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Indigo, a deep blue dye, reaches back thousands of years. People have used it to color textiles and, much later, to bring vibrance to pharmaceuticals and foods. The discovery of turning indigo into a stable, insoluble pigment—called a “lake”—represented a shift for industries demanding both striking color and firmness under strict processing conditions. In the last century, as food and drug regulation tightened, the medical and food communities began looking closer at both purity and safety in coloring agents. Pharmaceutical grades like BP, EP, and USP signal rigorous standards set by bodies including the British Pharmacopoeia, European Pharmacopoeia, and United States Pharmacopeia. Each standard pushes for better testing on heavy metals, residual solvents, and overall color consistency. Watching these changes unfold, it becomes clear that indigo’s story follows the broader push for cleaner, safer ingredients in everything from tablets to syrups.
Indigo Aluminum Lake stands out thanks to its stability, helping manufacturers lock in color without worrying about the pigment fading or bleeding. The “lake” form traps the indigo dye on an aluminum hydrate substrate, which not only improves its dispersion in tablets and capsules but keeps interactions with other ingredients in check. That’s especially important when dealing with strict regulatory scrutiny over color additives in medicine. Manufacturers select pharma-grade indigo aluminum lake for its compliance and reliable batch-to-batch consistency, not just its blue pigment. Importantly, this approval signals a product tested for potential contaminants that could threaten patient health.
In its standard state, indigo aluminum lake appears as a fine blue powder—uniform in shade and texture. It resists breaking down in water and oil, making it handy for both solid and liquid formulations. Melting doesn’t occur at typical processing temperatures, so it stays put through tablet manufacturing and coating. Chemically, it combines indigo (C16H10N2O2) with aluminum hydroxide, forming a stable matrix. This ends up protecting the dye from being leached out by humidity or standard solvents. Solubility tests show it stays suspended, which matters a lot for shelf-life and appearance of oral medicines.
Labeling on a compliant indigo aluminum lake BP EP USP package will tell you about dye content (often 10–40% by weight), residual heavy metals like lead or arsenic (kept below specified parts per million), and particle size distribution. Most labels indicate both the color index number (C.I. Pigment Blue 28) and the chemical makeup, as well as manufacturer and batch code. These details aren’t just for paperwork; they let manufacturers trace back problems in the rare case there’s a recall or adverse event report. With regulatory audits becoming more frequent, this transparency supports accountability from start to finish.
Making a pharma-grade indigo aluminum lake involves several careful steps. First, indigo dye (itself usually synthetically derived today to guarantee purity) dissolves in a caustic solution, often sodium hydroxide. Aluminum salt—typically aluminum sulfate—is slowly added. The two react and precipitate into an insoluble powder, as the dye molecules lock onto the aluminum hydroxide. Manufacturers wash this precipitate multiple times to remove unreacted substances and adjust pH to match pharmacopeial standards. Once dried and milled, the powder is tested for clarity and particle size. Getting every condition right keeps residual contaminants and clumping out of the product, after years of learning the hard way that shortcuts lead to recalls and regulatory headaches.
No formulation stands still. Chemists learned how indigo reacts under manufacturing conditions—the dye itself resists breakdown, but alkaline or acidic environments speed up hydrolysis or fading. Aluminum hydroxide’s role is to stabilize, so modifications focus on fine-tuning particle size or exploring alternatives to heavy metals when regulatory bodies flag cumulative toxicity concerns. Advanced chemical engineering allows tweaks to binding strength between indigo and the substrate, affecting how much color the lake gives to a finished tablet or capsule. Sometimes, research chases after ways to remove micro-impurities below the analytical limits of older tests, aiming to future-proof the material as testing technology advances.
The same pigment might arrive under different names, depending on region or supplier. Common names include C.I. Pigment Blue 28, FD&C Blue No. 2 Lake, CI 73015, and simply “Indigo Carmine Aluminum Lake.” Labels keep these standardized, but confusion sometimes crops up in international medicine shipping, since a single synonym could mean a slightly different chemical structure or purity in practice. In my work with pharmaceutical sourcing, tracing these terms back to exact manufacturing sources cleared up more than one batch mix-up.
