| Product identity | Calcium alpha-ketoglutarate, also called calcium 2-oxoglutarate | Confirms that the material is the calcium salt of alpha-ketoglutaric acid rather than free AKG or another calcium organic acid salt. | FTIR identity testing, chromatographic testing, and calcium assay |
| Chemical composition | Commonly represented as C10H10CaO10 for the anhydrous salt; molecular weight is approximately 314.25 g/mol | The reported formula and molecular weight depend on the declared hydration state and product specification. | Formula review, water-content testing, and elemental or calcium analysis |
| Primary raw material | Alpha-ketoglutaric acid or a qualified AKG solution | Raw-material purity affects assay, color, reaction consistency, and the level of organic impurities in the finished powder. | Supplier qualification, identity testing, assay, moisture, and impurity profile |
| Calcium source | Food- or pharmaceutical-grade calcium hydroxide or calcium carbonate, selected according to the process | The calcium source neutralizes the acid and influences reaction rate, filtration behavior, and by-product formation. | Identity, calcium content, insoluble matter, heavy metals, and microbiological testing where applicable |
| Reaction principle | Controlled neutralization of alpha-ketoglutaric acid with a calcium base in purified water | The reaction forms the calcium salt while process control helps limit unreacted acid, excess calcium, and localized pH variation. | Batch records, pH monitoring, temperature monitoring, and in-process sampling |
| Reaction pH | Often controlled near neutral; a practical development window is approximately pH 6.5–8.5, subject to validation | The final set point depends on the raw materials, salt form, solubility, and desired crystal characteristics. | Calibrated pH meter and documented in-process control |
| Reaction temperature | Moderate temperature processing, commonly around 20–60°C during neutralization | Temperature affects dissolution, reaction kinetics, color development, and precipitation behavior. | Calibrated temperature probe and batch-process records |
| Clarification and filtration | Removal of insoluble particles after reaction, followed by filtration or centrifugation | This step reduces insoluble residues and supports a cleaner, more uniform bulk powder. | Visual inspection, filter-integrity or equipment checks, and insoluble-matter testing |
| Crystallization or precipitation | Controlled cooling, concentration, or antisolvent-assisted precipitation may be used depending on solubility and process design | Crystal formation influences filtration speed, bulk density, particle size, and drying efficiency. | Process observation, solids recovery, particle-size analysis, and microscopy when required |
| Washing | Purified-water washing or another validated washing procedure | Washing helps reduce soluble residuals, including unreacted starting materials and process salts. | Conductivity, pH of wash filtrate, residue testing, and batch documentation |
| Drying | Vacuum, tray, fluid-bed, or other validated low-moisture drying process; temperature is product- and equipment-dependent | Controlled drying limits moisture while reducing the risk of discoloration, caking, or unnecessary thermal exposure. | Loss on drying or Karl Fischer water determination |
| Milling and sieving | Milling followed by sieving to achieve the agreed particle-size distribution; 80-mesh material is a common commercial reference point | Particle size affects flowability, blending, dissolution, dust generation, and filling performance. | Sieve analysis or laser diffraction particle-size testing |
| Appearance | White to off-white powder is commonly specified; color limits must be defined in the individual product specification | Appearance provides a rapid check for contamination, overheating, oxidation, or batch-to-batch variation. | Visual examination under standardized lighting |
| Assay and identity | Commercial specifications commonly target approximately 98.0% or higher assay, but the exact limit must be agreed in the certificate of analysis | Assay confirms the concentration of the intended active salt and supports lot-to-lot consistency. | Validated HPLC, titration, ion analysis, or another fit-for-purpose analytical method |
| Moisture | A typical bulk-powder target is often not more than 5.0%, with the contractual limit set by the intended application | Moisture affects powder flow, stability, caking tendency, and calculated assay on different bases. | Loss on drying or Karl Fischer method |
| Heavy metals and elemental impurities | Limits should be established according to the destination market, application, and applicable food, supplement, or pharmaceutical requirements | Calcium-containing products still require control of lead, arsenic, cadmium, mercury, and other relevant elemental impurities. | ICP-MS or ICP-OES |
| Microbiological quality | Total aerobic count, yeast and mold, and specified pathogens are controlled according to the product category and market requirements | Microbial limits are especially important when the powder is intended for ingestion or use in a food or dietary-supplement formulation. | Compendial or validated microbiological methods |
| Bulk packaging | Sealed food- or pharmaceutical-suitable inner liner inside a fiber drum, carton, or other approved bulk container | Moisture-barrier packaging helps protect the powder during storage and international transport. | Packaging inspection, seal verification, label review, and net-weight check |
| Storage conditions | Store tightly closed in a cool, dry, well-ventilated area, protected from moisture, heat, and direct sunlight | Appropriate storage helps maintain assay, appearance, flowability, and microbiological quality. | Warehouse temperature and humidity records, packaging checks, and stability monitoring |
