Concours de Résidanat en Pharmacie (Morocco)

According to the Beer-Lambert law (A = epsilon * c * l) utilized in pharmaceutical UV-visible spectrophotometric assays, what is the mathematical relationship between absorbance (A) and percent transmittance (%T)?

• AA = 2 - log10(%T)
• BA = log10(%T) - 2
• CA = 100 / %T
• DA = -ln(%T / 10)

In pharmaceutical analytical chemistry, which chromatographic parameter directly measures the efficiency of a high-performance liquid chromatography (HPLC) column in terms of theoretical plate count (N)?

• AN = 16 * (tR / W)^2
• BN = (tR2 - tR1) / W
• CN = tR * k'
• DN = alpha / (1 - alpha)

In reversed-phase high-performance liquid chromatography (RP-HPLC), what is the typical nature of the stationary phase and mobile phase, and what is the elution order of analytes?

• ANon-polar hydrophobic stationary phase (e.g., C18 octadecylsilyl) and polar aqueous-organ…
• BPolar hydrophilic stationary phase (e.g., unmodified silica) and non-polar organic mobile…
• CIon-exchange resin stationary phase with a pure non-polar mobile phase; neutral compounds…
• DImmobilized chiral stationary phase with supercritical CO2; racemic enantiomers elute sim…

During a compendial non-aqueous acid-base titration of a weak organic basic drug such as codeine or diazepam, which solvent and standard titrant are classically selected?

• AGlacial acetic acid (acide acétique glacial) as solvent and perchloric acid (acide perchl…
• BDistilled water as solvent and standardized sodium hydroxide (NaOH) as titrant
• CLiquid ammonia as solvent and hydrochloric acid (HCl) as titrant
• DPure chloroform as solvent and sulfuric acid (H2SO4) in ethanol as titrant

What is the Henderson-Hasselbalch equation used to calculate the pH of an aqueous buffer solution composed of a weak acid (HA) and its conjugate base (A-)?

• ApH = pKa + log10([A-] / [HA])
• BpH = pKa - log10([A-] / [HA])
• CpH = pKa * ([A-] / [HA])
• DpH = 14 - pKa + log10([HA] / [A-])

In nuclear magnetic resonance (1H-NMR) spectroscopy, what structural information is provided by the spin-spin coupling constant (J value, expressed in Hertz)?

• AThe spatial and dihedral angle relationship (Karplus relationship) and number of bonds se…
• BThe total absolute number of protons present in the molecule
• CThe exact molecular weight and elemental composition of the unknown fragment
• DThe electron density and chemical shielding tensor dependent directly on spectrometer fie…

In pharmaceutical mass spectrometry (MS), which ionization technique operates under atmospheric pressure, generates quasimolecular ions ([M+H]+ or [M-H]-) with minimal fragmentation ('soft ionization'), and is ideally suited for liquid chromatography coupling (LC-MS) of polar, thermolabile macromolecular pharmaceuticals?

• AElectrospray ionization (ESI)
• BElectron impact ionization (EI at 70 eV)
• CFast atom bombardment (FAB)
• DInductively coupled plasma ionization (ICP)

In the Michaelis-Menten kinetic model of single-substrate enzymatic reactions (v = (Vmax * [S]) / (Km + [S])), how is the Michaelis constant (Km) biochemically defined?

• AThe substrate concentration [S] at which the initial reaction velocity reaches half of th…
• BThe maximum rate of catalysis when the enzyme active sites are completely saturated
• CThe reciprocal of the catalytic turnover number (1 / kcat)
• DThe equilibrium association constant for enzyme-inhibitor complex formation

How does a classic competitive enzyme inhibitor alter the apparent Michaelis constant (Km) and maximum velocity (Vmax) in Lineweaver-Burk double-reciprocal plots (1/v versus 1/[S])?

• AKm is increased (apparent affinity decreased) while Vmax remains unchanged
• BVmax is decreased while Km remains unchanged
• CBoth Km and Vmax are decreased by an identical factor (parallel lines)
• DBoth Km and Vmax are increased proportionally

In the citric acid cycle (Krebs cycle), which mitochondrial enzyme catalyzes the only reaction that directly couples substrate-level phosphorylation to the generation of a high-energy nucleoside triphosphate (GTP or ATP)?

