Development of drugs - The concept of bioisosterism

The couples benzene-thiophene, benzene-pyridine, thiophenefurane represent prominent examples of bioisosterism in drug research. These cycles are aromatic and similar of expansion and electronical properties (isostere). The concept of bioisosterism includes also the replacement of substituents and atoms in pharmacologically active compounds. Selected drugs are shown to introduce into this important principle of rational drug design.