Candurin

Candurin^®: A Registered Pearlescent Pigment for Food and Pharmaceutical Use

Important Prefatory Note: Identity Clarification and Correction of Misinformation

Candurin^® is not a dietary supplement, herbal ingredient, botanical, or natural health product. It is a registered commercial brand of pearlescent pigments developed and marketed by Merck KGaA, Darmstadt, Germany (sold in North America through its subsidiary EMD Chemicals / EMD Millipore). Candurin^® pigments for food and pharmaceuticals create brilliant pearl effects and are marketed as a tool for safe and innovative edible design. A small number of supplement-industry content pages (as of 2025) have begun describing a substance they call "candurinis" as a traditional herbal ingredient with purported health benefits. These pages contain no verifiable citations to peer-reviewed literature, pharmacopeial monographs, regulatory records, or any authoritative scientific source. No substance called "candurinis" exists in the WHO monograph database, the NIH Office of Dietary Supplements fact-sheet library, the NCCIH herb database, the ESCOP or Commission E monograph collections, the Codex Alimentarius, or any comparable authoritative reference. Those pages appear to be AI-generated content that has fabricated an entirely fictional herbal identity and attached it to a well-known industrial pigment brand name. All such claims are omitted from this article in accordance with strict sourcing standards. What follows is an accurate, fully sourced encyclopedic reference to what Candurin^® actually is.

1. Identity and Chemical Nature

1.1 Brand and Manufacturer

One such coating currently marketed to provide a pearlescent or nacreous quality to various products is sold under the trade name Candurin^® by Merck KGaA. The FDA's publication of a final rule approving their use in pharmaceuticals came eight years after EMD Chemicals Inc. of Gibbstown, N.J., first petitioned the agency; the chemical and pigment maker is part of the German drug company Merck KGaA. Merck KGaA, Darmstadt, Germany, is entirely separate from U.S.-based Merck & Co. Inc.

1.2 Chemical Composition and Structure

Candurin^® pigments can be seen as composite materials and consist of thin potassium aluminium silicate (E 555, mica) platelets as carrier material, coated with a thin metal oxide layer of TiO₂ (E 171) and/or iron oxides (E 172).

Pearlescent pigments are prepared by precipitation of an inorganic metal oxide/hydroxide onto platelet-shaped substrates followed by calcination. These substrates may consist of natural or synthetic mica, glass flakes, silica flakes, alumina flakes or other platelets.

The pearlescent pigments are titanium oxide and/or iron oxide pigments supported on a base of lamellar substrate comprising mica or flakes of Al₂O₃, SiO₂, or TiO₂.

The mica substrate is more precisely identified in regulatory monographs. PAS-BPP consists of a coating of titanium dioxide (TiO₂) and/or iron oxide (Fe₂O₃) on PAS. PAS (potassium aluminium silicate) is more commonly referred to as mica, or more specifically, muscovite mica, and has an idealized formula of KAl₂[AlSi₃O₁₀](OH)₂.

1.3 Product Variants and Color Range

The pigments, available under the brand name of Candurin, are developed by coating the mineral mica with either synthetic iron oxide or titanium dioxide, and there are 16 variations that companies can choose from in shades of silver, gold, orange/red/brown iron oxide and paler hues of gold, red, green and blue, termed "interference" colours.

The mica-based colouring agents can be produced with a variety of different pearlescent effects depending upon the mica platelet particle size and the amount of titanium dioxide and/or iron oxide deposited on the mica. Sequential precipitation of iron oxide and titanium dioxide on the mica platelets is also used to create a spectrum of colour shades which include shades of silver, red, or gold.

The JECFA (Joint FAO/WHO Expert Committee on Food Additives) classification system differentiates these pigments into three formal types: PAS-BPP, Type I represents PAS coated with titanium dioxide only; PAS-BPP, Type II represents PAS coated with iron oxide only; and PAS-BPP, Type III represents PAS coated with both titanium dioxide and iron oxide.

The pigments are based on a natural silicate or silica in combination with titanium oxide and/or iron oxide. The spectrum ranges from silver, gold, and interference colors to vibrant red.

