ANTI FUNGAL DRUGS

 introduction 15.1

A polyene is a compound containing many double bonds that are conjugated. A macrocyclic polyene having a highly hydroxylated area on the ring opposing the conjugated system is referred to as a polyene antifungal. Polyene antifungals are consequently amphiphilic.

The polyene antimycotics attach to sterols, primarily ergosterol, in the fungal cell membrane. The cell membrane's transition temperature (Tg) is modified as a result, becoming less fluid and more crystalline. (In normal circumstances, membrane sterols thicken the plasma membrane by increasing the packing of the phospholipid bilayer.)

As a result, small organic molecules and monovalent ions (K+, Na+, H+, and Cl) leak from the cell, which is one of the main reasons cells die.

Animal cells are substantially less prone since they contain cholesterol rather than ergosterol. However, some amphotericin B is toxic at therapeutic dosages. Amphotericin B may attach to the cholesterol in animal membranes, raising the possibility of human harm.

When administered intravenously, amphotericin B causes kidney damage. A polyene's ability to bind sterol increases with the reduction of its hydrophobic chain. As a result, additional hydrophobic chain reduction may cause it to attach to cholesterol and become harmful to animals.

Antibiotics fall under the following categories:

antibiotic B

Candicidin

binds to cholesterol and has 35 carbons (toxic)

Hamycin

Natamycin has 33 carbons and has a good affinity for ergosterol.

Nystatin

Rimocidin

Antifungal agents that use imidazole, triazole, and thiazole

Except for abafungin, azole antifungal medications prevent the enzyme needed to transform lanosterol into ergosterol, lanosterol 14 -demethylase. Ergosterol depletion in fungi inhibits the growth of fungi by altering the structure and many other functions of the fungi's membrane.

The following are medications from the imidazole group:

Bifonazole

Butoconazole

Clotrimazole

Econazole

Fenticonazole

Isoconazole

Ketoconazole 

Luliconazole

Miconazole

The following are medications in the triazole family:

Albaconazole

Efinaconazole

Epoxiconazole

Fluconazole

Isavuconazole

Itraconazole

Posaconazole

An antifungal drug is a type of pharmaceutical fungicide or fungistatic that is used to treat and prevent mycoses including athlete's foot, ringworm, candidiasis, severe systemic infections such as cryptococcal meningitis, and others.