The coronavirus disease 2019 (COVID-19) has become a substantial threat to the international health sector and the global economy. As of 26 December 2021, the number of mortalities resulting from COVID-19 exceeded 5.3 million worldwide. The absence of an effective non-vaccine treatment has prompted the quest for prophylactic agents that can be used to combat COVID-19. This study presents the feasibility of chicken egg yolk antibody (IgY) anti-receptor-binding domain (RBD) spike SARS-CoV-2 as a strong candidate to neutralize the virus for application in passive immunization. For the purpose of preclinical studies, we radiolabeled IgY anti-RBD spike SARS-CoV-2 with radionuclide iodine-131. This allowed us to evaluate several biological characteristics of IgY in vitro, in vivo, and ex vivo. The preclinical data suggest that IgY anti-RBD spike SARS-CoV-2 could specifically bind to the SARS-CoV-2 antigens; however, little uptake was observed in normal cells (MRC-5) (<2%). Furthermore, the ex vivo biodistribution study revealed that IgY predominantly accumulated in the trachea of normal mice compared to other organs. We also found that IgY possessed a good safety profile when used as an intranasal agent. Taken together, we propose that IgY anti-RBD spike SARS-CoV-2 has the potential for application in passive immunization against COVID-19.

SPECTROPHOTOMETRIC DETERMINATION OF MOLYBDENUM CONTENT IN 99m Tc SOLUTION VIA Mo-TGA-KSCN COMPLEXES FORMATION. Quality of Technetium-99m solution is determined from its radiochemical, radionuclidic and chemical purity. One of the major concern about chemical purity of Tc-99m from irradiated natural molybdenum is its molybdenum content or Mo breaktrough. Spectrophotometric method is one of method that could be applied for Mo determination in Tc-99m solution. Molybdenum (V) could form a colored complexes with potassium thiocyanate (KSCN) but Molybdenum (VI) must be reduced before formed a complexes with KSCN. Thioglycolic Acid (TGA) was used as reducing agent to obtain reduced Mo (Mo(V)). A series of optimization process was carried out to find optimum condition of complex formation for analysis purposes. Optimized condition were 3 mL of 25% HCl was added into a volume of Mo sample, followed by 200 µL of 10% TGA, 1 mL of 10% KSCN, and water addition up to 10 mL total volume. The method is linear over 2 ppm to 30 ppm Mo with regression coeffisient 0.9988±0.0007. The detection limit was 0.212 ppm Mo. Color of the complex has a stability of absorbance up to 120 minutes while stored at room temperature. No significant deviation occured when 1000 ppm of oxalic acid, methyl ethyl ketone and iron added into sample solution. This complexing method is suitable for spectrophotometric determination of molybdenum content in Tc-99m solution as a part of quality control process.

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