Explain the selective toxicity of Fluconazole, Cotrimoxazole, and Amoxicillin.

Hey, good to see you again. Here's the explanation for the selective toxicity of the drugs: a) Fluconazole Fluconazole is an antifungal drug that selectively targets fungi by inhibiting the enzyme lanosterol 14--demethylase, which is crucial for the synthesis of ergosterol. Ergosterol is a vital component of fungal cell membranes, whereas human cell membranes contain cholesterol. By disrupting ergosterol synthesis, fluconazole weakens the fungal cell membrane, leading to fungal cell death, without significantly affecting human cells. b) Cotrimoxazole Cotrimoxazole is a combination of two antibiotics, sulfamethoxazole and trimethoprim, which exhibit selective toxicity by interfering with bacterial folate synthesis. Bacteria must synthesize their own folate (folic acid) for DNA and RNA production, using specific enzymes like dihydropteroate synthase (inhibited by sulfamethoxazole) and dihydrofolate reductase (inhibited by trimethoprim). Human cells, however, obtain folate from their diet and do not synthesize it, making them largely unaffected by these drugs. c) Amoxicillin Amoxicillin is a -lactam antibiotic that selectively targets bacteria by inhibiting the synthesis of their peptidoglycan cell wall. It binds to and inactivates penicillin-binding proteins (PBPs), which are enzymes involved in cross-linking peptidoglycan strands, a process essential for bacterial cell wall integrity. Human cells do not possess a cell wall, making amoxicillin highly selective for bacterial cells. Send me the next one 📸