1.4 Regulatory Nomenclature and Food Additive Numbers

Candurin^® pigments are regulated in different jurisdictions under overlapping but distinct frameworks. The individual component E-numbers used in the EU are as follows:

• E 555 – Potassium aluminium silicate (mica substrate)
• E 171 – Titanium dioxide (coating used in Type I and III pigments)
• E 172 – Iron oxides and hydroxides (coating used in Type II and III pigments)

These pearlescent pigments consist of mica (potassium aluminium silicate) platelets generally coated with titanium dioxide and/or iron oxides; all single components are approved food additives in the European Union (EU) (E 555, E 171 and E 172).

In the United States, the compound is regulated as a unit. In the United States, the compound pigment itself, under the name mica-based pearlescent pigments, is regulated under 21 Code of Federal Regulations (CFR) 73.350 rather than considering the components separately. As noted in 21 CFR 73.350, only titanium dioxide-based pearlescent pigments are currently permitted in the USA.

Under the international Codex/JECFA INS numbering system, INS No. 176 designates potassium aluminium silicate-based pearlescent pigments (PAS-BPP); INS No. 176(i) covers Type I (coated with titanium dioxide); INS No. 176(ii) covers Type II (coated with iron oxide); and INS No. 176(iii) covers Type III (coated with titanium dioxide and iron oxide). These potassium aluminium silicate-based pearlescent pigments are formed by depositing titanium and/or iron salts onto mica or potassium aluminium silicate, followed by calcination at high temperatures.

2. Historical Development and Background

Candurin^® has no traditional or historical use as a medicinal or dietary ingredient. It is an industrial product whose development history is rooted in the synthetic pigment and specialty chemicals industry, not in any food or herbal tradition. The earliest food and pharmaceutical uses were driven by technological rather than nutritional or medicinal rationales.

Pearlescent pigments of similar composition had long been used in cosmetics and personal care products (lipstick, eye shadow, nail polish) as well as in industrial applications including inks and automotive paint. Similar pigments are used in makeup, including lipstick, eye shadow and nail polish, as well as in inks and automotive paint.

The FDA's publication of a final rule approving their use in pharmaceuticals came eight years after EMD Chemicals Inc. of Gibbstown, N.J., first petitioned the agency. The chemical and pigment maker is part of the German drug company Merck KGaA. This FDA approval process, initiated in the late 1990s and concluded in 2006, marks the beginning of Candurin^®'s formal entry into the food and pharmaceutical sectors.

The pigments are made by coating the mineral mica with either titanium dioxide or iron oxide — or both. The FDA approved using the two separate combinations to color contact lenses in 2002. This contact-lens approval preceded and provided a safety precedent for subsequent food and pharmaceutical approvals.

3. Regulatory History and Approved Uses

3.1 United States (FDA)

The regulatory pathway for Candurin^® in the U.S. was lengthy and stepwise. The first major milestone was contact-lens approval in 2002. Then, in July 2005, FDA published a proposed rule for pharmaceutical use, and the final rule for pharmaceutical use was confirmed in 2006. Use of these pigments in pharmaceuticals was finally approved by the US Food and Drug Administration (FDA) — eight years after Merck first sought their approval.

For food, a separate color additive petition pathway was required. The FDA confirmed the effective date of July 5, 2006, for a final rule that amended the color additive regulations to provide for the safe use of titanium dioxide-coated mica-based pearlescent pigments as color additives in the following foods: cereals, confections and frostings, gelatin desserts, hard and soft candies (including lozenges), nutritional supplement tablets and gelatin capsules, and chewing gum.

The scope of approved food uses was subsequently expanded. In 2006, FDA approved at § 73.350 the use of titanium salts to produce TiO₂ on mica to make "mica-based pearlescent pigments." The agency expanded the uses in 2013 and 2015. Specifically, the FDA amended the color additive regulations to provide for the safe use of mica-based pearlescent pigments prepared from titanium dioxide and mica as color additives in cordials, liqueurs, flavored alcoholic malt beverages, wine coolers, cocktails, non-alcoholic cocktail mixers and mixes, and in egg decorating kits for coloring shell eggs.

