Roscarmellose

Croscarmellose Sodium (Roscarmellose / Sodium Croscarmellose): A Comprehensive Reference

Nomenclature and Identity

Roscarmellose is not a recognized standalone name in any major pharmacopeia, regulatory database, or peer-reviewed literature. All authoritative sources indicate this term is a variant rendering or misspelling of croscarmellose sodium, also written as sodium croscarmellose. The two terms refer to the same chemically defined compound, and this article covers that substance in full. Where the name "roscarmellose" appears on supplement labels, it invariably refers to croscarmellose sodium functioning as an inactive excipient (disintegrant), not as a bioactive ingredient.

Sodium croscarmellose is an internally cross-linked sodium carboxymethylcellulose used as a superdisintegrant in pharmaceutical formulations. E468 is the E number of crosslinked sodium carboxymethyl cellulose, used in food as an emulsifier. Its Chemical Abstracts Service (CAS) registry number is 74811-65-7.

According to the United States Pharmacopeia (USP), croscarmellose sodium is defined as the sodium salt of a cross-linked, partly O-(carboxymethylated) cellulose. Cross-linked sodium carboxymethyl cellulose is also known as croscarmellose sodium or modified cellulose gum.

Synonyms and alternative designations used in regulatory and scientific literature include:

• Croscarmellose sodium (INN / USAN)
• Sodium croscarmellose
• Cross-linked sodium carboxymethylcellulose (CMC)
• Modified cellulose gum
• E468 (European Union food additive number)
• Roscarmellose (variant/misspelling)

Croscarmellose sodium has a white, fibrous, free-flowing appearance. The resulting product is a white to off-white, odorless powder that swells strongly in water but does not dissolve.

Natural Source and Raw Materials

Although croscarmellose sodium is a chemically modified derivative, its starting material is entirely plant-derived. Croscarmellose sodium is a sodium salt of a crosslinked polymer of carboxymethylcellulose (CMC), which is derived from cellulose, a natural polymer found in the cell walls of plants.

Croscarmellose sodium may be sourced from wood pulp or cotton flock cellulose. Cellulose for industrial use is mainly obtained from wood pulp and from cotton. The source of cellulose has an impact on several important properties of the material. For instance, wood pulp-derived croscarmellose sodium tends to have a lower molecular weight, higher solubility, but decreased water binding and swelling capacities when compared with cotton flock-derived material.

While the manufacturing processes are necessary to give croscarmellose sodium its desired properties, they do mean that the final product is not a completely "natural" substance in the traditional sense. Instead, it is a synthetic derivative of a natural polymer (cellulose).

Manufacturing Process

The production of croscarmellose sodium proceeds through a defined multi-step chemical synthesis from plant cellulose.

Alkali cellulose is prepared by steeping cellulose, obtained from wood pulp or cotton fibers, in sodium hydroxide solution. The alkali cellulose is then reacted with sodium monochloroacetate to obtain carboxymethylcellulose sodium.

After the substitution reaction is completed and all of the sodium hydroxide has been used, the excess sodium monochloroacetate slowly hydrolyzes to glycolic acid. The glycolic acid changes a few of the sodium carboxymethyl groups to the free acid and catalyzes the formation of crosslinks to produce croscarmellose sodium. The croscarmellose sodium is then extracted with aqueous alcohol and any remaining sodium chloride or sodium glycolate is removed. After purification, croscarmellose sodium of purity greater than 99.5% is obtained.

Summarizing the key chemical steps:

• Cellulose extraction: The first step is to extract cellulose from plant sources such as wood pulp or cotton. This cellulose is purified to remove impurities and other plant materials.
• Carboxymethylation: The purified cellulose is chemically modified by introducing carboxymethyl groups (–CH₂COOH) to the cellulose molecules. This process creates carboxymethylcellulose (CMC), which is water-soluble and can hold water within its structure.
• Crosslinking: The carboxymethylcellulose is then treated with a crosslinking agent to form a three-dimensional network structure. This crosslinking process gives the material its distinctive swelling and disintegration properties.
• Drying and milling: The final product is dried and milled into a fine powder, which can then be used as an excipient in tablet or capsule formulations.

Pharmacopeial and Regulatory Status

The United States Pharmacopeia is the coordinating pharmacopeia for the international harmonization of compendial standards for the croscarmellose sodium monograph, as part of the process of international harmonization of monographs and general analytical methods of the European, Japanese, and United States pharmacopeias.

