The invention relates to a pharmaceutical preparation for oral administration comprising N-[5-(aminosulfonyl)-4-methyl-1,3-thiazol-2-yl]-N-methyl-2-[4-(2-pyridinyl)phenyl]acetamide or its hydrates and/or solvates, as well as an acid, a method for its production as well as the use of this preparation for the treatment and/or prophylaxis of diseases which are caused by herpes viruses, in particular diseases which are caused by herpes simplex viruses.