Under USP , critical manipulations of sterile preparations should be done in which environment?

An ISO Class 5 primary engineering control

An open bench cleaned with 70% alcohol

Syrup BP (about 66% w/v sucrose) is stable without added preservative. What is the main reason?

Its high osmotic pressure inhibits microbial growth

Its low viscosity prevents microbial spoilage

It is sterilised by gamma irradiation after filling

Its high pH destroys most bacteria on contact

Why are glyceryl trinitrate patches usually worn for 12-14 hours and then removed for 10-12 hours?

To avoid hepatic first-pass metabolism

To allow the drug to build up in the skin

Dosage forms, compounding and stability

50 Gulf Prometric Pharmacist (DHA, DOH, MOH, SCFHS, QCHP) practice questions on Dosage forms, compounding and stability, part of Pharmaceutics, Pharmacokinetics and Calculations. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Easy
Under USP <797>, critical manipulations of sterile preparations should be done in which environment?
1. AAn open bench cleaned with 70% alcohol
2. BAn ISO Class 8 anteroom
3. CAn ISO Class 5 primary engineering control
4. DA chemical fume cupboard
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Answer: C · An ISO Class 5 primary engineering control
USP <797> requires critical sterile manipulations to be performed inside an ISO Class 5 primary engineering control, such as a laminar airflow hood or biological safety cabinet, placed in a suitably clean room. An alcohol-wiped bench does not give HEPA-filtered unidirectional air. A fume cupboard protects the operator, not the product.
- A: An open bench has no HEPA-filtered air.
- B: An ISO Class 8 anteroom is used for gowning, not for critical manipulations.
- D: A fume cupboard protects the operator and is not a sterile work area.
Remember this
Aseptic compounding is done in ISO Class 5 air with HEPA filtration and good technique.
Question 2 · Medium
Syrup BP (about 66% w/v sucrose) is stable without added preservative. What is the main reason?
1. AIts low viscosity prevents microbial spoilage
2. BIts high osmotic pressure inhibits microbial growth
3. CIt is sterilised by gamma irradiation after filling
4. DIts high pH destroys most bacteria on contact
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Answer: B · Its high osmotic pressure inhibits microbial growth
A saturated or nearly saturated sugar solution has a high osmotic pressure that dehydrates microorganisms and prevents their growth. If the syrup is diluted, as in many flavoured syrups, a preservative is needed. Crystallisation or cap-locking can occur on storage.
- A: Syrups are viscous, not of low viscosity.
- C: Syrup is not irradiated.
- D: Sucrose syrup does not have a high pH.
Remember this
Concentrated syrups preserve themselves by osmotic pressure; dilution needs a preservative.
Question 3 · Hard
A vial of 1 g of antibiotic powder is labelled: add 3.5 mL of water to give a final volume of 4 mL. The prescribed dose is 600 mg. What volume should be drawn up?
1. A2.4 mL
2. B1.5 mL
3. C2.1 mL
4. D3.0 mL
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Answer: A · 2.4 mL
The powder displaces 0.5 mL, so the final volume is 4 mL and the concentration is 1,000 mg / 4 mL = 250 mg/mL. The dose of 600 mg needs 600 / 250 = 2.4 mL. Ignoring the displacement gives 1,000 / 3.5 = 286 mg/mL and a wrong volume of 2.1 mL.
- B: 1.5 mL does not follow from the concentration.
- C: 2.1 mL ignores the displacement of the powder.
- D: 3.0 mL would give 750 mg.
Remember this
Use the final volume after reconstitution, not the volume of diluent added.
Question 4 · Medium
Why are glyceryl trinitrate patches usually worn for 12-14 hours and then removed for 10-12 hours?
1. ATo prevent nitrate tolerance
2. BTo avoid hepatic first-pass metabolism
3. CTo reduce skin irritation only
4. DTo allow the drug to build up in the skin
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Answer: A · To prevent nitrate tolerance
Continuous nitrate exposure produces tolerance, with loss of vasodilator effect, through mechanisms such as reduced nitric oxide generation and neurohormonal activation. A nitrate-free interval of 8-12 hours restores sensitivity. Angina at night may be a problem if the free interval falls then.
- B: Transdermal delivery already avoids first-pass metabolism.
- C: Irritation is lessened by site rotation, but is not the main reason.
- D: The skin depot is not the purpose of the free period.
Remember this
A nitrate-free interval prevents tolerance to nitrate patches and long-acting tablets.
Question 5 · Medium
A man with Parkinson disease has difficulty swallowing and also needs an antiemetic. Which dosage form is most suitable?
1. AAn orodispersible tablet
2. BA sustained-release tablet
3. CA hard gelatin capsule
4. DA large film-coated tablet
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Answer: A · An orodispersible tablet
Orodispersible tablets disintegrate on the tongue within seconds and are swallowed with saliva, so no water or swallowing effort is needed. Film-coated tablets, capsules and sustained-release tablets must be swallowed whole. Ondansetron and domperidone are available in such forms.
- B: A sustained-release tablet cannot be crushed or broken.
- C: A capsule needs swallowing whole.
- D: A large film-coated tablet needs swallowing whole.
Remember this
Orodispersible forms suit patients with dysphagia, children and those with poor swallowing.
Question 6 · Medium
A man wearing a fentanyl patch applies a hot water bottle to his back for pain. What is the main danger?
1. AThe patch adhesive will dissolve in the heat
2. BIncreased absorption can cause opioid overdose
3. CThe patch will stick better and release less
