Validation of the sterility maintenance of 20% filled intramucosal glycerol solution bags using a manual filling pump

Introduction-objective

After intramucosal injection, glycerin allows coloration of colonic tumors, helping in surgical excision. During its manufacture, the sterilization is done by passing through a 0.22 m porosity filter which is the reference method of glycerin filtration because of its decomposition into toxic acrolein on heating. The long and difficult manufacturing process can generate musculo-articular problems. Manual filling pump systems for liquid transfer exist, but none have assessed the potential damaging produced by pressure exerted on the filter, thus compromising sterility.

Our objective was to measure pressure levels on filters using a Baxter brand manual filling pump.

Method

Pressure measurements were done with a sterile manometer syringe on the usual number of bags manufactured. Filling after two filtrations of 2x50mL (glycerin 10mL, NaCl 0.9% 40mL), of an empty bag of 100mL (EVAM). Filter was changed between two bags. The normality of the distribution has been tested by the Shapiro-Wilk test. A descriptive and inferential analysis was performed by comparing the observed means with the reference value (filter rupture pressure) by the Mann and Whitney or Student tests. The inter-operator comparison (two women and two men) pressures was carried out by the Kruskall-Wallis test. The degree of significance of the tests was set at 0.05.

Results

With a reference filter rupture pressure (PALL) of 5.2 bars, maximum pressure threshold has been fixed at 5 bars. Sterilization of the pump has been done by peracetic acid.

A total of 20 measurements were made on 10 manufactured 20% glycerol bags. The average pressures measured for four production runs by four different operators were: 4.271; 3.511; 3.850; 3.929 bars. For all four operators, the mean pressures were significantly below the reference value (p-values were respectively: 1.37E-7; 1.62E-9; 6.33E-9; 2.27E-9). No significant difference was found between the pressures of the four operators.

Discussion - Conclusion

The addition of the pump on the sterile field obliges to reorganize the working space which is reduced. Its sterilization results in a higher production cost. However, with less physical effort to provide, this pump saves time per batch and a greater number of batches per campaign. And, above all, the process helps maintain health at work.

This study showed an inter-preparator reproducibility and an absence of risk of filter damaging, which led to the routine use of the pump.