Inorganic Impurity Test

Inorganic Impurity Test

Protheragen-ING Lab provides specialized services for the detection of organic impurities in pharmaceuticals, aiming to ensure the safety and efficacy of pharmaceuticals. Inorganic impurities are key quality attributes of APIs and pharmaceuticals and may originate from raw materials, synthetic additives, excipients, and manufacturing processes used in the production of pharmaceuticals.

Importance of inorganic impurities

Inorganic impurities have a potential impact on the safety and efficacy of pharmaceutical products. They can lead to reduced product quality and even pose a threat to patient health. Understanding and controlling the level of inorganic impurities is therefore essential to ensure the quality of pharmaceutical products.

Our laboratory provides professional inorganic impurities testing services. We follow international standards and norms to ensure the accuracy and traceability of the testing process.

Common inorganic impurities

The following are some of the common inorganic impurities that may be generated during the production of APIs and formulations:

  • Reaction reagents.
  • Ligands.
  • Catalysts.
  • Heavy metals.
  • Other residual metals.
  • Inorganic salts.
  • Filter aids.
  • Activated carbon.

Among them, sulfate ions, chloride ions, and sulfur ions often originate from desiccants, catalysts, or pH-adjusting agents used in production, and the detection of residues of these ions can reflect the purity of the product. Pharmacopoeial methods will be used to detect trace residues that may have been introduced into the product.

For inorganic impurities not yet included in the pharmacopoeia, we can use ion chromatography, atomic absorption spectrophotometry, colorimetry, and other methods with a certain degree of specificity and sensitivity to detect them according to their physical and chemical properties.

Detection of common inorganic impurities

We use a variety of classic and effective analytical methods to detect inorganic impurities. Below are some of the common inorganic impurities and their detection methods:

  • Cauterization residue assay: The most versatile and fastest way to know the overall inorganic impurity content of a pharmaceutical product is to determine the cauterization residue. This method assesses the purity of the drug product by burning the sample at a high temperature and then determining the amount of inorganic impurities left behind.
  • Chloride assay: A semi-quantitative limit test is used, whereby the chloride content is tested semi-quantitatively by adding a silver nitrate reagent to an aqueous solution of the sample to be tested to form a silver chloride precipitate, and visually comparing the turbidity of the solution to that of a standard solution containing a known amount of chloride.
  • Fluoride assay: Trace fluoride ions in pharmaceutical materials are estimated by various calorimetric methods using reagents containing cerium.
  • Sulfate assay: A limit test is used in which insoluble barium sulfate is formed when a barium chloride reagent is added to a solution of test material acidified with hydrochloric acid.
  • Phosphate assay: Quantitative or semi-quantitative determination of phosphate ions in pharmaceuticals is usually based on the formation of colored heteropolyacids.
  • Heavy metal assay: Based on the use of Atomic Absorption Spectrophotometry or Atomic Fluorescence Spectroscopy in moderately acidic solutions for the detection of heavy metal elements.

These are just a few examples of common inorganic impurities and detection methods. The specific detection method will be selected based on the characteristics and requirements of the sample to be tested.

If you need inorganic impurity detection services, please contact us. We will provide customized solutions according to your needs and offer you professional technical support.