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Albania Pharmacist State Exam (Provimi i Shtetit - Farmaci) study materials
Albania Pharmacist State Exam (Provimi i Shtetit - Farmaci) study resources

Albania Pharmacist State Exam (Provimi i Shtetit - Farmaci) practice questions

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Question 1Pharmaceutical Chemistry and Medicinal Chemistry

Which functional group is characteristic of a carboxylic acid?

  1. -COO-R
  2. -CHO
  3. -COOH Correct answer.
  4. -OH attached to an aromatic ring

Explanation

A carboxylic acid contains the carboxyl group -COOH, in which a carbonyl carbon bears a hydroxyl group. This combination gives the acidic proton and the characteristic reactions of the class.

Question 2Pharmaceutical Chemistry and Medicinal Chemistry

A drug is a weak base with pKa 8.4. In plasma at pH 7.4, which statement about its ionization is correct?

  1. It is exactly 50% ionized at this pH
  2. It is mostly unionized, since pH is below its pKa Correct answer.
  3. It is fully protonated and uncharged
  4. It is mostly ionized, since pH is below its pKa

Explanation

For a weak base the protonated (ionized) form is favored when pH is below the pKa, but the fraction ionized depends on the difference between pKa and pH. A full pKa unit below the pKa gives roughly 90% ionization in the direction of the acid form, so the drug is predominantly ionized, meaning the unionized claim must be checked carefully.

Question 3Pharmaceutical Chemistry and Medicinal Chemistry

Which statement best describes the role of a prodrug in medicinal chemistry?

  1. It is a competitive antagonist with no intrinsic activity
  2. It is an excipient that improves tablet compression
  3. It is an inactive metabolite excreted unchanged
  4. It is a chemically modified form that releases the active drug after biotransformation Correct answer.

Explanation

A prodrug is a pharmacologically inactive derivative designed to improve delivery, absorption, or stability and is converted in the body to the active species. The conversion is usually enzymatic or chemical.

Question 4Pharmaceutical Chemistry and Medicinal Chemistry

Which physicochemical property most directly predicts that a small molecule will cross the blood-brain barrier by passive diffusion?

  1. High aqueous solubility at pH 7.4
  2. High lipophilicity with low polar surface area Correct answer.
  3. Presence of several ionizable carboxyl groups
  4. High molecular weight above 800 Da

Explanation

Passive brain entry favors moderately lipophilic, low-molecular-weight molecules with limited hydrogen-bonding capacity and low polar surface area. These features reduce the desolvation penalty for crossing lipid membranes.

Question 5Pharmaceutical Chemistry and Medicinal Chemistry

Which hybridization is present at the carbon atom of a methyl group (-CH3)?

  1. sp3d
  2. sp2
  3. sp
  4. sp3 Correct answer.

Explanation

A methyl carbon forms four single sigma bonds and therefore has tetrahedral geometry with sp3 hybridization. The four electron domains maximize separation at about 109.5 degrees.

Question 6Pharmaceutical Chemistry and Medicinal Chemistry

Which analytical technique is most appropriate for confirming the molecular ion mass of a new synthetic drug candidate?

  1. Infrared spectroscopy
  2. UV-visible spectroscopy
  3. Mass spectrometry Correct answer.
  4. Polarimetry

Explanation

Mass spectrometry provides the molecular ion and fragmentation pattern, giving molecular mass and structural information. It is the standard method for confirming molecular weight.

Question 7Pharmaceutical Chemistry and Medicinal Chemistry

A racemic mixture of a chiral drug is administered. Which statement is correct?

  1. The enantiomers may differ in potency and pharmacokinetics Correct answer.
  2. The mixture has no pharmacological effect
  3. Both enantiomers have identical pharmacological activity
  4. The enantiomers rotate plane-polarized light equally in the same direction

Explanation

Enantiomers have identical physical properties in achiral environments but can differ markedly in binding to chiral receptors, enzymes, and transporters. Consequently, potency, metabolism, and adverse effects may differ between the two forms.

