Copovidone (PVP/VA Copolymer): A Comprehensive Reference
1. Identity and Chemical Character
1.1 Chemical Names and Synonyms
Copovidone, also known as polyvinylpyrrolidone-vinyl acetate (PVP/VA), is a versatile pharmaceutical excipient commonly used in drug formulations. It is sometimes referred to as vinylpyrrolidone-vinyl acetate or copolyvidone. Its CAS number is 25086-89-9. Under Japanese pharmaceutical nomenclature it is catalogued as "Copolyvidone." The abbreviation PVP/VA reflects its two constituent monomers, and the designation "VA 64" derives from the proportion of vinyl acetate relative to vinylpyrrolidone in the most common commercial formulation.
1.2 Chemical Structure and Polymerization
Copovidone is a synthetic random copolymer produced by the free radical polymerization of vinylpyrrolidone (VP) and vinyl acetate (VA) with a 6:4 ratio of VP to VA. Copovidone is a synthetic random copolymer of N-vinylpyrrolidone and vinyl acetate. This co-polymerization introduces vinyl acetate units into the polymer chain, which significantly alters its physical and chemical properties. The resulting macromolecule carries both hydrophilic (pyrrolidinone) and slightly hydrophobic (acetate) segments within the same backbone, giving it an amphiphilic character that underlies many of its functional properties.
1.3 Molecular Weight
The average molecular weight of copovidone is usually expressed as a K-value and it ranges between 45 and 70. The K-value is a viscosity-derived index that correlates with chain length and molar mass. The most widely used pharmaceutical-grade product, Kollidon® VA 64, has a K-value in this range, corresponding to a weight-average molecular weight close to that of PVP K30.
1.4 Physical Form and Appearance
It is a freely flowing spray-dried powder with a spherical, hollow particle morphology, and was designed to overcome some of the limitations associated with polyvinylpyrrolidone (PVP), such as PVP's relatively stiff, brittle, and hygroscopic nature. The powders are white or slightly yellowish, have a faint characteristic odor.
1.5 Solubility
A key feature of this vinylpyrrolidone vinyl acetate copolymer is its solubility: it readily dissolves in most hydrophilic solvents, including water, ethanol, and isopropanol, making it highly adaptable for various formulation processes. While it exhibits good solubility, the vinyl acetate component makes it slightly less hydrophilic than homopolymer povidone, which can be advantageous for controlling water sensitivity and improving film properties.
1.6 Glass Transition Temperature
While the brittleness and stiffness of PVP are reflected in a relatively high glass transition temperature (Tg) of approximately 164 °C for a PVP K30 grade, PVP/VA shows a lower Tg of approximately 108–111 °C, with a molecular weight close to that of PVP K30. The decrease in the Tg of copovidone due to the addition of a comonomer to vinylpyrrolidone improves the copolymer plasticity and flexibility; thus, PVP/VA has a significantly lower Tg and is a lot more flexible and plastic compared to PVP.
1.7 Natural Source
Copovidone has no botanical or natural origin. It is an entirely synthetic polymer produced industrially from petroleum-derived monomers (N-vinylpyrrolidone and vinyl acetate). It is not derived from any plant, mineral, or animal source, and thus possesses no traditional herbal or nutritional history. Its identity as a "dietary supplement ingredient" or "natural ingredient" in the conventional sense is therefore not applicable; its use in human health contexts arises exclusively through its role as a pharmaceutical excipient and cosmetic ingredient.
1.8 Commercial Grades and Trade Names
Copovidone has been used for decades in the pharmaceutical industry. Up to about 1975 it was marketed under the name of Luviskol® VA 64, which today is used only for the technical/cosmetic grade of this copolymer. This is why older publications often refer to the use of Luviskol® VA 64 in pharmaceuticals. The principal contemporary pharmaceutical grades are Kollidon® VA 64 and Kollidon® VA 64 Fine (both from BASF SE, Ludwigshafen, Germany) and Plasdone™ S-630 and Plasdone™ S-630 Ultra (ISP / Ashland). In terms of monographs, Plasdone S-630 (PL-S630) and PVP VA64 are the same product. However, these copolymers are manufactured by two different manufacturers, and therefore have different solid-state and dissolution properties as a result of their manufacturing process. Differences in the manufacturing process from different suppliers of copovidone can influence the properties of the copovidone produced.
2. Pharmacopeial and Regulatory Status
Kollidon VA 64 and Kollidon VA 64 Fine meet the current European Pharmacopoeia (Ph. Eur.) and USP monograph "Copovidone" and the JPE monograph "Copolyvidone." A US-DMF with the number 6745 has been submitted in the United States. Copovidone is therefore an officially recognized excipient with pharmacopeial monographs in the European Pharmacopoeia, the United States Pharmacopeia (USP), and the Japanese Pharmaceutical Excipients (JPE) compendium. These monographs specify identity tests, purity criteria, residual monomer limits, moisture content, and microbial quality standards.
Copovidone is classified as an excipient (pharmacologically inactive substance); it is used as a tablet binder, a film-former, and as part of the matrix material used in controlled-release formulations. As an excipient in approved drug products, copovidone is subject to FDA oversight through the Inactive Ingredient Database and through drug master file (DMF) submissions. It is not listed on FDA's food GRAS inventory as a food additive; its regulatory approvals relate specifically to its use as a pharmaceutical excipient in approved dosage forms.
Pharmacopeial specifications for the most common grade include a pH value of 3.0–7.0, a K-value of 25.2–30.8, aldehydes content ≤500 ppm, peroxides ≤400 ppm, hydrazine ≤1 ppm, monomers (residue VP + residue VA) at 0.001%, impurity A (2-pyrrolidone) ≤0.5%, loss on drying ≤5.0%, sulphated ash ≤0.1%, heavy metals ≤20 ppm, VA content 35.3–42%, and nitrogen 7.0–8.0%.
3. Traditional and Historical Use
Because copovidone is an entirely synthetic polymer first developed by the German chemical industry in the mid-twentieth century, it has no traditional use in any ethnobotanical, Ayurvedic, Traditional Chinese Medicine, or folk-medicine tradition. The parent material, polyvinylpyrrolidone (PVP), was developed in Germany during the 1930s and initially used as a blood plasma expander in World War II; copovidone as a distinct copolymer came later. There is no documented pre-modern or pre-industrial use of copovidone or any structurally related synthetic polymer by any culture for medicinal, culinary, or ritual purposes.
Copovidone has been used for decades in the pharmaceutical industry. Up to about 1975 it was marketed under the name of Luviskol® VA 64, which today is used only for the technical/cosmetic grade of this copolymer. This is why older publications often refer to the use of Luviskol® VA 64 in pharmaceuticals. The earliest pharmaceutical applications were in tablet manufacturing, gradually expanding to controlled-release matrix systems and eventually to amorphous solid dispersion technology from the 1980s onward.
4. Key Constituents and Chemical Composition
4.1 Monomeric Units
Copovidone is composed of two chemicals — N-vinylpyrrolidone and vinyl acetate — which together give copolyvidone its excellent bonding ability. The pyrrolidinone ring provides strong intermolecular hydrogen-bonding capacity, while the acetate side chains reduce crystallinity and chain rigidity. This architectural combination distinguishes it from the homopolymer povidone (PVP), which carries only the pyrrolidinone unit.
4.2 Residual Impurities
Trace levels of reactive impurities such as peroxides have been found in many pharmaceutical excipients, including povidones, copovidones, polyethylene glycol, and polysorbates. The primary source of reactive impurities (hydrogen peroxides, organic hydroperoxides, or formaldehyde) can be either the production process by-products or the oxidative instability of excipients. Generally, peroxide impurity (hydrogen peroxide) has been reported to develop in polyvinyl pyrrolidone-based excipients (povidone, copovidone, and crospovidone) where hydrogen peroxide, a major reactive impurity, is liberated as a by-product via a radical chain reaction. As per United States Pharmacopeia USP-35, the initial limit of peroxides in copovidones should not be more than 400 ppm (NMT 0.04%).