• ASuccinyl-CoA synthetase (succinate thiokinase)
• BCitrate synthase
• CIsocitrate dehydrogenase
• DMalate dehydrogenase

What is the net yield of adenosine triphosphate (ATP) molecules generated per molecule of glucose oxidized exclusively through anaerobic glycolysis (conversion of glucose to lactate)?

• A2 molecules of ATP
• B4 molecules of ATP
• C32 molecules of ATP
• D38 molecules of ATP

During the beta-oxidation of saturated fatty acids in the mitochondrial matrix, each repetitive round of four successive enzymatic steps shortens the acyl-CoA chain by two carbons. What is the correct sequence of these four enzymatic reactions?

• AOxidation (FAD-dependent) -> Hydration -> Oxidation (NAD+-dependent) -> Thiolysis (Cleava…
• BHydration -> Oxidation -> Decarboxylation -> Reduction
• CReduction -> Dehydration -> Reduction -> Condensation
• DPhosphorylation -> Isomerization -> Cleavage -> Dehydrogenation

In the urea cycle (ornithine cycle), which mitochondrial enzyme serves as the rate-limiting, committed step and requires N-acetylglutamate (NAG) as an obligatory allosteric activator?

• ACarbamoyl phosphate synthetase I (CPS-I)
• BOrnithine transcarbamylase (OTC)
• CArgininosuccinate synthetase
• DArginase-1

Which thermodynamic equation relates the standard Gibbs free energy change (Delta G°') of a biochemical reaction to its equilibrium constant (K'eq) at standard physiological temperature (298 K)?

• ADelta G°' = -R * T * ln(K'eq)
• BDelta G°' = +R * T * log10(K'eq)
• CDelta G°' = Delta H°' + T * Delta S°'
• DDelta G°' = -n * F * E°'

In radioactive decay kinetics utilized in nuclear pharmacy and radiopharmacy, how is the physical radioactive half-life (T1/2) mathematically related to the decay constant (lambda)?

• AT1/2 = ln(2) / lambda approx. 0.693 / lambda
• BT1/2 = lambda / ln(2)
• CT1/2 = 1 / lambda^2
• DT1/2 = lambda * e^(-0.693)

In capillary electrophoresis (CE) of pharmaceutical compounds, what physical phenomenon causes the bulk movement of the entire electrolyte buffer solution toward the cathode upon application of a high electrical voltage across an unmodified silica capillary?

• AElectroosmotic flow (EOF / flux électro-osmotique)
• BElectrophoretic migration velocity of cations
• CJoule heating convection
• DDielectrophoretic separation

In pharmaceutical biostatistics and hypothesis testing, what is the definition of a Type I error (alpha risk)?

• ARejecting the null hypothesis (H0) when it is in reality true (false positive result)
• BFailing to reject the null hypothesis (H0) when it is in reality false (false negative re…
• CThe probability of correctly detecting a true difference between two drugs (statistical p…
• DThe sample size necessary to ensure a normal distribution under the central limit theorem

Which non-parametric statistical hypothesis test is appropriate to compare the medians of two independent, unpaired clinical patient groups when continuous outcome data do not follow a Gaussian normal distribution?

• AMann-Whitney U test (Wilcoxon rank-sum test)
• BStudent's independent two-sample t-test
• CPaired Student's t-test
• DPearson's correlation coefficient

In clinical epidemiology and diagnostic testing, what formula expresses the Positive Predictive Value (PPV / Valeur Prédictive Positive) of a pharmaceutical laboratory test?

• APPV = True Positives / (True Positives + False Positives)
• BPPV = True Positives / (True Positives + False Negatives)
• CPPV = True Negatives / (True Negatives + False Positives)
• DPPV = (True Positives + True Negatives) / Total Tested

What is the primary optical property measured by circular dichroism (CD) spectroscopy to determine the secondary structure (alpha-helices and beta-sheets) of therapeutic proteins?

• AThe differential absorption of left- and right-circularly polarized light by chiral chrom…
• BThe refractive index increment as a function of solute concentration
• CThe wavelength of maximum fluorescence emission upon tryptophan excitation
• DThe angle of total internal reflection at an immobilized gold biosensor surface

In potentiometric titrations using a glass electrode, what equation describes the relationship between the measured electromotive force (E) across the thin glass membrane and the hydrogen ion activity (aH+)?

