Amphotericin B causes nephrotoxicity via a direct tubular mechanism. The strategy of using liposomal amphotericin B (L-AmB) reduces nephrotoxicity because:
- A Liposomal encapsulation reduces renal tubular delivery of free amphotericin B while maintaining bioavailability to fungal cell membranes ✓
- B Liposomes decrease gastrointestinal absorption, reducing systemic exposure
- C Liposomal formulation enhances hepatic first-pass metabolism, lowering plasma drug levels
- D Liposomes chelate amphotericin B in the kidney tubule, preventing direct toxicity
Correct answer: A. Liposomal encapsulation reduces renal tubular delivery of free amphotericin B while maintaining bioavailability to fungal cell membranes
Explanation
Liposomal amphotericin B preferentially accumulates in organs rich in reticuloendothelial (mononuclear phagocyte) cells (liver, spleen, lungs — sites of fungal infection) while delivering less free drug to renal tubular epithelium. The lipid vehicle shields the drug from renal tubule exposure; drug is released preferentially at sites of fungal infection where phospholipase activity and altered membrane composition trigger release. This selective tissue distribution markedly reduces nephrotoxicity without compromising antifungal efficacy.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.