A revision to the harmonized standard for croscarmellose sodium has been approved by the Pharmacopeial Discussion Group (PDG). Having reached Stage 4 of the PDG process, the croscarmellose sodium monograph has been formally approved by the USP Complex Excipients Expert Committee.

On the regulatory side, croscarmellose sodium, a substance widely used in oral pharmaceutical formulations, is accepted by the FDA as a multipurpose GRAS food substance (21 CFR part 182.1745). Croscarmellose sodium meets the specifications for an "additive permitted for use in food in general unless otherwise specified under GMP" as detailed in the 2005 General Standards for Food Additives of the Food and Agriculture Organization's Codex Alimentarius.

In the European Union, E468 is approved under Regulation (EC) No 1333/2008 on food additives. Its use is restricted to specific food categories, and maximum permitted levels apply depending on the application. E468 is considered safe for consumption based on current scientific assessments. The European Food Safety Authority (EFSA) has reviewed the substance and found no significant safety concerns at the levels used in food and pharmaceutical applications.

Croscarmellose sodium emerged as a pharmaceutical excipient in the 1960s as part of the broader development of superdisintegrants designed to enhance tablet dissolution and bioavailability. Initially developed as a modification of carboxymethylcellulose, this cross-linked polymer was engineered to address the limitations of traditional disintegrants that often showed inconsistent performance across different formulation environments.

Traditional and Historical Use

Croscarmellose sodium has no history of traditional botanical or folk medicinal use. It is an entirely modern synthetic derivative of cellulose, developed in the twentieth century as the pharmaceutical tablet industry sought improved excipients. Native starch is recognised as the oldest tablet disintegrant and is used for this purpose typically at 10–15% (w/w) in tablet formulations. There are a great number of materials called disintegrants, which are made by modification of natural polymers or by chemical synthesis. Recently, a new generation of disintegrants called superdisintegrants emerged. These trigger compact disintegration within few minutes upon contact with water.

The underlying raw material, cellulose, does have a deep historical relationship with human activity, but always in industrial rather than medicinal contexts. Humans cannot digest cellulose and it is often referred to as 'dietary fibre' or 'roughage' and acts as a hydrophilic bulking agent for feces. About 33 percent of all plant matter is cellulose, although the cellulose content of cotton is 90 percent and of wood it is 50 percent. The deliberate chemical modification of cellulose into a crosslinked disintegrant represents a purely modern, industrially driven development without counterpart in any ethnobotanical tradition.

Chemical Structure and Key Properties

Croscarmellose sodium (CCS — also called crosslinked carboxymethyl cellulose) is obtained by chemical modification of cellulose in a two-step process. Cellulose is initially carboxymethylated, forming carboxymethyl cellulose (CMC).

CCS is cross-linked carboxymethylcellulose sodium and used as a superdisintegrant. CCS is hydrophilic, but made insoluble and fibrous by cross-linking of sodium salt of carboxymethylcellulose.

The degree of substitution (i.e., the number of carboxymethyl groups per anhydroglucose unit) is a critical quality parameter. Because swelling of CCS is attributed to the hydration of the carboxymethyl group, the degree of substitution determines CCS functionality. The degree of substitution of CCS, as per the United States National Formulary monograph, is 0.60–0.85.

CCS's backbone is sodium carboxymethyl cellulose; cross-linking between chains reduces solubility but leaves numerous hydrophilic carboxylate groups.

It contains no sugar or starch.

Mechanisms of Action

The functional activity of croscarmellose sodium within tablet and capsule formulations is well characterized. It operates primarily as a superdisintegrant — a substance that, when incorporated into a solid dosage form, rapidly promotes its breakdown after oral ingestion.

Swelling and Wicking

Cross-linking creates an insoluble but highly hydrophilic network; when water enters this network, the polymer swells many times its original volume and the mechanical stresses break the tablet apart.

The functionality of CCS as a superdisintegrant is related to its fluid uptake and swellability characteristics. Swelling, wicking, and strain recovery are proposed mechanisms for CCS.

When a tablet containing CCS comes into contact with gastrointestinal fluids, the CCS particles rapidly imbibe water through capillary action and direct absorption. This influx of water causes the polymer chains to expand and swell significantly. The volume increase exerted by the swelling CCS particles generates considerable internal stress within the tablet matrix. This stress overcomes the forces binding the tablet together, leading to its rapid disintegration into smaller fragments.

When a tablet containing croscarmellose sodium comes into contact with moisture, the excipient acts like a sponge, rapidly drawing in water. This process is often referred to as wicking, where water is drawn into the tablet matrix through capillary action, facilitated by the porous nature of the excipient.

