List of Excipients in Branded Drug DARAPRIM

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Vyera Pharmaceuticals LLC	DARAPRIM	pyrimethamine	69413-330	LACTOSE
Vyera Pharmaceuticals LLC	DARAPRIM	pyrimethamine	69413-330	MAGNESIUM STEARATE
Vyera Pharmaceuticals LLC	DARAPRIM	pyrimethamine	69413-330	STARCH, CORN
Vyera Pharmaceuticals LLC	DARAPRIM	pyrimethamine	69413-330	STARCH, POTATO
TILDE Sciences LLC	DARAPRIM	pyrimethamine	83649-330	LACTOSE
TILDE Sciences LLC	DARAPRIM	pyrimethamine	83649-330	MAGNESIUM STEARATE

Daraprim Excipient Strategy and Commercial Opportunities for Pyrimethamine Tablets

Last updated: August 27, 2026

Daraprim is a 25 mg immediate-release pyrimethamine tablet used with a sulfonamide and folinic acid for toxoplasmosis. Its commercial opportunity is driven less by molecule-level patent protection than by supply reliability, generic competition, dosage flexibility, pediatric usability, and lower-cost access. Excipients can support differentiated products, but a conventional 25 mg tablet remains the lowest-risk regulatory and manufacturing pathway.

What is Daraprim and which excipients does it contain?

Daraprim contains pyrimethamine, an antiparasitic diaminopyrimidine. The FDA-approved product is an oral tablet containing 25 mg of active ingredient. Treatment generally includes a sulfonamide and folinic acid because pyrimethamine can produce dose-related bone-marrow suppression. The product is used for toxoplasmosis, including disease in immunocompromised patients and congenital infection under specialist supervision (FDA, 2020).

The FDA-approved labeling identifies the inactive ingredients as lactose, corn starch, magnesium stearate, and sodium starch glycolate. The exact commercial formulation, supplier grades, processing conditions, and manufacturing controls may not be fully disclosed in public labeling.

Product attribute	Daraprim profile
Active ingredient	Pyrimethamine
Strength	25 mg
Dosage form	Immediate-release tablet
Administration	Oral
Primary use	Toxoplasmosis
Typical combination therapy	Sulfonamide plus folinic acid
Regulatory application	NDA 008578
Primary formulation opportunity	Generic immediate-release tablet
Main excipient issues	Low-dose content uniformity, dissolution, lactose tolerance, tablet robustness

The low drug load is important. Each tablet contains 25 mg of pyrimethamine, so excipient selection and blending control have a direct effect on content uniformity. The product also requires adequate mechanical strength without creating a dissolution delay.

What excipient strategy is appropriate for a Daraprim generic?

The most defensible strategy is a Q1/Q2-matched immediate-release tablet using excipients with established oral-use precedent. Q1 matching means using the same inactive ingredients. Q2 matching means matching their concentrations within applicable regulatory expectations.

A conventional formulation may use:

Formulation function	Candidate excipients	Commercial rationale
Diluent	Lactose monohydrate, microcrystalline cellulose, dibasic calcium phosphate	Controls tablet mass and supports dose uniformity
Disintegrant	Sodium starch glycolate, croscarmellose sodium, crospovidone	Supports rapid tablet breakup
Binder	Povidone, hydroxypropyl cellulose, pregelatinized starch	Improves granule and tablet strength
Glidant	Colloidal silicon dioxide	Improves powder flow
Lubricant	Magnesium stearate, sodium stearyl fumarate	Reduces sticking and ejection force
Taste and swallowability aid	Film coating, permitted flavor system	May improve pediatric administration
Colorant	Approved color system	Supports product identification and differentiation

The lowest-risk route would retain lactose, corn starch or an equivalent starch system, a superdisintegrant, and magnesium stearate. A formulation that replaces lactose with microcrystalline cellulose could target patients with lactose sensitivity, although lactose in a 25 mg tablet is unlikely to be the principal clinical concern for most users.

Which excipients matter most for low-dose pyrimethamine?

Content uniformity is the primary technical issue. Pyrimethamine must be distributed consistently throughout the blend despite its relatively low concentration. A direct-compression process may be viable if the active pharmaceutical ingredient has suitable flow and particle-size characteristics. Wet granulation can reduce segregation but introduces moisture, drying, and scale-up variables.

Critical development controls include:

1. Particle-size distribution of pyrimethamine.
2. Ordered mixing or geometric dilution for low-dose uniformity.
3. Blend segregation during transfer and hopper feeding.
4. Magnesium stearate mixing time, which can affect tablet strength and dissolution.
5. Tablet hardness and friability.
6. Disintegration and dissolution across the proposed shelf life.
7. Assay and content uniformity at batch release.

A supplier should avoid unnecessary excipient complexity. Each additional excipient creates another qualification, supply, extractables, compatibility, and regulatory-change-management obligation.

What formulation patents protect Daraprim?

Daraprim has limited modern formulation-patent protection compared with newer specialty medicines. Pyrimethamine was first developed decades ago, and the standard 25 mg immediate-release tablet is an established dosage form. The principal commercial barriers are therefore unlikely to be an active-ingredient patent or a sophisticated formulation patent.

A current Orange Book review should be used to confirm whether any enforceable patents are listed against NDA 008578. Publicly available product history indicates that Daraprim is an old product with no widely recognized blocking patent estate covering the conventional 25 mg immediate-release tablet.

Potentially protectable developments could include:

• A pediatric liquid formulation.
• A taste-masked suspension.
• A multiparticulate product.
• A modified-release dosage form.
• A co-packaged pyrimethamine, folinic acid, and sulfonamide regimen.
• A stability-enhanced formulation.
• A low-volume liquid for neonatal or congenital toxoplasmosis treatment.
• A ready-to-use hospital formulation.

A patent on a new excipient combination would need a credible technical effect. Routine substitution of lactose, starch, or a standard disintegrant would face obviousness and lack-of-inventiveness challenges. A stronger patent position would require demonstrated improvements in stability, dissolution, dose uniformity, palatability, or clinical administration.

When does Daraprim lose exclusivity?

Daraprim’s principal US exclusivity has already expired. The product’s age means that conventional generic entry is legally possible, subject to an approved ANDA, pharmaceutical equivalence, bioequivalence, manufacturing compliance, and any current regulatory requirements.

Exclusivity category	Daraprim position
New chemical entity exclusivity	Expired
Standard five-year NCE period	Not relevant to this legacy product
Three-year clinical-investigation exclusivity	No known current blocking period for the original product
Orphan-drug exclusivity	No known current exclusivity blocking a conventional generic
Pediatric exclusivity	No known current six-month extension affecting the original product
Listed patent protection	No widely recognized blocking estate for the conventional tablet
Generic pathway	505(j) ANDA is the likely route

An applicant should distinguish legal availability from practical market entry. A low-volume product can still have high entry barriers because of limited API sources, small commercial scale, narrow patient populations, pharmacovigilance obligations, and reimbursement uncertainty.

What is the Orange Book status of Daraprim?

Daraprim is associated with FDA NDA 008578. The Orange Book is the controlling source for current therapeutic-equivalence evaluations and patent-listing information. A generic applicant would need to determine whether the reference listed drug is currently designated and whether any listed patent certifications apply.

For a conventional generic, the likely certification position would be:

• Paragraph I if no relevant patent information is listed.
• Paragraph III if a listed patent remains unexpired and the applicant accepts delayed approval.
• Paragraph IV if the applicant asserts that a listed patent is invalid, unenforceable, or not infringed.

For an old immediate-release pyrimethamine tablet, a Paragraph IV challenge appears less likely to be the central commercial issue than establishing a viable market and obtaining reliable API supply.

Which companies are challenging Daraprim exclusivity?

No major, publicly established Paragraph IV campaign has become synonymous with Daraprim in the way that generic challenges have affected newer high-revenue products. Generic manufacturers may pursue ANDA approval without litigation if no blocking patents are listed or if the applicable patents have expired.

The competitive field is more likely to include:

• Generic pharmaceutical companies with infectious-disease portfolios.
• Specialty manufacturers serving hospital and public-health channels.
• Contract development and manufacturing organizations.
• Compounding pharmacies supplying liquid or patient-specific preparations.
• Specialty distributors and access-focused suppliers.

A manufacturer that enters with a standard tablet may compete primarily on price and availability. A manufacturer that develops a liquid, dispersible, or pediatric product can compete on administration and clinical workflow.

What commercial opportunities exist for excipient suppliers?

The largest excipient opportunities are linked to product redevelopment rather than simple supply of standard tablet ingredients.