• AThe Nernst equation: E = E° + (2.303 * R * T / F) * log10(aH+)
• BThe van 't Hoff equation: ln(K) = -Delta H / (R * T) + Delta S / R
• CThe Ilkovic equation: id = 607 * n * D^(1/2) * m^(2/3) * t^(1/6) * C
• DThe Arrhenius equation: k = A * e^(-Ea / (R * T))

Which enzyme of the pentose phosphate pathway (hexose monophosphate shunt) produces NADPH necessary for maintaining reduced glutathione in erythrocytes, and whose hereditary deficiency causes acute hemolytic anemia upon ingestion of fava beans or oxidant drugs (primaquine, rasburicase)?

• AGlucose-6-phosphate dehydrogenase (G6PD)
• BTransketolase
• C6-Phosphogluconate dehydrogenase
• DPyruvate kinase

In gas chromatography (GC), which detector is widely used for organic pharmaceutical compounds because of its high sensitivity, broad linear dynamic range, and response to many carbon-containing substances, but destroys the sample in a hydrogen-air flame?

• AFlame Ionization Detector (FID / Détecteur à ionisation de flamme)
• BThermal Conductivity Detector (TCD / Catharomètre)
• CElectron Capture Detector (ECD)
• DFlame Photometric Detector (FPD)

In biochemical purine catabolism, what enzyme oxidizes hypoxanthine to xanthine, and subsequently oxidizes xanthine to uric acid (acide urique), and is the primary pharmacological target of allopurinol and febuxostat?

• AXanthine oxidase (xanthine oxydase / xanthine déshydrogénase)
• BAdenosine deaminase (ADA)
• CHypoxanthine-guanine phosphoribosyltransferase (HGPRT)
• DUrate oxidase (rasburicase)

In pharmaceutical formulation physical chemistry, what is the thermodynamic phenomenon whereby the solubility of small solute nanoparticles or microdroplets increases significantly as droplet radius decreases, as described by the Ostwald-Freundlich equation?

• AKelvin effect / Ostwald ripening driving force (augmentation de solubilité avec la courbu…
• BTyndall light scattering effect
• CDonnan membrane equilibrium
• DThixotropic gel-sol hysteresis

What is the core bicyclic ring system characteristic of all penicillin antibiotics, and what fundamental nucleus is produced upon cleavage of the acyl side chain by penicillin acylase?

• AA thiazolidine ring fused to a beta-lactam ring (penam nucleus), producing 6-aminopenicil…
• BA dihydrothiazine ring fused to a beta-lactam ring (cephem nucleus), producing 7-aminocep…
• CA carbapenem ring containing an endocyclic carbon, producing clavulanic acid
• DA monocyclic beta-lactam ring without a fused secondary ring, producing aztreonam

In the structure-activity relationships of classic fluoroquinolones such as ciprofloxacin and levofloxacin, which pair of substitutions commonly improves penetration, target affinity, and antibacterial spectrum relative to early non-fluorinated quinolones?

• AA fluorine atom at position C-6 and a basic heterocyclic ring (e.g., piperazinyl or pyrro…
• BA carboxylic acid group at position C-2 and a nitro group at position C-5
• CA hydroxyl group at position C-4 and a methyl ester at position C-3
• DA fused imidazole ring at positions C-1 and C-8 with no aromatic halogens

Angiotensin-Converting Enzyme (ACE) inhibitors bind to the catalytic site of ACE by coordinating with an active-site divalent zinc ion (Zn2+). Which functional group in captopril serves as this zinc-binding ligand, and what common clinical adverse effects are directly attributed to this specific moiety?

• AA sulfhydryl (thiol, -SH) group, which causes cutaneous rash and taste disturbances (dysg…
• BA phosphinyl group, which causes acute interstitial nephritis
• CA dicarboxylate group, which causes systemic lupus erythematosus
• DA tetrazole ring, which causes severe reflex tachycardia

What common structural pharmacophore do all statin cholesterol-lowering agents share that enables potent competitive inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase?

