text: All statins have the same pharmacophore so the difference in their pharmacodynamic effect is mostly based on the substituents. The activity of each statin is dependent on the binding affinity of the compound for the substrate site and the length of time it binds to the site. Type 2 statins have unique fluorophenyl group that causes additional polar interaction between the enzyme and the statins, which results in a tighter binding to the enzyme. The newest statin, rosuvastatin has a unique polar methane sulfonamide group, which is quite hydrophilic and confers low lipophilicity. The sulfonamide group forms a unique polar interaction with the enzyme. As a result, rosuvastatin has superior binding affinity to the HMGR enzyme compared to the other statins, which is directly related to its efficiency to lower LDL cholesterol.