List of Excipients in Branded Drug CLOMIPRAMINE HYDROCHLORIDE

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
SpecGx LLC	CLOMIPRAMINE HYDROCHLORIDE	clomipramine hydrochloride	0406-8806	D&C RED NO. 33
SpecGx LLC	CLOMIPRAMINE HYDROCHLORIDE	clomipramine hydrochloride	0406-8806	D&C YELLOW NO. 10
SpecGx LLC	CLOMIPRAMINE HYDROCHLORIDE	clomipramine hydrochloride	0406-8806	FD&C YELLOW NO. 6

Generic Drugs Containing CLOMIPRAMINE HYDROCHLORIDE

Company	Ingredient	NDC	Excipient
Mylan Pharmaceuticals Inc	clomipramine hydrochloride	0378-3025	D&C RED NO. 28
Mylan Pharmaceuticals Inc	clomipramine hydrochloride	0378-3025	D&C YELLOW NO. 10
Mylan Pharmaceuticals Inc	clomipramine hydrochloride	0378-3025	FD&C BLUE NO. 1

What are the Most Frequently-Used Excipients in CLOMIPRAMINE HYDROCHLORIDE?

# Of NDCs	Excipient
6	ALCOHOL
8	AMMONIA
6	BUTYL ALCOHOL

Clomipramine Hydrochloride Excipient Strategy and Commercial Opportunities

Last updated: August 10, 2026

Clomipramine hydrochloride is a mature, off-patent tricyclic antidepressant with established use in obsessive-compulsive disorder. The commercial opportunity is unlikely to come from conventional immediate-release capsules alone. Growth is more likely in differentiated oral delivery, pediatric and swallowing-friendly formats, global-market reformulation, and manufacturing-cost reduction.

The strongest formulation strategy is an immediate-release product that preserves rapid dissolution, controls capsule-fill variability, avoids excipients associated with intolerance, and supports multiple strengths. More differentiated options include an oral solution, orally disintegrating tablet, sprinkle capsule, and modified-release product. Each requires a separate bioequivalence and product-development assessment because clomipramine has dose-related tolerability risks and a narrow commercial value proposition relative to low-cost generic competition.

What is clomipramine hydrochloride and how is it marketed?

Clomipramine hydrochloride is the hydrochloride salt of clomipramine, a tertiary-amine tricyclic antidepressant. It is marketed primarily as an oral immediate-release capsule. The reference product, Anafranil, was approved in the United States for obsessive-compulsive disorder. US capsule strengths have included 25 mg, 50 mg, and 75 mg.

Attribute	Commercial position
Active ingredient	Clomipramine hydrochloride
Drug class	Tricyclic antidepressant
Main approved US indication	Obsessive-compulsive disorder
Primary dosage form	Immediate-release oral capsule
Common strengths	25 mg, 50 mg, 75 mg
Reference product	Anafranil
US approval era	Original approval in the late 1980s
Generic status	Mature generic market
Biosimilar relevance	None
Primary commercial pressure	Low price and established generic substitution
Main differentiation routes	Liquid, orally disintegrating, sprinkle, modified release, excipient simplification

Clomipramine is metabolized extensively to desmethylclomipramine, an active metabolite. The drug has anticholinergic, sedating, cardiovascular, and seizure-related tolerability considerations. These characteristics constrain formulation claims and favor conservative release profiles unless a modified-release product can show a meaningful exposure or tolerability benefit.

What excipients are used in clomipramine hydrochloride capsules?

