In vitro comparison of different gall stone dissolution solvents.

Extracorporeal shockwave lithotripsy (ESWL) of gall bladder stones leaves residual fragments that need to be dissolved by chemical solvents. In this study we compared the in vitro dissolving capacity of methyl tert-butyl ether (MTBE), mono-octanoin, limonene, and limonene/mono-octanoin (70%/30%). From nine sets of five human gall stones obtained at cholecystectomy, four stones were used for dissolution and the fifth was used for chemical analysis of cholesterol, calcium, and bilirubin contents. Eight sets were cholesterol stones with a mean (SD) cholesterol content of 89.9 (5.6)%. These stones dissolved completely in either solvent, often leaving sand-like debris, with the exception of one stone. MTBE dissolved cholesterol gall stones 100 times faster than mono-octanoin and 10 times faster than limonene or the limonene/mono-octanoin mixture (p less than 0.001). The combination of limonene and mono-octanoin was as effective as limonene alone. Of the four solvents, MTBE is the best one to evaluate for dissolution of residual fragments after ESWL treatment of gall bladder stones.