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Taiwan Pharmacist Licensing Examination study materials
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Taiwan Pharmacist Licensing Examination practice questions

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Question 1Pharmaceutics

Which excipient is primarily added to a tablet formulation to promote disintegration of the tablet in the gastrointestinal tract?

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

Explanation

Disintegrants such as croscarmellose sodium draw water in and swell, breaking the tablet into granules. Magnesium stearate and talc are lubricants/glidants, and microcrystalline cellulose serves mainly as a diluent/binder.

Question 2Pharmaceutics

A pharmacist needs to prepare a sterile ophthalmic solution. Which property is most important for the formulation to be acceptable for ocular use?

  1. Isotonicity with tear fluid Correct answer.
  2. Presence of a preservative in a single-dose unit
  3. Presence of a strong buffer at pH 4
  4. High viscosity above 5000 cP

Explanation

Ophthalmic solutions should be isotonic, approximately pH 7.4, and sterile to minimize irritation and tissue damage. Excessive viscosity and extreme pH cause discomfort, and single-dose units are typically preservative-free.

Question 3Pharmaceutics

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

  1. Sublingual Correct answer.
  2. Oral
  3. Rectal (upper portion)
  4. Enteric-coated oral

Explanation

Sublingual absorption drains into the systemic circulation via the venous plexus, bypassing the portal vein and hepatic first-pass effect. Oral and enteric-coated products are absorbed into the portal circulation, and the upper rectum partially drains to the portal system.

Question 4Pharmaceutics

Which rheological behavior describes a fluid whose apparent viscosity decreases as shear rate increases?

  1. Pseudoplastic Correct answer.
  2. Plastic
  3. Newtonian
  4. Dilatant

Explanation

Pseudoplastic (shear-thinning) fluids show decreasing apparent viscosity with increasing shear rate. Newtonian fluids have constant viscosity, dilatant fluids shear-thicken, and plastic fluids require a yield stress before flow.

Question 5Pharmaceutics

Which factor most directly increases the rate of drug release from a matrix tablet according to the Higuchi model?

  1. Increasing drug solubility in the dissolution medium Correct answer.
  2. Decreasing the porosity of the matrix
  3. Increasing the tablet compression force
  4. Increasing the matrix polymer content

Explanation

In diffusion-controlled matrix release, higher drug solubility increases the concentration gradient and release rate. Higher polymer content, greater compression, and lower porosity all slow diffusion.

Question 6Pharmaceutics

A drug has a hepatic extraction ratio of 0.9. What is its approximate oral bioavailability assuming complete absorption and no gut metabolism?

  1. 0.9
  2. 1.0
  3. 0.5
  4. 0.1 Correct answer.

Explanation

Oral bioavailability is approximately 1 minus the hepatic extraction ratio when absorption is complete, so 1 − 0.9 = 0.1. High extraction drugs thus show extensive first-pass loss.

Question 7Pharmaceutics

Which method is appropriate for terminal sterilization of a heat-labile aqueous injection packaged in a sealed vial?

  1. Filtration through a 0.22 µm membrane
  2. Moist heat autoclaving at 121°C for 15 minutes Correct answer.
  3. Ethylene oxide exposure
  4. Dry heat at 160°C for 2 hours

Explanation

Moist heat autoclaving at 121°C for 15 minutes is the standard terminal sterilization method for aqueous solutions in sealed containers. Dry heat is for glassware and oils, ethylene oxide is for devices, and filtration is not a terminal sterilization of a sealed product.

Question 8Pharmaceutics

Which is the primary function of a hydrofluoroalkane propellant in a metered-dose inhaler?

  1. To increase the aerodynamic particle size
  2. To provide the energy that aerosolizes the drug Correct answer.
  3. To act as a surfactant to stabilize the suspension
  4. To dissolve the drug in the propellant

Explanation

The propellant provides the vapor pressure that expels and atomizes the formulation. Surfactants stabilize suspensions, and propellants generally do not dissolve hydrophilic drugs.

