Table 1.

Results of the quality control assays.

CQA	Method	Specification	Soberana Plus	PastoCovac Plus
Appearance	Direct Observation	White opaque suspension	Passed	Passed
pH	Potentiometry	6.0-7.2	7.09	6.78
Aluminum hydroxide content	Complexometry	1.5–3.5 mg/mL	2.31 mg/mL	2.57 mg/mL
Total protein content	Modified Lowry1	(100 ± 30) µg/mL	74 µg/mL	88 µg/mL
Adsorption percent	Modified Lowry	≥ 70%	91%	84%
Osmolality	Osmometer	–	284 mOsmol/Kg	281 mOsmol/Kg
Volume	Using separate syringes	Not less than stated amount	Passed	Passed
RBD identity	SDS-PAGE and Immonoblotting	Positive recognition	Passed	Passed
Endotoxin content	Chromogenic LAL2 Test	>100 EU/mL	0.4 EU/mL	0.45 EU/mL
Sterility	Culture	Absence of viable microorganism	Passed	Passed
Abnormal toxicity	Injection into a laboratory animal	None of the animals show any weight loss and toxic signs at the end of the observation	Passed	Passed
Immunogenicity	Injection into mice & ELISA	At least 70% of the animals showing a seroconversion with a titre 4 times higher than the non-immunized animals	90%	100%

¹Lowry Protein Assay.

²LAL: limulus amebocyte lysate.