List of Excipients in Branded Drug ALPROSTADIL

Generic Drugs Containing ALPROSTADIL

Company	Ingredient	NDC	Excipient
Teva Parenteral Medicines Inc	alprostadil	0703-1501	ALCOHOL
Meitheal Pharmaceuticals Inc	alprostadil	71288-206	ALCOHOL

What are the Most Frequently-Used Excipients in ALPROSTADIL?

# Of NDCs	Excipient
2	ALCOHOL

Alprostadil Excipient Strategy and Commercial Opportunities

Last updated: September 9, 2026

Alprostadil has a fragmented formulation market rather than a single dominant product architecture. The main commercial platforms are injectable products for erectile dysfunction or ductus arteriosus maintenance, intraurethral systems, and topical creams marketed outside the United States. The strongest opportunities are in preservative-free delivery, stable ready-to-use presentations, lower-cost combination kits, pediatric hospital supply, and locally acting formulations that reduce systemic exposure.

The active ingredient is prostaglandin E1. Its low-dose potency creates a favorable formulation profile, but its chemical instability, sensitivity to formulation conditions, administration-route constraints, and narrow product-use windows make excipient selection commercially important.

What alprostadil products are approved and marketed?

Alprostadil is approved in several dosage forms and therapeutic settings. Product availability varies materially by country.

Product or platform	Route	Primary use	Representative manufacturer or sponsor	Formulation model
Caverject	Intracavernosal injection	Erectile dysfunction	Pfizer and authorized generic suppliers	Lyophilized powder reconstituted before use
Caverject Impulse	Intracavernosal injection	Erectile dysfunction	Pfizer	Dual-chamber or ready-use injection system
Edex	Intracavernosal injection	Erectile dysfunction	Endo Pharmaceuticals and licensed suppliers	Alprostadil complexed with alpha-cyclodextrin
Muse	Intraurethral pellet	Erectile dysfunction	Meda, Viatris and regional licensees	Polyethylene glycol-based urethral delivery system
Prostin VR Pediatric	Intravenous infusion	Maintenance of ductus arteriosus patency	Pfizer and hospital suppliers	Concentrated ethanolic injection diluted before infusion
Vitaros	Topical urethral meatal cream	Erectile dysfunction	Apricus Biosciences and regional partners	Cream formulation with penetration-enhancing excipients
Alprostadil injection generics	Intracavernosal or intravenous use	Erectile dysfunction or neonatal indications	Multiple suppliers	Vial, ampoule, or kit-based presentations

Caverject and Edex are intracavernosal products. Muse delivers alprostadil through the urethra. Prostin VR Pediatric is used in neonatal and pediatric cardiac care and has a separate hospital procurement profile. Vitaros has been marketed in several non-U.S. jurisdictions but does not have the same U.S. regulatory position as the injectable and intraurethral products.

Which excipients are used in alprostadil formulations?

The excipient strategy depends on route, dose, stability target, and whether the product is supplied as a powder, solution, pellet, or cream.

Caverject and lyophilized injectable products

Caverject contains alprostadil with lactose monohydrate and sodium citrate in the powder formulation. Hydrochloric acid and sodium hydroxide are used for pH adjustment. The product is reconstituted with a supplied diluent before intracavernosal administration. Some presentations use bacteriostatic water containing benzyl alcohol, while product-specific labeling controls the permitted diluent and storage conditions.

The commercial logic is straightforward:

• Lactose provides a stable bulking matrix for a very low-dose active ingredient.
• Sodium citrate provides buffering capacity.
• Lyophilization reduces the active ingredient's exposure to aqueous degradation during storage.
• A separate diluent allows the manufacturer to control pH, ionic strength, and preservative content at the point of use.
• A supplied syringe or dual-chamber system reduces preparation errors.

The main opportunity is a preservative-free, ready-to-use presentation that maintains the stability of alprostadil without requiring reconstitution. Such a product would need to demonstrate container-closure compatibility, dose uniformity, particulate control, and acceptable in-use stability.

Edex and alpha-cyclodextrin complexes

Edex uses alprostadil complexed with alpha-cyclodextrin. Cyclodextrin complexation can improve apparent aqueous solubility and support rapid reconstitution or dissolution. It also provides a formulation platform that differs from the lactose-based lyophilized architecture used by Caverject.

Cyclodextrin-based systems create several potential commercial advantages:

• Smaller formulation volume.
• Improved handling of a poorly water-compatible active.
• Potentially faster dissolution.
• Differentiation from standard lyophilized generic presentations.
• A platform for prefilled cartridges or automated injection devices.

The principal development risks are cyclodextrin concentration, local tolerability, extractables and leachables, and the need to demonstrate that complexation does not alter the pharmacodynamic response or injection-site profile.