Reference and generic clomipramine capsules commonly use a conventional hard-gelatin capsule platform. Public product labeling has identified excipient classes such as lactose, corn starch, talc, gelatin, titanium dioxide, and approved capsule-coloring agents, although composition varies by manufacturer and strength.[1,2]

A typical immediate-release formulation may contain:

Excipient function	Candidate materials	Development purpose
Diluent	Lactose monohydrate, microcrystalline cellulose, mannitol, dibasic calcium phosphate	Achieve capsule fill weight and blend uniformity
Disintegrant	Crospovidone, croscarmellose sodium, sodium starch glycolate	Promote rapid capsule-plug dispersion
Glidant	Colloidal silicon dioxide	Improve powder flow
Lubricant	Magnesium stearate, sodium stearyl fumarate	Reduce tooling and capsule-filling friction
Wetting aid	Polysorbate 80, sodium lauryl sulfate	Improve dissolution where needed
Adsorbent or carrier	Colloidal silicon dioxide, silicified microcrystalline cellulose	Manage low-dose API distribution
Capsule shell	Gelatin or hydroxypropyl methylcellulose	Provide dosage-form enclosure
Colorant	Iron oxides, titanium dioxide, permitted organic colors	Product identification and light control

The excipient selection should be driven by API loading, powder flow, moisture sensitivity, dissolution performance, and the target market's excipient restrictions. A lactose-based product is cost-efficient but excludes patients with specific lactose intolerance concerns and complicates positioning for a "clean-label" or excipient-minimized product. A microcrystalline-cellulose or mannitol platform can support lactose-free positioning but may increase fill weight or cost.

How should an immediate-release clomipramine formulation be designed?

An immediate-release capsule remains the lowest-risk commercial platform. The formulation should prioritize rapid and reproducible dissolution rather than aggressive solubility enhancement.

API loading and blend uniformity

At 25 mg, clomipramine hydrochloride is a low-to-moderate dose relative to the total capsule mass. Content-uniformity risk depends on particle-size distribution, electrostatic behavior, and segregation during blending and encapsulation. Direct blending may be adequate if the API has suitable flow and particle-size control. Otherwise, geometric dilution, ordered mixing, dry granulation, or a carrier-based premix can reduce potency variability.

The manufacturer should establish:

• API particle-size distribution;
• bulk and tapped density;
• flowability;
• electrostatic tendency;
• moisture uptake;
• blend segregation behavior;
• assay and content-uniformity performance across capsule-filling speeds.

A formulation with excessive fines can create dusting, segregation, and weight variability. Granulation can improve flow but may add process cost and expose the API to moisture.

Diluent selection

Lactose monohydrate is commercially attractive because it is inexpensive, widely qualified, and compatible with capsule filling. Microcrystalline cellulose provides better dry-blend robustness and lactose-free positioning. Mannitol can support orally disintegrating or chewable products because of its mouthfeel, but its cost and hygroscopicity profile must be controlled.

Dibasic calcium phosphate may improve flow and reduce moisture sensitivity, but it can produce a denser fill and may alter disintegration behavior. It is less attractive when the product requires a large, rapidly dispersing capsule plug.

Disintegration and dissolution

Crospovidone is a practical first-line disintegrant for a capsule powder blend. Croscarmellose sodium and sodium starch glycolate are alternatives. The target should be rapid dispersion across the intended dissolution medium without relying on surfactant concentrations that could create an artificial release profile.

Clomipramine hydrochloride is a salt form, so a standard immediate-release formulation may not require extensive solubilization technology. Surfactants should be used only when dissolution testing demonstrates a reproducible benefit. Excessive surfactant can create variability across test methods and complicate scale-up.

Lubrication

Magnesium stearate is a standard choice, but over-lubrication can slow wetting and dissolution. Blending time should be controlled, and dissolution should be tested after process changes. Sodium stearyl fumarate can be evaluated where lower hydrophobicity or improved blend behavior is needed.

What formulation patents could protect clomipramine products?

The original composition and use patents for clomipramine are expected to have expired because the product was approved in the late 1980s. Commercial protection now depends on new formulation, manufacturing, delivery-system, or method-of-use claims rather than the basic active ingredient.

