Lecture 07

• What is the assay in drug manufacture?

  A quantitative test
• Why is the assay important in drug manufacture?

  It ensures the correct API content
• Where can the assay test be found?

  In the British Pharmacopoeia
• What does the assay measure in pharmaceutical analysis?

  Quantitative determination of an analyte
• What is included in each monograph in the BP for API?

  Procedure how to measure content
• What does the assay tell us about the API content?

  It measures API purity
• Why might assay results show more than 100% API content?

  Due to calibration errors and sample matrix
• What does the presence of impurities indicate in an assay?

  Low levels of impurities may be present
• What is the acceptable content range for Naproxen as an API?

  99.0% to 101.0%
• What is the acceptable content range for Naproxen in tablets?

  95.0% to 105.0% of stated amount
• Why is the margin for Naproxen in tablets larger than for API?

  Formulated products contain other ingredients
• What analytical method is used for Naproxen API?

  Titration
• How is Naproxen prepared for titration?

  Dissolve in water and methanol mixture
• Why is the titration method not used for formulated products?

  Impurities can interfere with results
• What method is used for analysing Naproxen tablets?

  UV absorption spectroscopy
• What is the method for analysing oral suspensions of Naproxen?

  UV absorption spectroscopy
• What method is used for analysing suppositories?

  Gas chromatography
• What is a Certified Reference Standard (CRS)?

  A pure sample of a compound
• What are the storage conditions for CRS?

  Away from sunlight and temperature control
• What are the most popular analytical techniques?

  HPLC, UV, and Titration
• What does the UV signal indicate in analysis?

  It is proportional to the amount present
• How is the amount calculated using Beer’s law?

  Using the formula A = ε x c x l
• What is HPLC used for in assays?

  Separation technique with UV detection
• Why is peak separation important in HPLC?

  It allows identification of individual components
• What is required for a titration to be valid?

  A reaction specific for the API
• How is the % w/w content of Ephedrine determined?

  By acid-base titration
• What is the procedure for titrating Ephedrine?

  Use NaOH after HCl neutralisation
• How is the content of Ephedrine calculated?

  Using the weight and molar mass
• What is the purity percentage of Ephedrine calculated?

  99.07% pure
• What are the key components of an assay in drug manufacture?

  • Quantitative test for API content
  • Procedure for measuring content
  • Acceptable limits for purity
  • Importance of impurity testing
• What are the differences in analytical methods for API and formulated products?

  API:

  • Titration method
  • Specific for pure compounds

  
  

  Formulated Products:

  • UV absorption spectroscopy
  • Sample preparation varies due to other ingredients
• What are the storage conditions for Certified Reference Standards (CRS)?

  • Store away from sunlight
  • Use amber vials
  • Maintain temperature control
• What are the common analytical techniques used in assays?

  • HPLC
  • UV absorption spectroscopy
  • Titration
  • Gas chromatography