Croscarmellose sodium (CCS) is a superdisintegrant that promotes tablet disintegration by swelling and wicking mechanisms. When in contact with water, the omni-directional increase in the croscarmellose sodium particle size pushes the tablet apart. The wicking action draws water into the tablet, which helps to disrupt intermolecular forces between particles in the tablet.

A peer-reviewed study published on PubMed Central confirmed the dominance of swelling in CCS's disintegration profile: the swelling values, water uptake and water sorption studies of these disintegrants all suggested that MCCII compacts disintegrate by a wicking mechanism similar to that of crospovidone, whereas a swelling mechanism was dominant for sodium starch glycolate and croscarmellose sodium.

Enhancement of Drug Bioavailability

The cross-linking reduces water solubility while still allowing the material to swell (like a sponge) and absorb many times its weight in water. As a result, it provides superior drug dissolution and disintegration characteristics, thus improving formulas' subsequent bioavailability by bringing the active ingredients into better contact with bodily fluids.

The enhanced drug bioavailability is a direct consequence of this rapid disintegration. By breaking down the tablet efficiently, CCS ensures that the API is released into the gastrointestinal tract much faster than it would be with less effective disintegrants. This quicker release leads to a higher concentration of the dissolved drug available for absorption into the bloodstream.

Dosage Forms and Concentrations Used

Croscarmellose sodium is used exclusively as an inactive excipient in solid dosage forms — tablets and capsules — and is not itself dosed as a bioactive ingredient. The quantities present in any given product are determined by the formulator, not by therapeutic need.

Croscarmellose sodium (CCS) is a cellulose chemically modified, water-insoluble superdisintegrant. CCS promotes rapid disintegration of tablets upon exposure to water by relying on capillary and swelling effects, and the commonly used amount in tablet formulations is 0.5–5.0%.

Typical concentrations in tablet formulations range from 0.5% to 5% of total weight.

While formulating tablets, croscarmellose sodium may be employed in direct-compression and wet-granulation processes.

Sodium croscarmellose also resolves formulators' concerns over long-term functional stability, reduced effectiveness at high tablet hardness levels, and similar problems associated with other products developed to enhance drug dissolution.

Body Systems and Health Areas of Association

Croscarmellose sodium does not act on any body system through a pharmacological mechanism. Its association with health relates entirely to its role as a delivery vehicle: it facilitates the reliable release and absorption of active pharmaceutical or nutraceutical ingredients in the gastrointestinal tract.

Gastrointestinal Tract

Disintegrants facilitate the breakup of a tablet in the intestinal tract after oral administration. Cross-linking allows enhanced bioavailability of the drug through superior drug dissolution. Without a disintegrant, tablets may not dissolve appropriately and may affect the amount of active ingredient absorbed, thereby decreasing effectiveness.

Croscarmellose sodium is an inert substance, meaning that it does not react with the body's chemistry, nor does it affect the pharmacokinetics of the active ingredients it is meant to help deliver.

According to the FDA Select Committee on GRAS food substances, carboxymethylcellulose sodium is virtually unabsorbed.

Biomedical / Surgical Applications

Beyond its role as an oral disintegrant, croscarmellose sodium has been investigated in biomedical contexts. It has been used for avoiding adhesions of the epidural scar and postsurgical soft tissue in biomedicine. This application exploits its ability to form a gel-like barrier. However, this lies outside the scope of dietary supplementation.

Scientific Evidence by Area of Use

Tablet Disintegration and Drug Release (Pharmaceutical Research)

The evidence base for croscarmellose sodium as a functional disintegrant is robust in the pharmaceutical formulation sciences, supported by extensive in vitro, preclinical, and comparative studies.

A published peer-reviewed study in PMC (NCBI) investigated the comparative performance of four superdisintegrants — including croscarmellose sodium — in spironolactone tablets using a factorial design. In this study, formulations of spironolactone with four disintegrants named as croscarmellose sodium, crospovidone, sodium starch glycolate and microcrystalline cellulose II (MCCII) were conducted. The effect of those disintegrants on the tensile strength, disintegration time, and dissolution rate of spironolactone-based compacts was evaluated using a factorial design with three categorical factors (filler, lubricant, and disintegrant).

Superdisintegrant croscarmellose sodium and crospovidone had significant differences in the results of disintegration and tablet hardness and dissolution of ODT tablets. This is because the mechanism of action of disintegration of croscarmellose sodium and crospovidone is different — croscarmellose sodium disintegrates by swelling and crospovidone undergoes wicking, followed by swelling.

