Pharmaceutical Analysis and Quality Control
What the exam tests
Pharmaceutical Analysis and Quality Control tests method development, validation, pharmacopoeial limits, and instrument troubleshooting.
Core rules
- Validation under ICH Q2 includes accuracy, precision, specificity, linearity, range, detection limit, quantitation limit, and robustness. System suitability is checked before the run, not after a failure.
- LOD = 3.3σ/S and LOQ = 10σ/S, where σ is the standard deviation of the response and S is the slope of the calibration curve.
- HPLC: retention time identifies, peak area quantifies; resolution, tailing factor, and theoretical plates describe system performance. Mass balance should account for impurities and degradation products.
- Titration depends on a clear equivalence point; indicator choice must match the pH jump.
Worked example
A calibration curve has slope S = 12.0 AU per mg/mL and the standard deviation of the blank response is σ = 0.15 AU. LOD = 3.3 × 0.15/12.0 = 0.0413 mg/mL; LOQ = 10 × 0.15/12.0 = 0.125 mg/mL. Report both, not just the LOD. A result below the LOQ is not reliably quantifiable even if it is above the LOD, so it should be reported as below the limit of quantitation.
Traps
Do not use the LOD formula for LOQ; do not validate with standards prepared in a different matrix from the sample; do not accept a correlation coefficient alone as proof of linearity; and do not ignore carryover or injection-precision failures.