Pediatric and neonatal formulations

Congenital toxoplasmosis creates a clear need for age-appropriate administration. A liquid or dispersible pyrimethamine formulation could reduce tablet manipulation, improve dose measurement, and support weight-based dosing. Excipient priorities include:

• Palatability.
• Chemical and microbial stability.
• Low viscosity suitable for oral syringes.
• Dose uniformity after shaking.
• Compatibility with enteral feeding devices.
• Preservative efficacy where appropriate.
• A manageable storage condition.

A pediatric product could follow a 505(b)(2) strategy if it relies on the approved pyrimethamine reference product but introduces a new dosage form or administration method. The regulatory burden would be greater than for a standard ANDA, but the product could have stronger differentiation.

Lactose-free and directly compressible tablets

A lactose-free formulation using microcrystalline cellulose, mannitol, or dibasic calcium phosphate could target institutional buyers seeking standardized excipient profiles. This is a modest opportunity because the clinical need is narrow, but the manufacturing value may be meaningful if the alternative formulation improves flow, compression, or supply resilience.

Taste-masked dispersible dosage forms

A dispersible product could address patients who cannot swallow tablets. Pyrimethamine’s taste, dose uniformity after dispersion, sedimentation, and compatibility with common liquids would require focused development. A co-processed excipient system may offer stronger differentiation than ordinary excipient substitution.

Stability-focused formulations

An excipient system that improves stability under temperature and humidity stress could reduce wastage in hospitals, clinics, and global-health programs. Relevant development areas include moisture protection, low-permeability packaging, antioxidant compatibility where justified, and robust dissolution after accelerated aging.

How strong is the patent estate for a new Daraprim formulation?

The patent estate for the original tablet is weak relative to modern specialty drugs. A new product could obtain composition-of-matter or formulation claims only if it contains a genuinely differentiated system.

Development concept	Patent potential	Regulatory route
Same 25 mg tablet with standard excipient substitution	Low	ANDA
Lactose-free 25 mg tablet	Low to moderate	ANDA if bioequivalent
Pediatric oral suspension	Moderate	505(b)(2) or ANDA, depending on reference and data
Taste-masked dispersible tablet	Moderate	505(b)(2) or ANDA
Modified-release pyrimethamine	Moderate to high	505(b)(2), with substantial development
Co-formulated anti-toxoplasmosis product	Moderate	505(b)(2) or new application
Novel nanoparticle or long-acting system	High technical risk	Likely 505(b)(2) or full development program

Patent strength would depend on claim breadth, demonstrated superiority, freedom to operate around excipient and process patents, and the ability to prove non-obvious performance.

What generic launch risks exist for Daraprim?

The main risks are commercial and operational.

Small addressable market

Toxoplasmosis is a specialized indication. Demand may be concentrated in infectious-disease centers, transplant programs, HIV-treatment settings, neonatal care, and public-health channels. A standard tablet entrant may face limited annual volume.

API supply

Pyrimethamine is an old active ingredient with a narrower supplier base than high-volume generic APIs. A reliable dual-source strategy can be more valuable than a marginal excipient cost reduction.

Product liability and safety controls

Pyrimethamine has clinically important hematologic toxicity. Labeling, pharmacovigilance, medication-error controls, and appropriate packaging are central to market acceptance.

Reimbursement and pricing

The Daraprim price controversy created substantial public scrutiny. A new entrant would face pressure to offer a materially lower acquisition cost while maintaining dependable supply. Net revenue cannot be inferred reliably from public list-price data.

Small-batch manufacturing economics

Small campaigns increase setup, testing, packaging, and inventory costs. A platform process shared with other low-dose tablets could improve utilization and reduce per-unit manufacturing expense.

How does Daraprim compare with competing toxoplasmosis products?

Daraprim is not interchangeable clinically with all antiparasitic or antimicrobial products. Treatment selection depends on disease site, immune status, pregnancy status, age, resistance, and tolerance.

Product or regimen	Role in toxoplasmosis	Excipient opportunity
Pyrimethamine plus sulfadiazine plus folinic acid	Established regimen	Pediatric liquid, dispersible tablet, co-pack
Pyrimethamine plus clindamycin plus folinic acid	Alternative regimen	Combination packaging and adherence support
Trimethoprim-sulfamethoxazole	Alternative in selected settings	More direct generic competition
Atovaquone	Alternative when standard therapy is unsuitable	Suspension and palatability competition
Pyrimethamine tablets from a generic supplier	Direct Daraprim substitute	Cost, supply, and dosage-form differentiation

The strongest commercial position is likely a reliable, affordable product with a pediatric administration option rather than an undifferentiated tablet.