4. DReduced absorption leaves him in pain
Answer and explanation in LearnFree account
Question 7 · Medium
A white layer forms on top of an emulsion and disappears on shaking. Which instability is this?
1. ACoalescence
2. BCreaming
3. CPhase inversion
4. DCracking
Answer and explanation in LearnFree account
Question 8 · Medium
The friability test is used to measure the resistance of uncoated tablets to abrasion. What loss is generally acceptable?
1. ANot more than 1%
2. BNot more than 5%
3. CNot more than 0.1%
4. DNot more than 10%
Answer and explanation in LearnFree account
Question 9 · Medium
A care-home resident cannot swallow tablets whole. Which of these tablets can be crushed and mixed with water?
1. ADiltiazem sustained-release 120 mg
2. BDiclofenac enteric-coated 50 mg
3. CFurosemide 40 mg
4. DNifedipine retard 20 mg
Answer and explanation in LearnFree account
Question 10 · Medium
A patient in intensive care has a nasogastric tube and is prescribed a pantoprazole delayed-release tablet. What is the best approach?
1. AUse a tube-suitable form, such as esomeprazole granules or IV pantoprazole
2. BCrush the tablet finely and flush it down the tube with water
3. CDissolve the tablet in sodium bicarbonate solution and give it down the tube
4. DLeave the proton pump inhibitor out until he can swallow
Answer and explanation in LearnFree account
Question 11 · Medium
On the Griffin scale, which HLB range suits emulsifiers used to form oil-in-water emulsions?
1. A3-6
2. B8-18
3. C20-25
4. D1-3
Answer and explanation in LearnFree account
Question 12 · Hard
A prescriber orders 40 mmol of potassium chloride to be added to a 1 L infusion. The pharmacy holds potassium chloride concentrate 15% w/v (relative molecular mass 74.5). What volume of the concentrate is needed?
1. AAbout 10 mL
2. BAbout 30 mL
3. CAbout 20 mL
4. DAbout 40 mL
Answer and explanation in LearnFree account
Question 13 · Medium
A pharmacist prepares heat-labile eye drops by filtration. Which pore size defines a sterilising-grade filter?
1. A0.22 micron
2. B1.2 micron
3. C0.45 micron
4. D5 micron
Answer and explanation in LearnFree account
Question 14 · Hard
A pharmacist must prepare 60 g of a 2.5% w/w hydrocortisone ointment using a 1% ointment and a 5% ointment. How much of the 5% ointment is needed?
1. A37.5 g
2. B15 g
3. C30 g
4. D22.5 g
Answer and explanation in LearnFree account
Question 15 · Medium
By approximately what factor does the rate of a chemical degradation reaction usually increase for each 10 °C rise in temperature?
1. ANo change
2. B2 to 3 times
3. C10 times
4. D1.1 times
Answer and explanation in LearnFree account
Question 16 · Medium
Which method is most appropriate for terminal sterilisation of a heat-stable aqueous injection in its final sealed container?
1. ADry heat at 160 °C for 2 hours
2. BEthylene oxide gas
3. CMoist heat at 121 °C for 15 minutes
4. DFiltration through a 0.22 micron membrane
Answer and explanation in LearnFree account
Question 17 · Easy
A pharmacist places a 'shake well before use' label on an oral suspension. What is its purpose?
1. ATo dissolve all of the drug in the liquid base
2. BTo redisperse settled particles for a uniform dose
3. CTo dissolve the preservative into the liquid base
4. DTo make the product sterile before each dose
Answer and explanation in LearnFree account
Question 18 · Easy
Which type of emulsion is miscible with water and typically used for oral liquid preparations?
1. AWater-in-oil
2. BMultiple oil-in-oil
3. COil-in-water
4. DAnhydrous
Answer and explanation in LearnFree account
Question 19 · Medium
A 6-year-old with asthma cannot coordinate pressing a pressurised metered-dose inhaler and breathing in. What is the best option?
1. AA pMDI used with a spacer
2. BA dry powder inhaler
3. CA pMDI alone with practice
4. DAn oral tablet instead
Answer and explanation in LearnFree account
Question 20 · Easy
Aspirin tablets stored in a humid cabinet smell of vinegar. Which degradation pathway is responsible?
1. AHydrolysis
2. BRacemisation
3. CPhotolysis
4. DOxidation
Answer and explanation in LearnFree account
Question 21 · Medium
During Ramadan a man takes an extended-release preparation once daily. What is the most appropriate timing?
1. ASkip the dose while fasting
2. BTake it at iftar, as it covers the next 24 hours
3. CTake it at suhoor and split it in half
4. DCrush it and take it in the afternoon
Answer and explanation in LearnFree account
Question 22 · Medium
An intravenous ceftriaxone dose is ordered for a neonate who is also receiving a calcium gluconate infusion. What is the main concern?
1. ALoss of calcium potency in the shared line
2. BRapid hydrolysis of the calcium gluconate salt
3. CReduced absorption of ceftriaxone into tissues
4. DPrecipitation of ceftriaxone-calcium, with fatal risk
Answer and explanation in LearnFree account
Question 23 · Medium
Under USP <795> (2023), which preparation has the longest default beyond-use date?
1. AA preserved aqueous oral liquid: 35 days refrigerated
2. BA non-preserved aqueous oral liquid: 14 days refrigerated
3. CA non-aqueous oral liquid: 90 days
4. DA solid non-aqueous capsule: 180 days
Answer and explanation in LearnFree account
Question 24 · Medium
Which procedure best removes pyrogens (endotoxins) from glassware before sterile compounding?
1. AWiping with 70% isopropyl alcohol
2. BFiltration through a 0.22 micron filter
3. CAutoclaving at 121 °C for 15 minutes
4. DDry heat at 250 °C for 30 minutes
Answer and explanation in LearnFree account
Question 25 · Hard
An oral suspension of 50 mg/mL loses 0.5 mg/mL of drug each day, independent of concentration. The expiry is set at 90% of the labelled content. What is the shelf life?
1. A10 days
2. B20 days
3. C5 days
4. D100 days
Answer and explanation in LearnFree account

