Reproducibility of GMP-compliant production of therapeutic stressed peripheral blood mononuclear cell-derived secretomes, a novel class of biological medicinal products

Table 8 Physicochemical properties of PBMC^sec 1 and 2 after 6 months of storage at different temperatures

Test	− 20 °C	+ 5 °C	+ 25 °C	+ 40 °C
Appearance of lyophilisate	White, no color deviations or discolorations, amorphous, homogenous	White, no color deviations or discolorations, amorphous, homogenous	White, no color deviations or discolorations, amorphous, homogenous	Reddish brown, uniformly stained, amorphous, not homogenous at the edge of the lyophilisate
Dissolution time	40 ± 5 s	36.5 ± 0.5 s	52.5 ± 10.5 s	Could not be completely dissolved within 15 min
Color of reconstituted solution	Equivalent to reference solution GY5	Equivalent to reference solution GY5	Equivalent to reference solution GY5	Not equivalent to any of the reference solutions GY1–GY7, color of solution and undissolved material was estimated to be in the range of yellow to reddish brown⁽¹⁾
Clarity and degree of opalescence	Clear, equivalent to reference suspension 1 (3 NTU)	Clear, equivalent to reference suspension 1 (3 NTU)	Between reference suspension 1 (3 NTU) and reference suspension 2 (6 NTU)	Parameters could not be evaluated due to large residues of undissolved sample material
Water content	4.39 ± 0.12%	4.59 ± 0.10%	5.46 ± 0.09%	7.33 ± 0.43%⁽¹⁾
pH	n.d.	n.d.	8.7 ± 0	7.09 ± 0.04 ⁽¹⁾
Osmolality	n.d.	n.d.	1.4 ± 0 osmol/kg	Parameter could not be evaluated due to large residues of undissolved sample material
Visible particles	n.d.	n.d.	0 against white background, 0 against black background	Visible particles could not be evaluated due to large residues of undissolved sample material

n.d. not determined
⁽¹⁾As samples could not be dissolved completely, the validity of these results is compromised

ISSN: 1757-6512