5. Mechanisms of Action and Functional Properties
5.1 Tablet Binding Mechanism
In tableting, copovidone can be used as a binder for direct compression and as a binder in wet granulation. As a water-soluble polymer binder, copovidone aids in the granulation process, ensuring uniform tablet properties and improving compressibility. Copovidone has better plasticity than povidone as a tablet binder, is less hygroscopic, more elastic, and better for film-forming applications than povidone. The mechanism of binding operates through multiple non-covalent interactions: hydrogen bonding via the carbonyl groups of the pyrrolidinone ring, van der Waals interactions facilitated by the polymer backbone, and physical entanglement of polymer chains around drug and excipient particles.
5.2 Film-Forming Mechanism
Copovidone is often added to coating solutions as a film-forming agent. It provides good adhesion, elasticity, and hardness, and can be used as a moisture barrier. Kollidon VA 64 forms films that are soluble at all pH values. They are less hygroscopic and more elastic than those formed by povidone (e.g. Kollidon 30). The vinyl acetate component is principally responsible for this reduced water uptake and greater film flexibility, acting as an internal plasticizer within the polymer matrix.
5.3 Solubilization and Amorphous Solid Dispersion Formation
Amorphous solid dispersions (ASDs) are a supersaturating drug delivery strategy where the amorphous drug and polymer carrier are formulated as a molecular-level dispersion. Enhanced bioavailability is achieved through the creation and maintenance of supersaturation due to the solubility advantage of the amorphous form, enabling improved absorption.
Copovidone participates in this mechanism by: (1) stabilizing the drug in its amorphous form through polymer-drug miscibility and hydrogen bonding; (2) inhibiting recrystallization during storage by increasing system viscosity and reducing molecular mobility; and (3) promoting wetting and dissolution upon contact with gastrointestinal fluid. Amorphous solid dispersions are used to enhance the mechanical and flow properties of poorly soluble drugs in addition to improvement in their dissolution rate.
5.4 Hot Melt Extrusion Processing Behavior
In hot melt extrusion (HME), PVP/VA is an approved carrier material for the production of amorphous solid dispersions by embedding drugs on a molecular level. The comparatively low glass transition temperature of PVP/VA (~108–111 °C) relative to PVP K30 (~164 °C) is a key processing advantage: it allows melt extrusion at lower barrel temperatures, reducing the thermal degradation risk for heat-sensitive drug molecules. Its good plasticity and low glass transition temperature make it suitable for hot melt extrusion to prepare solid dispersions, enhancing drug solubility and bioavailability.
6. Scientific Evidence by Area of Application
6.1 Amorphous Solid Dispersions and Oral Bioavailability Enhancement
Evidence strength: Strong (pharmaceutical science literature; multiple studies; supported by FDA-approved drug products)
Forty-eight drug products containing amorphous solid dispersions (ASDs) were approved by the U.S. Food and Drug Administration in the 12-year period between 2012 and 2023. These drug products comprise 36 unique amorphous drugs. Ten therapeutic categories are represented, with most drug products containing antiviral and antineoplastic agents. The most common ASD polymers are copovidone (49%) and hypromellose acetate succinate (30%), while spray drying (54%) and hot melt extrusion (35%) are the most utilized manufacturing processes to prepare the ASD drug product intermediate.
This clinical-regulatory evidence is among the most robust available for copovidone's functional role. The FDA-approved products directly demonstrate that copovidone-based ASDs deliver meaningful bioavailability gains for BCS Class II (low solubility, high permeability) and BCS Class IV drugs in human patients. Each approved ASD product has undergone full pharmacokinetic evaluation in clinical trials as part of the regulatory submission, providing strong human-level evidence of the bioavailability enhancement mechanism.
In the preclinical/animal literature, mefenamic acid, a BCS Class II nonsteroidal anti-inflammatory drug with poor aqueous solubility and dissolution-limited oral bioavailability, was the subject of a study focusing on developing a copovidone-based hot-melt extruded amorphous solid dispersion tablet specifically aimed at enhancing dissolution and systemic absorption. The optimized formulation exhibited a 5.54-fold increase in solubility and significantly enhanced in vitro dissolution compared to the pure drug and marketed tablet (p < 0.05). PXRD and DSC confirmed complete drug amorphization, while FTIR indicated the absence of adverse drug-excipient interactions between mefenamic acid and copovidone. Pharmacokinetic evaluation revealed substantial improvements, including a 2.1-fold increase in Cmax (p < 0.05) and a 1.7-fold increase in AUC₀–∞ (p < 0.05).
