Objective To investigate the organic components in cefmetazole sodium butyl rubber clousures for injection and their migration into drugs,and to evaluate the compatibility of pharmaceutical butyl rubber clousures with cefmetazole sodium.Methods The structures of volatile components in butyl rubber clousures of cefmetzole sodium for injection and those migrated into drugs were identified by GC/MS SCAN mode and National Institute of Standard and Technology(NIST)spectrum library.An HPLC method was established to quantitatively analyse the antioxidants and vulcanizing agents transferred from butyl rubber clousures into drugs.Results Organic compounds such as antioxidant BHT and silicone oil were identified by GC/MS.The HPLC was used to determine the peak area of antioxidant(168,264,330,1 076,1 010)and vulcanizing agent in the range of 0.5-100 μg·mL-1 with good linear relationship with the peak area.The average recoveries(low,medium,and high)of antioxidant and vulcanizing agents ranged from 90.0%to 110.0%,and the corresponding RSD were all less than 2%(n=9).It was found that the antioxidant BHT and silicone oil in cefmetazole sodium butyl rubber clousures for injection would migrate into the drug and affect the clarity of the solution.Conclusion GC-MS/HPLC method can be used as an effective method for quality control of packing materials(butyl rubber clousures)and drug compatibility studies,so as to ensure the safety of drug use by the public.