Every responsible manufacturer puts safety front and center. Pharma-grade indigo aluminum lakes get tested for contaminants, from heavy metals to microbial activity, and must meet low thresholds for leachable impurities. Operators wear full protective gear to avoid inhaling any powders in bulk handling environments, and equipment goes through repeated cleaning cycles to prevent cross-contamination. The industry learned hard lessons from earlier decades, where lack of oversight led once in a while to adulterated colorants slipping into patient hands. Now, traceability, validated cleaning procedures, and documentation of every step help keep safety claims grounded in data.
Most people spot indigo aluminum lakes in blue or purple pharmaceuticals—think coated tablets, capsules, syrups, even specialized topical creams. The pigment works in both enteric coatings and compressed tablets, giving a consistent color without leaching into blister packs or containers. The lake format provides key advantages in direct compression and sugar-coating, where water solubility would otherwise threaten the hue. Beyond medicine, food companies tap these lakes for candies and confections, and some countries approve them for cosmetics. For every use, regulatory bodies keep the focus squarely on ingestion or dermal exposure safety, since very little leaching or migration can be tolerated.
Research labs keep driving the pigment forward with studies on particle size control, better binding mechanisms, and replacement of aluminum with safer or bio-based carriers. Analytical chemistry now allows scanning lots for micro-impurities, and R&D groups seek ways to push those even lower, reducing patient risk for rare allergic or toxic reactions. In the last decade, nanotechnology and surface engineering have invited a new round of experiments into how lakes can be customized for slow-release or taste-masked medicines, so patients don’t have to make unpleasant trade-offs between appearance and efficacy. Scientists routinely publish studies comparing performance against older synthetic dyes, as regulatory trends shift toward ever-tighter thresholds on allowable color additive impurities.
The history of synthetic dyes includes episodes where overlooked impurity or breakdown product caused public health scares, pushing labs to keep a sharp eye on toxicity. Multiple animal and human studies evaluate indigo aluminum lake’s long-term effects, tracking absorption, distribution, metabolism, and excretion. These studies have repeatedly found minimal systemic absorption, with most passing unaltered through the gut. Nonetheless, clinical vigilance remains strong, as certain groups—especially children, pregnant women, and those with metabolic disorders—show lower tolerance for synthetic chemicals. Global bans on specific dye forms arose from toxicity signals, steering manufacturers to cleaner, well-characterized lakes, while toxicologists call for ongoing study as new analytical techniques uncover previously invisible contaminants.
Looking forward, the next decade won’t just be about brighter blues or tighter regulatory specs. Companies are experimenting with alternative carriers to replace aluminum, searching for options that both perform reliably and ease the burden on long-term human and environmental safety. Consumer demand for “clean label” medicines could open up pathways for natural origin, non-metal lakes, although technical barriers around color strength and stability run high. Regulatory agencies will keep updating standards and likely reduce allowable impurity thresholds even further. For manufacturers and scientists, indigo aluminum lake represents an ongoing laboratory—learning from the past, but pushing well beyond it to healthier, safer medicines.
Color grabs our attention every day, so it makes sense that pharmaceutical companies want their products to look appealing and recognizable. Indigo Aluminum Lake BP EP USP Pharma Grade gives pills, capsules, and syrups a deep blue shade that lets brands stand out, helps patients tell medicines apart, and builds trust in what goes inside. Children, seniors, and even busy adults often rely on the color of medication to make sure they aren’t mixing up doses. Studies from the U.S. FDA and European Medicines Agency show that colors like indigo help reduce medication errors in clinics and pharmacies. Mistaking one pill for another can turn a minor illness into an emergency. Color remains a practical tool in avoiding confusion, especially in high-stress hospital settings where staff need to quickly grab the right medicine for a patient.