Question 9Pharmaceutics

A pharmacist prepares a 10% w/w ointment using 5 g of drug. What mass of base is required?

  1. 55 g
  2. 45 g Correct answer.
  3. 50 g
  4. 95 g

Explanation

A 10% w/w ointment means 10 g drug per 100 g product. For 5 g drug, total product is 50 g, so base = 50 − 5 = 45 g.

Question 10Pharmaceutics

Which mechanism best explains why adding a cosolvent such as ethanol increases the solubility of a poorly water-soluble drug in an aqueous vehicle?

  1. It lowers the polarity of the solvent mixture Correct answer.
  2. It increases the dielectric constant of the vehicle
  3. It raises the ionic strength of the solution
  4. It promotes micelle formation

Explanation

Cosolvents like ethanol lower the overall polarity of the vehicle, improving solvation of lipophilic drugs. They decrease the dielectric constant rather than raise it and do not act through ionic strength or micellization.

Question 11Pharmaceutics

Which statement about a drug that follows zero-order elimination is correct?

  1. The half-life is constant regardless of dose
  2. A constant amount is eliminated per unit time Correct answer.
  3. The elimination rate is proportional to plasma concentration
  4. Doubling the dose doubles the elimination rate

Explanation

Zero-order (saturation) kinetics eliminates a constant amount per unit time because enzymes are saturated. Half-life is not constant, and the rate does not scale with concentration or dose.

Question 12Pharmaceutics

A tablet is formulated with a high proportion of a hygroscopic excipient and stored in a humid environment. Which defect is most likely to develop?

  1. Capping
  2. Picking
  3. Sticking Correct answer.
  4. Mottling

Explanation

Moisture uptake makes the tablet surface tacky, causing it to adhere to the punch face, known as sticking. Capping, mottling, and picking are related to compression and distribution rather than surface tackiness from humidity.

Question 13Pharmaceutics

Which property of a suppository base is most important for rapid systemic absorption after rectal administration?

  1. High melting point above 45°C
  2. High density
  3. Lipophilic base with slow dissolution
  4. Rapid melting or dissolution at body temperature Correct answer.

Explanation

A base that melts or dissolves quickly at rectal temperature releases drug rapidly for absorption. A high melting point or slow dissolution delays release, and density is not a key determinant.

Question 14Pharmaceutics

Which factor most significantly limits the oral bioavailability of a highly polar, high-molecular-weight drug?

  1. High intestinal permeability
  2. Poor aqueous solubility
  3. Low gastrointestinal membrane permeability Correct answer.
  4. Extensive hepatic metabolism

Explanation

Highly polar, large molecules cross the intestinal membrane poorly, limiting absorption and oral bioavailability. Hepatic metabolism and solubility are less limiting for such compounds compared with the permeability barrier.

Question 15Pharmaceutics

Which is the correct definition of the disintegration time requirement for uncoated immediate-release tablets in the USP?

  1. All tablets must disintegrate within 15 minutes Correct answer.
  2. All tablets must disintegrate within 60 minutes
  3. All tablets must disintegrate within 3 minutes
  4. All tablets must disintegrate within 30 minutes

Explanation

USP generally requires uncoated immediate-release tablets to disintegrate within 15 minutes in the specified medium. Coated and enteric tablets have longer or conditional requirements.

Question 16Pharmaceutics

A patient is switched from an immediate-release formulation to an extended-release formulation of the same drug. Which parameter is most directly affected by this change?

  1. The area under the curve
  2. The peak-to-trough fluctuation Correct answer.
  3. The volume of distribution
  4. The elimination half-life

Explanation

Extended-release formulations smooth the plasma concentration profile, reducing peak-to-trough fluctuation. Total AUC, half-life, and volume of distribution are typically unchanged because they reflect total exposure and disposition.

Question 17Pharmaceutics

Which method is used to determine the particle size distribution of a powder in the micrometer range based on light scattering?

