Different ratios of SA and LBG were dissolved in the deionized water.The IPN hydrogels of different formulations were prepared by ion gel method with glutaraldehyde （GA） and calcium chloride（CaCl₂） as the cross-linking agents. The physicochemical structures of the hydrogels were characterized with scanning electron microscope （SEM） and Fourier transform infrared spectroscopy （FTIR）. The entrapment efficiency（EE） of the hydrogels was determined by ultraviolet spectrophotometry and the drug release curves were drawn. The particle sizes and drug EE of the hydrogel beads under different ratios of LBG and GA were shown by three-dimensional histogram. Combined with the EE and drug release curve， the optimized formula was selected to wrap DDP to prepare DDP hydrogel beads. The CAL-27 cells were divided into control group， DDP solution group and DDP hydrogel beads group. The survival rates and apoptotic state of the CAL-27 cells in various groups at different time points were observed by MTS and AO/PI fluorescence staining.

The SEM results showed that the surface of the dried gel beads was rough or even uneven and wrinkled. The three-dimensional histogram results showed that the particle size was increased with the increasing of LBG level and was decreased with the increasing of GA level. With the increasing of LBG and GA levels， the EE of the hydrogel was increased. The FTIR results showed that DDP was encapsulated successfully by the IPN hydrogel. When the ratio of SA and LBG was 2.25∶0.75， the level of GA was 3%， and the concentration of CaCl₂ was 3%， the EE of hydrogel was 76.8%， and the drug sustained release time was 48 h.The MTS assay results showed that after treated for 6 and 12 h， the survival rates of the CAL-27 cells in DDP hydrogel beads group were slightly higher than those in DDP solution group （P<0.05）. At 24 and 48 h， the survival rates of the CAL-27 cells in DDP hydrogel beads group were lower than those in DDP solution group （P<0.05）. The cells in control group grew well from 6 to 48 h， and the proliferated cells were dyed green. At 6 and 12 h， the number of CAL-27 cells in DDP solution group and DDP hydrogel beads group was less than that in control group， and the number of survival cells in DDP hydrogel beads group was slightly more than that in DDP solution group. After 24 h， the growth rate of the CAL-27 cells in DDP hydrogel beads group became slower， and the number of survival cells in DDP hydrogel beads group was less than that in DDP solution group at 24 and 48 h.

DDP-IPN hydrogel with sustained-release DDP is successfully prepared and optimized， which has a sustained killing effect on the oral squamous cell carcinoma CAL-27 cells， and it is expected to develop into a new drug sustained-release system.