Potential patentable subject matter includes:

Modified-release formulations

A controlled-release clomipramine product could claim polymer matrices, coated multiparticulates, osmotic systems, or pH-dependent release. The commercial rationale would be reduced peak concentration, fewer daily doses, or improved tolerability. The technical risk is substantial because the active metabolite contributes to pharmacology and a modified-release product may change the parent-to-metabolite exposure relationship.

Orally disintegrating tablets

An ODT could use mannitol, crospovidone, low-substituted hydroxypropyl cellulose, and a porous compression process. Protection may focus on disintegration time, mechanical strength, taste masking, particle engineering, or a specific excipient ratio.

Oral liquid or concentrate

A liquid product could address patients who cannot swallow capsules, including selected pediatric or geriatric populations. The formulation must manage bitterness, chemical stability, preservative compatibility, container adsorption, dosing accuracy, and light protection.

Sprinkle capsules

A capsule containing coated pellets or taste-masked particles could be opened and administered with soft food. Claims could cover pellet coating, particle size, dose uniformity after sprinkling, and maintenance of immediate release.

Excipient-minimized products

A lactose-free, dye-free, gelatin-free, or low-allergen product may have commercial value. These characteristics alone are usually weak patent subjects, but a specific composition with demonstrated stability, dissolution, and manufacturing advantages may support formulation claims.

When does clomipramine lose exclusivity?

Clomipramine lost meaningful US regulatory and compound-patent exclusivity decades ago. The current market is therefore governed primarily by abbreviated new drug application competition, manufacturing economics, product availability, and local regulatory requirements.

Exclusivity category	Current commercial relevance
Original compound patent	Expired
Original formulation protection	Expired or commercially obsolete
FDA reference-product exclusivity	Long expired
Current biosimilar exclusivity	Not applicable
New formulation exclusivity	Possible only for a newly developed product
Orphan-drug exclusivity	Not generally associated with the established OCD product
Generic substitution	Established

The Orange Book should be reviewed for the current reference listing, approved strengths, therapeutic-equivalence codes, and any active patent or exclusivity entries.[3] A mature generic product should not be treated as patent-blocked merely because historical patents appear in older records.

What is the Orange Book status of clomipramine hydrochloride?

Clomipramine hydrochloride is an established small-molecule product, not a biologic. Orange Book analysis should focus on:

• the reference listed drug;
• approved generic strengths;
• dosage-form equivalence;
• therapeutic-equivalence codes;
• any current patent-use-code entries;
• any active exclusivity dates;
• approved labeling differences.

No biosimilar pathway applies. Generic applicants use the ANDA pathway and must generally demonstrate pharmaceutical equivalence and bioequivalence to the reference product. A new delivery system, new indication, or clinically differentiated formulation may require a 505(b)(2) strategy rather than a conventional ANDA.

Are Paragraph IV challenges relevant to clomipramine?

Paragraph IV litigation is most relevant when an ANDA applicant challenges an active Orange Book patent. For a mature clomipramine product, the practical risk is lower than for a recently launched drug because the original patent estate is old and generic products are already established.

A Paragraph IV strategy could still arise if a new formulation patent is listed for a reformulated clomipramine product. The commercial effect would depend on:

1. whether the patent is listed against the relevant product;
2. whether the generic copies the claimed formulation;
3. whether the patent covers the active ingredient, dosage form, or method of use;
4. whether a 30-month stay is triggered;
5. whether the applicant seeks a skinny label for a method-of-use patent.

For a conventional generic capsule, the principal launch risk is unlikely to be a new compound patent. It is more likely to involve regulatory deficiencies, supply interruption, manufacturing observations, or an inability to achieve reliable bioequivalence.

What FDA regulatory pathway applies to new clomipramine products?

ANDA pathway

A conventional immediate-release capsule that matches the reference product in active ingredient, strength, dosage form, route, and labeling can generally pursue an ANDA. The key development requirements are pharmaceutical equivalence, bioequivalence, stability, manufacturing control, and compliant labeling.