  1. Karl Fischer titration
  2. Differential scanning calorimetry
  3. Laser diffraction Correct answer.
  4. Gas chromatography

Explanation

Laser diffraction measures particle size by the angular dependence of scattered light. Karl Fischer measures water content, gas chromatography separates volatile compounds, and DSC measures thermal transitions.

Question 18Pharmaceutics

Which excipient is added to a suspension to increase viscosity and slow sedimentation of dispersed particles?

  1. Xanthan gum Correct answer.
  2. Sodium chloride
  3. Sodium lauryl sulfate
  4. Sodium bisulfite

Explanation

Thickening agents such as xanthan gum increase viscosity and reduce sedimentation rate according to Stokes' law. Surfactants, electrolytes, and antioxidants do not primarily control viscosity.

Question 19Pharmaceutics

Which statement about the glass transition temperature (Tg) of an amorphous solid is correct?

  1. Tg is always higher than the melting point
  2. Tg is independent of moisture content
  3. Above Tg the material is brittle and glassy
  4. Below Tg molecular mobility is greatly reduced Correct answer.

Explanation

Below Tg, an amorphous solid is in a glassy state with low molecular mobility, which stabilizes formulations. Above Tg it becomes rubbery, and moisture typically lowers Tg.

Question 20Pharmaceutics

Which type of emulsion is formed when the continuous phase is oil and the dispersed phase is water?

  1. Microemulsion
  2. Multiple emulsion
  3. Oil-in-water (O/W)
  4. Water-in-oil (W/O) Correct answer.

Explanation

A water-in-oil (W/O) emulsion has oil as the continuous phase and water droplets dispersed within it. O/W is the reverse, and microemulsions or multiple emulsions are defined by droplet size or structure.

Question 21Pharmaceutics

A drug solution is stored at 25°C and degrades by first-order kinetics with a rate constant of 0.02 per month. What is the approximate shelf life (t90) in months?

  1. 50 months
  2. 5.3 months Correct answer.
  3. 11.5 months
  4. 1.1 months

Explanation

For first-order degradation, t90 = 0.105/k. With k = 0.02 per month, t90 ≈ 0.105/0.02 ≈ 5.3 months.

Question 22Pharmaceutics

A drug has a volume of distribution of 50 L and a clearance of 5 L/h. What is its elimination half-life?

  1. 35 h
  2. 10 h
  3. 2.5 h
  4. 6.9 h Correct answer.

Explanation

Half-life equals 0.693 × Vd / CL = 0.693 × 50 / 5 ≈ 6.9 h.

Question 23Pharmaceutics

Which statement about polymorphism is correct?

  1. The most stable polymorph always has the highest solubility
  2. Different polymorphs can have different dissolution rates Correct answer.
  3. Polymorphs have identical crystal lattice structures
  4. Polymorphs differ only in particle size

Explanation

Polymorphs share the same chemical composition but differ in crystal packing, leading to different physical properties including dissolution rate and solubility. The most stable form typically has the lowest solubility.

Question 24Pharmaceutics

In a two-compartment pharmacokinetic model after intravenous bolus, which parameter describes the rate of drug distribution from the central to the peripheral compartment?

  1. k21
  2. k10
  3. alpha
  4. k12 Correct answer.

Explanation

k12 is the micro-rate constant for transfer from the central to the peripheral compartment. k21 is the return rate, k10 is elimination from the central compartment, and alpha is the distribution-phase macro-rate constant.

Question 25Pharmaceutics

A pharmacist must prepare a 0.9% w/v sodium chloride solution. How many grams of sodium chloride are needed to prepare 500 mL?

  1. 0.45 g
  2. 4.5 g Correct answer.
  3. 9.0 g
  4. 45 g

Explanation

A 0.9% w/v solution contains 0.9 g per 100 mL. For 500 mL, the amount is 0.9 × 5 = 4.5 g.