• AA 3,5-dihydroxyheptanoic acid moiety (or its closed delta-lactone prodrug form) that mimi…
• BA phenoxyisobutyric acid core that activates nuclear PPAR-alpha receptors
• CA 1,4-dihydropyridine nucleus that blocks voltage-gated calcium channels
• DA steroidal cyclopentanoperhydrophenanthrene core that binds bile acids

In the medicinal chemistry of 1,4-dihydropyridine calcium channel blockers (e.g., nifedipine, amlodipine), which structural feature is essential for maintaining optimal vascular L-type Ca2+ channel blocking activity while avoiding cardiac depression?

• AA substituted phenyl ring at C-4 oriented orthogonally to the 1,4-dihydropyridine ring, w…
• BAn unoxidized pyridine ring with identical carboxylate esters at all positions
• CA bulky bicyclic indole ring substituted at the N-1 ring nitrogen
• DReduction of the dihydropyridine ring to a saturated piperidine ring

What structural chemical difference distinguishes doxorubicin (adriamycin) from daunorubicin, and what biochemical mechanism explains the cumulative, dose-dependent cardiotoxicity common to the anthracycline antineoplastic class?

• ADoxorubicin possesses a primary hydroxyl group at C-14 instead of a methyl group; cardiot…
• BDoxorubicin has a halogenated ring causing irreversible alkylation of coronary arteries
• CDoxorubicin lacks the daunosamine aminosugar, causing massive myocardial calcium efflux
• DDoxorubicin contains an active disulfide bridge that inhibits cardiac creatine kinase

In pharmacognosy, what are the three essential chemical structural components of cardiotonic glycosides isolated from Digitalis purpurea and Digitalis lanata (e.g., digoxin, digitoxin)?

• AA steroid nucleus (cyclopentanoperhydrophenanthrene), an alpha,beta-unsaturated five-memb…
• BA flavone nucleus, a benzoic acid group, and an esterified choline
• CA pentacyclic triterpene, an indole alkaloid, and a phosphate group
• DA coumarin ring, an aliphatic diamine, and a glucuronic acid moiety

Which classical colorimetric chemical reaction is specified in pharmacognosy and pharmacopoeias for the qualitative identification of tropane alkaloids (hyoscyamine, atropine, scopolamine) derived from Solanaceae species (Atropa belladonna, Datura stramonium)?

• AVitali-Morin reaction (intense violet/purple coloration upon treatment with fuming nitric…
• BThalleioquin reaction (green coloration with bromine water and ammonia)
• CMurexide reaction (purple ammonium purpurate formation)
• DFroehde reaction (molybdic acid green-to-blue coloration)

In pharmacognosy, which tetracyclic indole nucleus forms the structural parent skeleton of all peptide and amine ergot alkaloids (ergotamine, ergometrine) produced by the parasitic rye fungus Claviceps purpurea?

• ALysergic acid (acide lysergique, with the ergoline tetracyclic ring system)
• BQuinoline ring system
• CPhenanthrene ring system
• DIsoquinoline ring system

Quinine and quinidine are natural alkaloids extracted from the bark of Cinchona succirubra. What is their stereochemical relationship?

• AThey are diastereomers (differing in stereochemical configuration at asymmetric centers C…
• BThey are identical structural enantiomers (mirror images at all stereocenters)
• CThey are structural constitutional isomers differing in the position of the quinuclidine…
• DThey are conformational rotamers that spontaneously interconvert in aqueous solution

Opium obtained from the latex of Papaver somniferum contains two major structural classes of alkaloids. Which pairing correctly classifies these alkaloids into their chemical structural groups?

• AMorphine, codeine, and thebaine are morphinan (phenanthrene) alkaloids; papaverine and no…
• BMorphine is a tropane alkaloid; papaverine is a purine alkaloid
• CCodeine is an indole alkaloid; thebaine is an imidazole alkaloid
• DPapaverine is a steroid alkaloid; noscapine is an anthraquinone glycoside

Paclitaxel (Taxol) and docetaxel are antineoplastic taxane diterpenoids derived semi-synthetically from 10-deacetylbaccatin III extracted from the needles of the European yew (Taxus baccata). What is their specific cellular mechanism of action on the cytoskeleton?