In pharmaceutical use, FDA established a concentration limit: the FDA rule allows mica to be used to color drugs meant to be swallowed and increases the amount of synthetic iron dioxide allowed in those medicines. The pigments cannot make up more than 3 percent of the weight of a drug.

For food beverages, the maximum use level is also capped: the maximum use level of the pigments proposed by the petitioner is 0.07 percent by weight in the beverages, mixers, and mixes.

3.2 European Union (EFSA and European Commission)

The EU regulatory framework for Candurin^®-type pigments is notably more complex and contested than in the U.S. According to the interested business operators, potassium aluminium silicate is only used for the manufacturing of 'potassium aluminium silicate-based pearlescent pigments' and the components — potassium aluminium silicate, titanium dioxide or iron oxides — are bound to each other by strong physical forces and cannot be separated from each other by standard methods.

EFSA's 2020 re-evaluation of E 555 reached a significant regulatory conclusion: the description of the technological role of mica in 'potassium aluminium silicate-based pearlescent pigments' does not meet the definition of 'carrier' according to Regulation (EC) No 1333/2008. The EFSA Panel therefore considered that 'potassium aluminium silicate-based pearlescent pigments' is a new entity, not listed in Regulation (EC) No 1333/2008 and not previously evaluated in the EU.

Separately, a major regulatory change affected the titanium dioxide component. The European Commission, on 14 January 2022, adopted Regulation (EU) 2022/63 withdrawing the authorisation to use titanium dioxide (TiO₂, also known as E 171) in food products, based on a scientific opinion from EFSA published on 6 May 2021, which concluded that E 171 can no longer be considered safe when used as a food additive.

3.3 International (JECFA / Codex Alimentarius)

The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has published food-grade specifications for potassium aluminium silicate-based pearlescent pigments, Type I (i.e., mica-based titanium dioxide), Type II (i.e., mica-based iron oxide), and Type III (i.e., mica-based titanium dioxide and iron oxide).

JECFA established a tolerable weekly intake for the aluminium content: a PTWI (provisional tolerable weekly intake) of 2 mg/kg body weight for total aluminium was established at the 74th JECFA (2011).

4. Functional Applications

4.1 Food Applications

Pearlescent pigments are used as colourants to increase the attractiveness of food products, especially in the patisserie and confectionery sector. The PAS-BPP are intended for use in a variety of candies, confectionaries, decorations, and in certain transparent alcoholic and non-alcoholic beverages.

These pigments can be either mixed with each other, or with other existing colours to create an infinite number of desired combinations. The pigments can produce sparkly metallic, satiny and shimmery finishes, as well as different hues of red and gold, depending partly on the color of the underlying food product.

Candurin^® pigments are stable under typical food processing and storage conditions. The mica-based colouring agents were reported as being stable in various conditions, including gastric and intestinal fluids. Study results showed that the pigments were practically insoluble in these fluids.

4.2 Pharmaceutical Applications

The pearlescent pigments can be used in any drugs that are swallowed, including pills, tablets, and liquids. In pharmaceutical manufacturing, their addition is straightforward. The pigment is simply added as an extra ingredient into the coating formulation that companies already use to coat their tablets or capsules at the end of the manufacturing process.

Three distinct pharmaceutical rationales are documented in the scientific and regulatory literature:

4.2.1 Patient Compliance and Medication Identification

According to Almut von der Brelie, Candurin^® Marketing Manager at Merck KGaA: "The likelihood of patients getting medicines mixed up is significantly reduced by the unique pearlescent appearance of Candurin^® pigments." The mineral-based, non-artificial pigments that are used to coat the tablets fulfill international quality and safety standards of the pharmaceutical and food industry.

A study has confirmed that patients attribute greater efficacy to tablets that are coated with Candurin^®. Pearlescent coatings in general are considered to aid visual differentiation: pearlescent coatings are easily recognized by physicians, pharmacists, and patients as the original manufacturer's product.

