Minazol is a topical powder that contains the active ingredient miconazole. Miconazole is an antifungal medication. Thus, it is effective in treating ringworm or fungal infection.
Gentrisone cream contains a topical steroid betamethasone dipropionate, a topical antibacterial agent gentamycin and topical antifungal agent clotrimazole. As Gentrisone contains a strong topical steroid, it is effective for treating eczema and skin dermatitis.
While Gentrisone contains a topical antifungal agent, it is not an ideal treatment for fungal infections as the steroid component makes it more difficult to clear the fungal. If you use a topical steroid cream to treat a fungal infection, there is a risk of worsening the spread of the fungal infection.
In short, it is preferable to treat a fungal infection with a pure anti-fungal cream than a combination cream containing topical steroids.