the present invention discloses the ph - sensitive nanoparticles composed of ph - sensitive polymer , hydrophobic material , internal stabilizer , external stabilizer content and insulin drug . the present invention also includes a method for preparation of ph - sensitive nanoparticles , in particular , a multiple emulsions solvent evaporation method . the ph - sensitive nanoparticles of the present invention show good ph - sensitive property with 100 - 300 nanometer particle size . significant decrease in blood glucose level is observed in streptozotocin - induced diabetic rats and the bioavailability of insulin is more than 10 % after oral administration of the insulin - loaded ph - sensitive nanoparticles .