Indigo Aluminum Lake BP EP USP Pharma Grade doesn’t pop up by accident in a medicine’s ingredients list. It must fit strict rules from agencies like USP (United States Pharmacopeia), BP (British Pharmacopoeia), and EP (European Pharmacopoeia). These rules demand clean, consistent, and safe batches every time. Anything less could affect the appearance, or worse, the safety of the medicine. Drug makers dealing with chronic disease treatments like diabetes often use this grade for long-term reliability. Consistent results from these colorants cut down on complaints and recalls. Regulators ask for full documentation before approving colored tablets for public use, so anything meeting "pharma grade" earns a badge of trust.
Some folks wonder why companies don’t just stick to plant-based dyes. The reality: nature hasn’t produced a blue shade stable enough to survive heat, light, and the long shelf lives modern healthcare demands. Indigo Aluminum Lake holds its color from warehouse to medicine cabinet without losing strength or safety. It resists fading, doesn’t react badly with active ingredients, and keeps tablets or capsules looking the same even in different conditions across the world. Most natural dyes simply can’t compete with that staying power.
For children’s medicine, appeal can mean everything. A tablet that looks friendly encourages kids to take what they need, lowering the stress parents face during dosing. Flavor and smell play a role, but color goes straight to the senses. Pediatricians often say that recognizable colors help caregivers explain that medicine equals getting better.
For chronic treatments where patients rely on dozens of pills, blue from Indigo Aluminum Lake helps people keep track. Older adults and the visually impaired benefit from these clear visual cues, a fact backed up by healthcare advocacy groups. Fewer mistakes mean fewer trips to the hospital.
Nobody wants to add more than needed to a drug, so industry researchers still hunt for alternatives with less aluminum or longer track records in every population. There’s always a push for reducing additives and responding to patient concerns about synthetic ingredients. Transparent labeling, third-party batch testing, and listening to consumer feedback will play a big part in shaping the future of pharmaceutical coloring.
Medicine should serve people, not only through its chemistry but through the way it reaches every hand safely and clearly. Indigo Aluminum Lake BP EP USP Pharma Grade isn’t glamorous, but its blue mark leaves an impact on health, safety, and peace of mind.
Color in medicine stirs up a simple truth: if a pill doesn’t look right, people hesitate to take it. Manufacturing uses ingredients like Indigo Aluminum Lake, a blue pigment, to make products look consistent and appealing. This pigment shows up in both medicines and food. Questions about its safety come up, mainly because what goes into the body must meet high standards, not just for coloring, but also for what it might leave behind.
Manufacturers turn to grades like BP (British Pharmacopoeia), EP (European Pharmacopoeia), and USP (United States Pharmacopeia) for a reason. These grades set out to define purity and control contaminant levels. Meeting these requirements isn’t just paperwork; it’s proof of a substance’s fit for medical and food use. Nothing guarantees perfection, but an ingredient stamped with all three approvals walks through a tough set of checks.
Color helps more than just the look of a tablet. Think about giving the right pill to the right patient or helping a child take necessary medicine without a fuss. Governments and agencies want to know if a colorant like Indigo Aluminum Lake brings any harm. Studies run long-term and short-term toxicity tests, looking for allergic reactions, organ effects, or buildup of unsafe metals. Scientific bodies in the US and Europe have combed over Indigo Aluminum Lake and concluded that it’s safe within tight limits.
Not everyone trusts food dyes, and some resist artificial colors in medicine and foods. Reports connect certain dyes and children’s hyperactivity, but the evidence for Indigo Aluminum Lake remains limited and inconsistent. Most real-world problems come from coloring that exceeds regulated amounts or skips necessary purification. In my own work with raw ingredient selection, quality control checks for heavy metals stand out, since even small doses can add up over time. Reputable suppliers provide certificates of analysis, so companies can confirm these limits and spot any deviations early.
Shifting away from synthetic dyes isn’t easy. Natural options often fade faster or interact strangely with other ingredients. Costs run higher, and shelf life drops off. Some manufacturers explore plant-based colors, but replacing a well-tested dye demands re-testing and regulatory approval all over again. Consumers pushing for natural coloring do push companies to develop alternatives, though, so the market keeps evolving.
