A Solvent Mixture of Methyl Tert-butyl ether with Fluorocarbon for Cholesterol Gallstone Dissolution

Since methyl tert-butyl ether (MTBE), which has recently received a lot of interest as a directly cholelitholytic agent for its rapid effect, cannot dissolve in bile and floats on it (specific gravity, 0.747), stone-solvent contact which is the rate-limiting factor in gallstone dissolution is unexpectedly insufficient. If excessive amounts of MTBE escape from the biliary tract and are absorbed systemically, such local and systemic toxicities as vomiting dyspnea, somnolence, duodenitis and so on are often produced. We used fluorocarbon, which was developed as an excellent substitute for red blood cells (oxygen carrier), to obtain a solvent mixture with MTBE, and found that MTBE dissolved completely in fluorocarbon. A mixed stone initially weighing 137 mg decreased in weight to 91 mg (66.4%) after 3 hr exposure to the solvent mixture of MTBE (0.5 ml) and fluorocarbon (1.5 ml), whereas another stone (initially 403 mg) weighed 327 mg (81.1%) after exposure to a mixture of MTBE (2 ml) and bile (1 ml). Fluorocarbon and MTBE, therefore, will be able to constitute a solvent mixture to fill in the space for gallstone dissolution (for example, gallbladder) safely for much greater stone-solvent contact.