Revision and Mock Exam Practice for BDT 352

How to use this lesson

This lesson pulls together the whole of BDT 352. Read the summary, then attempt the quiz at the end without looking back. For every question you get wrong, go back to the lesson named.

Topic summary

1. Industrial processing: unit operations

• Unit operations are the basic steps of manufacture.
• Fluid flow: liquids and gases moved by pumps and pipes. Material flow: solids moved by gravity, conveyors and hoppers.
• Size reduction: cutting, compression, impact, attrition. Mills: cutter, roller, hammer, ball, fluid energy.
• Size separation: sieving. A higher mesh number means a finer sieve.
• Extraction: maceration, percolation, infusion, decoction, digestion, Soxhlet.
• Distillation: simple, fractional, steam, vacuum. Evaporation: vapour not collected.
• Drying: tray, fluid bed, spray, vacuum, freeze. Check by loss on drying.
• Filtration, clarification and granulation (wet, dry, fluid bed).

2. Small-scale production

• Liquids: solutions, suspensions, emulsions. Scale every ingredient by the same factor. Check appearance, volume, pH and relative density.
• Solids: tablet steps from weighing to packing, and capsule filling. Tests: weight variation, hardness, friability, disintegration, dissolution.
• Semi-solids: creams, ointments, pastes, gels, jellies and suppositories by moulding, with displacement value.
• Aerosols: container, valve, actuator, dip tube, concentrate and propellant. Safety rules.

3. Packaging, stability and storage

• Packaging protects, contains, identifies, informs and is convenient. Primary, secondary and tertiary packs.
• Materials: glass (amber for light), plastics, metals, paper, rubber. Closures: child-resistant and tamper-evident.
• Stability: chemical, physical, microbiological. Factors: temperature, moisture, light, oxygen, pH, germs, container, time.
• Shelf life and expiry. Storage: cool, dry, away from light. Cold chain at 2 to 8 °C.

4. QA, QC and GMP

• QA is the whole system. GMP is making products to the standard. QC is testing.
• GMP areas: personnel, premises, equipment, materials, production, documentation, quality control, complaints and recalls, self-inspection.
• Batch records and batch numbers allow tracing and recall.

Formulas to know

scale factor = batch size ÷ master formula size
yield (%) = actual ÷ theoretical × 100
loss on drying (%) = weight lost ÷ original weight × 100
friability (%) = (initial − final) ÷ initial × 100
base for suppositories = (number × mould capacity) − (total drug ÷ displacement value)
tincture 1 in n: drug (g) = volume (mL) ÷ n
concentration factor = starting volume ÷ final volume
percentage of label claim = amount found ÷ labelled amount × 100

Worked revision examples

Scaling. Master formula for 500 mL contains 25 g of drug. Make 20 litres.

1. Scale factor = 20 000 ÷ 500 = 40
2. Drug = 25 × 40 = 1 000 g = 1 kg

Displacement value. 10 suppositories, each with 300 mg of drug (DV 1.5), in 2 g moulds.

1. Drug = 10 × 0.3 = 3 g
2. Base displaced = 3 ÷ 1.5 = 2 g
3. Base needed = (10 × 2) − 2 = 18 g

Friability. 10.00 g of tablets weighs 9.95 g after the test.

• (10.00 − 9.95) ÷ 10.00 × 100 = 0.5%

Common mistakes in the examination

• Mixing up QA, QC and GMP.
• Mixing up distillation and evaporation.
• Forgetting units, or giving g when the answer is kg.
• Not scaling all ingredients.
• Forgetting that the drug displaces some base in suppositories.
• Writing one word for a list question. Give the required number of points.
• Leaving out working. Show each step.

Planning a long answer

For a question such as "Describe the production of tablets":

1. Define the product briefly.
2. List the steps in order, with one line for each.
3. Name the equipment at each step.
4. State the quality checks and the tests.
5. Finish with packing, labelling and storage.

Mock quiz

Try the mixed questions below. Aim to answer each one before you look at the explanation.