Discovery and development of statins 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. Lipophilicity of the statins is considered to be quite important since the hepatoselectivity of the statins is related to their lipophilicity. The more lipophilic statins tend to achieve higher levels of exposure in non-hepatic tissues, while the hydrophilic statins tend to be more hepatoselective. The difference in selectivity is
Specialty drugs in the United States not only costs more, but they also take longer to develop than other large market pharmaceuticals (See Drug development). In addition, there are often fewer drug choices for rare or hard-to-treat diseases. This results in less competition in the marketplace for these drugs due to patent protection, which allows these firms to act as monopolists (See Drug Price Competition and Patent Term Restoration Act). Due to this lack of competition, policies that serve to limit prices in other markets can be ineffective or even counter-productive when applied to specialty drugs. High prices for specialty drugs are a problem for both