Wlodarski et al. studied the physicochemical properties of tadalafil tablets using PVP-VA following direct compression of solid dispersions prepared by spray drying and ball milling techniques. Both formulations showed the greatest enhancement in the dissolution rate of tadalafil.
Atazanavir-copovidone ASDs were studied, where atazanavir is a relatively high-Tg compound with a limit of congruency (LoC) of 5% drug loading. Surface-normalized dissolution studies revealed that addition of 5% w/w of surfactant (sodium dodecyl sulfate or cetrimonium bromide) to the binary copovidone-based ASD doubled the LoC (from 5 to 10% drug loading), resulting in a more than 30-fold increase in total release compared to the corresponding binary ASD.
6.2 Tablet Binding and Granulation Performance
Evidence strength: Strong (extensive pharmaceutical technology literature and decades of industrial use)
Kollidon® VA 64 and Kollidon® VA 64 Fine are excellent binders for tablets and granules. Between 2% and 8%, as a proportion of the final weight of the preparation, is usually used. The reduced hygroscopicity and plasticity of VP/VA Copolymer VA64 compared to other PVP grades make it an ideal choice for formulations prone to capping or lamination during tablet compression, ensuring the integrity of the final product. The tablet-binding performance of copovidone has been validated across a large body of pharmaceutical technology studies and is embedded in numerous approved drug product formulations. This represents the most extensively documented application, with evidence derived from thousands of manufacturing batches in regulated pharmaceutical production environments.
6.3 Controlled and Sustained Release Matrix Systems
Evidence strength: Moderate to strong (preclinical/in vitro evidence well established; incorporated in approved drug products)
Copovidone's unique polymer structure is ideal for developing sustained-release drug delivery systems, allowing for gradual and predictable drug dissolution over time. Kollidon® VA 64 and Kollidon® VA 64 Fine are used in the pharmaceutical industry as dry binder in tablets, as matrix formers for amorphous solid dispersions, as retarding and as film-forming agents. In matrix-tablet systems, copovidone functions by swelling upon hydration and forming a gel layer that controls the rate of drug diffusion outward, enabling extended-release profiles. The controlled-release matrix application is supported by approved extended-release dosage forms and is an accepted formulation strategy.
6.4 Characterization of Copovidone Grades for HME: A Comparative Study
Evidence strength: Preliminary (single-study, process science focus)
A 2025 study published in Pharmaceutics investigated the properties and processability of two copovidone grades — Plasdone™ S-630 (PS-630) and the novel Plasdone™ S-630 Ultra (PS-630U) — to assess their suitability as ASD carrier materials. The thermal and physicochemical characteristics of both polymers were evaluated, focusing on glass transition temperature and polymer melt rheology. The process performance in HME was investigated on small-scale as well as in production-scale extrusion. The two model drugs itraconazole and griseofulvin were used to examine drug dissolution and degradation during HME via in-line UV-vis spectroscopy. This type of study is focused on pharmaceutical process science rather than clinical outcomes, and its findings inform manufacturing decisions rather than directly demonstrating human health benefits.
6.5 Polymer Blends for 3D Printing Applications
Evidence strength: Preliminary (experimental, no clinical data)
Key findings from a 2024 study revealed that Copovidone/HPMC ASLF formed a miscible, single-phase system with one glass transition temperature, while Copovidone/Eudragit EPO resulted in an immiscible, phase-separated microstructure with two glass transition temperatures. Research into copovidone's use in fused deposition modeling (FDM)-based 3D printing for pharmaceutical dosage form manufacture is early-stage and has not yet translated into approved products; evidence is confined to in vitro and materials characterization studies.