Muse intraurethral pellets

Muse uses a solid intraurethral delivery system. Polyethylene glycol is identified as a formulation component in product information. The pellet must dissolve after insertion and release alprostadil across the urethral mucosa.

For this dosage form, excipient selection controls:

• Pellet mechanical strength.
• Insertion performance.
• Disintegration time.
• Local moisture uptake.
• Drug release in the urethral environment.
• Residual discomfort and irritation.
• Manufacturing yield and dose uniformity.

The most attractive development path is a smaller, faster-dissolving pellet or an applicator that improves placement consistency. A lower-dose product with equivalent clinical effect could also reduce adverse events and improve patient acceptance.

Prostin VR Pediatric injection

Prostin VR Pediatric is a concentrated alprostadil injection supplied for dilution before continuous intravenous infusion. The formulation uses dehydrated alcohol as the principal solvent system, and the product is handled in a hospital setting.

Hospital-use opportunities are different from erectile-dysfunction products. Buyers prioritize:

• Reliable supply.
• Ampoule or vial breakage resistance.
• Barcode and medication-error reduction.
• Low extractables and leachables.
• Compatibility with infusion bags, tubing, and pumps.
• Clear dilution instructions.
• Shelf-life and cold-chain performance.

A ready-to-dilute or pharmacy-compounded presentation could reduce manipulation in neonatal intensive-care units. A premixed infusion product would face greater stability, packaging, microbial-control, and dose-flexibility requirements but could command a hospital-safety premium.

Topical alprostadil creams

Topical alprostadil creams, including Vitaros-type products, use penetration-enhancing and emulsion-supporting excipients. Public product information identifies components such as ethanol, propylene glycol, docusate sodium, citrate buffers, and water, with product-specific polymers and stabilizers varying by jurisdiction.

A topical platform must balance two opposing objectives:

1. Increase local penetration through the glans and urethral opening.
2. Limit systemic absorption, partner exposure, and local irritation.

Docusate sodium and alcohol can improve wetting and permeability but may increase irritation risk. Propylene glycol can act as a solvent and humectant but can also contribute to local intolerance in sensitive users. The commercial opportunity is a lower-irritancy cream, gel, foam, or film with more predictable absorption and less transfer to a sexual partner.

What excipient attributes matter most for alprostadil?

Alprostadil formulation development should prioritize five technical attributes.

Chemical stability

The active ingredient requires control of pH, water activity, oxygen exposure, light exposure, and temperature. A lyophilized or nonaqueous system can reduce degradation during storage. Antioxidants may be considered, but they must be justified by degradation studies and evaluated for local or systemic tolerability.

Solubility and dose uniformity

Alprostadil is used at microgram-level doses in erectile-dysfunction products. Small losses to vial walls, syringes, filters, or tubing can affect delivered dose. Surfactants, complexing agents, and container-surface treatments may reduce adsorption, but each introduces regulatory and compatibility work.

Local tolerability

The intracavernosal route has limited tolerance for pH extremes, osmolality changes, particulates, preservatives, or solvents. Urethral and topical products have an even narrower margin because ethanol, propylene glycol, surfactants, and penetration enhancers can produce burning or irritation.

Sterility and microbiological control

Injectable products require sterile manufacturing and container-closure integrity. Creams and urethral systems require microbial limits or sterility controls appropriate to the route and dosage form. A preservative-free product may improve tolerability but increases dependence on aseptic manufacturing and single-use packaging.

Device compatibility

A formulation cannot be evaluated separately from its delivery system. Syringe materials, needles, cartridges, applicators, infusion tubing, and elastomeric closures can affect potency, adsorption, extractables, dose accuracy, and patient handling.

What commercial opportunities exist for alprostadil excipients?

The most viable opportunities are incremental product improvements rather than a new active-ingredient market.

Opportunity	Technical approach	Commercial rationale
Preservative-free injection	Single-use prefilled syringe or cartridge	Reduces benzyl alcohol exposure and preparation steps
Stable ready-to-use solution	pH and solvent optimization with oxygen control	Eliminates reconstitution and may improve adherence
Improved cyclodextrin system	Alpha- or modified cyclodextrin complexation	Supports solubility and device-based delivery
Lower-irritancy topical product	Reduced alcohol, optimized penetration enhancer, buffered emulsion	Addresses burning and local intolerance
Faster-dissolving urethral pellet	Polymer and particle-size engineering	Improves administration time and convenience
Neonatal premix	Dilution-ready infusion container	Reduces pharmacy preparation and medication errors
Dual-chamber delivery device	Separate active and diluent until administration	Extends stability while preserving ease of use
Generic excipient substitution	Cost-optimized lactose, citrate, PEG, or solvent system	Reduces manufacturing cost if bioequivalence and quality are maintained
Partner-protected topical formulation	Low-transfer cream or film	Reduces exposure concerns and differentiates the product
Cold-chain-reduced presentation	Lyophilized or improved nonaqueous system	Expands distribution in lower-resource markets

Excipient suppliers can capture value through pharmaceutical-grade cyclodextrins, low-peroxide polyethylene glycol, specialty penetration enhancers, low-extractables elastomers, and ready-to-use sterile packaging. Contract manufacturers can compete through integrated powder filling, dual-chamber assembly, and device combination-product capabilities.

