Fundamentals of Drug Regulatory Affairs

A: Principle: Trends within specification can still signal an assignable cause under ICH Q9. Applied here: A drifting input variable that feeds the assay is a plausible root cause, so the investigation boundary has to widen upstream before any retest logic. Misapplied principle trap: Option B tempts engineers who treat specs as binary pass/fail and ignore trend-based risk signals.

A: Principle: Qualification relies on documented evidence of fitness for intended use. Applied here: Without range and accuracy data, you can't confirm control of a monitored parameter in IQ/OQ, even for utilities. Misapplied principle trap: Option D catches engineers who separate utilities from GMP impact too aggressively.

A: Principle: Reaction rate acceleration scales exponentially, but duration still matters. Applied here: Six hours at 35 °C contributes marginal additional degradation versus thousands of hours at 25 °C, assuming no humidity spike. Misapplied principle trap: Option C appeals to engineers who remember Arrhenius but skip the time integration step.

A: Principle: Isolated failures point to localized, not systemic, causes. Applied here: A single vial failing with acceptable system suitability aligns with prep or handling error, not instrument-wide faults. Misapplied principle trap: Option B fits HPLC lore but doesn't match the absence of retention time drift.