Drugs Containing Excipient (Inactive Ingredient) DIETHYL PHTHALATE

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Branded drugs containing DIETHYL PHTHALATE excipient, and estimated key patent expiration / generic entry dates

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Allergan Inc	KADIAN	morphine sulfate	0023-6011	DIETHYL PHTHALATE
Bristol-Myers Squibb Company	VIDEX EC	didanosine	0087-6671	DIETHYL PHTHALATE
Upsher-Smith Laboratories LLC	QUDEXY	topiramate	0245-1071	DIETHYL PHTHALATE

Generic drugs containing DIETHYL PHTHALATE excipient

Company	Ingredient	NDC	Excipient
Allergan Inc	morphine sulfate	0023-6011	DIETHYL PHTHALATE
Bristol-Myers Squibb Company	didanosine	0087-6671	DIETHYL PHTHALATE
Amneal Pharmaceuticals of New York LLC	morphine sulfate	0115-1277	DIETHYL PHTHALATE

Diethyl Phthalate Pharmaceutical Excipient Market Dynamics and Financial Trajectory

Last updated: September 27, 2026

Diethyl phthalate, or DEP, is a mature, low-cost pharmaceutical excipient used mainly as a plasticizer in enteric and film-coating systems. Its pharmaceutical demand is stable but structurally constrained by toxicology scrutiny, phthalate-substitution programs, customer qualification requirements, and competition from citrate, acetate, sebacate, and adipate plasticizers.

DEP has no meaningful standalone drug exclusivity. Commercial value is concentrated in manufacturing consistency, pharmacopeial quality, regulatory documentation, supply reliability, and compatibility with coating polymers. Public companies generally do not report pharmaceutical DEP revenue separately, so the financial trajectory must be assessed through end-market exposure, product substitution, regulatory pressure, and specialty-chemical economics rather than a transparent excipient segment forecast.

What is diethyl phthalate and how is it used in pharmaceuticals?

Diethyl phthalate is an ester of phthalic acid and ethanol with CAS Registry Number 84-66-2. In pharmaceutical manufacturing, it is primarily a plasticizer and solvent used to modify polymer films.

Attribute	Diethyl phthalate
Chemical name	Diethyl benzene-1,2-dicarboxylate
CAS number	84-66-2
Primary pharmaceutical role	Plasticizer and coating-process aid
Common use	Enteric and delayed-release coatings
Physical form	Clear, oily liquid
Pharmacopeial status	Covered by compendial specifications in relevant markets
Drug status	Excipient, not an active pharmaceutical ingredient
Main commercial issue	Substitution risk linked to phthalate toxicology concerns

DEP improves film flexibility and reduces brittleness in polymer coatings. It can be used with cellulose derivatives and other coating polymers, including systems designed for delayed drug release. Its value is functional rather than pharmacological: it affects film formation, mechanical durability, permeability, and processing behavior.

The excipient is also used outside pharmaceuticals in fragrances, cosmetics, adhesives, coatings, inks, and personal-care products. Those markets are materially larger than pharmaceutical applications and influence production scale, raw-material economics, and supplier economics.

What pharmaceutical formulations are protected by diethyl phthalate?

DEP itself is not generally protected by a live composition-of-matter patent. The compound has been known and commercially used for decades. Patent protection may apply to a formulation, coating architecture, manufacturing process, or drug product that uses DEP, but the presence of DEP alone does not create exclusivity.

Formulation patents

Potentially relevant patent claims can cover:

• A drug core coated with an enteric polymer and DEP.
• Specific DEP concentrations within a coating dispersion.
• A defined polymer-to-plasticizer ratio.
• Delayed-release or colon-targeted release profiles.
• Coating processes that improve adhesion, stability, or dissolution performance.
• Combination use of DEP with pigments, surfactants, pore formers, or alternative plasticizers.
• A particular dosage form, such as a multiparticulate capsule or coated tablet.

These claims are usually product-specific. They do not prevent the broader market from using DEP in unrelated formulations.

Method-of-use patents

Method-of-use patents may protect the therapeutic use of a drug product containing a DEP-plasticized coating. Such patents generally protect the medicine and indication, not the excipient supply chain. A generic manufacturer can often design around a formulation claim by changing the coating polymer, plasticizer, concentration, or process, subject to bioequivalence and dissolution requirements.

How strong is the patent estate for diethyl phthalate?

The standalone patent estate for DEP as a pharmaceutical excipient is weak because the molecule is old, widely disclosed, and commercially available from multiple suppliers.

