Objective The purposes of this study were to investigate effects of chloroqquine (CQ) on inhibiting the decom- position of hydrogen peroxides (HP), and to optimize composition of the tooth- bleaching agent.Methods According to the princi- ple of the color-changing reaction between horse radish peroxidase and substrate, the tooth-bleaching agent made of HP was divided into fourgroupswith different amounts of CQ. The stability ofHPwas observed using ELISAfor3 months.Results Withthe prolon- gation of store time, the absorbance of HP solutions containing different concentrations of CQ declined at different degrees, which showed a dependent relation between absorbance values and concentrations of CQ. Within the range of experiment concentrations of CQ, the higher the concentration of CQwas, the strongerthe stability ofHPwas. And the duration of tooth-bleaching effects in 150. 0 mg/ml of CQwas prolonged 4 to 6 times compared to thatwithout CQ.Conclusion The data indicate that CQ can inhibit the de- composition of HP. The bleaching effect of the tooth-bleaching agent which is made of HP and proper amount of CQ is satisfactory.
