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Pharmaceutical Sciences practice

40 questions · untimed. Pharmaceutics, dosage forms, pharmacokinetics calculations, compounding, stability and biopharmaceutics, mapped to SCFHS blueprint Area 2.0. Use Report a mistake on any question if you spot an error.

Read the free Pharmaceutical Sciences notes for this quiz — pharmacokinetics rules, dosage forms, compounding standards, stability and worked calculations, with a free PDF.

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All questions in Pharmaceutical Sciences practice

  1. A hospital pharmacist reviews a new intravenous medicine for a 70 kg adult inpatient on a medical ward. The medicine follows first-order elimination with an elimination rate constant of 0.10 per hour, and the team asks how long its plasma concentration takes to fall by one half. What is the elimination half-life?

    • 6.9 hours
    • 3.5 hours
    • 13.9 hours
    • 69.3 hours
    Show answer

    6.9 hours. Half-life equals 0.693 divided by the elimination rate constant: 0.693 divided by 0.10 per hour equals about 6.9 hours.

    • 3.5 hours: Incorrect: 3.5 hours would need a rate constant near 0.20 per hour, twice the stated value.
    • 13.9 hours: Incorrect: 13.9 hours doubles the correct result and would need a rate constant near 0.05 per hour.
    • 69.3 hours: Incorrect: 69.3 hours misplaces the decimal point when dividing 0.693 by 0.10.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-001)

  2. A clinical pharmacist is asked to estimate a loading dose for a 60 kg adult admitted to a coronary care unit. The medicine has a volume of distribution of 40 litres, the target plasma concentration is 15 milligrams per litre, and intravenous bioavailability is complete. What loading dose should be calculated?

    • 150 milligrams
    • 300 milligrams
    • 2400 milligrams
    • 600 milligrams
    Show answer

    600 milligrams. Loading dose equals volume of distribution multiplied by target concentration, divided by bioavailability: 40 litres times 15 milligrams per litre equals 600 milligrams.

    • 150 milligrams: Incorrect: 150 milligrams uses only one quarter of the stated volume of distribution.
    • 300 milligrams:
    • 2400 milligrams: Incorrect: 2400 milligrams multiplies by body weight again even though the volume is already given in litres.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-002)

  3. An intensive care pharmacist checks a continuous intravenous infusion order for an adult patient whose medicine clearance is 5 litres per hour. The prescriber wants an average steady-state plasma concentration of 20 milligrams per litre once the infusion has run long enough to plateau. What infusion rate achieves that concentration?

    • 25 milligrams per hour
    • 100 milligrams per hour
    • 50 milligrams per hour
    • 400 milligrams per hour
    Show answer

    100 milligrams per hour. At steady state the infusion rate equals clearance multiplied by the target steady-state concentration: 5 litres per hour times 20 milligrams per litre equals 100 milligrams per hour.

    • 25 milligrams per hour: Incorrect: 25 milligrams per hour would give a steady-state concentration of only 5 milligrams per litre.
    • 50 milligrams per hour:
    • 400 milligrams per hour: Incorrect: 400 milligrams per hour would give a steady-state concentration of 80 milligrams per litre.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-003)

  4. A pharmacokinetics trainee studies a single 1000 milligram intravenous bolus dose given to a healthy adult volunteer in a hospital research unit. The measured area under the plasma concentration time curve is 125 milligram hours per litre, and the trainee must report total body clearance. What value is correct?

    • 4 litres per hour
    • 8 litres per hour
    • 16 litres per hour
    • 125 litres per hour
    Show answer

    8 litres per hour. After an intravenous dose, clearance equals dose divided by area under the curve: 1000 milligrams divided by 125 milligram hours per litre equals 8 litres per hour.

    • 4 litres per hour: Incorrect: 4 litres per hour would need an area under the curve of 250 milligram hours per litre.
    • 16 litres per hour: Incorrect: 16 litres per hour would need an area under the curve of 62.5 milligram hours per litre.
    • 125 litres per hour: Incorrect: 125 is the area under the curve itself, not a clearance value.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-004)

  5. In a crossover study unit, a pharmacist compares equal 500 milligram doses given to the same fasting adult volunteers. The intravenous area under the curve is 100 milligram hours per litre and the oral area under the curve is 40 milligram hours per litre, using identical assay methods. What is the absolute oral bioavailability?

    • 0.20 as a fraction
    • 0.40 as a fraction
    • 0.60 as a fraction
    • 2.50 as a fraction
    Show answer

    0.40 as a fraction. Absolute bioavailability equals the oral area under the curve divided by the intravenous area under the curve when doses are equal: 40 divided by 100 equals 0.40.

    • 0.20 as a fraction: Incorrect: 0.20 halves the correct ratio without any dose adjustment to justify it.
    • 0.60 as a fraction: Incorrect: 0.60 subtracts the ratio from one, which gives the fraction lost rather than the fraction reaching the circulation.
    • 2.50 as a fraction: Incorrect: 2.50 inverts the ratio, dividing the intravenous area by the oral area.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-005)

  6. A ward pharmacist estimates distribution for a 55 kg adult who received a 500 milligram intravenous bolus on a surgical ward. Extrapolated plasma concentration at time zero is 10 milligrams per litre, before elimination has lowered the measured level to any meaningful extent. What is the apparent volume of distribution?

    • 5 litres in total
    • 50 litres in total
    • 500 litres in total
    • 5000 litres in total
    Show answer

    50 litres in total. Volume of distribution equals amount in the body divided by plasma concentration: 500 milligrams divided by 10 milligrams per litre equals 50 litres.