Question 26Pharmaceutics

Which document issued by a regulatory authority contains legally binding requirements for the manufacture and quality control of pharmaceutical products?

  1. Standard operating procedure (SOP)
  2. Good Manufacturing Practice (GMP) guide Correct answer.
  3. Formulary
  4. Pharmacopoeia

Explanation

A GMP guide is a regulatory document that sets out legally enforceable requirements for manufacturing and quality control to ensure product safety, efficacy, and quality. Pharmacopoeias provide analytical methods and specifications, formularies guide prescribing, and SOPs are internal company instructions.

Question 27Pharmaceutics

Which type of tablet is designed to release drug only after passing through the stomach, using a polymer coating that dissolves at higher pH?

  1. Sublingual tablet
  2. Effervescent tablet
  3. Chewable tablet
  4. Enteric-coated tablet Correct answer.

Explanation

Enteric coatings are pH-sensitive polymers that remain intact in the acidic stomach and dissolve in the more alkaline environment of the intestine, protecting acid-labile drugs or the gastric mucosa. Chewable and effervescent tablets are not coated for pH-dependent release, and sublingual tablets are placed under the tongue for rapid absorption.

Question 28Pharmaceutics

A pharmacist needs to prepare 200 mL of a 2% w/v solution from a 10% w/v stock solution. What volume of stock solution is required?

  1. 50 mL
  2. 40 mL Correct answer.
  3. 10 mL
  4. 20 mL

Explanation

Using the dilution equation C1V1 = C2V2, the volume of stock is (2% × 200 mL) / 10% = 40 mL. The remaining volume is made up with solvent to 200 mL.

Question 29Pharmaceutics

Which statement best describes the mechanism by which an antioxidant such as butylated hydroxytoluene (BHT) protects a pharmaceutical formulation?

  1. It chelates trace metal ions that catalyze oxidation.
  2. It scavenges free radicals by donating hydrogen atoms. Correct answer.
  3. It lowers the pH to stabilize the drug.
  4. It absorbs ultraviolet light that initiates oxidation.

Explanation

BHT is a chain-breaking antioxidant that donates a hydrogen atom to lipid radicals, converting them to more stable products and interrupting the radical chain reaction of oxidation. Chelating agents and UV absorbers act by different mechanisms.

Question 30Pharmaceutics

A water-soluble drug is formulated as a matrix tablet using hydroxypropyl methylcellulose (HPMC). Which mechanism best explains the extended drug release from this system?

  1. Diffusion of dissolved drug through a static, hydrated polymer gel layer. Correct answer.
  2. Osmotic pumping driven by a semipermeable membrane coating.
  3. Enzymatic cleavage of polymer chains in the colon.
  4. Ion exchange between the drug and a resin complex.

Explanation

HPMC hydrates to form a viscous gel layer around the tablet; drug release is controlled mainly by diffusion through this gel layer, which gradually erodes. Osmotic pumps require a semipermeable membrane and an osmotic agent, ion-exchange systems use resin binding, and enzymatic cleavage is not the primary mechanism for HPMC matrices.

Question 31Pharmaceutical Chemistry

Which functional group is characteristic of a carboxylic acid?

  1. -CHO
  2. -OH
  3. -CO-
  4. -COOH Correct answer.

Explanation

A carboxylic acid contains a carbonyl carbon bonded to a hydroxyl group, written -COOH. The -OH alone is an alcohol and -CHO is an aldehyde.

Question 32Pharmaceutical Chemistry

Aspirin is the common name for which compound?

  1. Acetaminophen
  2. Salicylic acid
  3. Ibuprofen
  4. Acetylsalicylic acid Correct answer.

Explanation

Aspirin is acetylsalicylic acid, formed by acetylating the phenolic hydroxyl of salicylic acid. Salicylic acid itself is the precursor and is more irritating to the stomach.

Question 33Pharmaceutical Chemistry

In a benzene ring, how many pi electrons are delocalized in the aromatic system?

