelling but may require tighter control of compression and moisture. Sodium starch glycolate is established in conventional tablets but can produce slower performance if overused or exposed to excessive moisture.

Low-dose content uniformity

Buspirone products frequently use 5 mg and 7.5 mg strengths. At these doses, direct compression can be commercially efficient, but the formulation must control segregation between the active ingredient and high-volume fillers.

Suitable approaches include:

• Ordered mixing with microcrystalline cellulose
• Granulation for improved flow and uniformity
• Co-processing of mannitol and microcrystalline cellulose
• Low-shear premixing followed by geometric dilution
• Near-infrared process monitoring for blend uniformity

Mannitol is particularly useful when developing a pleasant-mouthfeel product. Lactose is economical and established, but it is less attractive for lactose-intolerant positioning and may create compatibility or labeling issues for certain patient segments.

Moisture and stability

A moisture-controlled packaging system is relevant for rapidly disintegrating tablets and taste-masked particles. The excipient system should avoid unnecessary hygroscopicity, particularly where sodium starch glycolate, sorbitol, or highly porous carriers are used.

Recommended controls include:

• Low-water-activity excipients
• Aluminum-aluminum blister packaging for premium products
• Desiccant bottles for lower-cost products
• Moisture-barrier film coatings
• Controlled residual water during granulation and drying
• Stability testing under ICH long-term and accelerated conditions

Magnesium stearate concentration and blending time require control because over-lubrication can reduce tablet tensile strength and slow dissolution.

What excipient strategy is best for an orally disintegrating buspirone tablet?

An orally disintegrating tablet, or ODT, is the most practical differentiated formulation opportunity. It could address patients who have difficulty swallowing conventional tablets and could improve convenience during acute anxiety episodes, although it would not remove the need for divided dosing.

A representative ODT platform could include:

Formulation function	Candidate excipient class
Diluent and mouthfeel	Mannitol, erythritol, co-processed mannitol-cellulose
Disintegration	Crospovidone or croscarmellose sodium
Binder	Low-substituted hydroxypropyl cellulose or polyvinylpyrrolidone
Glidant	Colloidal silicon dioxide
Lubricant	Magnesium stearate or sodium stearyl fumarate
Taste masking	Polymer coating, ion-exchange resin, cyclodextrin, or lipid barrier
Flavor system	Mint, berry, or neutral flavor system
Sweetener	Sucralose, acesulfame potassium, or aspartame where appropriate

Taste masking is the principal technical barrier. Buspirone can generate bitterness or unpleasant mouthfeel, and an ODT creates direct exposure to taste receptors. A simple sweetener-only system may be inadequate.

Three taste-masking approaches have commercial relevance:

1. Polymer-coated drug particles. Ethylcellulose, methacrylate copolymers, or other pH-independent barriers can reduce immediate taste release while allowing gastrointestinal release.
2. Ion-exchange resin complexes. These can suppress oral release and release buspirone in the gastrointestinal tract, but resin capacity and dose uniformity must be validated.
3. Cyclodextrin or lipid-based complexes. These may improve palatability but can add cost and introduce scale-up or regulatory complexity.

An ODT should be designed to disintegrate within approximately 30 seconds under the applicable regulatory method without creating a false claim of faster systemic action. Buspirone’s pharmacokinetics and first-pass metabolism, rather than tablet disintegration alone, determine clinical onset.

What commercial opportunities exist for buspirone oral liquids?

An oral solution or suspension could target patients who cannot swallow tablets, including older adults, patients with dysphagia, and care-home populations. The product would also support flexible titration below the lowest marketed tablet strength.

The main formulation challenges are:

• Chemical stability in aqueous media
• Microbial preservation
• Dose uniformity after storage
• Bitter taste
• Sorption to packaging
• Precipitation across pH and temperature ranges
• Compatibility with dosing syringes

A suspension may offer greater stability than a true solution if buspirone concentration, pH, or excipient selection makes solubilization difficult. Suspending agents such as xanthan gum, hydroxypropyl cellulose, or microcrystalline cellulose-carboxymethylcellulose can be considered, but viscosity must remain suitable for oral syringes.

A liquid product could be positioned around titration and swallowing difficulty rather than superior efficacy. The commercial opportunity is likely narrower than for a conventional generic because pharmacies and payers tend to favor low-cost tablets.

Can a modified-release buspirone product reduce dosing frequency?