    • 5 litres in total: Incorrect: 5 litres misplaces the decimal point in the division.
    • 500 litres in total: Incorrect: 500 litres multiplies dose by concentration instead of dividing by it.
    • 5000 litres in total: Incorrect: 5000 litres combines both errors and is far beyond any plausible distribution volume here.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-006)

  7. A medicines information pharmacist advises a ward team starting a regular oral medicine for a stable adult outpatient. The medicine has an elimination half-life of 8 hours, first-order kinetics, and no loading dose is planned for this particular prescription. Roughly how long until plasma concentrations reach steady state?

    • About 8 hours of dosing
    • About 16 hours of dosing
    • About 80 hours of dosing
    • About 40 hours of dosing
    Show answer

    About 40 hours of dosing. With first-order kinetics, steady state is approached after about four to five half-lives: five times 8 hours is about 40 hours.

    • About 8 hours of dosing: Incorrect: one half-life reaches only about half of the eventual steady-state level.
    • About 16 hours of dosing:
    • About 80 hours of dosing: Incorrect: 80 hours is ten half-lives, well past the point where the level has effectively plateaued.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-007)

  8. A pharmacy student follows a single intravenous dose in a teaching hospital simulation using a medicine eliminated by first-order kinetics. The starting plasma concentration is measured immediately after distribution is complete, and no further doses are given during the observation period. What fraction remains after three half-lives?

    • One half of the start level
    • One third of the start level
    • One eighth of the start level
    • One ninth of the start level
    Show answer

    One eighth of the start level. Each half-life halves the amount: after three half-lives one half cubed remains, which is one eighth of the starting level.

    • One half of the start level: Incorrect: one half remains after a single half-life, not after three.
    • One third of the start level:
    • One ninth of the start level: Incorrect: one ninth comes from dividing by three twice, but first-order decay halves rather than thirds.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-008)

  9. A hospital pharmacist reviews phenytoin for a 68-year-old inpatient whose dose was recently increased by a small amount on the neurology ward. The measured concentration then rose far more than the dose increase, surprising the junior doctor who expected a proportional change in level. What pharmacokinetic property best explains this pattern?

    • Saturable metabolism near capacity
    • Zero-order input from the gut wall
    • Renal tubular secretion saturation
    • Plasma protein binding saturation
    Show answer

    Saturable metabolism near capacity. Phenytoin shows capacity-limited Michaelis-Menten metabolism: near the maximum rate, small dose increases cause disproportionately large concentration rises.

    • Zero-order input from the gut wall: Incorrect: the pattern follows saturable elimination, not a change in the rate of drug input.
    • Renal tubular secretion saturation: Incorrect: phenytoin is cleared mainly by hepatic metabolism, not by saturable renal secretion.
    • Plasma protein binding saturation: Incorrect: binding changes alter the free fraction, but the disproportionate rise after a small dose increase is the classic sign of saturable metabolism.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-009)

  10. A renal ward pharmacist reviews a medicine that is eliminated almost entirely unchanged by the kidneys for a 74-year-old patient. Recent results show creatinine clearance has fallen from 90 to 30 millilitres per minute, while liver function tests and albumin remain within their usual ranges. What maintenance adjustment best fits this change?

    • Increase the dose size steadily
    • Reduce dose or extend the interval
    • Shorten the dosing interval steadily
    • Leave every dose fully unchanged
    Show answer

    Reduce dose or extend the interval. For a renally cleared medicine, falling creatinine clearance lowers clearance, so the maintenance dose is reduced or the interval extended to avoid accumulation.

    • Increase the dose size steadily: Incorrect: increasing the dose would raise exposure further as renal clearance falls.
    • Shorten the dosing interval steadily: Incorrect: shortening the interval adds doses while each dose is cleared more slowly.
    • Leave every dose fully unchanged: Incorrect: unchanged dosing lets the medicine accumulate toward toxicity at one third of the former clearance.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-010)

  11. A pharmacist interpreting drug levels for a malnourished 80-year-old inpatient notes a low serum albumin result beside a total phenytoin concentration that looks low. The patient takes a highly protein bound medicine, and the clinical team asks why the total level may mislead them. What is the best explanation?

    • Albumin destroys the free drug
    • Total level rises as binding falls
    • Bound drug becomes active drug
    • Free fraction rises as binding falls
    Show answer

    Free fraction rises as binding falls. With low albumin, less drug is bound, so the free active fraction rises; a low total level can still give a therapeutic or toxic free level.

    • Albumin destroys the free drug: Incorrect: albumin binds drug reversibly and does not destroy the free fraction.
    • Total level rises as binding falls: Incorrect: reduced binding lowers the total concentration measured, it does not raise it.
    • Bound drug becomes active drug: Incorrect: protein bound drug is pharmacologically inactive until it dissociates; binding does not activate it.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-011)

  12. A critical care pharmacist discusses a medicine with a very high hepatic extraction ratio for a patient whose liver blood flow has fallen after major surgery. The medicine is given intravenously, intrinsic metabolic capacity is preserved, and the team asks what mainly limits its clearance now. What is the best answer?

    • Hepatic blood flow rate
    • Plasma albumin level
    • Renal tubular flow rate
    • Gastric emptying rate
    Show answer

    Hepatic blood flow rate. For high extraction medicines, hepatic clearance approaches liver blood flow, so clearance is flow-limited and falls when hepatic blood flow falls.