When does alprostadil lose exclusivity?

The principal U.S. alprostadil products have been marketed for decades, and their original compound and formulation exclusivities have generally expired. The commercial market is therefore primarily generic, multisource, and device-driven.

Exclusivity category	Current commercial position
Original active-ingredient exclusivity	Expired for legacy alprostadil products
Original injectable formulation claims	Largely expired or commercially weak in the U.S.
U.S. Orange Book patent exposure	Product-specific and subject to current FDA listing data
Pediatric hospital product protection	Primarily dependent on manufacturing, supply, regulatory status, and contracting
Topical cream protection	More dependent on jurisdiction, delivery technology, and formulation claims
Device and packaging protection	Potentially relevant for new combination products
Trade-secret protection	Important for process controls, impurity limits, and device assembly

A new entrant should not assume that an old alprostadil formulation is free of all legal constraints. Patent risk can remain around a specific device, manufacturing process, excipient ratio, container system, or method of use. Those risks must be assessed against current FDA Orange Book listings, issued patent records, and the relevant national registers.

What is the Orange Book and Paragraph IV status of alprostadil?

FDA Orange Book treatment is product-specific. Injectable and intraurethral alprostadil products may be listed by reference product and dosage form, while unapproved or non-U.S. topical products do not receive the same U.S. Orange Book position.

For a generic applicant, the key questions are:

1. Is the reference product listed in the Orange Book?
2. Are any patents currently listed for the reference product?
3. Has the applicant filed Paragraph IV certifications?
4. Is the proposed product therapeutically equivalent or a 505(b)(2) product?
5. Does the device require separate combination-product review?
6. Does the formulation differ enough to trigger additional clinical or human-factor requirements?

Alprostadil products with old approval dates often present abbreviated regulatory pathways, but formulation and device differences can change the filing strategy. A topical cream without a U.S. reference product may face a more complex 505(b)(2) or new drug application pathway rather than a straightforward ANDA route.

What patent litigation and settlements affect alprostadil?

Alprostadil has not developed the same high-value patent litigation profile as major oncology, immunology, or metabolic drugs. The relevant legal risks are usually narrower:

• Formulation patents covering cyclodextrin complexes.
• Device patents covering dual-chamber syringes or applicators.
• Method-of-use claims for erectile dysfunction or neonatal cardiac indications.
• Manufacturing patents covering sterile filling, lyophilization, or complex formation.
• Trade-secret claims involving process parameters or impurity control.

Publicly visible litigation and settlement activity has been limited compared with major branded medicines. Commercial diligence should focus more heavily on current patent registers, FDA approval histories, ANDA records, device ownership, and supplier agreements than on historic blockbuster-style settlement precedent.

How strong is the alprostadil patent estate?

The legacy compound estate is weak because alprostadil has been commercially available for many years. New patent strength depends on technical specificity and enforceability.

Patent subject	Relative strength
Alprostadil molecule itself	Very weak or expired
Basic injectable solution	Weak unless tied to a narrow stability or compatibility limitation
Lyophilized powder	Moderate only with specific composition and performance data
Cyclodextrin complex	Moderate, depending on claim scope and prior art
Topical penetration system	Moderate to strong if clinical performance is differentiated
Dual-chamber or prefilled device	Moderate, subject to device prior art
Manufacturing process	Moderate if difficult to design around
New neonatal premix	Moderate if stability and container claims are narrow and supported
Low-transfer topical formulation	Potentially strong if supported by comparative clinical data

The most defensible new intellectual property will combine composition, device, process, and clinical-performance claims. A broad claim to "alprostadil with an excipient" is unlikely to provide durable protection in a mature field.

How does alprostadil compare with competing erectile-dysfunction drugs?

Alprostadil competes with oral phosphodiesterase-5 inhibitors such as sildenafil, tadalafil, vardenafil, and avanafil. It also competes with vacuum devices, penile implants, and compounded therapies.