Question 8Pharmaceutical Chemistry and Medicinal Chemistry

Which reaction type is most characteristic of the aromatic ring in benzene?

  1. Electrophilic aromatic substitution Correct answer.
  2. Radical addition
  3. Nucleophilic substitution
  4. Electrophilic addition

Explanation

The aromatic ring is electron-rich and stabilized by delocalization, so it undergoes substitution rather than addition, preserving aromaticity. Electrophilic aromatic substitution is the classic pathway.

Question 9Pharmaceutical Chemistry and Medicinal Chemistry

Which structural feature makes a molecule a good hydrogen-bond acceptor?

  1. A carbon-hydrogen bond
  2. A nonpolar alkyl chain
  3. A carbonyl oxygen with lone pairs Correct answer.
  4. A quaternary ammonium nitrogen

Explanation

Hydrogen-bond acceptors require an electronegative atom with lone pairs, such as carbonyl oxygen or basic nitrogen. These lone pairs interact with hydrogen-bond donors.

Question 10Pharmaceutical Chemistry and Medicinal Chemistry

A carboxylic acid drug (pKa about 4.5) is placed in the acidic environment of the stomach (pH about 1.5). Which statement is correct?

  1. It is predominantly ionized and poorly absorbed
  2. It is completely ionized and trapped in the stomach
  3. It cannot dissolve in gastric fluid
  4. It is predominantly unionized and can be absorbed Correct answer.

Explanation

When the environmental pH is well below the pKa of a weak acid, the protonated, uncharged form predominates. The unionized species is more lipophilic and can diffuse across gastric membranes.

Question 11Pharmaceutical Chemistry and Medicinal Chemistry

Which drug-metabolizing reaction is an example of phase II conjugation?

  1. N-dealkylation
  2. Aromatic hydroxylation
  3. Oxidative deamination
  4. Glucuronidation Correct answer.

Explanation

Phase II reactions conjugate the drug or its metabolite with an endogenous molecule such as glucuronic acid, sulfate, or glutathione, increasing water solubility. Glucuronidation is the most common example.

Question 12Pharmaceutical Chemistry and Medicinal Chemistry

Which feature of the sulfonamide group explains its antibacterial action?

  1. It binds the 30S ribosomal subunit
  2. It is a structural analog of p-aminobenzoic acid Correct answer.
  3. It inhibits bacterial cell wall transpeptidase
  4. It blocks DNA gyrase

Explanation

Sulfonamides are isosteric analogs of p-aminobenzoic acid and competitively inhibit dihydropteroate synthase in folate synthesis. This deprives bacteria of folate needed for nucleotide synthesis.

Question 13Pharmaceutical Chemistry and Medicinal Chemistry

Which property is typical of beta-lactam antibiotics that accounts for their selective toxicity?

  1. They bind human ribosomal RNA
  2. They alkylate human DNA
  3. They inhibit human cholesterol synthesis
  4. They acylate bacterial transpeptidases Correct answer.

Explanation

Beta-lactams act as acylating agents on bacterial penicillin-binding proteins, the transpeptidases that cross-link peptidoglycan. Human cells lack this cell wall target, giving selective toxicity.

Question 14Pharmaceutical Chemistry and Medicinal Chemistry

Which structural modification of a lead compound is most likely to increase its aqueous solubility?

  1. Adding a lipophilic trifluoromethyl group
  2. Adding a basic amine that can be protonated Correct answer.
  3. Replacing a hydroxyl with a methyl group
  4. Adding a long alkyl chain

Explanation

Introducing an ionizable basic amine allows protonation at physiological pH, producing a charged species with improved aqueous solubility. The salt form of such an amine is often used in formulations.

Question 15Pharmaceutical Chemistry and Medicinal Chemistry

Which statement about a chiral center is correct?

