Unknown impurities Isolation and Characterisation

    Our expertise in enrichment of unknown impurities by various degradation conditions like…photolytic degradation, acid degradation, alkaline degradation, thermal degradation, oxidative degradation OR by synthetic approach followed by isolation of impurity & structure confirmation.

    According to International Conference on Harmonization (ICH) guidelines identifying and characterizing all impurities that are present at a level of 0.10% or more are recommended to identity the structure of unknown impurity from new drug substance.

    To identify the unknown structure by spectroscopic method like… NMR (Nuclear Magnetic Resonance spectroscopy), Mass (Mass spectroscopy: ESI and APCI mode),IR (Infrared spectroscopy), UV (UV- Visible spectroscopy),LC-MS (Liquid Chromatography and Mass Spectrometry).

    We enriched the some of degradation impurities approx. 15 % from 0.02 % by force degradation experiments followed by purify by Prep HPLC to obtained 98 % pure unknown impurity which was characterized by 1H NMR, 13C NMR, 2D NMR, DEPT-(45,90,135) 1H–1H COSY, HMBC, HSQC, and NOESY.

    Steps Involved

    Unknown impurity isolation and characterization are crucial steps in pharmaceutical research and development, as well as in various other industries such as chemical manufacturing. The process involves identifying and analyzing impurities that may be present in a chemical compound or drug substance. These impurities can arise from various sources, including the raw materials used in synthesis, reaction intermediates, and degradation products. The goal is to ensure the purity, safety, and efficacy of the final product. Here is an overview of the steps involved in unknown impurity isolation and characterization:

    1. Sample Preparation
    • Start by obtaining a sample of the compound or drug substance containing the unknown impurity.

    • Ensure that the sample is representative of the material being tested.
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    2. Isolation
    • Separation techniques are employed to isolate the impurity from the bulk material. Common techniques include:
      • Column Chromatography: Utilizing a stationary phase to separate compounds based on their interactions with the column.
      • HPLC (High-Performance Liquid Chromatography): Employing a high-pressure liquid chromatography system to separate and isolate impurities.
      • Preparative TLC (Thin-Layer Chromatography): Separating compounds on a thin layer of absorbent material.
      • Crystallization: Allowing the impurity to crystallize out of the solution.
      • Extraction: Utilizing solvents to selectively remove the impurity from the mixture.
    3. Characterization
    • Once the impurity is isolated, various analytical techniques are used to characterize it. Key methods include:
      • Spectroscopy: Techniques like NMR (Nuclear Magnetic Resonance), IR (Infrared), and UV-Vis spectroscopy can provide information about the impurity’s chemical structure.
      • Mass Spectrometry (MS): Helps determine the molecular weight and fragmentation pattern of the impurity.
      • X-ray Crystallography: Useful for determining the three-dimensional structure of crystalline impurities.
      • Elemental Analysis: Determines the elemental composition of the impurity.
      • Thermal Analysis: Evaluates the impurity’s stability and melting point.
      • Microscopy: Visual inspection of the impurity’s physical characteristics.
      • NMR Diffusion and Relaxation Experiments: Provides information about the impurity’s size, shape, and mobility.
    4. Identification
    • Use the data obtained from the characterization techniques to identify the chemical structure of the impurity.

    • This involves comparing the experimental data with known standards or databases, and it may require the expertise of analytical chemists.
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    5. Quantification
    • Determine the concentration or amount of the impurity in the original sample.

    • This is often done using validated analytical methods such as HPLC or GC (Gas Chromatography).
    6. Documentation
    • Record all experimental data, procedures, and results in a detailed report.

    • This documentation is critical for regulatory compliance and future reference.
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    7. Risk Assessment
    • Assess the potential impact of the impurity on the quality, safety, and efficacy of the final product.

    • Determine if any corrective actions or process optimizations are needed to minimize impurities in future production.
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    8. Regulatory Compliance
    • Ensure that the impurity levels meet regulatory guidelines and standards.