Safe use of Indigo Aluminum Lake depends on supply chain honesty and rigorous lab verification. Surprise regulatory inspections and third-party lab testing help build trust. In pharmaceutical production, mistakes don’t hide for long, as even slight color differences can trigger recalls or halt release. The safest outcome grows from a mix of tough grade standards, regular audits, and open communication between manufacturers, inspectors, and end users.
Safety for any food or drug additive changes with new science, better detection tools, and shifts in public opinion. Indigo Aluminum Lake, in pharma grades like BP, EP, and USP, has passed through decades of close review. Companies and scientists both have a duty to keep asking hard questions and backing up their answers with clear data, helping consumers trust the color of what they eat and what they swallow for their health.
Indigo Aluminum Lake shows up in plenty of products, from pills to candies. This colorant comes from indigo, a pigment people have recognized for centuries, and gets its “lake” classification by binding with aluminum salts, offering stable color that holds up in different manufacturing conditions. The FDA marks it as a certified color, often labeled FD&C Blue No. 2 Aluminum Lake. What really grabs attention isn’t just the source or stability, but the amount used in anything people eat or apply.
The blend of effectiveness and safety drives decisions about how much goes in a product. For pharmaceuticals, most tablets use concentrations between 0.1% and 3% of Indigo Aluminum Lake by weight. Over the years, I've seen manufacturers almost always lean toward the low end, using just enough to dye their product without overstepping regulatory limits. Too much blue and customers start to distrust how “natural” their medicine or vitamin looks.
Chewable products, lozenges, and gummies often fall into that same percentage range. Pharmaceutical technologists rely on established studies and real-world feedback; they notice that levels above 3% hardly ever add more visual impact, but definitely increase risk of side effects or consumer complaints.
In foods, confectioners and bakers approach color with caution. Candies, frostings, and snack coatings rarely go beyond 0.5% by weight. Sometimes, dense coatings (think of a candy shell or a colored tablet) need brighter appearances, so levels might rise to 1%, but that’s usually the exception. Food scientists regulate batches carefully, knowing that even a slight excess triggers regulatory flags or recalls. In more than a few production runs, companies caught trouble for higher-than-expected lake content—costly mistakes that nobody enjoys.
Color looks like a simple part of formulation, but it plays a strong psychological role. Too weak, and consumers see inconsistency. Too heavy, and customers react badly. The FDA and similar authorities in other countries set upper limits for Indigo Aluminum Lake for good reason. For example, the acceptable daily intake (ADI) in the US for Indigo Carmine (from which the lake is derived) sits at 2.5 milligrams per kilogram of body weight. If kids eat a lot of brightly colored candy, the margin narrows fast. Parents worry, and so should manufacturers.
Regulations require companies to list colorants clearly. Pharmaceutical brands understand that a recall for exceeding lake concentration isn’t just a paperwork headache—it's a reputation hit. There have been recall stories from both food and drug industries over the last decade tied to colorant overruns, showing that following guidelines isn’t an optional best practice; it’s core to trust and safety.
Manufacturing teams keep strict batch records, frequently test raw materials, and rely on calibrated dosing equipment. Making sure the colorant is distributed properly goes beyond just following a recipe: even mixing and solid lab checks prevent pockets of concentrated color. I’ve seen teams switch suppliers after inconsistent pigment loads, all to avoid problems down the line. In training, up-and-coming formulation specialists learn quickly that they can’t just “eyeball” color—precision wins out, every time.
Sticking to well-established concentration limits, respecting regulatory advice, and running routine tests offer the best shot at delivering colorful, trusted products to consumers—without costly missteps or side effects.
Pharmaceutical coloring isn’t about helping a pill look nice on a shelf. Coloring agents matter because regulators know that if these compounds fall out of line, the medicine’s safety drifts right out the door. Indigo Aluminum Lake, a color additive used in tablets, capsules, and coatings, finds itself under strict watch. I have followed several regulatory paths in the pharma sector. Here’s what stands out: you get peace of mind only after ticking all the regulatory boxes. Anything less can lead to costly recalls or, worse, a risk to patient safety.
