Comparison of Two Methods for Determination of Antibiotic Moisture

OBJECTIVE Determination of water content in antibiotics by gas chromatography and Fisher's method, to investigate the feasibility of determination of water content in antibiotics by gas chromatography. METHODS Determination by gas chromatography with a headspace capillary gas chromatography-thermal conductivity detector method by using Agilent HP-PLOT/Q(30 m×0.530 mm, file 40 μm) capillary column. The high purity helium was used as the carrier gas with the flow of 3 mL·min^-1. The injection volume was 250 μL with the split ratio of 20:1. The injection temperature was 200℃. The Column temperature program:initial temperature 150℃, keep 6 min, 60℃ per minute at a rate of up to 250℃, keep 5 min. The detector temperature of thermal conductivity detector was 250℃ and the current was 70 mA. Fisher's method adopted the volumetric titration method in the first method of moisture determination in the fourth general rule 0832 of the 2015 edition of the "People's Republic of China Pharmacopoeia". RESULTS Except ceftriaxone sodium for injection and cefazoloxime sodium for injection, there was no significant difference between the two determination methods for other antibiotic samples. CONCLUSION The gas chromatography established in this paper can be used to determine the moisture content of some antibiotics.