    • Plasma albumin level: Incorrect: albumin binding matters most for low extraction, capacity-limited medicines rather than flow-limited ones.
    • Renal tubular flow rate: Incorrect: renal tubular flow governs renally secreted medicines, not intravenous hepatic clearance here.
    • Gastric emptying rate: Incorrect: gastric emptying affects oral absorption rate, not clearance of an intravenous dose.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-012)

  13. A generic manufacturer presents bioequivalence results to a hospital formulary pharmacist comparing a test tablet with the reference product in fasting volunteers. Both products contain the same active ingredient, strength, and dosage form, and the study used a standard crossover design. What acceptance range applies to the key exposure measures?

    • 70.00 to 143.00 percent range
    • 90.00 to 111.00 percent range
    • 80.00 to 125.00 percent range
    • 95.00 to 105.00 percent range
    Show answer

    80.00 to 125.00 percent range. Bioequivalence is accepted when the 90 percent confidence interval for the geometric mean ratio of area under the curve and peak concentration lies within 80.00 to 125.00 percent.

    • 70.00 to 143.00 percent range: Incorrect: 70.00 to 143.00 percent is too wide and is not the standard acceptance interval.
    • 90.00 to 111.00 percent range: Incorrect: 90.00 to 111.00 percent is narrower than the accepted regulatory interval.
    • 95.00 to 105.00 percent range: Incorrect: 95.00 to 105.00 percent resembles a content uniformity style limit, not a bioequivalence interval.

    Source: FDA, Guidance for Industry: Bioavailability and Bioequivalence Studies for Orally Administered Drug Products — General Considerations, 2003 · Read the note for this topic · Report a mistake (sple-ps-013)

  14. A formulation scientist briefs a pharmacy student about a poorly water soluble medicine that crosses intestinal membranes very readily once dissolved. The drug is classified using the Biopharmaceutics Classification System during a hospital journal club about oral absorption problems. Which step most often limits its absorption rate?

    • Diffusion across the membrane
    • Dissolution in gut fluids
    • Blood flow to the liver
    • Excretion into the bile
    Show answer

    Dissolution in gut fluids. A low solubility, high permeability Class II drug dissolves slowly, so dissolution in gastrointestinal fluids is usually the rate-limiting step for absorption.

    • Diffusion across the membrane: Incorrect: a high permeability drug crosses the membrane readily once it is in solution.
    • Blood flow to the liver: Incorrect: hepatic blood flow affects first-pass clearance after absorption, not the absorption rate itself.
    • Excretion into the bile: Incorrect: biliary excretion removes drug after absorption and does not limit entry from the gut.

    Source: FDA, Guidance for Industry: Waiver of In Vivo Bioavailability and Bioequivalence Studies for Immediate-Release Solid Oral Dosage Forms Based on a Biopharmaceutics Classification System, 2017 · Read the note for this topic · Report a mistake (sple-ps-014)

  15. A pharmaceutics lecturer shows a trainee two batches of the same poorly soluble tablet medicine in a university skills laboratory. One batch was milled to a much smaller particle size before compression, while every other ingredient and process step stayed exactly the same. What effect should the smaller particles have?

    • Slower dissolution from less surface
    • Faster excretion from less surface
    • Slower absorption from more surface
    • Faster dissolution from more surface
    Show answer

    Faster dissolution from more surface. Reducing particle size increases surface area exposed to fluid, and by the Noyes-Whitney relationship the dissolution rate increases.

    • Slower dissolution from less surface: Incorrect: smaller particles expose more surface area, not less, so dissolution speeds up.
    • Faster excretion from less surface: Incorrect: particle size in the tablet does not change the excretion rate of absorbed drug.
    • Slower absorption from more surface: Incorrect: faster dissolution of a poorly soluble drug supports faster, not slower, absorption.

    Source: Aulton and Taylor, Aulton's Pharmaceutics: The Design and Manufacture of Medicines, 5th edition, Elsevier — dosage form design and stability chapters, 2018 · Read the note for this topic · Report a mistake (sple-ps-015)

  16. A clinical pharmacist explains oral absorption to a student using a weak acid medicine with a pKa of 3.5 taken on an empty stomach. Gastric fluid is strongly acidic, and the student asks in which form the weak acid mainly exists in that gastric fluid. What is the best answer?

    • Mainly ionised and charged
    • Mainly unionised and uncharged
    • Mainly bound to plasma albumin
    • Mainly converted to its salt
    Show answer

    Mainly unionised and uncharged. A weak acid in fluid well below its pKa exists mainly in its unionised, uncharged form, which is the form that crosses lipid membranes most readily.

    • Mainly ionised and charged: Incorrect: a weak acid ionises when the surrounding pH rises above its pKa, not in strong acid.
    • Mainly bound to plasma albumin: Incorrect: plasma albumin binding happens after absorption into blood, not in gastric fluid.
    • Mainly converted to its salt: Incorrect: salt formation is a formulation step; acidic gastric fluid favours the free acid form.

    Source: Aulton and Taylor, Aulton's Pharmaceutics: The Design and Manufacture of Medicines, 5th edition, Elsevier — dosage form design and stability chapters, 2018 · Read the note for this topic · Report a mistake (sple-ps-016)

  17. A quality pharmacist investigates why two crystalline batches of the same medicine dissolve at different rates in the laboratory. Chemical assay results are identical, melting behaviour differs slightly, and no degradation products are found in either batch at release testing. What solid-state property best explains the difference?