Indigo Aluminum Lake with BP, EP, and USP tags signals adherence to British, European, and US Pharmacopoeias. These aren’t just country preferences. Each set of guidelines expects low levels of heavy metals like lead or arsenic, clear labeling of any impurities, and controls for bacterial or fungal contamination. This isn’t open for debate—testing must pinpoint exact specs, batch after batch. I’ve talked to analytical chemists who run these tests, and they all mention how a single off-spec reading can halt production lines for days.
Regulators love paperwork. Indigo Aluminum Lake’s journey gets documented from the raw pigment to the boxed ingredient. Every material lot receives a certificate of analysis, verifying compliance down to parts per million. These aren’t ceremonial documents—they are demanded during audits, and missing paperwork means the product can’t move forward in manufacturing. There’s real value in those stacks of certificates, as a missing slip can mean a failed audit and a delayed launch, lessons that hit hard during my early runs on pharma projects.
Auspices like BP, EP, and USP set the bar for particle size, solubility, purity, and absence of toxic compounds. Standards evolve as science reveals new risks. I’ve seen regulatory teams scramble when a new contaminant hits the headlines and pharmacopoeias tighten specs. To stay current, suppliers keep investing in new purification steps and recalibrate tests according to the latest updates. A company that ignores these changes risks both legal trouble and a damaged reputation, which can take years to rebuild.
Modern manufacturers can’t afford to work in isolation. If something in the process changes, from a new piece of equipment to a new supplier for a raw dye, the entire validation package gets updated and resubmitted. Mistakes don’t stay hidden for long. The best suppliers keep lines of communication open with regulators, answer questions from auditors fast, and share change-control documentation with pharmaceutical clients. In all my consultations, responsiveness has been a clear marker separating reliable ingredient partners from the rest.
Getting everyone—regulators, ingredient suppliers, and drug manufacturers—talking more often could speed up compliance and cut down misunderstandings. More automated monitoring in the manufacturing plant, with real-time data uploads and alerts, means catching deviations before a batch ships. Upgrading these old paper logs saves enormous headaches during recalls and builds trust all around. The journey to top-quality Indigo Aluminum Lake is tough, but well worth the effort, since every patient expects (and deserves) nothing less.
Working in pharmaceuticals and cosmetics taught me early to respect ingredients like Indigo Aluminum Lake. Used often for color, this synthetic pigment works its way into everything from pills to syrups and makeup. Indigo Aluminum Lake checks boxes for purity and safety, especially in the pharma space, but only if handled with real care. Risks pop up when basic precautions get overlooked. There’s no prize for mishandling raw material that ends up in medicine cabinets everywhere.
Humidity and strong odors play the role of silent saboteurs. Store Indigo Aluminum Lake in a dry, cool, well-ventilated place, far from other chemicals and moisture. Cardboard boxes and leaky lids don’t cut it—use tightly sealed, food-grade containers. A pharmacist once told me a moisture-damaged lot clumped so badly, it would have ruined production if caught any later. This pigment absorbs moisture, and that little detail churns out major headaches—clumping, color shifts, even bacterial trouble if left unchecked.
Light exposure can dull the vibrancy of Indigo Aluminum Lake and start slow chemical changes. Direct sunlight isn’t a small risk; always stash it away from windows and bright spots. Room temperature works for short-term storage, but long-term stashing should happen below 25°C (77°F). Never freeze it—extremes mess up the pigment. The importance of a temperature-controlled storeroom can’t be overstated. Any time a regulator drops by, they check logs first. Lax controls can lead to recalls or fines. Not everyone talks about this, but maintaining logs for temperature and humidity creates protection if questions ever come up.
Indigo Aluminum Lake isn’t toxic under normal use, but inhaling dust isn’t wise and neither is letting it touch food or drink areas. Gloves, protective eyewear, and lab coats help keep things clean. I learned to use a dust mask after seeing a batch of powder coat an entire workspace. The risk isn’t just to the operator; cross-contamination has a domino effect in shared environments. Avoiding double-dipping scoops or using unwashed tools stops problems before they start. Clean-up must happen with care—a vacuum with HEPA filter catches stray dust, and wet-cleaning tools prevent pigment from floating around and landing where it shouldn’t.
