The present invention relates to topical pharmaceutical microemulsions of cyclosporine Acomprising a half (C -C 4 ) alkyl esters of poly (methyl vinyl ether-co- maleic anhydride) (PVM/MA) copolymers. The invention also relates to a process for the preparation of said compositions and to their use in the prevention and/or treatment of several diseases, particularly psoriasisand atopic dermatitis.