Stability studies of lysozyme for preformulation

Objective To investigate the influence of pH value,temperature,protectant and organic solvent on the physical stability and biological activity of lysozyme.Methods The concentration of lysozyme was determined by HPLC and the biological activity of lysozyme was tested by turbidimetric method.Results Lysozyme was physically stable at pH4.0 and pH10.0.The biological activity of lysozyme was kept well at pH4.0 while it was totally destroyed at pH1.0.Low temperature tended to protect lysozyme from damage.Mannitol protected lysozyme at the beginning and then accelerated its destruction.Organic solvent seriously destroyed lysozyme while the biological activity of lysozyme remained to some degree.Conclusion The pH value,temperature,protectant and organic solvent can obviously influence the physical stability and biological activity of lysozyme.