Patent category	Likely strength for DEP	Commercial impact
Compound patent	Negligible	No standalone molecule exclusivity
Manufacturing-process patent	Low to moderate	May protect purity or process economics
Excipient-combination patent	Moderate in narrow products	Can affect specific formulations
Drug-product formulation patent	Moderate to strong if narrowly drafted	May delay or complicate generic entry
Method-of-use patent	Product-dependent	Usually linked to the drug, not DEP
Supplier-specific patent	Low	Qualification and quality systems matter more

The relevant competitive barrier is usually regulatory and technical qualification rather than patent exclusion. Pharmaceutical customers may require compendial compliance, residual-solvent control, impurity profiles, change-control procedures, audit access, and multiple-batch consistency. These requirements can slow substitution even when no patent prevents it.

What is the FDA regulatory status of diethyl phthalate?

DEP is recognized as an excipient used in drug products, and FDA Inactive Ingredient Database records provide evidence of historical use in approved products. The database is product- and route-specific. It does not establish a universal safe daily intake or authorize every concentration and dosage form.

FDA review of a drug containing DEP focuses on the finished product, route of administration, amount of excipient, exposure, manufacturing controls, and safety justification. A new use, higher exposure, or different route may require additional toxicological support.

DEP is not a drug active ingredient and does not receive a standalone FDA approval comparable to an NDA or ANDA. Excipient suppliers generally support customers through:

• USP-NF or equivalent quality documentation.
• Certificate-of-analysis packages.
• Elemental impurity and residual-solvent data.
• Extractables and leachables information.
• Change-control commitments.
• Good manufacturing practice documentation.
• Toxicological and regulatory statements.

What is the Orange Book status of diethyl phthalate?

DEP has no standalone Orange Book listing because the Orange Book lists approved drug products and their patents or exclusivity, not ordinary excipients as independent products.

An approved drug using DEP may have Orange Book-listed patents covering the drug substance, formulation, method of use, dosage form, or delivery system. Those listings belong to the drug product sponsor. They do not give the excipient manufacturer control over DEP sales.

Paragraph IV litigation can arise when a generic applicant challenges a listed patent covering a DEP-containing formulation. The dispute would concern the branded drug patent, not ownership of DEP as a chemical.

When does diethyl phthalate lose exclusivity?

DEP has no meaningful remaining compound exclusivity to lose. Its commercial use is based on an established chemical, established manufacturing routes, and customer approvals.

For a particular medicine, exclusivity depends on:

1. FDA regulatory exclusivity for the drug product.
2. Orange Book-listed patents.
3. Formulation and method-of-use claims.
4. Pediatric or other statutory extensions.
5. The generic applicant’s Paragraph IV strategy.
6. The feasibility of a non-infringing coating design.

The expiry of a drug patent may reduce demand for one branded product, but it can expand total DEP demand if generic manufacturers adopt the same coating architecture. Conversely, generic entry can reduce DEP demand when competitors use alternative plasticizers or simplified dosage forms.

Which companies supply or compete in pharmaceutical-grade DEP?

The DEP market is fragmented between large chemical manufacturers, regional producers, and specialty excipient distributors. Supplier identity can vary by geography and by whether the customer requires pharmaceutical-grade material rather than industrial grade.

The relevant competitive groups include:

Supplier group	Competitive advantage	Primary limitation
Large chemical producers	Scale, continuity, analytical capability	Pharmaceutical revenue is usually not separately reported
Specialty excipient suppliers	Regulatory support and customer service	Higher unit cost and less manufacturing scale
Regional producers	Price and local availability	Qualification, audit, and consistency concerns
Distributors	Inventory and geographic reach	Dependence on upstream manufacturers
Alternative-plasticizer suppliers	Ability to support substitution	Reformulation and regulatory requalification costs

Customers typically evaluate more than nominal price. The commercial decision includes specification control, batch-to-batch variability, supply continuity, documentation quality, lead time, and the cost of changing a registered formulation.

What substitutes compete with diethyl phthalate in pharmaceutical coatings?

The principal substitutes are non-phthalate plasticizers and alternative coating systems.