    • Different printed label artwork
    • Different tablet colour pigments
    • Different crystal polymorph forms
    • Different capsule shell sizes
    Show answer

    Different crystal polymorph forms. Polymorphs are different crystal forms of the same molecule; they can differ in solubility and dissolution rate despite identical chemical composition.

    • Different printed label artwork: Incorrect: label artwork has no effect on how a tablet dissolves in the laboratory.
    • Different tablet colour pigments: Incorrect: pigment choice changes appearance and would not explain a dissolution difference of this kind.
    • Different capsule shell sizes: Incorrect: capsule shell size is unrelated to a crystalline tablet batch comparison.

    Source: Aulton and Taylor, Aulton's Pharmaceutics: The Design and Manufacture of Medicines, 5th edition, Elsevier — dosage form design and stability chapters, 2018 · Read the note for this topic · Report a mistake (sple-ps-017)

  18. A medicines information pharmacist counsels a patient who noticed that taking a particular oral medicine with a large high-fat meal delayed the time of its strongest effect. Blood levels eventually reached a similar extent of absorption in the fed and fasting study arms. What has the meal mainly changed?

    • Increased renal clearance rate
    • Increased hepatic enzyme amount
    • Reduced tablet assay content
    • Delayed gastric emptying rate
    Show answer

    Delayed gastric emptying rate. A high-fat meal slows gastric emptying, delaying delivery to the small intestine and so delaying the time to peak concentration without necessarily changing total exposure.

    • Increased renal clearance rate: Incorrect: renal clearance acts after absorption and would change total exposure rather than mainly delaying the peak.
    • Increased hepatic enzyme amount: Incorrect: a single meal does not increase the amount of hepatic enzyme available for metabolism.
    • Reduced tablet assay content: Incorrect: food taken with a dose cannot change the assayed content of the tablet itself.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-018)

  19. A hospital pharmacist compares routes for a medicine that is extensively metabolised in the gut wall and liver before reaching the systemic circulation. A sublingual formulation is proposed for a patient who cannot swallow tablets after oral surgery on the ward. Why can the sublingual route give higher availability?

    • It slows venous drainage away
    • It increases first-pass metabolism
    • It partly bypasses first-pass loss
    • It converts drug to metabolite
    Show answer

    It partly bypasses first-pass loss. Sublingual veins drain into the systemic circulation, so part of the dose avoids gut wall and hepatic first-pass metabolism and availability rises.

    • It slows venous drainage away: Incorrect: the advantage comes from where the veins drain, not from slowing drainage away from the site.
    • It increases first-pass metabolism: Incorrect: increasing first-pass metabolism would lower, not raise, the fraction reaching the circulation.
    • It converts drug to metabolite: Incorrect: conversion to metabolite before reaching the circulation is exactly the loss this route avoids.

    Source: Shargel, Wu-Pong and Yu, Applied Biopharmaceutics and Pharmacokinetics, 7th edition, McGraw-Hill — pharmacokinetics chapters, 2016 · Read the note for this topic · Report a mistake (sple-ps-019)

  20. A formulation pharmacist tries to improve an oral solution for a weak base medicine that dissolves poorly in intestinal fluid. Changing the medicine to a suitable salt form is proposed during development work in the pharmaceutics laboratory, before any animal or human testing begins. What is the main reason for choosing a salt form?

    • To increase the tablet film coat
    • To remove the need for labelling
    • To improve dissolution and solubility
    • To change the pharmacological target
    Show answer

    To improve dissolution and solubility. Salt selection is a standard way to improve the solubility and dissolution rate of an ionisable drug without changing the active molecule itself.

    • To increase the tablet film coat: Incorrect: a film coat is a separate dosage form feature and is not the purpose of salt selection.
    • To remove the need for labelling: Incorrect: every medicine still needs full labelling whatever salt form is chosen.
    • To change the pharmacological target: Incorrect: the salt dissociates to the same active species, so the pharmacological target is unchanged.

    Source: Aulton and Taylor, Aulton's Pharmaceutics: The Design and Manufacture of Medicines, 5th edition, Elsevier — dosage form design and stability chapters, 2018 · Read the note for this topic · Report a mistake (sple-ps-020)

  21. A ward nurse asks a pharmacist whether a once-daily extended-release tablet can be crushed and mixed with food for an inpatient who struggles to swallow whole tablets. The tablet uses a controlled-release matrix designed to release its medicine slowly over the full dosing interval. What is the safest advice?

    • Crush it finely before food
    • Swallow it whole as directed
    • Split it and crush each half
    • Dissolve it in hot water first
    Show answer

    Swallow it whole as directed. Crushing an extended-release matrix destroys the controlled-release mechanism and can release the whole dose at once, so the tablet is swallowed whole as directed.

    • Crush it finely before food: Incorrect: fine crushing destroys the release matrix and risks dose dumping.
    • Split it and crush each half: Incorrect: splitting and crushing a matrix tablet still destroys its controlled release.
    • Dissolve it in hot water first: Incorrect: hot water would extract the dose rapidly and defeat the extended-release design.

    Source: DailyMed — METOPROLOL SUCCINATE TABLET, FILM COATED, EXTENDED RELEASE label, 2.4 Administration · Read the note for this topic · Report a mistake (sple-ps-021)

  22. A pharmacy student asks why a medicine that is destroyed by stomach acid is supplied as a gastro-resistant tablet for adult outpatients. The tablet passes through the stomach intact during normal use and only breaks apart later in the journey through the gut. Where is the medicine designed to be released?