Candurin^® pigments appear in clinical trial formulations as color additives in tablet coatings. For example, in a clinical trial of safinamide for Parkinson's disease, placebo film-coated tablets were composed of inactive ingredients used in the safinamide tablets (microcrystalline cellulose, crospovidone, colloidal silicon dioxide, magnesium stearate, and hypromellose and polyethylene glycol for the coating), and Candurin^® pigments were included for colour modification.

4.2.2 Anti-Counterfeiting

Candurin^® also offers advantages in combating product piracy. "As one component of a safety concept, Candurin^® is an outstanding way to make product piracy more difficult," says von der Brelie. The color-shifting properties provide a covert authentication marker. Pearlescent coatings, in general, could increase counterfeiting protection because the unique color-shifts across the tablet surface are difficult to duplicate without knowing the specific combination of pigment properties and processing procedures.

With pearlescent coatings, a rainbow of colors is possible. These colors can only be duplicated by knowing the specific pigment grade combination, and the technology is custom-produced to exact specifications.

4.2.3 Brand Differentiation

It has been proposed that consumers develop greater brand loyalty for distinctively appearing products as compared to those containing the same active ingredient in an unremarkable appearance (i.e., a white compressed tablet). It has also been proposed that imparting a pearlescent appearance to tablets would provide a means of further differentiating new products, even from those having a bright or highly polished finish coat.

5. Physical and Chemical Properties

The optical effects of Candurin^® arise from the physical interaction of light with the multilayer platelet structure. Depending on the thickness of the flakes employed and the metal oxide layers applied and on the type of metal oxide, pigments of this type are distinguished by particularly intense interference colours and/or by strong angle-dependent colour flop effects. The latter are apparent inasmuch as an observer perceives different colours on changing his observation position relative to the pigmented object.

The particle size range is critical to both the optical properties and the regulatory classification of these pigments. After reviewing FDA's FOIA responses, the agency explicitly considered particle sizes and found that the particles ranged from 1,000 to 150,000 nanometers in size. The smallest size was ten times greater than the average particle size in E 171 or synthetic TiO₂. Given the much larger particle size, petitioners think mica-based pearlescent pigments may not be chemically or pharmacologically related to synthetic TiO₂ or E 171.

The preferred range for food applications is codified: particularly preferred pearlescent pigments for the foods sector are mica flakes (synthetic or natural) or SiO₂ flakes coated with a metal oxide layer (TiO₂ or Fe₂O₃ or Fe₃O₄) having a thickness of 10 nm to 500 nm. The thicknesses of the flakes are in the range from 200 nm to 900 nm.

Stability in physiological fluids was directly assessed by regulatory authorities. In a prior FDA safety evaluation, the agency concluded that the bioavailability of ingested mica-based pearlescent pigments and/or their individual components is expected to be low based on the chemical nature of these inorganic pigments and their individual components and the low solubility of mica-based pearlescent pigments in media relevant to human health (e.g., digestive fluids in the gastrointestinal tract).

6. Safety Assessment

6.1 FDA Safety Determination (United States)

In the final FDA rule, first published on July 22, 2005, the agency stated it "concludes that there is no toxic potential when ingested at levels estimated by the agency."

A key concern raised during the FDA review process was whether the iron oxide content could release soluble iron at levels hazardous to patients managing iron intake. This was directly addressed: "Extensive studies performed on these pigments clearly demonstrate that they are an extremely poor source of soluble iron and that, because of their chemical makeup, the use of the Candurin pigments in drug products would not interfere with double-blind clinical studies or interact with prescription medicines."

Concerns were raised by consumer groups over the use of such pigments in drugs for cosmetic purposes, particularly over the question of whether they would produce iron salt contaminants. However, both the FDA and Merck gave assurances that there are no grounds for concern.

6.2 EFSA Safety Assessment and the Titanium Dioxide Question (European Union)

The EU regulatory position is more complex and has evolved significantly. Titanium dioxide (TiO₂), also known as E 171, is commonly used as a white colorant in food, pharmaceuticals, cosmetics, and toothpaste. However, in May 2021, the EFSA expert panel, in evaluating the safety of titanium dioxide (E 171) as a food additive, concluded that a concern for genotoxicity could not be ruled out. This occurred several years after EFSA had previously considered titanium dioxide to be safe as a food additive.

