Nonionic surface-active agents used as synthetic emulsifiers include

Correct Answer: C

Rationale: Sorbitan esters (spans) (C) are nonionic surfactants used as synthetic emulsifiers, stabilizing emulsions (e.g., creams) by reducing surface tension without ionization. Tragacanth (A) is a natural gum, not synthetic. Sodium lauryl sulphate (B) is anionic, not nonionic. Option D is a placeholder. No original E exists. Spans' lipophilic nature (low HLB) aids oil-in-water emulsions, enhancing drug delivery and stability, widely used in topical and oral pharmaceuticals for their versatility.

Correct Answer: B

Rationale: Creatinine clearance measures glomerular filtration rate (GFR) (B), estimating kidney filtration capacity (mL/min) via serum/urine creatinine, reflecting renal health (e.g., in drug dosing). Renal excretion rate (A) includes secretion/reabsorption. Active secretion (C) and passive absorption (D) are distinct processes. Drug metabolism (original E) is hepatic. GFR's clinical use adjusts renally excreted drugs (e.g., aminoglycosides), ensuring safety in renal impairment, a cornerstone of pharmacokinetics.

Correct Answer: C

Rationale: CYP3A4 (C) is expressed in both intestinal epithelium and kidney, metabolizing many drugs (e.g., midazolam), impacting first-pass and systemic clearance. CYP2D6 (A) is primarily hepatic. CYP1A1/2 (B) is in liver/lung, inducible by smoking. CYP2E1 (D) is hepatic, ethanol-related. No original E. CYP3A4's dual presence reduces bioavailability (e.g., cyclosporine), mediates interactions (e.g., with grapefruit juice), and is critical in drug metabolism studies, influencing dosing and efficacy.

Correct Answer: B

Rationale: Glucose is best described as a monosaccharide (B), a single sugar unit (C₆H₁₂O₆) not hydrolyzable into simpler carbohydrates, serving as an energy source (e.g., dextrose IV). A sugar (A) is broader. Disaccharides (C, e.g., sucrose) and polysaccharides (D, e.g., starch) hydrolyze. Oligosaccharides (original E) are 3-10 units. Glucose's simplicity drives its rapid absorption, critical in hypoglycemia treatment, distinguishing it in carbohydrate chemistry and pharmacokinetics.

Correct Answer: B

Rationale: Plasmids carry optional genes (B), circular double-stranded DNA in bacteria (e.g., antibiotic resistance genes), not essential for growth (C). They're not single-stranded (A) or linear (D). No original E. These extrachromosomal elements enable bacterial adaptability, critical in resistance spread (e.g., beta-lactamases), impacting antibiotic efficacy, a major pharmacology and public health concern.