    • In the stomach acid itself
    • In the mouth during chewing
    • In the oesophagus lining
    • In the small intestine lumen
    Show answer

    In the small intestine lumen. An enteric or gastro-resistant coat resists acidic gastric fluid and dissolves at the higher pH of the small intestine, releasing the drug there.

    • In the stomach acid itself: Incorrect: release in stomach acid would destroy this acid-labile medicine, which is what the coat prevents.
    • In the mouth during chewing: Incorrect: release in the mouth would expose the drug to swallowing and gastric acid afterwards.
    • In the oesophagus lining: Incorrect: the coat is designed to stay intact through the oesophagus and stomach.

    Source: Aulton and Taylor, Aulton's Pharmaceutics: The Design and Manufacture of Medicines, 5th edition, Elsevier — dosage form design and stability chapters, 2018 · Read the note for this topic · Report a mistake (sple-ps-022)

  23. A dispensary pharmacist compares two oral suspensions of the same medicine during a quality review meeting. One forms loose flocs that redisperse easily on shaking, while the other forms a hard compact cake that resists shaking after storage. Which system is preferred for a resuspendable product?

    • Flocculated with loose sediment
    • Deflocculated with hard caking
    • Deflocculated with clear layer
    • Flocculated with dry powder
    Show answer

    Flocculated with loose sediment. A flocculated suspension settles as loose aggregates that redisperse readily on shaking, giving uniform doses; a deflocculated system can form a hard, non-redispersible cake.

    • Deflocculated with hard caking: Incorrect: deflocculated particles pack into a hard cake that is difficult to redisperse evenly.
    • Deflocculated with clear layer: Incorrect: a clear supernatant layer signals settling problems rather than a preferred resuspendable system.
    • Flocculated with dry powder: Incorrect: a dry powder describes the product before reconstitution, not a stored suspension system.

    Source: Aulton and Taylor, Aulton's Pharmaceutics: The Design and Manufacture of Medicines, 5th edition, Elsevier — dosage form design and stability chapters, 2018 · Read the note for this topic · Report a mistake (sple-ps-023)

  24. An outpatient pharmacist inspects a returned oral emulsion that has developed a concentrated cream layer at the top after standing. The layer disappears completely when the bottle is shaken gently, and no free oil droplets or merged globules can be seen afterwards. How should this change be described?

    • Irreversible cracking of emulsion
    • Complete coalescence of droplets
    • Reversible creaming of emulsion
    • Chemical hydrolysis of the oil
    Show answer

    Reversible creaming of emulsion. Creaming is a reversible separation where droplets rise or settle but keep their identity, so gentle shaking restores a uniform emulsion; cracking with coalescence is irreversible.

    • Irreversible cracking of emulsion: Incorrect: cracking means droplets have merged and the emulsion cannot be restored by shaking.
    • Complete coalescence of droplets: Incorrect: coalesced droplets merge into larger globules and do not redisperse on gentle shaking.
    • Chemical hydrolysis of the oil: Incorrect: hydrolysis is a chemical degradation of the oil, not a physical layer that vanishes on shaking.

    Source: Aulton and Taylor, Aulton's Pharmaceutics: The Design and Manufacture of Medicines, 5th edition, Elsevier — dosage form design and stability chapters, 2018 · Read the note for this topic · Report a mistake (sple-ps-024)

  25. A compounding pharmacist explains suppository bases to a trainee preparing a small batch in the dispensary. One base softens and liquefies at body temperature, releasing its medicine in the rectum without needing any water to dissolve the base itself. Which behaviour describes that base?

    • It swells with absorbed water
    • It dissolves in rectal fluid
    • It effervesces in rectal fluid
    • It melts at body temperature
    Show answer

    It melts at body temperature. Fatty bases such as cocoa butter are designed to melt at body temperature, releasing the incorporated drug into the rectal cavity.

    • It swells with absorbed water: Incorrect: swelling gels form a hydrated matrix, a different release mechanism from a melting fatty base.
    • It dissolves in rectal fluid: Incorrect: water-soluble polyethylene glycol bases dissolve in rectal fluid rather than melting.
    • It effervesces in rectal fluid: Incorrect: effervescence needs an acid and carbonate pair generating gas, which is not how this base releases drug.

    Source: Aulton and Taylor, Aulton's Pharmaceutics: The Design and Manufacture of Medicines, 5th edition, Elsevier — dosage form design and stability chapters, 2018 · Read the note for this topic · Report a mistake (sple-ps-025)

  26. A community pharmacist counsels a patient starting a medicated skin patch that delivers medicine continuously for several days. The patient plans a beach holiday, uses a sauna weekly, and has areas of broken eczema on both arms and shoulders. Which counselling point is most important?

    • Apply it over broken skin areas
    • Rotate sites on intact skin
    • Press a hot towel over it daily
    • Cut it to fit smaller skin areas
    Show answer

    Rotate sites on intact skin. Patches are applied to intact skin with site rotation to limit irritation; broken skin and external heat can increase absorption unpredictably.

    • Apply it over broken skin areas: Incorrect: broken skin loses its barrier function and can allow excessive, unpredictable absorption.
    • Press a hot towel over it daily: Incorrect: heat increases skin blood flow and drug release, raising the risk of excessive absorption.
    • Cut it to fit smaller skin areas: Incorrect: cutting a patch can damage its rate-controlling structure and should not be advised unless the product is designed for it.