This conclusion directly led to the EU-wide withdrawal of E 171 as a food additive: the European Commission adopted, on 14 January 2022, Regulation (EU) 2022/63 withdrawing the authorisation to use titanium dioxide (TiO₂, also known as E 171) in food products. This measure was endorsed unanimously by the Member States.

However, the EFSA 2021 conclusion is contested by regulators in other jurisdictions. Other international health scientists have generally disagreed with EFSA's opinion on the safety of E 171 TiO₂. A common theme voiced by the United Kingdom, Canada, Australia, and New Zealand agencies is that it is inappropriate to compare nanoparticle toxicity studies of dispersed/sonicated nanoparticles with the content of E 171 TiO₂ in foods because the test materials used in key EFSA studies are not representative of E 171 TiO₂ particles.

Importantly, the nanoparticle concern that prompted the E 171 ban does not translate directly to Candurin^®-type mica-based pearlescent pigments, given the substantially larger particle sizes in those pigments (as noted in Section 5 above). The EFSA Panel treated them separately, concluding in 2020 that mica-based pearlescent pigments as a whole should be evaluated as new food additives — meaning their combined composite form had not been individually risk-assessed.

Regarding the aluminium component (from the mica substrate), EFSA found data gaps: exposure to aluminium from this single use at the maximum permitted level could theoretically far exceed the TWI (tolerable weekly intake). Considering that only very limited toxicological data and insufficient information on the physicochemical characterisation of both food additives were available, the Panel concluded that the safety of sodium aluminium silicate (E 554) and potassium aluminium silicate (E 555) could not be assessed.

The EFSA panel recommended that additional data be provided. The Panel recommended that data in line with the current Guidance document on evaluation of food additives is required for E 554 and E 555 to perform the risk assessment of these food additives and evaluate the potential exceedance of the TWI for aluminium resulting from their use as food additives.

6.3 Low Bioavailability as a Key Safety Consideration

A central argument for the safety of Candurin^®-type pigments is their low solubility and thus low systemic bioavailability when ingested. In a prior FDA safety evaluation, the agency concluded that the bioavailability of ingested mica-based pearlescent pigments and/or their individual components is expected to be low based on the chemical nature of these inorganic pigments and their individual components and the low solubility of mica-based pearlescent pigments in media relevant to human health (e.g., digestive fluids in the gastrointestinal tract).

It was concluded that the mica-based colouring agents would contribute a negligible amount of potassium and/or iron to dietary intake of these elements.

7. Dosage Forms and Use Levels

Candurin^® is not consumed as a standalone ingredient but is incorporated into food or pharmaceutical products as a coloring agent at defined levels. The following use levels have been documented in regulatory sources:

• Pharmaceuticals (U.S.): The pigments cannot make up more than 3 percent of the weight of a drug.
• Food beverages (U.S.): The maximum use level in beverages, mixers, and mixes is 0.07 percent by weight.
• Food products generally: The TiO₂ pigment content is controlled. The content of TiO₂ pigment in food is specified at 0.005%–15% by weight.
• Application medium (industrial formulation): The pearlescent pigment or mixture of pearlescent pigments is preferably employed in an amount of 0.05–45% by weight, based on the total weight of the application medium.

In pharmaceutical film coating systems, the pigment is simply added as an extra ingredient into the coating formulation that companies already use to coat their tablets or capsules at the end of the manufacturing process.

8. Scientific Evidence: What Is and Is Not Established

Because Candurin^® is a coloring agent rather than a therapeutic or nutritional substance, the scientific evidence base is organized around safety (toxicology, bioavailability, and genotoxicity) rather than efficacy for health outcomes. There are no clinical trials examining Candurin^® as a dietary supplement, and no mechanistic pharmacological data associating it with any therapeutic benefit. The following summarizes the actual evidence by domain:

8.1 Bioavailability and Toxicokinetics

The body of evidence consistently points to very low bioavailability of mica-based pearlescent pigments. FDA concluded that the bioavailability of ingested mica-based pearlescent pigments and/or their individual components is expected to be low based on the chemical nature of these inorganic pigments and the low solubility of mica-based pearlescent pigments in media relevant to human health. This finding has not been revisited by new bioavailability studies since the initial FDA evaluation.