  1. It must be part of an aromatic ring
  2. It must contain a double bond
  3. It must be a carbon bearing four different substituents Correct answer.
  4. It must be a carbon bearing two identical groups

Explanation

A chiral center (stereocenter) is typically an sp3 carbon bonded to four different groups, giving non-superimposable mirror images. Identical substituents create a plane of symmetry and eliminate chirality.

Question 16Pharmaceutical Chemistry and Medicinal Chemistry

A compound has a partition coefficient (log P) of 5.2. Which consequence is most likely?

  1. Poor membrane permeability due to excessive polarity
  2. Complete inability to bind plasma proteins
  3. Very rapid renal excretion of the unchanged drug
  4. Extensive tissue distribution and possible accumulation in fat Correct answer.

Explanation

A high log P indicates strong lipophilicity, favoring distribution into fat and other lipid-rich tissues. Such compounds often show prolonged half-lives and accumulation.

Question 17Pharmaceutical Chemistry and Medicinal Chemistry

Which analytical method is used to determine the concentration of a drug in a formulated tablet by measuring absorbance at a specific wavelength?

  1. Nuclear magnetic resonance
  2. X-ray diffraction
  3. UV-visible spectrophotometry Correct answer.
  4. Flame photometry

Explanation

UV-visible spectrophotometry measures absorbance of light by a chromophore, and Beer-Lambert law relates absorbance to concentration. It is widely used for quantitative assay of formulations.

Question 18Pharmaceutical Chemistry and Medicinal Chemistry

Which nitrogen-containing functional group is most basic in aqueous solution?

  1. A pyrrole nitrogen
  2. An amide nitrogen
  3. A primary aliphatic amine nitrogen Correct answer.
  4. An aromatic amine nitrogen

Explanation

A primary aliphatic amine has a localized lone pair that readily accepts a proton, making it strongly basic. Delocalization or aromaticity stabilizes the lone pair in the other groups and reduces basicity.

Question 19Pharmaceutical Chemistry and Medicinal Chemistry

Which type of isomerism describes two compounds with the same molecular formula but different connectivity of atoms?

  1. Diastereomerism
  2. Constitutional isomerism Correct answer.
  3. Enantiomerism
  4. Conformational isomerism

Explanation

Constitutional (structural) isomers differ in the order in which atoms are connected. Stereoisomers, by contrast, share connectivity and differ only in spatial arrangement.

Question 20Pharmaceutical Chemistry and Medicinal Chemistry

A new drug shows a short plasma half-life because it undergoes extensive first-pass hepatic oxidation. Which strategy could prolong its action?

  1. Administering it with a strong enzyme inducer
  2. Adding an ester group that is rapidly hydrolyzed
  3. Blocking the site of metabolic oxidation with a fluorine atom Correct answer.
  4. Increasing its lipophilicity without limit

Explanation

Fluorine substitution at a metabolic soft spot can block cytochrome P450 oxidation because the C-F bond resists oxidation. This reduces first-pass metabolism and can prolong the half-life.

Question 21Pharmaceutical Chemistry and Medicinal Chemistry

Which property of a drug molecule is described by the term 'bioisostere'?

  1. A stereoisomer with opposite rotation
  2. A salt form used to improve dissolution
  3. A metabolite with no biological activity
  4. A group that mimics another group's steric and electronic properties Correct answer.

Explanation

Bioisosteres are groups with similar size, shape, and electronic properties that can replace one another while preserving biological activity. Classic examples include replacing -OH with -NH2 or -Cl with -CF3.

Question 22Pharmaceutical Chemistry and Medicinal Chemistry

Which statement correctly describes the effect of a bulky ortho substituent on an aromatic ester?

  1. It converts the ester into an amide
  2. It can sterically hinder hydrolysis and increase stability Correct answer.
  3. It removes the aromaticity of the ring
  4. It accelerates hydrolysis by stabilizing the transition state

Explanation

Bulky groups near the ester carbonyl can sterically shield it from nucleophilic attack by water or esterases. This hindrance slows hydrolysis and can improve stability.