    Source: Aulton and Taylor, Aulton's Pharmaceutics: The Design and Manufacture of Medicines, 5th edition, Elsevier — dosage form design and stability chapters, 2018 · Read the note for this topic · Report a mistake (sple-ps-026)

  27. A respiratory pharmacist teaches a parent whose young child cannot coordinate pressing a metered-dose inhaler and breathing in at the same time. Much of each dose currently strikes the back of the throat, and the child coughs instead of inhaling the medicine deeply. Which device change best helps this child?

    • Add a valved holding chamber
    • Remove the inhaler mouthpiece
    • Shake the dose into the air
    • Use the inhaler lying flat
    Show answer

    Add a valved holding chamber. A valved holding chamber or spacer holds the aerosol cloud so the child can inhale it over several breaths, reducing throat deposition and coordination demands.

    • Remove the inhaler mouthpiece: Incorrect: removing the mouthpiece makes directing the aerosol into the airway harder, not easier.
    • Shake the dose into the air: Incorrect: firing the dose into the air wastes the medicine before it can be inhaled.
    • Use the inhaler lying flat: Incorrect: body position does not solve the coordination problem that a holding chamber addresses.

    Source: Aulton and Taylor, Aulton's Pharmaceutics: The Design and Manufacture of Medicines, 5th edition, Elsevier — dosage form design and stability chapters, 2018 · Read the note for this topic · Report a mistake (sple-ps-027)

  28. A tablet production pharmacist investigates a batch that loses too much weight as dust and chipped edges during a standard rotating drum test in the quality control laboratory. The tablets meet their assay specification, and the problem is recorded as a mechanical strength failure. Which tablet property has failed?

    • Friability within set limits
    • Dissolution within set limits
    • Content uniformity limits
    • Disintegration time limits
    Show answer

    Friability within set limits. Friability testing measures weight loss from abrasion and chipping in a rotating drum; excessive loss is a mechanical strength failure.

    • Dissolution within set limits: Incorrect: dissolution testing measures drug release into fluid, not weight lost as dust and chips.
    • Content uniformity limits: Incorrect: content uniformity compares drug amount between tablets and the batch already meets assay.
    • Disintegration time limits: Incorrect: disintegration time measures how fast a tablet breaks apart in fluid, not abrasion in a drum.

    Source: Aulton and Taylor, Aulton's Pharmaceutics: The Design and Manufacture of Medicines, 5th edition, Elsevier — dosage form design and stability chapters, 2018 · Read the note for this topic · Report a mistake (sple-ps-028)

  29. A sterile compounding pharmacist supervises a trainee preparing an intravenous admixture inside the hospital cleanroom suite. The critical compounding manipulations must happen where the cleanest air meets the product first, inside the primary engineering control on the work bench. Which air quality class is required there?

    • Unclassified room air quality
    • ISO Class 7 air quality
    • ISO Class 8 air quality
    • ISO Class 5 air quality
    Show answer

    ISO Class 5 air quality. USP <797> requires sterile compounding critical sites to be in an ISO Class 5 primary engineering control, with cleaner air than the surrounding buffer area.

    • Unclassified room air quality: Incorrect: unclassified room air cannot be used for critical sterile manipulations.
    • ISO Class 7 air quality: Incorrect: ISO Class 7 describes the buffer area around the primary control, not the critical site itself.
    • ISO Class 8 air quality: Incorrect: ISO Class 8 describes an ante-area standard, which is dirtier than a critical compounding zone.

    Source: USP <797> Pharmaceutical Compounding — Sterile Preparations, United States Pharmacopeia, revised chapter effective 1 November 2023, 2023 · Read the note for this topic · Report a mistake (sple-ps-029)

  30. A dispensary pharmacist compounds a nonpreserved water-containing oral liquid for a child because no licensed product is available locally. The preparation contains no antimicrobial preservative, is packaged in a tight light-resistant container, and will be stored in the pharmacy refrigerator. What beyond-use date limit applies?

    • 35 days under refrigeration
    • 14 days under refrigeration
    • 90 days at room temperature
    • 180 days at room temperature
    Show answer

    14 days under refrigeration. Under USP <795>, a nonpreserved aqueous compounded preparation is limited to a beyond-use date of 14 days when stored refrigerated.

    • 35 days under refrigeration: Incorrect: 35 days applies to preserved aqueous preparations, and this liquid contains no preservative.
    • 90 days at room temperature: Incorrect: 90 days is the limit for nonaqueous liquids, not a water-containing oral liquid.
    • 180 days at room temperature: Incorrect: 180 days applies to solid dosage forms under the chapter, not aqueous liquids.

    Source: USP <795> Pharmaceutical Compounding — Nonsterile Preparations, United States Pharmacopeia, revised chapter effective 1 November 2023, 2023 · Read the note for this topic · Report a mistake (sple-ps-030)

  31. A hospital pharmacist sets up compounding of a hazardous chemotherapy infusion for an adult oncology patient. Staff protection depends on engineering controls, work practices, and personal protective equipment being used together throughout preparation and cleaning of the work area. Which room condition is required for sterile hazardous compounding?

    • Neutral pressure and open windows
    • Positive pressure and recirculated air
    • Negative pressure and externally vented
    • Positive pressure and unvented air
    Show answer

    Negative pressure and externally vented. USP <800> requires sterile hazardous drug compounding in an externally vented, negative-pressure containment setup so leaks move inward and exhaust is removed safely.

