Study on the Stability of Sheep Oxytocin in the Osmotic Pump

The experiment was aimed to evaluate the stability of oxytocin in osmotic pump (ALZET^®) at 39.1℃. The experiment was divided into 3 groups, i.e. the osmotic pump group, microcentrifugal tube group and control group. The control group remained frozen at -80℃, the other two groups were incubated in 39.1℃ incubator, and the samples were collected at different time points. All samples were analyzed by ultra-performance liquid chromatography tandem quadrupole/flight time mass spectrometry (UPLC-Q-TOF MS) method. The oxidation process of oxytocin in osmotic pump at 39.1℃ was analyzed by comparing the peak area of main oxidized products extracted ion chromatogram. The results showed that the degree of oxidation increased with time in osmotic pump and microcentrifugal tube at 39.1℃, and there was no significant difference between the two groups (P >0.05). The percentage of oxytocin prototype of samples which collected at different time points of osmotic pump group and microcentrifugal tube group versus control group were 83.6% to 117.8% and 83.2% to 116.2%, respectively, suggested that the trials involved in the osmotic pump implantation of oxytocin in sheep need to consider the effect of content changes caused by oxytocin oxidation on the test results.