Question 23Pharmaceutical Chemistry and Medicinal Chemistry

Which technique separates enantiomers of a chiral drug using a chiral stationary phase?

  1. Liquid-liquid extraction with water
  2. Chiral high-performance liquid chromatography Correct answer.
  3. Gel filtration
  4. Simple distillation

Explanation

Chiral HPLC uses a chiral stationary phase that forms transient diastereomeric complexes with each enantiomer, giving different retention times. This enables resolution of enantiomers.

Question 24Pharmaceutical Chemistry and Medicinal Chemistry

Which functional group transformation is an example of oxidation in drug metabolism?

  1. Conversion of a primary alcohol to a carboxylic acid Correct answer.
  2. Reduction of a nitro group to an amine
  3. Conjugation of a phenol with glucuronic acid
  4. Hydrolysis of an ester to an acid and alcohol

Explanation

Oxidation increases the oxidation state of carbon, as when a primary alcohol is converted through an aldehyde to a carboxylic acid. Cytochrome P450 enzymes commonly catalyze such reactions.

Question 25Pharmaceutical Chemistry and Medicinal Chemistry

Which structural feature of a molecule most strongly increases its binding affinity for a hydrophobic receptor pocket?

  1. A charged carboxylate group
  2. A polar hydroxyl group
  3. A lipophilic aromatic ring that fits the pocket Correct answer.
  4. A highly hydrated sugar moiety

Explanation

A lipophilic aromatic ring can engage in hydrophobic and van der Waals interactions with a nonpolar pocket, increasing binding affinity. Shape complementarity further strengthens the interaction.

Question 26Pharmaceutical Chemistry and Medicinal Chemistry

Which statement best describes the relationship between a drug's pKa and the pH at which it is 50% ionized in aqueous solution?

  1. The pKa equals the pH at which the drug is 50% ionized. Correct answer.
  2. The pKa is always numerically equal to the pH of maximum ionization.
  3. Ionization is independent of pH for weak acids.
  4. The pKa describes the pH at which the drug is fully unionized.

Explanation

For a weak acid or base, the Henderson-Hasselbalch relationship shows that when solution pH equals the pKa, the concentrations of ionized and unionized forms are equal, i.e., 50% ionized. This is the defining meaning of pKa for drug ionization.

Question 27Pharmaceutical Chemistry and Medicinal Chemistry

A medicinal chemist wants to replace a metabolically labile methyl group on an aromatic ring to block oxidative metabolism while keeping similar size and lipophilicity. Which change is most appropriate?

  1. Replace the methyl with a carboxylic acid.
  2. Replace the methyl with a hydroxyl group.
  3. Replace the methyl with an amino group.
  4. Replace the methyl with a trifluoromethyl group. Correct answer.

Explanation

Fluorine substitution blocks metabolic oxidation at that position while preserving size and increasing lipophilicity, so a trifluoromethyl group is a classic bioisosteric replacement for a metabolically vulnerable methyl. Polar groups such as hydroxyl, carboxyl, or amino alter physicochemical properties substantially and do not serve this blocking role as well.

Question 28Pharmaceutical Chemistry and Medicinal Chemistry

Which statement correctly describes the role of the sulfonamide group in the mechanism of sulfonamide antibacterial agents?

  1. It binds irreversibly to bacterial 50S ribosomal subunits.
  2. It is a structural analog of p-aminobenzoic acid and inhibits dihydropteroate synthase. Correct answer.
  3. It alkylates bacterial DNA, causing strand breaks.
  4. It disrupts the bacterial cell membrane by forming pores.

Explanation

Sulfonamides are structural analogs of p-aminobenzoic acid (PABA) and competitively inhibit dihydropteroate synthase, blocking folate synthesis in bacteria. This is a classic example of antimetabolite action through structural mimicry.

