Quality Control of Medicines: Quantitative

What are the learning aims of this session? (2 points)

1. Interpret chromatographic data to determine if a sample meets specification limits

2. Understand the application of Lambert-Beer law in medicine QC

What are the three types of quantitative analyses in chromatography? (3 points)

1. Single point calibration

2. Multiple points calibration

3. Single point calibration with internal standard

How does quantitative chromatography work? (3 points

1. Based on detector response (AUC - Area Under the Curve)

2. AUC is proportional to concentration within a linear range

3. Too high or too low concentrations distort this relationship

Q: What is single point calibration? (3 points)

1. Inject known standard solution and record AUC

2. Inject unknown sample and compare AUCs

3. unknown Concentration = (AUC of soln 1/ AUC of standard soln 2) X known concentration in soln 2

What is the formula for single point calibration? (1 point)

1. Unknown concentration = (AUC2 - AUC1) X Known concentration

What is multiple point calibration? (5 points)

1. Prepare standard stock solution

2. Create serial dilutions with known concentrations

3. Analyze each by HPLC and record AUC

4. Plot calibration curve of AUC vs. concentration

5. Interpolate unknown sample-s AUC on the curve

What was the paracetamol calibration curve example result? (3 points)

1. Sample AUC = 45205 units

2. Interpolated concentration = 1.266 mg/100 mL

3. Adjusted for dilution factor: 40 - 1.266 = 50.64 mg/100 m

How do you determine compliance using paracetamol AUC result? (2 points)

. Compare with manufacturer claim: 50 mg/100 mL

2. Percentage = (50.64 - 50) - 100% = 101.28% - within allowed -5%

What is single point calibration with internal standard? (3 points)

1. Add internal standard (IS) of known concentration to both standard and sample

2. Calculate response factor = (AUC compound / AUC IS)

3. Compare response factors between solutions to find unknown concentration

What are the example values used for aspirin and benzoic acid? (4 points)

1. Sol 1 (Standard): 1 mM aspirin, 1 mM benzoic acid, RF = 8000 / 8500 = 0.9412

2. Sol 2 (Unknown): AUC = 7000, IS AUC = 8300, RF = 0.8433

3. Concentration = 1 - (0.8433 / 0.9412) = 0.7556 mM aspirin

4. Internal standard corrects for instrument variation