Abstract
Local anesthetics are used to reduce pain, but they are so frequently injected to patients. So, we prepared lidocaine solid lipid microspheres (SLM) as long acting abdominal injection using spray drying method and evaluated drug entrapment, particle size, SEM, zeta potential and in vitro and in vivo drug release pattern, The particle sizes of SLM were 30∼100$\mu$m and it is enough to inject into abdominal tissue. The entrapment efficiency of SLM was over 95% as spray drying method. Surfactant and PC decreased the burst effect by 20∼30%. In in vivo test, C-6 showed controlled release concentration profile in plasma for 8 days and C-5 sustained longer than we expected.