Modified release is technically possible but commercially and clinically more demanding. Buspirone has a short half-life and is usually administered in divided doses, creating a rationale for extended delivery. A sustained-release formulation could use hydrophilic matrices, multiparticulate pellets, coated beads, or osmotic technology.

Potential matrix excipients include:

• Hypromellose
• Polyethylene oxide
• Carbomers
• Ethylcellulose
• Ammonio methacrylate copolymers
• Glyceryl behenate
• Hydrogenated vegetable oils

The principal risk is that buspirone’s pharmacodynamic benefit and tolerability may depend on exposure patterns that differ from a simple extended-release profile. A modified-release product would likely need comparative pharmacokinetic work and may require clinical evidence under a 505(b)(2) pathway if the sponsor seeks a new dosing regimen or labeling claims not supported by an ANDA.

Food effects require particular attention. The current label reports increased buspirone exposure when administered with food.[1] A new controlled-release system must evaluate fed and fasted conditions, alcohol effects, dose dumping, and interactions with CYP3A4 inhibitors.

What regulatory pathway applies to a new buspirone formulation?

A conventional tablet that is pharmaceutically equivalent and bioequivalent to a reference listed drug can generally proceed through an abbreviated new drug application, or ANDA. A product with a materially different dosage form, route, release profile, or clinical claim may require a 505(b)(2) application.

Product concept	Likely U.S. pathway
Conventional immediate-release tablet	ANDA if bioequivalent and pharmaceutically equivalent
Different-strength generic tablet	ANDA, subject to applicable requirements
ODT equivalent to an eligible reference	ANDA may be possible if the product meets equivalence requirements
Oral solution or suspension	ANDA or 505(b)(2), depending on reference and equivalence framework
Extended-release tablet	Usually 505(b)(2) if no suitable reference pathway applies
Buccal or sublingual product	Generally 505(b)(2)
New pediatric or adherence claim	May require additional clinical and regulatory support

The Orange Book should be reviewed for the current reference listed drug, patent listings, exclusivity, and dosage-form status before selecting a filing strategy.[3] Historical buspirone exclusivity and core composition-of-matter protection have expired. The commercial protection for a new product would therefore depend on formulation patents, regulatory exclusivity where available, trademarks, manufacturing know-how, and market access.

What patents protect buspirone formulations?

Core buspirone compound protection is expired in the United States. Generic buspirone has been marketed for many years, and the active ingredient is not protected by a current composition-of-matter monopoly.

The potentially relevant protection for a new entrant would come from:

• ODT composition patents
• Taste-masked particle patents
• Extended-release matrix or multiparticulate patents
• Oral liquid stabilization patents
• Manufacturing-process patents
• Device or packaging patents
• Narrow method-of-use patents

The strength of these rights would depend on claim breadth, freedom-to-operate analysis, prior-art density, and whether the claims cover commercially necessary excipients or only optional formulation variants. A patent limited to one polymer ratio or one dissolution window may be easier to design around than a broad particle-engineering claim.

Because buspirone is a mature molecule, patentability risk is high for routine combinations of known excipients. A defensible filing should establish an unexpected technical result, such as improved taste masking without delayed release, reduced food sensitivity, superior stability, or a clinically meaningful exposure profile.

What is the Orange Book and litigation status for buspirone?

Buspirone’s historical pioneer product was Bristol-Myers Squibb’s BuSpar. The market now consists mainly of generic manufacturers. The core product has no remaining pioneer exclusivity of commercial significance.

No major active patent-litigation strategy is generally associated with the mature U.S. buspirone tablet market. Paragraph IV risk would arise if a company lists new formulation patents for an ODT, liquid, or modified-release product and generic challengers file ANDAs alleging invalidity, noninfringement, or unenforceability.

For a conventional generic, the principal risks are usually:

• ANDA approval timing
• Bioequivalence failure
• Manufacturing cost
• Contracting with wholesalers and pharmacy benefit managers
• Price erosion
• Limited differentiation

How does buspirone compare with competing anxiety medicines?

Buspirone competes with generic selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, hydroxyzine, benzodiazepines, and newer branded anxiety products.