  1. 4
  2. 8
  3. 6 Correct answer.
  4. 2

Explanation

Benzene has three conjugated double bonds contributing six pi electrons, satisfying Huckel's 4n+2 rule with n=1. This delocalization gives benzene its characteristic stability.

Question 34Pharmaceutical Chemistry

Which type of isomerism do (R)- and (S)-lactic acid exhibit?

  1. Optical isomerism Correct answer.
  2. Functional group isomerism
  3. Positional isomerism
  4. Geometric isomerism

Explanation

(R) and (S) forms are non-superimposable mirror images differing in configuration at a stereocenter, which is optical isomerism. They rotate plane-polarized light in opposite directions.

Question 35Pharmaceutical Chemistry

Which element is present in the structure of penicillin antibiotics?

  1. Selenium
  2. Sulfur Correct answer.
  3. Boron
  4. Phosphorus

Explanation

Penicillins contain a beta-lactam fused to a thiazolidine ring, and the thiazolidine ring includes a sulfur atom. This sulfur-containing bicyclic core is a defining structural feature.

Question 36Pharmaceutical Chemistry

Which of the following is a beta-lactam antibiotic?

  1. Erythromycin
  2. Gentamicin
  3. Tetracycline
  4. Amoxicillin Correct answer.

Explanation

Amoxicillin contains the four-membered beta-lactam ring and is classified as a penicillin. The beta-lactam ring is the reactive acylating group that inhibits transpeptidase.

Question 37Pharmaceutical Chemistry

The active form of vitamin C is chemically classified as which type of compound?

  1. A fat-soluble quinone
  2. A water-soluble lactone Correct answer.
  3. A steroid
  4. A tocopherol

Explanation

Vitamin C (ascorbic acid) is a water-soluble lactone containing an enediol group. Its enediol structure allows it to act as a reducing agent and antioxidant.

Question 38Pharmaceutical Chemistry

Which bond type is formed by sharing of electron pairs between two atoms?

  1. Covalent bond Correct answer.
  2. Hydrogen bond
  3. Metallic bond
  4. Ionic bond

Explanation

A covalent bond results from sharing of electron pairs between atoms, as in carbon-carbon bonds. Ionic bonds involve electron transfer, and hydrogen bonds are weaker electrostatic attractions.

Question 39Pharmaceutical Chemistry

A drug has a pKa of 4.5. At pH 7.4, what is the approximate ratio of ionized to unionized drug for a weak acid?

  1. About 1:1
  2. About 100:1
  3. About 10:1
  4. About 1000:1 Correct answer.

Explanation

For a weak acid, pH - pKa = log([A-]/[HA]). Here 7.4 - 4.5 = 2.9, so [A-]/[HA] = 10^2.9, approximately 800 to 1000, closest to 1000:1.

Question 40Pharmaceutical Chemistry

Which chromatographic technique separates compounds primarily by differences in their partition between a mobile and stationary phase based on polarity?

  1. Atomic absorption spectroscopy
  2. Reverse-phase HPLC Correct answer.
  3. Mass spectrometry
  4. Gas chromatography

Explanation

Reverse-phase HPLC uses a nonpolar stationary phase and polar mobile phase, separating compounds by their hydrophobic partitioning. More polar compounds elute earlier.

Question 41Pharmaceutical Chemistry

In an IR spectrum, a strong sharp absorption near 1700 cm-1 most likely indicates which group?

  1. Carbonyl (C=O) Correct answer.
  2. Nitrile (C≡N)
  3. Hydroxyl (O-H)
  4. Amine (N-H)

Explanation

Carbonyl stretching typically appears as a strong band near 1700 cm-1. Hydroxyl and amine stretches appear in the 3300-3600 cm-1 region, and nitriles near 2200 cm-1.

Question 42Pharmaceutical Chemistry

In 1H NMR spectroscopy, which factor primarily determines the chemical shift of a proton?

