Radiochemical purity and particles number determinations of modified 99mTc-macroaggregated albumin

Anew procedure for the aggregation of human albumin and 99mTc-labelling of the prepared macroaggregated albumin are presented. Simple methods for quantifying of all the radiochemical impurities existing in 99mTc-MAA were tested. Thus, 85% methanol was used as the mobile phase in paper and ITL chromatography with Whatman No 1 and ITLC-SAstrips. Asystem of two solvents (acetone and 1MNaCl or 0.9%NaCl) was used for 3MM paper, ITLC-SA and ITLC-SG strips and silica gel plates as the stationary phase. Low-voltage paper electrophoresis with Whatman 3MM paper sheets soaked in barbiturate buffer and the gel chromatography column method (Sephadex G-25) were also applied. Filtration through syringe filters, proposed by European and Yugoslav Pharmacopoeia, was performed for comparison. The application of the mentioned tests lead to consistent results for the labelling efficiency (> 98.5%) and percent radiochemical impurities of 99mTc-MAA. Determination of the particles number in a counter chamber and their size distribution under a light microscope with a calibrated ocular scale gave the result of 300000 ?350000 particles per 1 mg of HA. This confirmed that the human albumin macroaggregates prepared by our new procedure is remarkably improved and convenient for routine diagnostic purposes. U radu je prikazan novi postupak agregacije ljudskog albumina i obelezavanje dobijenih makroagregata albumina tehnecijumom-99m. U cilju odredjivanja prisutnih radiohemijskih necistoca dobijenog 99mTc-MAA primenjuju se jednostavne radiohemijske metode. Tako se 85% metanol koristi kao mobilna faza pri papirnoj (Whatman No 1) i hromatografiji na tankom sloju (ITLC-SA). Pri upotrebi 3MM papira, ITLC-SA, ITLC-SG traka i silika-gel ploca kao mobilna faza koristi se sistem od dva rastvaraca: aceton i 1 M NaCl ili 0.9 % NaCl. U radu su takodje koriscene niskonaponska elektroforeza sa trakama Whatman 3 MM papira pokvasenim u barbituratnom puferu, kao i gel-hromatografija na koloni (Sephadex G-25). U cilju poredjenja dobijenih rezultata koriscena je i metoda filtracije kroz odgovarajuce filtre, kako je propisano Evropskom i Jugoslovenskom farmakopejom. Rezultati dobijeni za prinos obelezavanja i sadrzaj svih prisutnih radiohemijskih necistoca primenom navedenih metoda su u saglasnosti sa propisanim. Odredjivanje broja dobijenih cestica i njihove raspodele po velicini je pokazalo da se od 1 mg ljudskog albumina koriscenog za agregaciju dobija 300000 ? 350000 cestica. Ovi rezultati potvrdjuju d