    • Neutral pressure and open windows: Incorrect: open windows give uncontrolled airflow and no containment of hazardous particles.
    • Positive pressure and recirculated air: Incorrect: positive pressure with recirculation would push hazardous contamination toward staff areas.
    • Positive pressure and unvented air: Incorrect: positive unvented pressure combines both faults, spreading and retaining contamination.

    Source: USP <800> Hazardous Drugs — Handling in Healthcare Settings, United States Pharmacopeia, 2020 · Read the note for this topic · Report a mistake (sple-ps-031)

  32. A compounding pharmacist must prepare a cream by mixing a 10 percent strength cream with a 2 percent strength cream already stocked in the dispensary. The prescriber requests an intermediate 6 percent strength cream for a patient with a localised skin condition. In what ratio should the two creams be mixed?

    • Ten parts high to two parts low
    • Six parts high to two parts low
    • Two parts high to six parts low
    • Four parts high to four parts low
    Show answer

    Four parts high to four parts low. By alligation, parts of the high strength equal 6 minus 2, which is 4, and parts of the low strength equal 10 minus 6, which is 4, giving a one to one mix.

    • Ten parts high to two parts low: Incorrect: ten and two simply restate the stock strengths and ignore the target strength.
    • Six parts high to two parts low: Incorrect: six and two are the target and low strengths themselves, not the alligation differences.
    • Two parts high to six parts low: Incorrect: two and six reverse the differences and would give a strength below the target.

    Source: Ansel and Stockton, Pharmaceutical Calculations, 15th edition, Wolters Kluwer — percentage, alligation and flow-rate chapters, 2017 · Read the note for this topic · Report a mistake (sple-ps-032)

  33. A dispensary pharmacist prepares 240 millilitres of a 0.5 percent weight in volume solution for an outpatient clinic procedure. The stock chemical is a pure powder, the balance has been calibrated that morning, and the final volume will be made up accurately in a graduated flask. How much powder is needed?

    • 0.12 grams of powder
    • 12 grams of powder
    • 1.2 grams of powder
    • 120 grams of powder
    Show answer

    1.2 grams of powder. A 0.5 percent weight in volume solution contains 0.5 grams in 100 millilitres, so 240 millilitres needs 0.5 times 2.4, which is 1.2 grams.

    • 0.12 grams of powder: Incorrect: 0.12 grams is one tenth of the required amount and would make a 0.05 percent solution.
    • 12 grams of powder: Incorrect: 12 grams would make a 5 percent solution, ten times too strong.
    • 120 grams of powder: Incorrect: 120 grams would make a 50 percent mixture, far beyond the requested strength.

    Source: Ansel and Stockton, Pharmaceutical Calculations, 15th edition, Wolters Kluwer — percentage, alligation and flow-rate chapters, 2017 · Read the note for this topic · Report a mistake (sple-ps-033)

  34. A ward pharmacist checks an intravenous infusion order written for an adult inpatient recovering after surgery on the general ward. The prescription asks for 1000 millilitres of maintenance fluid to run evenly over 8 hours using an infusion pump programmed in millilitres per hour. What rate should be set?

    • 125 millilitres per hour
    • 62.5 millilitres per hour
    • 250 millilitres per hour
    • 800 millilitres per hour
    Show answer

    125 millilitres per hour. Flow rate equals volume divided by time: 1000 millilitres divided by 8 hours equals 125 millilitres per hour.

    • 62.5 millilitres per hour: Incorrect: 62.5 millilitres per hour would take 16 hours to deliver the prescribed volume.
    • 250 millilitres per hour: Incorrect: 250 millilitres per hour would finish the litre in only 4 hours.
    • 800 millilitres per hour: Incorrect: 800 millilitres per hour confuses the total volume in millilitres with an hourly rate.

    Source: Ansel and Stockton, Pharmaceutical Calculations, 15th edition, Wolters Kluwer — percentage, alligation and flow-rate chapters, 2017 · Read the note for this topic · Report a mistake (sple-ps-034)

  35. A stability scientist models a medicine that degrades by first-order kinetics in a long-term stability study. The measured degradation rate constant is 0.021 per day at the labelled storage temperature, and the team defines shelf life as the time to 90 percent potency remaining. What is that time?

    • 50 days to 90 percent
    • 10 days to 90 percent
    • 21 days to 90 percent
    • 5 days to 90 percent
    Show answer

    5 days to 90 percent. For first-order degradation, the time to 90 percent remaining equals 0.105 divided by the rate constant: 0.105 divided by 0.021 per day equals 5 days.

    • 50 days to 90 percent: Incorrect: 50 days misplaces the decimal point when dividing 0.105 by 0.021.
    • 10 days to 90 percent: Incorrect: 10 days would correspond to a rate constant of about 0.0105 per day, half the stated value.
    • 21 days to 90 percent: Incorrect: 21 days simply restates the rate constant digits and ignores the 0.105 numerator.

    Source: ICH Harmonised Guideline Q1A(R2), Stability Testing of New Drug Substances and Products, 2003 · Read the note for this topic · Report a mistake (sple-ps-035)

  36. A formulation pharmacist reviews stability data for a medicine whose main breakdown route is reaction with water in an aqueous oral liquid. Batches stored in permeable containers that let moisture move freely show faster potency loss than batches in tight sealed containers over the same period. What degradation route is involved?