Substitute	Typical commercial rationale	Main tradeoff
Triethyl citrate	Widely accepted non-phthalate alternative	May require process and dissolution adjustment
Acetyl triethyl citrate	Plasticization and compatibility profile	Can have different film mechanics
Dibutyl sebacate	Flexibility and hydrophobicity	Different regulatory and formulation profile
Propylene glycol	Low-cost plasticizer in selected systems	Higher volatility and compatibility limitations
Polyethylene glycol	Flexible film formation in some polymers	Moisture sensitivity and process effects
Tributyl citrate	Alternative citrate chemistry	May alter release and mechanical properties
Acetyl tributyl citrate	Strong plasticization	Cost and formulation-specific qualification
No-plasticizer systems	Simplified excipient composition	May increase brittleness or processing difficulty

Substitution is not automatic. A reformulation can require coating-process development, dissolution testing, stability studies, bioequivalence assessment, regulatory filings, and manufacturing validation. For this reason, DEP can remain in legacy products even where the sponsor prefers a non-phthalate system.

How do regulatory concerns affect the diethyl phthalate market?

Phthalates are subject to increased scrutiny because some members of the chemical class have reproductive and developmental toxicity concerns. Regulatory treatment differs by compound, exposure route, jurisdiction, and product category. DEP is not regulated identically to higher-concern phthalates such as di(2-ethylhexyl) phthalate or dibutyl phthalate.

Market pressure still arises from:

• Broad corporate policies limiting phthalates.
• Hospital and procurement restrictions.
• Consumer and patient perception.
• Tighter toxicological review of excipient exposure.
• European chemical-management requirements.
• Sponsor preference for non-phthalate formulations.
• Supply-chain requests for alternatives and dual sourcing.

The practical result is a two-speed market. Existing approved products can maintain demand, while new product development increasingly favors citrate or other non-phthalate plasticizers.

What is the financial trajectory for pharmaceutical-grade diethyl phthalate?

The pharmaceutical DEP business is likely to remain a low-growth or declining niche within a broader mature chemical market. Public financial disclosures generally aggregate DEP with broader plasticizers, specialty chemicals, or performance additives. A reliable pharmaceutical-only revenue figure is therefore not available from standard annual reports.

Revenue drivers

Pharmaceutical DEP revenue depends on:

• The number of approved products using DEP.
• Continued sales of legacy delayed-release medicines.
• Generic adoption of existing coating technologies.
• New product development using DEP.
• Supplier retention and dual-sourcing decisions.
• Regional regulatory acceptance.
• Conversion to non-phthalate alternatives.

Margin drivers

Margins are affected by:

• Phthalic anhydride and ethanol costs.
• Plant utilization.
• Energy and logistics costs.
• Pharmaceutical-grade testing and documentation.
• Small-batch production requirements.
• Customer audit and qualification costs.
• Distributor markups.
• Price competition from industrial-grade supply.

Pharmaceutical-grade material can command a premium over industrial DEP, but the premium reflects compliance, testing, traceability, and documentation. It does not necessarily indicate high structural profitability. Buyers with approved formulations may resist frequent supplier changes, which can support retention and pricing stability.

Base-case market outlook

Period	Expected market condition	Financial implication
Near term	Stable demand from legacy formulations	Revenue supported by recurring orders
Medium term	Slow substitution in new products	Flat to declining pharmaceutical volumes
Longer term	Greater non-phthalate adoption	Lower strategic value and weaker growth
Downside case	Regulatory or procurement restrictions accelerate	Faster volume erosion and stranded qualification assets
Resilient case	Legacy products remain unchanged and generic use expands	Stable volumes despite limited new adoption

The strongest commercial position belongs to suppliers with low-cost production, pharmaceutical documentation, regional inventory, and the ability to supply both DEP and substitute plasticizers. A single-product DEP strategy has greater long-term exposure to substitution.

What generic entry risks exist for DEP-containing drugs?

Generic entry risk is product-specific. DEP can increase or reduce that risk depending on how central it is to the drug’s release mechanism.

A generic applicant may pursue three routes:

1. Copy the listed formulation and coating system.
2. Use a different excipient composition while meeting dissolution and bioequivalence requirements.
3. Challenge formulation or method patents under Paragraph IV.

The largest risk to the originator is usually not the excipient itself. It is the loss of drug-product exclusivity when competitors can reproduce the required release profile with commercially available polymers and plasticizers.

For DEP suppliers, generic entry has mixed effects. Generic launches can create new customers and increase total excipient volume. Price erosion and formulation redesign can offset that volume benefit.

What patent litigation and settlement issues affect diethyl phthalate?

