text: In organic chemistry, a methiodide is a chemical derivative produced by the reaction of a compound with methyl iodide.  Methiodides are often formed through the methylation of tertiary amines:
  : RN + CHI → (CH)RNI
  Whereas the parent amines are hydrophobic and often oily, methiodides, being salts, are somewhat hydrophilic and exhibit high melting points.  Methiodides exhibit altered pharmacological properties as well.  
  Examples include:
  * Cocaine methiodide, a charged cocaine analog which cannot pass the blood brain barrier and enter the brain
  * Bicuculline methiodide, a water-soluble form of bicuculline
  Tertiary phosphines and phosphite esters also form methiodides.