    • Hydrolysis by water reaction
    • Oxidation by air reaction
    • Photolysis by light energy
    • Racemisation of one isomer
    Show answer

    Hydrolysis by water reaction. Breakdown by reaction with water is hydrolysis; protecting the product from moisture and using suitable containers slows this route.

    • Oxidation by air reaction: Incorrect: oxidation is reaction with oxygen, typically from air, and is controlled by antioxidants or inert atmosphere.
    • Photolysis by light energy: Incorrect: photolysis is breakdown driven by light exposure and is controlled by light-resistant packaging.
    • Racemisation of one isomer: Incorrect: racemisation converts one enantiomer toward its mirror form and is not moisture-driven potency loss.

    Source: Aulton and Taylor, Aulton's Pharmaceutics: The Design and Manufacture of Medicines, 5th edition, Elsevier — dosage form design and stability chapters, 2018 · Read the note for this topic · Report a mistake (sple-ps-036)

  37. A pharmacy technician asks why most solid oral medicines degrade faster during a hot summer in a storeroom without temperature control. Stability studies of the same products at several controlled temperatures all show the same breakdown products forming, only at different speeds over time. What principle explains the faster breakdown?

    • Higher temperature speeds reaction rate
    • Higher temperature stops molecular motion
    • Lower temperature speeds reaction rate
    • Lower temperature removes all moisture
    Show answer

    Higher temperature speeds reaction rate. Reaction rates increase as temperature rises, an Arrhenius relationship, so degradation proceeds faster in a hot storeroom than under controlled cool storage.

    • Higher temperature stops molecular motion: Incorrect: higher temperature increases molecular motion and collision energy; it does not stop motion.
    • Lower temperature speeds reaction rate: Incorrect: lowering temperature slows reaction rates, which is why refrigeration extends many shelf lives.
    • Lower temperature removes all moisture: Incorrect: cooling does not remove all moisture, and condensation can even add moisture to a cold product.

    Source: ICH Harmonised Guideline Q1A(R2), Stability Testing of New Drug Substances and Products, 2003 · Read the note for this topic · Report a mistake (sple-ps-037)

  38. A dispensary pharmacist repackages a light-sensitive medicine into pharmacy stock bottles for a busy outpatient dispensary. The original manufacturer supplied the medicine in amber glass, and stability data show rapid potency loss when solutions of the medicine stand in clear glass under bright light. Which container should be used?

    • Open white plastic tray
    • Clear glass dispensing bottle
    • Amber light-resistant container
    • Transparent measuring cylinder
    Show answer

    Amber light-resistant container. A light-resistant amber container protects a photosensitive medicine from the light-driven degradation shown in its stability data.

    • Open white plastic tray: Incorrect: an open tray adds light, air, and moisture exposure with no protection at all.
    • Clear glass dispensing bottle: Incorrect: clear glass transmits the light that the stability data show degrades this medicine.
    • Transparent measuring cylinder: Incorrect: a measuring cylinder is for measuring volumes, not for storing a light-sensitive medicine.

    Source: ICH Harmonised Guideline Q1A(R2), Stability Testing of New Drug Substances and Products, 2003 · Read the note for this topic · Report a mistake (sple-ps-038)

  39. A patient returns an emulsion cream that was left in a freezing car overnight during winter travel abroad. The pharmacist sees separated free oil and a watery layer that does not recombine on shaking, although the same product was smooth and uniform when it was dispensed last month. What is the best action?

    • Discard the cracked emulsion
    • Warm it and reuse it
    • Shake it and reuse it
    • Dilute it and reuse it
    Show answer

    Discard the cracked emulsion. Freezing can crack an emulsion by coalescence; once droplets have merged and shaking cannot restore uniformity, the product is discarded.

    • Warm it and reuse it: Incorrect: warming does not repair a cracked emulsion and may speed further degradation.
    • Shake it and reuse it: Incorrect: shaking cannot reverse coalescence once droplets have merged into free oil.
    • Dilute it and reuse it: Incorrect: diluting changes the strength and still leaves a non-uniform, unreliable product.

    Source: Aulton and Taylor, Aulton's Pharmaceutics: The Design and Manufacture of Medicines, 5th edition, Elsevier — dosage form design and stability chapters, 2018 · Read the note for this topic · Report a mistake (sple-ps-039)

  40. A community pharmacist explains dating to a trainee after repackaging tablets and compounding a short course of capsules for a patient. The trainee confuses the date printed by the manufacturer with the date the pharmacy assigns after opening, repackaging, or compounding a preparation. Which statement is correct?

    • Beyond-use date equals licence date
    • Manufacturer expiry follows compounding
    • Beyond-use date follows compounding
    • Manufacturer expiry equals assay date
    Show answer

    Beyond-use date follows compounding. The beyond-use date is assigned by the pharmacy for a compounded or repackaged preparation, based on the compounding chapters and stability evidence; it is distinct from the manufacturer expiry date.

    • Beyond-use date equals licence date: Incorrect: a licence or authorisation date is a regulatory milestone, not a pharmacy-assigned use date.
    • Manufacturer expiry follows compounding: Incorrect: the manufacturer expiry date is set by the manufacturer for the unopened marketed product.
    • Manufacturer expiry equals assay date: Incorrect: an assay date records when testing happened and does not define how long a product may be used.

    Source: USP <795> Pharmaceutical Compounding — Nonsterile Preparations, United States Pharmacopeia, revised chapter effective 1 November 2023, 2023 · Read the note for this topic · Report a mistake (sple-ps-040)