Iran Pharmacy Ph.D. Entrance Exam flashcards

37 cards. Read the term and the definition here. The deck at the top of this page is optional.

Bioavailability (F)

The fraction of an administered dose reaching systemic circulation unchanged. Absolute F compares oral to intravenous AUC; relative F compares two non-intravenous products.

Noyes–Whitney equation

Describes dissolution rate dC/dt = (D·A/h)(Cs − C). It shows rate increases with surface area and solubility, and decreases with diffusion layer thickness.

Higuchi square-root release

Matrix-controlled drug release proportional to the square root of time: Q = kH·t^1/2. Applies to diffusion-controlled systems with excess solid drug in the matrix.

Korsmeyer–Peppas model

Mt/M∞ = k·t^n. Exponent n near 0.5 indicates Fickian diffusion; n near 1 indicates Case-II relaxation; intermediate values indicate anomalous transport.

Therapeutic index

Ratio TD50/ED50; a larger value indicates a wider margin between toxic and effective doses. Certain safety factor uses LD1/ED99.

Competitive antagonist

Binds reversibly at the agonist site, shifting the log dose–response curve right without lowering Emax. Higher agonist concentrations can overcome the block.

First-order half-life

t1/2 = 0.693·Vd/CL. It is constant for first-order elimination and independent of dose; steady state is reached after about four to five half-lives.

Organophosphate antidotes

Atropine blocks muscarinic effects; pralidoxime reactivates acetylcholinesterase before enzyme aging. Given together in significant poisoning.

Lipinski Rule of Five

Predicts oral absorption: MW ≤ 500, logP ≤ 5, H-bond donors ≤ 5, H-bond acceptors ≤ 10. Two or more violations suggest poor bioavailability.

Bioisostere

A functional group replacement that retains similar biological activity while altering properties such as metabolism or pKa. Examples include tetrazole for carboxylate.

Prodrug

A pharmacologically inactive derivative converted in the body to the active drug, often to improve absorption or target delivery. Enalapril is hydrolyzed to enalaprilat.

Ligand efficiency

Binding free energy divided by number of heavy atoms (ΔG/N). Used to compare lead compounds and prioritize smaller, more efficient molecules.

Alkaloids

Basic nitrogen-containing natural products such as morphine and quinine. Extracted by acid–base partitioning and often toxic at high doses.

Cardiac glycosides

Steroid lactone glycosides such as digoxin that inhibit Na+/K+-ATPase, increasing intracellular calcium and contractility. They have a narrow therapeutic index.

Isoprene rule

Terpenoids are built from C5 isoprene units: monoterpenes C10, sesquiterpenes C15, diterpenes C20, triterpenes C30. Menthol is a monoterpene.

Soxhlet extraction

Continuous reflux extraction using a solvent that repeatedly cycles through the plant material. It is exhaustive but uses heat and large solvent volumes.

Beer–Lambert law

Absorbance A = ε·b·c; proportional to concentration and path length. Deviations occur at high concentration, with polychromatic light, or due to chemical interactions.

Chromatographic resolution

Rs = 2(tR2 − tR1)/(w1 + w2). Baseline separation generally requires Rs ≥ 1.5. Resolution improves with selectivity, efficiency, and retention.

Van Deemter equation

H = A + B/u + C·u; plate height depends on eddy diffusion, longitudinal diffusion, and mass transfer. Optimum flow minimizes H and maximizes efficiency.

LOD and LOQ

LOD is the lowest detectable amount (S/N ≈ 3:1); LOQ is the lowest quantifiable amount (S/N ≈ 10:1). Both can be estimated from calibration SD.

Cockcroft–Gault equation

Estimates creatinine clearance: CrCl = [(140 − age) × weight]/(72 × SCr), multiplied by 0.85 for females. Used to adjust renally cleared drugs.

Vancomycin AUC monitoring

For serious MRSA infection, target AUC24/MIC 400–600. Trough-only monitoring of 15–20 mg/L is an alternative when AUC is unavailable.

Therapeutic drug monitoring

Measurement of drug concentrations for drugs with narrow therapeutic index and clear concentration–effect relationships, such as digoxin, lithium, phenytoin, and tacrolimus.

Heart failure quadruple therapy

Combining an ARNI/ACEi/ARB, evidence-based beta-blocker, mineralocorticoid receptor antagonist, and SGLT2 inhibitor reduces mortality in reduced-ejection-fraction heart failure.

Polymerase chain reaction

Cyclic amplification of DNA by denaturation (~95 °C), primer annealing (~50–65 °C), and extension (~72 °C). Taq polymerase lacks proofreading exonuclease activity.

Monoclonal antibody

Antibody from a single B-cell clone, produced by hybridoma or recombinant technology. Humanized IgG1 antibodies are common therapeutics.

CRISPR-Cas9

Genome editing using a guide RNA to direct Cas9 to a complementary sequence adjacent to a PAM. Double-strand breaks are repaired by NHEJ or HDR.

Biosimilar

A biologic highly similar to an approved reference product in safety and efficacy, demonstrated through analytical, functional, and clinical comparability studies.

Reported speech

Indirect quotation that shifts tense back one step and adjusts time and place words. 'I will start tomorrow' becomes 'she would start the next day'.

Hedging in scientific writing

Using cautious language such as 'may', 'suggest', or 'appear to' to avoid overstating conclusions. It reflects uncertainty and is standard in research reports.

Case–control study

Observational design comparing past exposures in people with and without an outcome. It estimates odds ratios and is efficient for rare diseases.

Intention-to-treat analysis

Analyzes all randomized participants in their assigned groups regardless of adherence. It preserves randomization and estimates practical effectiveness.

Number needed to treat

NNT = 1/absolute risk reduction. It indicates how many patients must be treated for one additional beneficial outcome.

Type I and II errors

Type I error (α) is rejecting a true null hypothesis; type II error (β) is failing to reject a false null. Power equals 1 − β.

Cox proportional hazards model

Survival regression estimating hazard ratios for covariates while adjusting for time-to-event. The proportional hazards assumption must be checked.

Principlism

Ethical framework using autonomy, beneficence, nonmaleficence, and justice. It guides decisions about consent, confidentiality, and resource allocation.

Conflict of interest

A financial or personal interest that could bias professional judgment. It must be disclosed and managed, especially in prescribing and research.