6.6 Cosmetic Applications: Hair Styling and Skin Care
Evidence type: Applied/industrial (no clinical endpoint studies in the health-benefit sense)
Copovidone is also used in cosmetics as a thickener, dispersant, lubricant, film-forming agent and binder. In cosmetics, copovidone functions as a film-former and hair-fixing agent, contributing to the performance and appeal in hair styling products and other personal care items. The use of copovidone in cosmetics is well established commercially, particularly in hair sprays and gels where the film-forming properties provide hold. No clinical trials have evaluated copovidone as a standalone cosmetic active ingredient for therapeutic endpoints such as hair growth, scalp health, or skin disease.
7. Body Systems and Health Areas Associated with Copovidone
Copovidone is not a biologically active ingredient and does not, by itself, target specific organ systems or physiological pathways. Its association with body systems arises entirely from the drugs it carries in finished dosage forms. The following summarizes these indirect associations:
- Gastrointestinal system: Copovidone is the most prevalent carrier polymer in FDA-approved oral ASD drug products. The most common ASD polymers are copovidone (49%) and hypromellose acetate succinate (30%). Many of these drug products target GI absorption, making the GI tract the principal site of copovidone's functional activity (dissolution facilitation).
- Antiviral and antineoplastic therapy: Most FDA-approved ASD drug products contain antiviral and antineoplastic agents. Copovidone is accordingly present in formulations for HIV, hepatitis C, and cancer therapies where it enables the delivery of poorly soluble active compounds.
- Cardiovascular and metabolic drugs: Copovidone-based solid dispersions have been studied with drugs such as tadalafil (erectile dysfunction / pulmonary arterial hypertension), felodipine (antihypertensive), and atorvastatin (lipid-lowering), covering cardiovascular and metabolic health indications at the drug level.
- Anti-inflammatory therapy: Mefenamic acid, a BCS Class II NSAID, was formulated as a copovidone-based HME ASD for enhanced dissolution and systemic absorption.
- Skin and hair (topical/cosmetic): In topical and cosmetic contexts, copovidone interacts with the integumentary system, primarily providing film-forming properties with no documented pharmacological effect on the skin or scalp.
8. Dosage Forms and Reported Formulation Levels
Copovidone itself is not administered as a supplement at a defined therapeutic dose; it is an excipient whose level in a formulation is determined by pharmaceutical technology requirements. Published sources report the following concentration ranges:
- Tablet binder (direct compression or wet granulation): Between 2% and 8%, as a proportion of the final weight of the preparation, is the usual range for Kollidon® VA 64 and Kollidon® VA 64 Fine as binders for tablets and granules.
- Film coating solutions: Copovidone is incorporated into coating suspensions, typically as a minor component providing adhesion and flexibility to the coating film. The amount of copolyvidone in the coating agent is, for example, within a range from about 5 to about 50% by weight, preferably from about 10 to about 30% by weight, and more preferably from about 10 to about 20% by weight.
- Amorphous solid dispersion matrix: In ASD formulations, copovidone typically constitutes a large proportion of the drug product intermediate. Patent literature illustrates one formulation approach specifying "solid dispersions of about 20 wt. % drug substance in about 80 wt. % copovidone." Drug loading in binary ASDs generally ranges from approximately 5% to 40% w/w drug, with copovidone comprising the remainder.
- Antiviral ASD products: In one described embodiment, the composition of copovidone in a tadalafil formulation is vinylpyrrolidone:vinyl acetate = 60:40.
The actual amount of copovidone ingested per dose in a finished drug product varies widely depending on the formulation, but given typical tablet weights and excipient levels, daily exposure is generally in the milligram range per dosage unit and is not considered a source of pharmacological activity.
9. Safety Considerations
9.1 Preclinical Toxicology (Animal Studies)
A pivotal long-term animal study examined the safety of copovidone at high dietary exposure levels. Kollidon VA 64 (copovidone, CAS No. 25086-89-9) was administered in the diet to male and female Wistar rats (0, 700, 1400, and 2800 mg/kg body weight) for 24 months, and to male and female Beagle dogs (0, 500, 1500, and 2500 mg/kg body weight/day) for 52 weeks. Clinical signs, body weight, food consumption, hematology, and gross and histopathological evaluations were conducted on both rats and dogs, and dogs also underwent hearing tests, ophthalmoscopic examinations, electrocardiograms, blood pressure measurement, and clinical chemistry and urinalysis evaluations. No adverse in-life observations related to treatment were observed in either species. The rats exhibited dark discoloration of the feces that was attributed to the intake and excretion of large amounts of test substance and was not considered to be an adverse effect.