Question 29Pharmaceutical Chemistry and Medicinal Chemistry

A lead compound contains a tertiary amine that is highly basic (pKa about 10) and causes poor oral absorption due to permanent protonation at intestinal pH. Which structural modification is most likely to improve absorption while retaining the pharmacophore?

  1. Add a second basic amine to increase overall basicity.
  2. Convert the tertiary amine to a quaternary ammonium salt.
  3. Replace the amine with a sulfonic acid group.
  4. Introduce an electron-withdrawing group near the amine to lower its pKa toward physiological pH. Correct answer.

Explanation

Lowering the pKa of a basic center by adding electron-withdrawing substituents reduces the fraction protonated at intestinal pH, increasing the unionized, membrane-permeable form. This is a standard strategy to improve absorption of basic drugs.

Question 30Pharmaceutical Chemistry and Medicinal Chemistry

Two compounds share the same molecular formula but differ only in the spatial arrangement of atoms around a double bond, giving distinct cis and trans forms. Which type of isomerism is this?

  1. Optical isomerism
  2. Geometric (diastereomeric) isomerism Correct answer.
  3. Conformational isomerism
  4. Constitutional isomerism

Explanation

Cis-trans isomers around a double bond are geometric isomers, a subclass of diastereomers, because the restricted rotation of the double bond fixes the spatial arrangement. They are not mirror images, so they are not optical isomers.

Question 31Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

Which pharmaceutical form is defined as a liquid preparation in which solid particles are dispersed in a liquid vehicle and are intended to settle on standing?

  1. Emulsion
  2. Elixir
  3. Suspension Correct answer.
  4. Syrup

Explanation

A suspension is a disperse system of insoluble solid particles in a liquid vehicle; because the particles are larger than colloidal size they tend to sediment on standing and must be shaken before use. Emulsions disperse a liquid in a liquid, while elixirs and syrups are true solutions.

Question 32Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

In the wet granulation process, what is the primary function of the granulating liquid?

  1. To sterilise the powder blend
  2. To reduce the bulk density of the powder
  3. To dissolve the active substance completely
  4. To bind powder particles into larger agglomerates Correct answer.

Explanation

The granulating liquid mobilises binder and partially dissolves particle surfaces so that primary particles adhere into granules with improved flow and compressibility. It is not intended to dissolve the whole drug load or to sterilise the product, and granulation generally increases rather than decreases bulk density.

Question 33Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

Which excipient is included in a tablet formulation mainly to promote disintegration of the tablet in the gastrointestinal tract?

  1. Lactose
  2. Magnesium stearate
  3. Croscarmellose sodium Correct answer.
  4. Talc

Explanation

Croscarmellose sodium is a superdisintegrant that swells rapidly on contact with water and breaks the tablet into primary particles. Magnesium stearate and talc are lubricants/glidants, and lactose is a filler.

Question 34Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

Which route of administration completely avoids first-pass hepatic metabolism?

  1. Intravenous Correct answer.
  2. Buccal
  3. Rectal
  4. Oral

Explanation

Drug given intravenously enters the systemic circulation directly, so it bypasses the gut wall and liver before reaching the circulation and has 100% bioavailability by definition. Oral drug is subject to first-pass metabolism, and rectal and buccal absorption are only partially protected from it.

Question 35Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

According to the European Pharmacopoeia, a preparation labelled as an ophthalmic ointment must be manufactured so that it is:

  1. Sterile Correct answer.
  2. Isotonic with tears
  3. Buffered to pH 7.4
  4. Preserved with a bactericide

Explanation

Because the eye is a sensitive, poorly defended site, all ophthalmic preparations, including ointments, must comply with the sterility test. Ointments are non-aqueous and therefore cannot be made isotonic or buffered to pH 7.4, and preservatives are optional depending on the container and use.

Question 36Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

Which unit operation is used to reduce the particle size of a dry powder by impact and attrition in a rotating drum containing grinding media?

