Media Fill Test for validation of autologous leukocytes separation and labelling by (99m)Tc-HmPAO

Manufacturing of sterile products must be carried out in order to minimize risks of microbiological contamination. White blood cells (WBC) labelled with (99m)Tc-exametazime ((99m)Tc-hexamethylpropyleneamine oxime; (99m)Tc-HMPAO) are being successfully applied in the field of infection/inflammation scintigraphy for many years. In our radiopharmacy lab, separation and labelling of autologous leukocytes with (99m)Tc-HMPAO were performed in a laminar flow cabinet not classified and placed in a controlled area, whereas (99m)Tc-HMPAO radiolabelling procedure was carried out in a hot cell with manipulator gloves. This study was conducted to validate this process using a Media Fill simulation test.

The study was performed using sterile Tryptic Soy Broth (TSB) in place of active product, reproducing as closely as possible the routine aseptic production process with all the critical steps, as described in the our internal standard operative procedures (SOP). The final vials containing the media of each processed step were then incubated for 14 days and examined for the evidence of microbial growth.

No evidence of turbidity was observed in all the steps assayed by the Media Fill.

In the separation and labelling of autologous leukocytes with (99m)Tc-HmPAO, Media-Fill test represents a reliable tool to validate the aseptic process.