What licensing and partnership opportunities exist?

Licensing opportunities may involve:

• US rights to a generic or 505(b)(2) pyrimethamine product.
• Regional rights for pediatric formulations.
• Co-development with infectious-disease specialists.
• API and finished-dose supply agreements.
• Hospital and public-health procurement contracts.
• Co-packaging with folinic acid and a compatible sulfonamide.

A specialty pharmaceutical company could license a pediatric formulation to an established infectious-disease marketer. An excipient or CDMO company could pursue a turnkey development package covering formulation, analytical methods, scale-up, stability, and commercial manufacture.

What geographic markets offer the best opportunity?

The US offers the clearest regulatory reference product and a defined ANDA pathway. European and other markets may require separate regulatory submissions, local reference-product analysis, and country-specific reimbursement work.

Potential target regions include:

• United States: clear reference-product framework and specialty pricing pressure.
• European Union: fragmented reimbursement and national access decisions.
• Latin America: demand for affordable anti-infective supply and pediatric dosage forms.
• Low- and middle-income markets: potential need for stable, low-cost products, but higher price sensitivity and procurement complexity.
• Hospital markets: opportunity for unit-dose packaging, oral syringes, and medication-use standardization.

A global strategy should not assume that US formulation approval automatically establishes international market access.

Key Takeaways

• Daraprim is a 25 mg immediate-release pyrimethamine tablet for toxoplasmosis.
• The original product has an old, conventional formulation and limited apparent modern patent protection.
• A Q1/Q2-matched immediate-release tablet is the lowest-risk generic strategy.
• Content uniformity, blend segregation, dissolution, and tablet robustness are the central formulation issues.
• Pediatric liquids, dispersible tablets, and taste-masked products offer the strongest excipient-driven differentiation.
• A new dosage form may support 505(b)(2) development and formulation patent claims.
• Commercial success depends on API security, small-batch economics, supply reliability, and lower acquisition cost.
• The market is specialized, with opportunities concentrated in infectious-disease centers, transplant programs, neonatal care, hospitals, and public-health procurement.
• No widely recognized blocking patent estate appears to protect the conventional Daraprim tablet, but current Orange Book and FDA records control any filing decision.

FAQs

Can lactose be removed from a generic Daraprim tablet?

Yes. A lactose-free formulation may use microcrystalline cellulose, mannitol, or another suitable diluent. The applicant must demonstrate pharmaceutical equivalence, bioequivalence, acceptable dissolution, and adequate stability.

Is a pyrimethamine oral suspension commercially attractive?

Yes, particularly for congenital toxoplasmosis, pediatric patients, and patients unable to swallow tablets. The main development requirements are taste masking, dose uniformity, sedimentation control, microbial stability, and an appropriate dosing device.

Could an excipient supplier patent a Daraprim formulation?

Potentially, but routine substitution of standard excipients is unlikely to produce strong claims. Patentability improves when the excipient system delivers a demonstrated technical effect, such as improved stability, dissolution, palatability, or dose uniformity.

Does Daraprim require a biosimilar strategy?

No. Daraprim contains a chemically synthesized small-molecule active ingredient, pyrimethamine. The appropriate regulatory framework is generally an ANDA or, for a differentiated formulation, a 505(b)(2) application rather than a biosimilar application.

What is the most defensible commercial entry product?

A reliable 25 mg immediate-release generic tablet is the lowest-risk entry product. A pediatric liquid or dispersible dosage form offers greater differentiation but requires more development, regulatory work, and post-approval lifecycle management.

References

1. U.S. Food and Drug Administration. (2020). Daraprim (pyrimethamine) tablets, 25 mg: Prescribing information. FDA.

2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA, Center for Drug Evaluation and Research.

3. U.S. Food and Drug Administration. (2023). Inactive ingredient database. FDA, Center for Drug Evaluation and Research.

4. U.S. Food and Drug Administration. (2022). ANDA submissions: Content and format of an abbreviated new drug application. FDA, Center for Drug Evaluation and Research.

5. U.S. Food and Drug Administration. (2023). Applications covered by section 505(b)(2). FDA, Center for Drug Evaluation and Research.

6. National Library of Medicine. (2024). DailyMed: Daraprim pyrimethamine tablet. U.S. National Library of Medicine.