first, mix lactic acid with distilled water and put it on a mametic and heat it to 55 degree celsius. then gently pour chitosan into it and then drop tween into it. next close the lid and drill it. next drop oil then keep stir it until all the mixture completely mix. then let it cool down bit. then drop it in solution of NAOH + H2O . next wash NAOH from the beads put the bead in a plate and finally bake it.