Amphotericin B has the highest efficacy among systemic antifungals but significant nephrotoxicity. Which formulation strategy reduces nephrotoxicity while maintaining antifungal efficacy?

• A Micellar preparation with polysorbate 80 increasing renal clearance of amphotericin
• B Addition of flucytosine to reduce the required amphotericin dose by 50%
• C Liposomal amphotericin B (L-AMB) — lipid carriers preferentially deliver drug to macrophages/fungal sites, reducing free drug concentration in renal tubular cells ✓
• D Subcutaneous depot formulation bypassing renal first-pass elimination

Explanation

Liposomal amphotericin B (AmBisome) encapsulates amphotericin B in unilamellar phospholipid liposomes. These liposomes preferentially fuse with ergosterol-rich fungal membranes and are taken up by macrophages in infected tissues (lungs, liver, spleen), releasing drug at the site of infection while reducing free amphotericin exposure to renal proximal tubular cells. This results in significantly lower nephrotoxicity (less decline in GFR, less hypokalaemia, less hypomagnesaemia) compared to the conventional deoxycholate formulation, while maintaining equivalent antifungal activity for invasive fungal infections.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.