API QUALITY CONTROL — WHERE QUALITY BEGINS
Can a medicine be better than the API used to manufacture it?
The answer is No.
The quality of a pharmaceutical product begins with the quality of its Active Pharmaceutical Ingredient (API) and other starting materials. A poor-quality API can affect the safety, efficacy, stability and overall performance of the finished medicine.
So, what does API Quality Control actually check? 🤔
🧪 Key API Quality Attributes
🔹 Identification – Is this the correct API?
🔹 Assay – How much active ingredient is present?
🔹 Related Substances – Are impurities within specified limits?
🔹 Water/Moisture – Could moisture affect stability or quality?
🔹 Sulphated Ash / ROI – Is inorganic residue within limits?
🔹 Residual Solvents – Are remaining manufacturing solvents controlled?
🔹 Elemental Impurities – Are potentially harmful elements controlled?
🔹 Chiral Purity – Is the required enantiomer present?
🔹 Genotoxic Impurities – Are DNA-reactive impurities controlled?
🔹 Particle Size / Appearance – Where applicable, does the API meet physical requirements?
🔬 Different tests require different techniques:
FTIR / HPLC / UV → Identification, HPLC / UV / Titration → Assay, HPLC → Related substances, Karl Fischer / LOD → Water/Moisture ,Headspace GC → Residual solvents , ICP-MS / ICP-OES → Elemental impurities ,📋 API Specification vs CoA…This is another important area for QC professionals.
Specification = What the API must meet.
CoA = What a particular batch actually achieved.
🎯 VERY IMPORTANT Q&A
Q1. What are the common tests performed on an API?
👉 Identification, assay, related substances, moisture, sulphated ash/ROI, residual solvents, elemental impurities and applicable tests such as chiral purity or particle size.
Q2. What is the first analytical test performed on an incoming API?
👉 Identification testing. It confirms that the material received is actually the material stated on the label.
Q3. Which technique is commonly used for residual solvent testing?
👉 Headspace Gas Chromatography (HS-GC).
Q4. What would you do if an API fails the assay specification?
👉 Do not release the material. Inform the responsible person and initiate an OOS investigation according to the approved procedure. Review calculations, sample preparation and instrument performance before any retesting.
Q5. Which ICH guidelines are important for API impurities?
👉 ICH Q3A – API impurities, ICH Q3C – Residual solvents, ICH Q3D – Elemental impurities, ICH M7 – DNA-reactive/genotoxic impurities.
💡 Remember:Quality doesn’t start with the finished tablet.Quality starts with the raw material.
Good API Quality → Good Manufacturing → Good Medicine → Patient Safety. 💊
🎓 For Pharma Students & QC Freshers:
