Production optimization of 99Mo/99mTc zirconium molybate gel generators at semi-automatic device: DISIGEG

DISIGEG is a synthesis installation of zirconium (99)Mo-molybdate gels for (99)Mo/(99m)Tc generator production, which has been designed, built and installed at the ININ. The device consists of a synthesis reactor and five systems controlled via keyboard: (1) raw material access, (2) chemical air stirring, (3) gel dried by air and infrared heating, (4) moisture removal and (5) gel extraction. DISIGEG operation is described and dried condition effects of zirconium (99)Mo- molybdate gels on (99)Mo/(99m)Tc generator performance were evaluated as well as some physical-chemical properties of these gels. The results reveal that temperature, time and air flow applied during the drying process directly affects zirconium (99)Mo-molybdate gel generator performance. All gels prepared have a similar chemical structure probably constituted by three-dimensional network, based on zirconium pentagonal bipyramids and molybdenum octahedral. Basic structural variations cause a change in gel porosity and permeability, favouring or inhibiting (99m)TcO(4)(-) diffusion into the matrix. The (99m)TcO(4)(-) eluates produced by (99)Mo/(99m)Tc zirconium (99)Mo-molybdate gel generators prepared in DISIGEG, air dried at 80°C for 5h and using an air flow of 90mm, satisfied all the Pharmacopoeias regulations: (99m)Tc yield between 70-75%, (99)Mo breakthrough less than 3×10(-3)%, radiochemical purities about 97% sterile and pyrogen-free eluates with a pH of 6.