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 are often defined as specialty because their price is much higher than that of non-specialty drugs. Medicare defines any drug for which the negotiated price is $670 per month or more, as a specialty drug which is placed in a specialty tier that requires a higher patient cost sharing. Drugs are also identified as specialty when there is a special handling requirement or the drug is only available via a limited distributions network. By 2015 "specialty medications accounted for one-third of all spending on drugs in the United States, up from 19 percent in 2004 and heading toward 50 percent