  1. Lyophilisation
  2. Ball milling Correct answer.
  3. Sieving
  4. Fluidised bed drying

Explanation

A ball mill reduces particle size by impact and attrition as the grinding media tumble inside the rotating drum. Sieving classifies particles by size without comminution, while fluidised bed drying and lyophilisation are drying operations.

Question 37Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

Which statement correctly describes a suppository base that is a triglyceride of saturated fatty acids (such as theobroma oil)?

  1. It melts at body temperature and is suitable for lipophilic drugs Correct answer.
  2. It is an ionic surfactant that enhances absorption
  3. It is a strong buffer that neutralises rectal pH
  4. It is water-soluble and dissolves rapidly in the rectum

Explanation

Cocoa butter-type bases are mixtures of triglycerides that melt at about 30–36 °C, releasing drug in the rectum; they are suitable for lipophilic drugs but poorly release hydrophilic ones. They are not water-soluble, not surfactants, and not buffers.

Question 38Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

Which term describes the property of a powder to flow freely because interparticulate friction is low?

  1. Flowability Correct answer.
  2. Hygroscopicity
  3. Compressibility
  4. Polymorphism

Explanation

Flowability describes how easily a powder mass moves under gravity and is commonly assessed by angle of repose, Carr's index or Hausner ratio. Hygroscopicity concerns moisture uptake, compressibility concerns volume reduction under pressure, and polymorphism concerns crystal form.

Question 39Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

A pharmacist must compound 200 g of a 5% w/w hydrocortisone cream from a 20% w/w stock cream and a base. What mass of the stock cream is required?

  1. 20 g
  2. 40 g
  3. 50 g Correct answer.
  4. 100 g

Explanation

Using the alligation/ dilution relation C1V1 = C2V2 with masses: 20% × x = 5% × 200 g, so x = 1000/20 = 50 g of the 20% cream, made up to 200 g with 150 g base.

Question 40Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

Which manufacturing method produces a tablet in which the drug is released only after a lag time and then at a controlled rate, using an outer layer that dissolves in the intestine?

  1. Enteric-coated tablet Correct answer.
  2. Immediate-release compression
  3. Effervescent tablet
  4. Sublingual tablet

Explanation

An enteric coat is insoluble in gastric acid but dissolves at intestinal pH, giving a lag time before the core releases drug. Immediate-release tablets release drug at once, effervescent tablets dissolve rapidly in water, and sublingual tablets release drug under the tongue.

Question 41Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

In a suspension, which excipient is added to prevent the dispersed particles from settling into a hard cake that cannot be redispersed?

  1. Suspending agent Correct answer.
  2. Colouring agent
  3. Sweetening agent
  4. Antioxidant

Explanation

Suspending agents (thickeners such as cellulose derivatives or clays) increase vehicle viscosity and form a structured network that slows sedimentation and keeps the sediment easily redispersible. Sweeteners and colours affect palatability and appearance, and antioxidants prevent chemical degradation.

Question 42Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

Which factor most strongly increases the rate of drug release from a hydrophilic matrix tablet based on hydroxypropyl methylcellulose?

  1. Decreasing the polymer concentration Correct answer.
  2. Increasing the polymer concentration
  3. Increasing the tablet hardness
  4. Increasing the polymer molecular weight

Explanation

In a hydrophilic matrix the polymer hydrates to form a viscous gel layer that controls diffusion; lowering the polymer concentration reduces gel viscosity and thickness, so drug diffuses out faster. Higher molecular weight, higher concentration and greater hardness all slow release.

Question 43Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

Which statement about the sterilisation of a heat-labile ophthalmic solution by filtration is correct?

  1. Filtration removes both bacteria and viruses
  2. A 0.45 µm filter is adequate for sterilisation
  3. Filtration destroys bacterial endotoxins
  4. A 0.22 µm filter is used and the process is aseptic Correct answer.