Stability in gastrointestinal conditions was confirmed by Health Canada's assessment: the mica-based colouring agents were reported as being stable in various conditions, including gastric and intestinal fluids. Study results showed that the pigments were practically insoluble in these fluids.

8.2 Genotoxicity Concerns Specific to the TiO₂ Component

The most scientifically contested area concerns the titanium dioxide component of Type I and Type III Candurin^® variants. EFSA's 2021 opinion on E 171 TiO₂ concluded that TiO₂ can no longer be considered as a safe food additive, based primarily on a concern that genotoxicity could not be excluded in nanoparticle studies. However, a group of experts recently considered the genotoxicity of TiO₂ and could not find support for a direct DNA damaging mechanism of TiO₂ (nano and other forms).

Regulatory agencies outside the EU — including those in Canada, Australia, New Zealand, and the United Kingdom — have generally not adopted the EU ban position, arguing the nanoparticle studies cited by EFSA are not representative of the particle sizes found in food-grade TiO₂. The significantly larger particle sizes in mica-based pearlescent pigments (starting at 1,000 nm compared to the sub-30 nm nanoparticles implicated in EFSA's key toxicity studies) are further grounds for treating Candurin^®-type pigments as distinct from synthetic E 171.

8.3 Aluminium Exposure from the Mica Substrate

EFSA's FAF Panel calculated the regulatory maximum exposure to E 555 as a carrier for titanium dioxide (E 171) and iron oxides and hydroxides (E 172), and found that exposure to aluminium from this single use at the maximum permitted level could theoretically far exceed the TWI. However, this calculation was a theoretical maximum based on the full authorized carrier proportion (up to 90% of the pigment by weight). The actual dietary exposure in real product formulations, where pigments are used at low concentrations, has been assessed as considerably lower. It was concluded that the mica-based colouring agents would contribute a negligible amount of potassium and/or iron to dietary intake of these elements.

8.4 Compliance and Error Reduction

There is cited evidence that the visual distinctiveness of Candurin^®-coated tablets benefits patient compliance. A study has confirmed that patients attribute greater efficacy to tablets that are coated with Candurin^®. No systematic review or randomized trial directly measuring medication error rates attributable to Candurin^® coating versus non-pearlescent coating has been identified in the peer-reviewed literature; the compliance benefit is inferred from the broader body of literature on tablet appearance and patient identification of medications.

9. Interactions and Considerations for Specific Populations

Because Candurin^® is an excipient/colorant and not an active pharmaceutical ingredient, its direct pharmacological interactions are minimal. The following source-backed considerations are documented:

• Iron metabolism: The iron oxide component in Type II and Type III Candurin^® pigments does not contribute meaningfully to systemic iron exposure. Extensive studies clearly demonstrate that these pigments are "an extremely poor source of soluble iron" and that "the use of the Candurin pigments in drug products would not interfere with double-blind clinical studies or interact with prescription medicines."
• Patients requiring iron restriction: Gatewood Organization LLC, a regulatory consulting group, had questioned whether the pigments would put some drugs off limits to patients who must watch their intake of iron. The FDA denied these objections, saying it had provided no "factual information" to back up its claims.
• Aluminium exposure: For patients with renal impairment who may have reduced aluminium clearance, the theoretical aluminium contribution from the mica substrate — assessed by EFSA as potentially exceeding the TWI at maximum permitted levels — is a monitoring consideration, though the practical contribution from actual food-use levels has been assessed as negligible by Health Canada and others.
• Titanium dioxide (EU): Products manufactured for the EU market using Candurin^® variants containing TiO₂ (E 171) must comply with Regulation (EU) 2022/63, which withdrew E 171's authorization for food use as of February 2022. Iron oxide-only (Type II) variants are unaffected by this specific ban.