Labeling matters more than most expect. Mislabeled pigment caused panic in a team I joined years ago. Always mark containers with the product name, batch number, receipt date, and expiry. Document any movement in and out. This accountability supports traceability if quality or safety gets questioned down the line. Outdated lots shouldn’t go unnoticed—track those dates and rotate stock, so nothing old ends up in finished goods.
Disposal of pigment scraps leans on local environmental rules. Pouring down the drain never ends well, and landfills aren’t always approved. Work with disposal firms or check in with hazardous waste guidelines. Reducing spills by training staff saves money and hassle. Spill kits by the storage area help, since powders don’t wait for business hours to cause problems. Even the smell sticks around if not cleaned up soon.
Sourcing from trusted suppliers gives peace of mind. Audits, quality reports, and regulatory documents aren’t just red tape—they form the backbone of consumer safety. Ignoring these steps in storage and handling doesn’t just threaten individual batches; it risks long-term relationships with buyers and regulators. A few simple habits, kept up every day, protect both the product and the unsuspecting end user.
| Names | |
| Preferred IUPAC name | aluminium indigo disulfonate |
| Other names |
C.I. 73015 Aluminum Lake Indigotine Aluminum Lake Indigo Carmine Lake FD&C Blue No. 2 Aluminum Lake |
| Pronunciation | /ˈɪn.dɪˌɡoʊ əˈluː.mɪ.nəm leɪk biː piː iː piː juː ɛs piː ˈfɑː.mə ɡreɪd/ |
| Identifiers | |
| CAS Number | 1327-16-6 |
| Beilstein Reference | 3921680 |
| ChEBI | CHEBI:38899 |
| ChEMBL | CHEMBL3311532 |
| ChemSpider | 3081040 |
| DrugBank | DB11260 |
| ECHA InfoCard | ECHA InfoCard: 100043014 |
| EC Number | 1328-51-4 |
| Gmelin Reference | Gmelin Reference: **107432** |
| KEGG | C11268 |
| MeSH | D044954 |
| PubChem CID | 132937 |
| RTECS number | VY8050000 |
| UNII | TF93G3PC49 |
| UN number | UN1219 |
| CompTox Dashboard (EPA) | DTXSID60709806 |
| Properties | |
| Chemical formula | C16H8N2Na2O8S2·xAl(OH)3 |
| Molar mass | 626.46 g/mol |
| Appearance | Dark blue to bluish-violet powder |
| Odor | Odorless |
| Density | 0.5 g/cm³ |
| Solubility in water | Insoluble in water |
| log P | -2.6 |
| Acidity (pKa) | 14.2 |
| Basicity (pKb) | 12.5 |
| Magnetic susceptibility (χ) | Diamagnetic |
| Viscosity | 5% w/v aqueous solution: 5 – 15 cps |
| Dipole moment | 1.97 D |
| Pharmacology | |
| ATC code | A16AX |
| Hazards | |
| Main hazards | Harmful if swallowed. Causes serious eye irritation. May cause respiratory irritation. |
| GHS labelling | GHS labelling: Not classified as hazardous according to GHS criteria; no GHS pictograms, signal word, hazard statements, or precautionary statements required. |
| Pictograms | GHS07, GHS08 |
| Signal word | Warning |
| Hazard statements | No hazard statements. |
| Precautionary statements | P264, P270, P273, P280, P301+P312, P305+P351+P338, P501 |
| LD50 (median dose) | > 5000 mg/kg (rat, oral) |
| NIOSH | Not Listed |
| PEL (Permissible) | 10 mg/m3 (as Al) |
| REL (Recommended) | 0.2 mg/kg body weight |
| Related compounds | |
| Related compounds |
Indigo Carmine Ferric Ammonium Citrate Aluminum Lake FD&C Blue No. 2 Indigotine Indigo Blue Brilliant Blue FCF E132 Tartrazine Aluminum Lake |
Chengguan District, Lanzhou, Gansu, China
