Preparation of technetium-99 m human albumin nanospheres for use in the measurement of reticuloendothelial clearance capacity

Abstract

Background:The rate at which radioactive albumin particles clear from the bloodstream is used to measure reticuloendothelial capacity. Traditionally, iodine radioisotopes have been used. Non-active albumin particles mixed with the technetium-99 m labelled particles of the readily available radiopharmaceutical 99m Tc Albumin Nanocolloid (ANC) would be more convenient. Aim: To prepare human albumin nanospheres (HAN) with a diameter similar to 99m Tc-ANC and to investigate their stability. Experimental: HAN were prepared by heating 30 g/l albumin solution pH 10 at 701C for 20 min then 751C for 17.5 min, adjusting to pH 7.5 and sterilizing by filtration. Seven batches were prepared. The HAN diameter was measured by photon correlation spectroscopy at 0-3 months. Various measures of stability were performed. Results: The mean diameter of the HAN was 3.971.9, 4.071.5, 4.471.6 and 4.272.0 nm at 0, 1, 2 and 3 months. After mixing HAN and 99m Tc-ANC, no changes in particle size or radiolabelling of ANC were detected. Conclusions: HAN with a diameter comparable to the particles in 99m Tc-ANC were prepared successfully. The diameter of HAN does not change over 3 months or after mixing with 99m Tc-ANC. The particle size and labelling efficiency of 99m Tc-ANC are not affected by the addition of HAN.

Quantifying changes in innate immune function following liver transplantation for chronic liver disease

“…7 Preparation of radiolabelled nanospheres Albumin nanospheres were prepared as previously described. 8 Briefly, 330 mL human albumin solution 40 g/L (Albuminativ; Octapharma AB, Stockholm, Sweden) was diluted to a concentration of 30 g/L with Sodium Chloride 0.9% in a 500 mL vial. Under aseptic conditions, 20 mL aliquots of the albumin nanosphere suspension were filtered through sterile 220 nm Millex GS filters (Millipore UK LTD, Watford, UK) into sterile vials and stored at 2 C-8 C. On the day of the study, 1 mL 99m Tc-Albumin Nanocolloid Injection (15 MBq/mL) (Nanocoll; GE Healthcare, Amersham PLC, Little Chalfont, UK) was added to a vial containing 20 mL albumin nanosphere suspension.…”