505(b)(2) pathway

A 505(b)(2) application may be appropriate for:

• an oral solution;
• an ODT;
• a modified-release dosage form;
• a new dosage strength;
• a new route of administration;
• a formulation with a clinically relevant delivery advantage.

This pathway may permit reliance on existing safety and efficacy findings while requiring additional bridging data. It can create a new regulatory and patent position, but the commercial return must justify development and market-access costs.

Pediatric positioning

Clomipramine is used in pediatric clinical practice, but the regulatory and commercial case for a pediatric formulation depends on jurisdiction, indication, age group, dosing flexibility, and clinical evidence. An oral liquid or sprinkle product may have a stronger practical rationale than a new high-cost delivery system.

What commercial opportunities exist for clomipramine excipient innovation?

Lactose-free and excipient-restricted capsules

A lactose-free capsule using microcrystalline cellulose, mannitol, or a co-processed filler can target hospitals, pharmacies, and patients who seek excipient alternatives. The opportunity is incremental rather than premium unless the product solves a documented supply or tolerability problem.

Dye-free and gelatin-free products

Dye-free capsules can support institutional procurement and sensitivity-conscious positioning. Hydroxypropyl methylcellulose capsules can serve vegetarian, religious, or gelatin-avoidant markets. These changes have modest technical risk and can be implemented without altering the release profile materially.

Oral solution

An oral solution has the clearest patient-access rationale. It can support flexible dosing and swallowing-impaired populations. Key risks include taste, preservative selection, microbial control, chemical stability, packaging compatibility, and measurement-device accuracy.

Orally disintegrating tablet

An ODT can address swallowing difficulty and improve administration convenience. It must control bitterness, friability, moisture sensitivity, and dose uniformity. A rapidly disintegrating, taste-masked tablet could obtain stronger market differentiation than a conventional capsule but would require more formulation work.

Modified release

Modified release offers the greatest potential differentiation but also the highest development risk. A successful product would need a clear exposure or adherence advantage. The clinical value may be limited if adverse effects arise from both clomipramine and its active metabolite.

Manufacturing-cost reduction

The most defensible near-term opportunity may be process optimization. A robust direct-blend capsule can reduce granulation, drying, and validation costs. Co-processed excipients may improve flow and reduce unit operations, but the manufacturer must demonstrate equivalent dissolution and long-term stability.

How does clomipramine compare with competing antidepressants?

Clomipramine competes clinically with selective serotonin reuptake inhibitors, other tricyclic antidepressants, and behavioral therapy. For OCD, generic SSRIs often have stronger first-line positioning because of tolerability and prescribing familiarity. Clomipramine retains value in treatment-resistant or selected patients but carries a more complex adverse-effect profile.

Product category	Formulation opportunity	Commercial implication
Clomipramine immediate-release capsule	Low-cost generic supply	High competition, limited margin
Clomipramine liquid	Flexible dosing and swallowing support	Moderate differentiation
Clomipramine ODT	Administration convenience	Potential premium if taste and stability are solved
Clomipramine modified release	Lower peak exposure or fewer doses	Higher development and regulatory risk
Generic SSRIs	Broad supply and multiple dosage forms	Strong competitive pressure
Other tricyclics	Established low-cost alternatives	Limits pricing power

What manufacturing and intellectual-property barriers affect clomipramine?

Manufacturing barriers are more important than basic API patent barriers. The key controls are:

• API particle-size and polymorph control;
• blend uniformity at low dose;
• capsule-fill weight consistency;
• dissolution across pH conditions;
• moisture and light protection;
• impurity and degradation-product control;
• capsule-shell compatibility;
• packaging performance;
• supply reliability for qualified excipients.

Potential IP protection is strongest where the formulation produces a measurable technical effect, such as a defined release profile, improved stability, reduced bitterness, or reliable dose delivery from a liquid or sprinkle product. Generic excipient substitution without a novel performance result is unlikely to create a durable patent estate.

What generic launch risks exist for clomipramine?