• AHyper-stabilizing GDP-bound beta-tubulin microtubules by promoting assembly and preventin…
• BInhibiting tubulin polymerization and causing depolymerization of existing mitotic spindl…
• CIntercalating into DNA double helices and inhibiting DNA topoisomerase II
• DAlkylating the N-7 position of purines in ribosomal RNA

In pharmaceutical technology, what fundamental equation describes the dissolution rate of a solid drug substance into a liquid dissolution medium under sink conditions?

• AThe Noyes-Whitney equation: dM / dt = (D * A / h) * (Cs - C)
• BThe Stokes-Einstein equation: v = 2 * r^2 * (rho - rho0) * g / (9 * eta)
• CThe Fick's first law of steady-state gas effusion
• DThe Young-Laplace capillary pressure equation

In tablet compression and manufacturing, which excipient is classified as a 'superdisintegrant' that promotes rapid tablet break-up in gastrointestinal fluids by extensive water uptake and dramatic three-dimensional swelling without forming viscous gels?

• ACroscarmellose sodium (sodium carboxymethylcellulose cross-linked)
• BMagnesium stearate
• CAnhydrous lactose
• DTalc powder

Under the Biopharmaceutics Classification System (BCS), how are Class II drugs defined, and what pharmaceutical formulation strategy is primary in improving their in vivo oral bioavailability?

• ALow aqueous solubility and high intestinal membrane permeability; improving formulation d…
• BHigh aqueous solubility and high membrane permeability; no formulation modification is ne…
• CHigh aqueous solubility and low membrane permeability; adding chemical absorption permeat…
• DLow aqueous solubility and low membrane permeability; bypassing the portal system via int…

What reference cycle is commonly used to illustrate saturated-steam moist-heat sterilization of suitable aqueous preparations?

• A121°C for a minimum of 15 minutes at saturated water vapor pressure (approx. 205 kPa / 2…
• B100°C for 60 minutes at atmospheric pressure
• C160°C for 2 hours in a dry hot-air oven (Poupinel)
• D80°C for 30 minutes with simultaneous ultraviolet irradiation

In the Hydrophilic-Lipophilic Balance (HLB) system established by Griffin for surfactant selection in pharmaceutical emulsions, what HLB range is optimal for formulating water-in-oil (W/O) emulsions?

• AHLB values between 3 and 6
• BHLB values between 8 and 16
• CHLB values between 16 and 20
• DHLB values between 0 and 1

During the industrial lyophilization (freeze-drying) of a thermolabile biological injectable, what occurs during the primary drying stage, and what physical boundary condition must never be exceeded to prevent product 'collapse'?

• ASublimation of frozen crystalline ice into water vapor under reduced vacuum; the product…
• BDesorption of bound unfrozen water at ambient room pressure without vacuum
• CRapid flash boiling of liquid water at 100°C under positive pressure
• DThermal condensation of organic excipients into an insoluble polymer matrix

Which rheological flow profile is desirable for liquid pharmaceutical suspensions and topical gels, in which apparent viscosity decreases as the applied shear rate increases (shear-thinning), allowing easy shaking and pouring while preventing particle sedimentation at rest?

• APseudoplastic flow (écoulement pseudoplastique)
• BDilatant flow (shear-thickening flow)
• CNewtonian flow with constant viscosity
• DIdeal Bingham plastic flow with infinite yield stress

In the technology of stealth liposomal nanocarriers (such as liposomal doxorubicin / Caelyx), what chemical modification of the outer phospholipid bilayer prevents rapid recognition and phagocytosis by the mononuclear phagocyte system (MPS / RES)?

• ACovalent grafting of polyethylene glycol (PEG) polymer chains (PEGylation) onto the lipid…
• BIncorporation of heavy polyvalent aluminum ions into the core
• CReplacing all natural phospholipids with uncharged paraffin waxes
• DCross-linking surface proteins with glutaraldehyde

In the structure-activity relationship of classical antibacterial sulfonamides such as sulfamethoxazole, which feature is central to PABA mimicry at dihydropteroate synthase?

• AA free primary aromatic amino group (NH2) para to the sulfonyl moiety on a benzene ring,…
• BA nitro group (-NO2) at the meta position of a pyridine ring
• CAn alkylated tertiary amine directly bound to the sulfonamide nitrogen
• DA hydroxylated naphthyl core with no sulfur atoms