Drug–Excipient Interaction Research (Human Bioavailability Study)

A comparative bioavailability study published in a peer-reviewed pharmaceutical journal examined whether the known in vitro binding of croscarmellose sodium to weakly basic drugs translated into reduced drug availability in humans. The study investigated the physiological significance of the in vitro drug-excipient interaction between croscarmellose sodium NF and weakly basic drugs. Three formulations of lactose-based tablets containing a 25 mg dose of phenylpropanolamine HCl (PPA), and compressed to comparable hardness, were used: a tablet with no disintegrant (control), a tablet with 10% starch, and a tablet with 10% croscarmellose sodium. Cumulative urinary excretion for 6 healthy subjects in a cross-over study was examined to determine if the drug-excipient interaction resulted in decreased availability.

Even though an in vitro dissolution test in distilled water resulted in 40% drug bound for the CROS tablets, no significant differences in average cumulative amount of drug excreted were found in the control (22.94 mg), starch (22.41 mg), or croscarmellose sodium (22.85 mg) groups. This suggests that, at physiological conditions, CCS does not meaningfully reduce the bioavailability of the active drug it carries — an important finding for formulation confidence.

Evidence strength: This specific human crossover study was small (n=6). The body of formulation science supporting CCS's disintegrant function, however, is extensive in the peer-reviewed literature, constituting one of the most well-documented excipient profiles in pharmaceutical science.

Epidural/Surgical Adhesion Prevention (Biomedical)

It has been used for avoiding adhesions of the epidural scar and postsurgical soft tissue in biomedicine. This is a niche area distinct from oral supplementation, and the evidence base for this specific use is separate from dietary supplement science.

Safety Profile

Regulatory Safety Classification

The U.S. Food and Drug Administration (FDA) classifies croscarmellose sodium as Generally Recognized as Safe (GRAS), indicating it has been found to be safe for its intended use. Furthermore, the safety profile of croscarmellose sodium has been reviewed and confirmed by other regulatory agencies and pharmacopeias across the world.

The European Food Safety Authority (EFSA) also permits its use in food products, within certain usage limits to safeguard consumers' health.

Absorption and Systemic Exposure

Despite its synthetic origin, studies indicate that croscarmellose sodium is not absorbed by the gastrointestinal tract, which supports its non-toxic classification. While croscarmellose sodium promotes the bioavailability of active compounds in tablets and capsules, it is generally unabsorbed in the body.

Toxicological Data

The no observed adverse effect level (NOAEL) for croscarmellose sodium in a 90-day oral (dietary) toxicity study in rats was 50,000 ppm, equivalent to 3,922 mg/kg/day in males and 4,712 mg/kg/day in females. No adverse effects were observed in this study.

An intake of 30 g/day has been recommended as the upper limit of safety for modified celluloses in general (National Research Council, 1989). The amount of CCS present in any single tablet or capsule formulation at standard concentrations (0.5–5% of tablet weight) represents a tiny fraction of this figure.

Incompatibilities and Formulation Interactions

The efficacy of disintegrants, such as croscarmellose sodium, may be slightly reduced in tablet formulations prepared by either the wet-granulation or direct-compression process that contain hygroscopic excipients such as sorbitol.

Croscarmellose sodium is not compatible with strong acids or with soluble salts of iron and some other metals such as aluminum, mercury, and zinc.

When selecting a grade of croscarmellose sodium, attention should be paid to its impurity profile. The common impurities in croscarmellose sodium include chloroacetic acid, nitriles, and nitrates, which are potentially reactive with active ingredients.

Drug–Excipient Interactions

The ionic nature of croscarmellose sodium presents a critical limitation, as it can form complexes with cationic drugs through electrostatic interactions. These interactions may result in reduced drug dissolution rates and altered bioavailability profiles. Particularly problematic are APIs containing metal ions or basic functional groups, which demonstrate strong affinity for the carboxylate groups present in croscarmellose sodium's polymer structure.

The superdisintegrant readily absorbs moisture from the environment, which can lead to physical and chemical interactions with moisture-sensitive APIs. This moisture uptake creates a microenvironment that may accelerate degradation pathways, particularly for APIs susceptible to hydrolysis or oxidation reactions.

Sodium Content Considerations

Because croscarmellose sodium is a sodium salt of carboxymethylcellulose, it contributes a small amount of sodium to a formulation. At typical usage levels (0.5–5% of tablet weight) and the small absolute mass of tablets, this contribution is negligible in the context of dietary sodium intake for most individuals. However, individuals managing severe sodium restriction should be aware that sodium-containing excipients, including croscarmellose sodium, are present in many tablet formulations.