There is no broad patent-litigation category focused on DEP as a standalone pharmaceutical material. Litigation generally concerns:

• Delayed-release drug formulations.
• Coated multiparticulates.
• Polymer-plasticizer combinations.
• Manufacturing methods.
• Release profiles.
• Infringement by generic drug applicants.

Settlement agreements may permit generic entry before patent expiry, with restrictions related to launch timing, formulation changes, or authorized-generic supply. These agreements can affect DEP demand indirectly by determining whether a generic uses the branded coating approach or develops an alternative.

How does diethyl phthalate compare with non-phthalate excipients?

DEP retains advantages in legacy process familiarity, availability, and cost. Non-phthalate alternatives have a stronger position in new development because they reduce regulatory and procurement friction.

Factor	DEP	Citrate and other alternatives
Legacy formulation experience	Strong	Product-dependent
Cost	Generally competitive	Often higher or comparable
Regulatory perception	Increasingly pressured	Usually more favorable
Reformulation burden	None for existing products	Required when replacing DEP
New-product preference	Weaker	Stronger
Supply availability	Broad	Broad but varies by grade
Patent exposure	Usually product-specific	Also product-specific

What geographic markets matter most for pharmaceutical DEP?

North America and Europe remain important because of their large regulated pharmaceutical markets and established delayed-release products. Europe presents greater substitution pressure because chemical regulation, sustainability policies, and customer procurement standards can influence excipient selection.

Asia-Pacific is important for manufacturing scale, generic drug production, and cost-sensitive formulation development. Demand can remain durable where established products use DEP and regulatory conversion costs are high. Local supplier qualification and documentation quality determine access more than chemical availability alone.

Global suppliers must manage different requirements for:

• USP-NF compliance.
• Ph. Eur. compliance.
• Japanese Pharmacopoeia or local standards.
• Good manufacturing practice audits.
• Registration-support documentation.
• Import controls and change notifications.

Key Takeaways

• Diethyl phthalate is a mature pharmaceutical excipient used mainly as a plasticizer in coating systems.
• It has no meaningful standalone drug or compound exclusivity.
• Formulation and method-of-use patents can protect specific DEP-containing medicines, but not the general use of DEP.
• FDA regulation is product-specific; DEP is not independently approved like an active drug.
• DEP has no standalone Orange Book listing.
• Pharmaceutical demand is likely stable in legacy products but weaker in new-product development.
• Non-phthalate plasticizers, especially citrate-based alternatives, are the main competitive threat.
• Public companies generally do not disclose pharmaceutical DEP revenue separately.
• Financial performance depends more on supply qualification, documentation, production scale, and substitution risk than on patent power.
• Generic entry can expand total excipient volume while reducing prices and accelerating formulation redesign.

FAQs About Diethyl Phthalate Pharmaceutical Excipient Economics

Is diethyl phthalate still used in enteric-coated tablets?

Yes. DEP remains used in selected enteric and delayed-release coating systems, especially legacy formulations. New development increasingly evaluates non-phthalate alternatives.

Is diethyl phthalate banned in pharmaceuticals?

No universal global ban applies to all pharmaceutical uses of DEP. Regulatory treatment depends on jurisdiction, route, dose, product, and toxicological assessment.

Can a generic drug manufacturer use diethyl phthalate without a license?

Generally, yes. DEP is a widely available chemical and excipient. A generic manufacturer may still need to address patents covering the specific drug formulation, coating process, or release profile.

Does diethyl phthalate have an FDA acceptable daily intake?

FDA Inactive Ingredient Database presence does not establish a universal acceptable daily intake. Safety is assessed in the context of the finished drug, route, exposure, and formulation.

What is the best commercial alternative to diethyl phthalate?

Triethyl citrate is one of the most established alternatives, but the optimal substitute depends on the coating polymer, target dissolution profile, process conditions, stability requirements, and regulatory strategy.

References

1. U.S. Food and Drug Administration. (n.d.). Inactive Ingredient Database. https://www.accessdata.fda.gov/scripts/cder/iig/index.cfm
2. United States Pharmacopeial Convention. (2024). United States Pharmacopeia and National Formulary. USP Convention.
3. European Directorate for the Quality of Medicines & HealthCare. (2024). European Pharmacopoeia. Council of Europe.
4. European Medicines Agency. (2007). Committee for Medicinal Products for Human Use guideline on excipients in the dossier for application for marketing authorisation of a medicinal product. https://www.ema.europa.eu/
5. European Chemicals Agency. (n.d.). Substance information: Diethyl phthalate. https://echa.europa.eu/
6. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book