25 more Dosage forms, compounding and stability questions

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Dosage forms, compounding and stability

Under USP <797>, critical manipulations of sterile preparations should be done in which environment?

Syrup BP (about 66% w/v sucrose) is stable without added preservative. What is the main reason?

A vial of 1 g of antibiotic powder is labelled: add 3.5 mL of water to give a final volume of 4 mL. The prescribed dose is 600 mg. What volume should be drawn up?

Why are glyceryl trinitrate patches usually worn for 12-14 hours and then removed for 10-12 hours?

A man with Parkinson disease has difficulty swallowing and also needs an antiemetic. Which dosage form is most suitable?

A man wearing a fentanyl patch applies a hot water bottle to his back for pain. What is the main danger?

A white layer forms on top of an emulsion and disappears on shaking. Which instability is this?

The friability test is used to measure the resistance of uncoated tablets to abrasion. What loss is generally acceptable?

A care-home resident cannot swallow tablets whole. Which of these tablets can be crushed and mixed with water?

A patient in intensive care has a nasogastric tube and is prescribed a pantoprazole delayed-release tablet. What is the best approach?

On the Griffin scale, which HLB range suits emulsifiers used to form oil-in-water emulsions?

A prescriber orders 40 mmol of potassium chloride to be added to a 1 L infusion. The pharmacy holds potassium chloride concentrate 15% w/v (relative molecular mass 74.5). What volume of the concentrate is needed?

A pharmacist prepares heat-labile eye drops by filtration. Which pore size defines a sterilising-grade filter?

A pharmacist must prepare 60 g of a 2.5% w/w hydrocortisone ointment using a 1% ointment and a 5% ointment. How much of the 5% ointment is needed?

By approximately what factor does the rate of a chemical degradation reaction usually increase for each 10 °C rise in temperature?

Which method is most appropriate for terminal sterilisation of a heat-stable aqueous injection in its final sealed container?

A pharmacist places a 'shake well before use' label on an oral suspension. What is its purpose?

Which type of emulsion is miscible with water and typically used for oral liquid preparations?

A 6-year-old with asthma cannot coordinate pressing a pressurised metered-dose inhaler and breathing in. What is the best option?

Aspirin tablets stored in a humid cabinet smell of vinegar. Which degradation pathway is responsible?

During Ramadan a man takes an extended-release preparation once daily. What is the most appropriate timing?

An intravenous ceftriaxone dose is ordered for a neonate who is also receiving a calcium gluconate infusion. What is the main concern?

Under USP <795> (2023), which preparation has the longest default beyond-use date?

Which procedure best removes pyrogens (endotoxins) from glassware before sterile compounding?

An oral suspension of 50 mg/mL loses 0.5 mg/mL of drug each day, independent of concentration. The expiry is set at 90% of the labelled content. What is the shelf life?