ANTIFUGAL DRUGS AND PHARMACOLOGICAL ACTIVITIES

                               


Terbinafine -Terbinafine hydrochloride (Lamisil) is a synthetic allylamine antifungal.Terbinafine inhibits ergosterol synthesis by inhibiting the fungal squalene monooxygenase (squalene 2,3-epoxidase), an enzyme that is part of the fungal cell wall synthesis pathway.Terbinafine hydrochloride is used for the treatment of dermatophyte infections.



Itraconazole-is a triazole antifungal agent that inhibits cytochrome P-450-dependent enzymes resulting in impairment of ergosterol synthesis. It has been used against histoplasmosis, blastomycosis, cryptococcal meningitis & aspergillosis.Itraconazole is a highly selective inhibitor of fungal cytochrome P-450 sterol C-14 α-demethylation via the inhibition of the enzyme cytochrome P450 14α-demethylase. This enzyme converts lanosterol to ergosterol, and is required in fungal cell wall synthesis. The subsequent loss of normal sterols correlates with the accumulation of 14 α-methyl sterols in fungi and may be partly responsible for the fungistatic activity of fluconazole. Mammalian cell demethylation is much less sensitive to fluconazole inhibition.



Clotrimazole-is an imidazole derivative with a broad spectrum of antimycotic activity. It inhibits biosynthesis of the sterol ergostol, an important component of fungal cell membranes. Its action leads to increased membrane permeability and apparent disruption of enzyme systems bound to the membrane.It is used for the local treatment of oropharyngeal candidiasis and vaginal yeast infections, also used in fungal infections of the skin such as ringworm, athlete's foot, and jock itch



Ciclopirox- is a broad-spectrum antifungal medication that also has antibacterial and anti-inflammatory properties. Its main mode of action is thought to be its high affinity for trivalent cations, which inhibit essential co-factors in enzymes.



Fluconazole-is a synthetic antifungal agent of the imidazole class, is used to treat vaginal candidiasis. It inhibits the fungal lanosterol 14 alpha-demethylase which thereby prevents the formation of ergosterol which is an essential component in the fungal cell membrane



Ketoconazole-is an imidazole antifungal agent.It is used for treating candidiasis, chronic mucocutaneous candidiasis, oral thrush, candiduria, blastomycosis, coccidioidomycosis, histoplasmosis, chromomycosis, and paracoccidioidomycosis.Ketoconazole interacts with 14-α demethylase, a cytochrome P-450 enzyme necessary for the conversion of lanosterol to ergosterol. This results in inhibition of ergosterol synthesis and increased fungal cellular permeability. Other mechanisms may involve the inhibition of endogenous respiration, interaction with membrane phospholipids, inhibition of yeast transformation to mycelial forms, inhibition of purine uptake, and impairment of triglyceride and/or phospholipid biosynthesis.



Miconazole-is An imidazole antifungal agent.It is used either on the skin or in the vagina for fungal infections. Miconazole interacts with 14-α demethylase, a cytochrome P-450 enzyme necessary to convert lanosterol to ergosterol. As ergosterol is an essential component of the fungal cell membrane, inhibition of its synthesis results in increased cellular permeability causing leakage of cellular contents. Miconazole may also inhibit endogenous respiration, interact with membrane phospholipids, inhibit the transformation of yeasts to mycelial forms, inhibit purine uptake, and impair triglyceride and/or phospholipid biosynthesis.