  1. The magnetic environment created by the electron cloud Correct answer.
  2. The mass of the molecule
  3. Number of neighboring protons
  4. The instrument's magnetic field strength alone

Explanation

The chemical shift reflects the local magnetic environment of a proton, which is influenced by its electron density and shielding. Electron-withdrawing groups deshield protons and increase the shift.

Question 43Pharmaceutical Chemistry

Which property of a drug molecule most directly determines its ability to cross lipid membranes by passive diffusion?

  1. Lipophilicity (log P) Correct answer.
  2. Molecular weight only
  3. Color of the compound
  4. Melting point

Explanation

Lipophilicity, commonly expressed as log P, governs partitioning into lipid bilayers and thus passive diffusion. Both excessive hydrophilicity and excessive lipophilicity can limit absorption.

Question 44Pharmaceutical Chemistry

Which reaction type best describes the hydrolysis of an ester?

  1. Radical polymerization
  2. Nucleophilic acyl substitution Correct answer.
  3. Electrophilic addition
  4. Elimination

Explanation

Ester hydrolysis proceeds by nucleophilic attack at the carbonyl carbon, displacing the alkoxide, which is a nucleophilic acyl substitution. The tetrahedral intermediate collapses to the acid and alcohol.

Question 45Pharmaceutical Chemistry

Which of the following best describes a prodrug?

  1. A compound that must be biotransformed to release the active drug Correct answer.
  2. A compound that is permanently inactive
  3. A compound that inhibits all drug-metabolizing enzymes
  4. A compound that is active without any chemical change

Explanation

A prodrug is an inactive or less active derivative that undergoes biotransformation in the body to release the active species. Enalapril, for example, is hydrolyzed to enalaprilat.

Question 46Pharmaceutical Chemistry

Which conjugation reaction most commonly involves glucuronic acid?

  1. Sulfation
  2. Acetylation
  3. Methylation
  4. Glucuronidation Correct answer.

Explanation

Glucuronidation attaches glucuronic acid to a substrate, typically via UDP-glucuronosyltransferase, increasing water solubility for excretion. It is a major phase II pathway.

Question 47Pharmaceutical Chemistry

Which structural feature is required for a compound to act as a competitive inhibitor at an enzyme active site?

  1. A metal ion center
  2. A permanent positive charge
  3. Irreversible covalent bonding to the enzyme
  4. Structural resemblance to the substrate Correct answer.

Explanation

Competitive inhibitors typically resemble the substrate and bind reversibly at the active site, raising apparent Km without changing Vmax. Structural mimicry allows occupancy of the substrate-binding pocket.

Question 48Pharmaceutical Chemistry

Which of the following drugs is a chiral molecule that is administered as a single enantiomer to improve its pharmacological profile?

  1. Warfarin (racemate)
  2. Thalidomide (racemate)
  3. Ibuprofen (racemate)
  4. Esomeprazole Correct answer.

Explanation

Esomeprazole is the single (S)-enantiomer of omeprazole, developed to provide more consistent metabolism by CYP2C19. Single-enantiomer drugs avoid the differing activities of the opposite enantiomer.

Question 49Pharmaceutical Chemistry

Which of the following is an example of a bioisosteric replacement?

  1. Adding a methyl group to a ring
  2. Replacing -OH with -NH2 Correct answer.
  3. Removing a functional group entirely
  4. Replacing carbon with silicon in all positions

Explanation

Bioisosteres are groups with similar size and electronic properties that can be interchanged while retaining activity, such as replacing -OH with -NH2. This substitution often modulates metabolism or hydrogen bonding.

Question 50Pharmaceutical Chemistry

Which of the following statements about enantiomers is correct?

  1. They have different molecular formulas
  2. They are superimposable on their mirror images
  3. They have identical melting points in all cases
  4. They rotate plane-polarized light in opposite directions Correct answer.

Explanation

Enantiomers are non-superimposable mirror images that rotate plane-polarized light equally but in opposite directions. They have identical physical properties in achiral environments.