Explanation

Sterilising-grade filtration uses a membrane with a nominal pore size of 0.22 µm or smaller to retain bacteria, and the filtrate must be handled aseptically because the process is not terminal. A 0.45 µm filter does not reliably retain bacteria, viruses pass through sterilising filters, and endotoxins are not removed by filtration.

Question 44Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

What is the main purpose of adding a glidant such as colloidal silicon dioxide to a tablet powder blend?

  1. To accelerate disintegration
  2. To increase the hardness of the final tablet
  3. To improve powder flow by reducing interparticulate friction Correct answer.
  4. To mask an unpleasant taste

Explanation

Glidants are fine particles that coat the surface of larger particles, reducing interparticulate friction and improving flow into the die. They are not primarily hardeners, taste-masking agents or disintegrants.

Question 45Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

A pharmacist prepares a 10% w/w ointment but the prescription requires 30 g at 2% w/w. What mass of white soft paraffin must be added to the 10% ointment to obtain the correct strength?

  1. 12 g
  2. 18 g
  3. 6 g
  4. 24 g Correct answer.

Explanation

The 30 g of 2% ointment contains 0.6 g of drug, which is present in 6 g of the 10% ointment; the remaining 24 g must therefore be base. Adding 24 g of white soft paraffin dilutes 6 g of the 10% ointment to 30 g at 2%.

Question 46Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

Which property of a powder is measured by the angle of repose?

  1. Solubility
  2. Flow characteristics Correct answer.
  3. Particle density
  4. Moisture content

Explanation

The angle of repose is the angle formed by a heap of powder poured onto a surface; a small angle indicates good flow and a large angle indicates poor flow. It does not measure density, moisture or solubility.

Question 47Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

In the context of emulsion stability, what is meant by phase inversion?

  1. Separation of the emulsion into two visible layers
  2. Conversion of an oil-in-water emulsion into a water-in-oil emulsion Correct answer.
  3. Loss of the emulsifying agent by adsorption to the container
  4. Growth of dispersed droplets by molecular diffusion

Explanation

Phase inversion is the change of an emulsion from one type to the other, for example o/w to w/o, often triggered by a change in phase volume ratio, electrolyte concentration or temperature. Creaming, coalescence and Ostwald ripening are different instability mechanisms.

Question 48Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

Which statement best explains why a drug with a very short biological half-life is a good candidate for a sustained-release oral dosage form?

  1. It eliminates hepatic first-pass metabolism
  2. It reduces the dosing frequency needed to keep plasma levels in the therapeutic range Correct answer.
  3. It allows a larger total daily dose to be given at once
  4. It increases the aqueous solubility of the drug

Explanation

Sustained release delivers drug over an extended period so that plasma concentrations remain within the therapeutic window with less frequent dosing, which improves adherence. It does not abolish first-pass metabolism, change solubility, or justify simply giving a larger single dose.

Question 49Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

Which of the following is the correct description of the term 'bioavailability' as applied to a pharmaceutical product?

  1. The time taken for the drug to be completely eliminated
  2. The concentration of drug in the formulation
  3. The total amount of drug excreted in the urine over 24 hours
  4. The proportion of the administered dose that reaches the systemic circulation unchanged, and the rate at which it does so Correct answer.

Explanation

Bioavailability describes both the extent (fraction of dose) and the rate at which unchanged drug reaches the systemic circulation from the administered dosage form. Urinary excretion, formulation concentration and elimination time are different pharmacokinetic quantities.

Question 50Pharmaceutics and Pharmaceutical Technology (dosage forms, compounding, manufacturing)

A paediatric patient requires 7.5 mg of a drug per dose. The available oral solution contains 5 mg/5 mL. What volume must be measured?

  1. 2.5 mL
  2. 10.0 mL
  3. 5.0 mL
  4. 7.5 mL Correct answer.

Explanation

The concentration is 1 mg/mL (5 mg in 5 mL), so 7.5 mg corresponds to 7.5 mL. Setting up the proportion 5 mg/5 mL = 7.5 mg/x gives x = 7.5 mL.