10. Summary of Evidence Strength

The evidence base for Candurin^® is entirely within the domain of food additive safety and pharmaceutical excipient science, not dietary supplement efficacy. The following characterizes the strength of evidence in each area:

• Low bioavailability / inertness in GI tract: Well-established by FDA and Health Canada safety evaluations; consistent with the physicochemical properties of the inorganic pigment complex.
• Anti-counterfeiting utility: Supported by industry evidence and regulatory context; no independent controlled studies comparing counterfeit detection rates with and without Candurin^® coatings have been identified in the peer-reviewed literature.
• Patient compliance / identification: Supported by one referenced but unpublished industry study; plausible on the basis of established color-identification psychology; not assessed in systematic reviews.
• TiO₂ genotoxicity risk: Contested; EFSA (2021) found it could not be excluded; regulatory agencies in the UK, Canada, Australia, and New Zealand have not reached the same conclusion. Particle-size differences between Candurin^®-type pearlescent pigments and bulk E 171 are relevant and acknowledged by the FDA.
• Aluminium exposure: Identified as a theoretical concern at maximum authorized levels by EFSA (2020); assessed as negligible in practical use conditions by Health Canada.

There is no peer-reviewed scientific evidence — in vitro, animal, or human/clinical — supporting the use of Candurin^® as a dietary supplement, herbal remedy, or therapeutic agent for any health condition. Any content presenting it in those terms is without authoritative factual basis.

References

• EMD Group / Merck KGaA — Candurin® Official Product Page
• EMD Group / Merck KGaA — Candurin® in Pharmaceuticals
• OutSourcing-Pharma — "Pearlescent pigments may help halt counterfeiting, says Merck KGaA" (2006)
• NBC News — "Prettier pills: FDA OKs pearly pigments"
• U.S. Federal Register — Listing of Color Additives Exempt From Certification; Mica-Based Pearlescent Pigments (2015 Final Rule, 21 CFR 73.350)
• U.S. Federal Register — Mica-Based Pearlescent Pigments; Confirmation of Effective Date (July 5, 2006)
• EFSA Journal — Re-evaluation of sodium aluminium silicate (E 554) and potassium aluminium silicate (E 555) as food additives (2020)
• PMC / EFSA Journal — Re-evaluation of E 554 and E 555 as food additives (full text, PMC7448050)
• European Commission — Re-evaluation of E 171 (Titanium Dioxide) Withdrawal, Regulation (EU) 2022/63
• PMC / Frontiers in Toxicology — Safety of titanium dioxide (E171) as a food additive for humans (Warheit, 2024; PMC11295244)
• PMC / Foods — Use of Food Additive Titanium Dioxide (E171) before the Introduction of Regulatory Restrictions Due to Concern for Genotoxicity (2021; PMC8391306)
• PubMed — Characterisation of iron oxide-containing pearlescent pigments used as food colourants: nano-labelling required in the EU? (2022)
• Food Additives & Contaminants: Part A — Characterisation of TiO2-containing pearlescent pigments with regard to EU labelling obligations (2021)
• Health Canada — Proposal to Enable the Use of Three New Colouring Agents: Potassium Aluminium Silicate-Based Pearlescent Pigments
• FAO/JECFA — Mica-Based Pearlescent Pigments (PAS-BPP) Monograph
• International Association of Color Manufacturers (IACM) — Mica-Based Pearlescent Pigments Profile
• Merck Patent GmbH — Colouring of Surfaces (Patent Application, US2018/0223103)
• USPTO Patent 6,902,609 — Pearlescent Film Coating Systems and Substrates Coated Therewith
• ClinicalTrials.gov NCT03881371 — Safinamide Parkinson's Disease Trial Protocol (Candurin® pigments cited as excipient)
• Pharmaceutical Technology — Innovations in Tablet Coating (pearlescent pigments as PCIDs)
• Pharmaceutical Executive — "More Than Just a Pretty Color" (pearlescent coating technology)