The interaction of the bentonite of the Manrak deposit of the East-Kazakhstan region with the AK-29 and richlokam local anesthetics has been studied to synthesize the new prolonged medical compounds. The methods of equilibrium swelling, sedimentation, electrophoresis, rotational viscosimetry, and IR spectroscopy have been used. The comparative analysis of interaction of bentonite clay with medical compounds has been carried out. The dependence of interaction nature on an anesthetic structure has been observed. Results of anesthetic release from polymer show a high degree of their fixation and prolongation. (C) 2007 Wiley Periodicals, Inc.