Attribute	Alprostadil injection	Alprostadil urethral or topical	PDE5 inhibitor tablets
Onset	Rapid	Variable, generally rapid to moderate	Moderate
Administration	Invasive	Less invasive	Oral
Systemic exposure	Lower than oral PDE5 therapy in many uses	Variable	Systemic
Main formulation challenge	Sterility, pH, stability, dose accuracy	Permeation and irritation	Tablet dissolution and systemic pharmacokinetics
Patient acceptance	Often limited by injection	Better than injection for some users	Usually highest
Differentiation opportunity	Device and convenience	Tolerability and absorption	New combinations and patient segmentation

Alprostadil retains commercial value where oral therapy is ineffective, contraindicated, poorly tolerated, or unsuitable. Its formulation opportunity is therefore concentrated in convenience, reliability, and route-specific tolerability.

What generic launch scenarios exist?

A generic entrant can pursue several launch models:

1. A conventional lyophilized vial with a supplied diluent.
2. A lower-cost alprostadil injection with a standard syringe.
3. A device-led product using a cartridge or dual-chamber system.
4. A 505(b)(2) product with improved stability or reduced preparation time.
5. A topical or urethral product in jurisdictions where a suitable regulatory reference exists.
6. A hospital-focused neonatal product with improved dilution and barcode controls.

The lowest regulatory and development risk is generally a conventional injectable product that matches the reference formulation and delivery method. The highest commercial differentiation is likely to come from ready-to-use delivery, reduced pain or irritation, and neonatal medication-safety improvements.

What geographic markets offer the best opportunity?

The United States is attractive for generic injectable competition but has a mature reimbursement and product landscape. Europe and Canada offer opportunities for topical and urethral systems, subject to country-specific authorization and reimbursement. Latin America, the Middle East, and parts of Asia may offer demand for lower-cost injectable products, but registration, procurement, and local manufacturing requirements vary.

Hospital alprostadil products can be commercially attractive in markets with established neonatal cardiac surgery capacity. The commercial model depends on institutional contracts and uninterrupted supply rather than high retail pricing. Erectile-dysfunction products are more suitable for pharmacy, private-clinic, and direct-distribution channels.

Key Takeaways

• Alprostadil is a mature active ingredient with limited value in the molecule itself and greater value in formulation and delivery.
• The principal excipient platforms are lactose-citrate lyophilizates, alpha-cyclodextrin complexes, polyethylene glycol-based pellets, ethanolic injections, and topical emulsions.
• The strongest product opportunities are preservative-free injections, ready-to-use devices, lower-irritancy topical systems, and neonatal premixes.
• Legacy compound and basic formulation exclusivities are generally expired, leaving device, process, and narrow formulation claims as the main patent opportunities.
• A generic injectable is the lowest-risk entry route; a differentiated topical, urethral, or device-based product offers greater commercial upside but higher regulatory complexity.
• Excipient suppliers can compete through cyclodextrins, low-peroxide solvents, penetration enhancers, sterile packaging, and combination-product manufacturing.
• FDA Orange Book, patent-register, ANDA, and device records must be reviewed on a product-by-product basis before launch or licensing decisions.

FAQs

Is alprostadil chemically stable in water?

Alprostadil stability depends on pH, temperature, oxygen exposure, container materials, and formulation composition. Lyophilized and nonaqueous systems are commonly used to improve shelf stability.

Which excipient is most important in Edex?

Alpha-cyclodextrin is central to the Edex formulation platform because it complexes with alprostadil and supports its delivery in an injectable dosage form.

Can alprostadil be formulated without benzyl alcohol?

Yes. A preservative-free presentation can use single-dose sterile packaging, a lyophilized powder, a dual-chamber device, or another formulation that avoids multidose preservation requirements.

Is Vitaros approved by the FDA?

Vitaros has been marketed in certain non-U.S. jurisdictions. It does not hold the same U.S. approval position as established U.S. alprostadil injectable and intraurethral products.

What is the best patent strategy for a new alprostadil product?

The strongest strategy usually combines a specific composition with a delivery device, manufacturing process, stability limitation, or clinically demonstrated tolerability advantage. Broad claims covering alprostadil and ordinary excipients are less likely to provide durable protection.

References

1. U.S. Food and Drug Administration. (2024). Caverject (alprostadil) prescribing information. FDA.

2. U.S. Food and Drug Administration. (2024). Edex (alprostadil for injection) prescribing information. FDA.

3. U.S. Food and Drug Administration. (2024). Muse (alprostadil urethral suppository) prescribing information. FDA.

4. U.S. Food and Drug Administration. (2024). Prostin VR Pediatric (alprostadil) prescribing information. FDA.

5. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.

6. European Medicines Agency. (n.d.). Alprostadil product information and national authorization records. EMA.

7. Apricus Biosciences, Inc. (n.d.). Vitaros product and formulation information. Apricus Biosciences.

8. U.S. Pharmacopeia. (2024). General chapters for sterile pharmaceutical preparations, packaging systems, and excipient quality. United States Pharmacopeial Convention.