Product class	Formulation opportunity	Commercial implication
Buspirone tablets	ODT, liquid, extended release	Low-cost active with room for convenience differentiation
SSRIs and SNRIs	Liquid, delayed release, multiparticulate	Larger established markets but stronger generic competition
Benzodiazepines	ODT, oral solution, extended release	Higher misuse and regulatory concerns
Hydroxyzine	Capsules, tablets, liquid	Sedation and anticholinergic positioning issues
New branded anxiolytics	Proprietary formulations and indications	Higher pricing but greater clinical and regulatory cost

Buspirone has a relative commercial advantage in having no controlled-substance scheduling and lower abuse concerns than benzodiazepines. It has a relative disadvantage in slow commercial adoption, divided dosing, and the availability of inexpensive generic alternatives.

What revenue exposure and launch scenarios exist?

Public companies generally do not report buspirone revenue separately because the product is a small component of diversified generic portfolios. A conventional tablet launch is therefore likely to face immediate price competition unless the entrant has a manufacturing-cost advantage or a supply agreement.

The strongest launch scenarios are:

1. Low-cost tablet supply. The product competes on reliable supply, multiple strengths, and low cost.
2. ODT niche product. The product targets swallowing difficulty and adherence, with a higher unit price but smaller volume.
3. Oral liquid. The product targets institutional care, dysphagia, and flexible titration.
4. Extended-release product. The product seeks once-daily or reduced-frequency dosing, but requires greater clinical and regulatory investment.
5. Combination or co-packaging strategy. The sponsor improves adherence or titration through packaging rather than creating a new pharmacologic product.

Geographic opportunities are strongest where buspirone is approved and where generic supply is fragmented. U.S. products face ANDA competition and payer pressure. European and other markets require country-specific formulation, bioequivalence, labeling, and reimbursement analysis.

How strong is the buspirone formulation opportunity?

The opportunity is moderate for differentiated delivery and weak for another conventional tablet. The most credible product strategy is an ODT or oral liquid built around taste masking, dose flexibility, and patient usability.

Opportunity	Technical complexity	Differentiation	Commercial attractiveness
Standard tablet	Low	Very low	Low
ODT	Moderate	Moderate	Moderate
Oral solution	Moderate	Moderate	Moderate in institutional care
Oral suspension	Moderate	Moderate	Selective
Extended release	High	High	Potentially high, with regulatory risk
Buccal or sublingual	High	High	Uncertain
Pediatric formulation	Moderate to high	Moderate	Limited by labeling and clinical requirements

Key Takeaways

• Buspirone is a mature, off-patent molecule dominated by immediate-release generic tablets.
• Excipient strategy should focus on rapid disintegration, low-dose content uniformity, moisture control, and taste masking.
• ODT and oral-liquid products offer the clearest near-term formulation opportunities.
• Extended release could reduce dosing frequency but would carry greater pharmacokinetic, food-effect, and regulatory risk.
• Routine excipient combinations are unlikely to support strong patent protection without unexpected technical results.
• Conventional tablet launches face substantial price erosion and limited standalone revenue visibility.
• The best commercial positioning is convenience, swallowing support, titration flexibility, or supply reliability rather than a new anxiolytic mechanism.
• Current Orange Book listings, patent claims, and reference-product status must control the final freedom-to-operate and regulatory assessment.

FAQs

Can buspirone be formulated as an orally disintegrating tablet?

Yes. An ODT is technically feasible, but taste masking, dose uniformity, friability, moisture protection, and rapid disintegration must be validated.

Which excipient is best for buspirone taste masking?

No single excipient is universally optimal. Polymer-coated particles, ion-exchange resins, and cyclodextrin-based systems are the principal platforms for screening.

Does buspirone have a strong remaining composition-of-matter patent?

No. Core U.S. composition-of-matter protection has expired. New commercial protection would need to come from formulation, manufacturing, packaging, or method-of-use claims.

Could a buspirone extended-release product qualify for an ANDA?

Possibly, but the pathway depends on the existence of a suitable reference product and whether the proposed release profile and labeling fit the abbreviated pathway. A 505(b)(2) application may be required for a materially new release system.

Is buspirone commercially attractive for a specialty generic manufacturer?

It can be attractive as a differentiated formulation, particularly an ODT or oral liquid. A conventional tablet has limited strategic value unless the manufacturer has a cost, supply, channel, or contracting advantage.

References

1. U.S. Food and Drug Administration. (2024). Buspirone hydrochloride tablets: U.S. prescribing information. DailyMed.

2. National Library of Medicine. (2024). Buspirone hydrochloride tablet: Inactive ingredients and product labeling. DailyMed.

3. U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.