A conventional generic launch faces limited patent delay but meaningful execution risk. The main risks are:

1. failure to match reference-product dissolution;
2. content-uniformity failures at commercial scale;
3. capsule-shell or colorant changes that trigger regulatory questions;
4. supply disruption for API or critical excipients;
5. inconsistent availability across strengths;
6. limited pharmacy demand because of low market volume;
7. price erosion from multiple approved suppliers.

A differentiated product faces additional risks involving clinical bridging, taste masking, food-effect studies, dose proportionality, and labeling restrictions.

What is the revenue exposure and market opportunity?

Clomipramine revenue is concentrated in mature generic sales, so a conventional capsule is unlikely to support high-margin growth without scale, supply reliability, or geographic expansion. The largest value drivers are:

• securing reliable API supply;
• maintaining all major strengths;
• offering lactose-free or gelatin-free versions;
• entering markets with limited dosage-form competition;
• developing liquid or ODT products;
• obtaining institutional contracts;
• using a 505(b)(2) strategy for a clinically differentiated delivery system.

A manufacturer should avoid assuming that a new excipient profile alone will support premium pricing. The product needs a patient, prescriber, pharmacy, or procurement benefit that is visible in the label and measurable in supply or administration performance.

Key Takeaways

• Clomipramine hydrochloride is a mature, off-patent small molecule with established generic competition.
• Immediate-release capsules remain the lowest-risk commercial product.
• Lactose-free, dye-free, gelatin-free, and low-excipient formulations offer practical but limited differentiation.
• Oral liquids, ODTs, and sprinkle capsules have stronger patient-access rationales.
• Modified release has the highest potential value and the highest regulatory and clinical risk.
• Patent opportunities now depend on formulation, delivery, manufacturing, or method-of-use claims.
• Paragraph IV risk is limited for the legacy product but can re-emerge around newly listed formulation patents.
• Manufacturing robustness, supply continuity, and bioequivalence are more important than legacy compound patents.
• A 505(b)(2) strategy is more appropriate than an ANDA when the product changes delivery, release, or clinical use.
• The strongest near-term commercial strategy is a reliable, cost-efficient capsule platform paired with one differentiated dosage form.

FAQs

Can clomipramine hydrochloride be formulated as an oral solution?

Yes. An oral solution is technically feasible, but the development program must address bitterness, chemical stability, preservative effectiveness, microbial control, packaging compatibility, and dose-measurement accuracy.

Is lactose-free clomipramine commercially viable?

Yes, particularly for hospital formularies, specialty pharmacies, and patients seeking excipient alternatives. The product will need clear labeling and a cost structure that remains competitive with standard generic capsules.

Does clomipramine have biosimilar competition?

No. Clomipramine hydrochloride is a chemically synthesized small molecule and competes through generic drug pathways rather than biosimilar approval.

Could a clomipramine ODT receive new market exclusivity?

Potentially, if the ODT is approved as a new formulation and satisfies the applicable regulatory requirements. Exclusivity would depend on the regulatory basis, the approved claims, and any qualifying clinical or formulation innovation.

What is the strongest patent strategy for a new clomipramine product?

A patent strategy based on a defined technical effect is strongest. Examples include improved stability, taste masking, controlled release, dose uniformity, or a specific delivery system with demonstrated performance. A simple change from lactose to another filler is unlikely to provide durable protection.

References

1. DailyMed. (n.d.). Clomipramine hydrochloride capsule prescribing information. U.S. National Library of Medicine.
2. U.S. Food and Drug Administration. (n.d.). Anafranil (clomipramine hydrochloride) prescribing information. FDA.
3. U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
4. U.S. Food and Drug Administration. (2019). Inactive ingredient database. FDA.
5. International Council for Harmonisation. (2009). Q8(R2): Pharmaceutical development. ICH.
6. International Council for Harmonisation. (2006). Q9: Quality risk management. ICH.
7. United States Pharmacopeial Convention. (2024). United States Pharmacopeia and National Formulary. USP.