Hygroscopicity and Storage

Due to the hygroscopicity of croscarmellose sodium, a tight container is more suitable for packaging and storage of this material according to USP general chapter <659>.

Physical Forms of Croscarmellose Sodium

Manufacturers offer CCS in various physical forms (granular vs. fibrous) and from different cellulose sources (cotton linters vs. wood pulp).

The source of cellulose can result in differences in the physical properties of CCS. CCS derived from wood pulp has lower molecular weight, higher water solubility, a slightly lower pH, decreased water capacity and swelling rate compared to CCS made from cotton linters.

Another important property that influences disintegrant properties is particle size. The larger the particle size, the greater the water uptake and, hence, swelling properties. This effect is attributed to the formation of a viscous layer upon contact with water, and a smaller particle size forms a more viscous layer because of enhanced interactions with water.

Use in Dietary Supplements

In the USA, it is used as a disintegrant in prescription drugs and has generally recognized as safe (GRAS) status for use in dietary supplements. It appears in the "other ingredients" listing of supplement labels — not as a bioactive — and its function is solely to ensure the tablet breaks apart correctly after swallowing.

It is a very commonly used pharmaceutical additive approved by the U.S. Food and Drug Administration. Its purpose in most tablets — including dietary supplements — is to assist the tablet in disintegrating in the gastrointestinal tract promptly.

An example from a commercially available supplement label (Youtheory® Turmeric Advanced) shows it listed as: other ingredients: dicalcium phosphate, stearic acid, microcrystalline cellulose, roscarmellose sodium, modified cellulose, silicon dioxide, and magnesium stearate (vegetable source). This confirms that "roscarmellose sodium" in supplement contexts is simply croscarmellose sodium functioning as an inactive tablet disintegrant.

Summary of Evidence Strength

The scientific evidence for croscarmellose sodium in its intended functional role — as a pharmaceutical superdisintegrant promoting tablet disintegration and supporting drug/nutrient bioavailability — is extensive, well-replicated, and reflected in official pharmacopeial monographs across multiple jurisdictions (USP/NF, European Pharmacopoeia, Japanese Pharmacopoeia). Its safety profile at pharmaceutical use levels is well established through regulatory review, animal toxicology, and GRAS designation.

However, croscarmellose sodium has no evidence base as a bioactive health supplement ingredient in its own right. It exerts no pharmacological effect on any body system at the levels used in tablet formulations. No human clinical trials exist investigating croscarmellose sodium as a therapeutic agent. Any health benefit associated with a supplement containing this ingredient derives from the active ingredients in that supplement, the delivery of which CCS may support by ensuring timely tablet disintegration.

References

• United States Pharmacopeia (USP) – Croscarmellose Sodium Monograph Harmonization
• USP Pharmacopeial Forum 30(4): Croscarmellose Sodium Harmonization Document
• USP Pharmacopeial Forum 28(5): Croscarmellose Sodium Harmonization Stage 6 Draft
• FDA NDA 22-542 Pharmacological Review – Croscarmellose Sodium GRAS and Safety Data
• FDA NDA 22-222 – Croscarmellose Sodium NOAEL Toxicology Data
• European Commission Scientific Committee for Food – Opinion on Cross-Linked Sodium Carboxymethyl Cellulose
• ScienceDirect Topics – Croscarmellose Sodium Overview (International Journal of Pharmaceutics)
• PMC (NCBI) – Functional Assessment of Four Types of Disintegrants and their Effect on Spironolactone Release Properties
• ScienceDirect – Bioavailability of Phenylpropanolamine HCl from Tablet Dosage Forms Containing Croscarmellose Sodium
• Wikipedia – Sodium Croscarmellose
• Wikipedia – Cellulose (E468 derivation)
• PharmaCentral – Croscarmellose Sodium Excipient Profile
• Pehel Specialities – Study of Croscarmellose Sodium: Granular vs Fibrous and Cotton Linter vs Wood Pulp
• Beneceutical – FAQ: Croscarmellose Sodium
• Drugs.com – Croscarmellose Sodium: What Is It and Where Is It Used?
• Artgerecht – E468: Crosslinked Sodium Carboxymethylcellulose
• IJPPR – Review of the Use of Croscarmellose Sodium as Superdisintegrant (Antari et al., 2021)
• PatSnap Eureka – Maximizing Croscarmellose Sodium Compatibility with Active Drug Ingredients