Process for producing dextran products having substantially uniform molecular size for pharmaceutical and therapeutic preparations

Claim 1

IN THE PRODUCTION OF DEXTRAN PREPARATIONS OF SUBSTANTIALLY UNIFORM MOLECULAR SIZE, THE PROCESS WHICH COMPRISES ADDING, TO AN AQUEOUS SOLUTION OF PARTIALLY-DEGRADED DEXTRAN HAVING A WIDE RANGE OF MOLECULAR SIZE, A QUANTITY OF A WATERMISCIBLE ORGANIC SOLVENT WHICH IS A NON-SOLVENT FOR DEXTRAN AND SELECTED FROM A CLASS CONSISTING OF ALCOHOLS AND KETONES, THE AMOUNT ADDED BEING ONLY SUFFICIENT TO PRODUCE A PRECIPITATE AND TO LEAVE A SUBSTANTIAL WUANTITY OF DEXTRAN STILL DISSOLVED, REMOVING THE RESULTING PRECIPITATE CONTAINING A RELATIVELY-UNIFROM HIGH-MOLECULARL DEXTRAN FRACTION FROM THE SOLUTION, ADDING AN ADDITIONAL QUANTITY OF THE ORGANIC SOLVENT TO THE SOLUTION SUFFICIENT TO FORM A SECOND PRECIPITATE THEREIN WHILE LEAVING A QUANTITY OF LOW-MOLECULAR DEXTRAN STILL DISSOLVED, AND RECOVERING THE SAID SECOND PRECIPITATE CONTAINING DEXTRAN OF A RELATIVELY-UNIFROM INTERMEDIATE MOLECULAR SIZE.