Biodegradable controlled release microspheres for the prolonged administration of a local anesthetic agent, and a method for the manufacture thereof are disclosed. The microspheres are formed of a biodegradable polymer degrading significantly within a month, with at least 50% of...http://www.google.com/patents/US5700485?utm_source=gb-gplus-sharePatent US5700485 - Prolonged nerve blockade by the combination of local anesthetic and glucocorticoid 