9.2 General Safety Profile
Copovidone is generally regarded as nontoxic. However, oral consumption of excessive quantities may produce stomach upset. It has not been shown to be sensitizing to the skin. Animal studies in rats and dogs do not show significant toxicity with high dietary levels.
9.3 Peroxide Impurity and Drug Incompatibility
The most clinically relevant safety consideration for copovidone is not its direct toxicity but rather its potential to degrade co-formulated drug substances through peroxide-mediated oxidation. This is a formulation science safety issue rather than a consumer safety concern, but it is scientifically significant:
Copovidones may induce oxidative degradation via the following mechanisms: radical-initiated oxidation (autoxidation) and peroxide-mediated oxidation. Drug substances that are sensitive to oxidation, especially APIs with piperazine and tertiary amine functional groups, are highly susceptible to interaction with copovidones via different mechanisms such as N-oxide formation.
It has been reported that the potency of raloxifene was decreased through oxidative degradation as evidenced by the formation of raloxifene N-oxide, an amine oxide degradant by peroxide impurities present in copovidone. The findings indicate that a reaction between peroxides and the tertiary amine group of raloxifene is responsible for electron transfer-induced oxidative degradation.
Initial peroxide levels were higher in Kollidon VA 64 (KVA64) and Plasdone S630 (PS630) compared to Plasdone S630 Ultra (PS630U), leading to greater oxidative degradation of the drug in fresh ASD tablets. However, stability testing showed lower oxidative degradation impurities in ASD tablets prepared at higher barrel temperatures, likely due to greater peroxide degradation.
The presence of peroxide impurities leads to the degradation of drug products containing oxygen-sensitive active pharmaceutical ingredients, resulting in decreased product performance, loss in potency, and formation of toxic degradation impurities. The International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) entails that the characterization and biological safety evaluation of degradation impurities are needed if the impurity profile is above the threshold levels based on daily dose.
9.4 Hygroscopicity Considerations
The hygroscopic nature of polymers can often be a challenge in pharmaceutical formulations, but copovidone exhibits reduced hygroscopicity compared to other polyvinylpyrrolidone variants. Despite this advantage relative to PVP homopolymer, copovidone still absorbs some atmospheric moisture. Although the initial peroxide levels are within the pharmacopeial limit, controlling the generation and growth of peroxides upon stability is necessary for drug product stabilization. Packaging and storage conditions for copovidone-containing drug products are therefore important considerations in pharmaceutical development.
9.5 Supplier and Grade Variability
Differences in the manufacturing process from different suppliers of copovidone can influence the properties of the copovidone produced. Some of these properties may be critical material attributes for the manufacturing process or performance of a drug product. For example, different suppliers' products may have different glass transition temperatures. This means that even pharmacopeially compliant batches from different manufacturers may not be interchangeable without re-validation of the drug product, representing a quality and consistency consideration for manufacturers.
10. Summary of Evidence Strength
- Pharmaceutical excipient function (tablet binding, film coating): Well established; supported by decades of industrial use, pharmacopeial monographs, and approved drug products. Not a clinical health benefit per se.
- Bioavailability enhancement via ASDs: Strongly supported; copovidone is the most common polymer in FDA-approved ASD drug products (49% of approvals 2012–2023); pharmacokinetic improvements demonstrated in multiple preclinical and clinical drug-level studies.
- Long-term in vivo safety (animal): Established through a two-year rat carcinogenicity / chronic toxicity study and a one-year canine study, both showing no treatment-related adverse effects at high dietary doses.
- Drug-excipient oxidative incompatibility: Well-documented in the pharmaceutical stability literature; relevant to formulation design rather than consumer safety.
- Cosmetic functional use: Industrially established; no clinical endpoint data for therapeutic claims.
- 3D printing and novel manufacturing applications: Preliminary; in vitro/materials science only.
References
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