Fig. 5: Stability of the virosome particle size after storage of the vaccine solid forms under various environmental conditions. | npj Vaccines

Fig. 5: Stability of the virosome particle size after storage of the vaccine solid forms under various environmental conditions.

From: New GMP manufacturing processes to obtain thermostable HIV-1 gp41 virosomes under solid forms for various mucosal vaccination routes

Fig. 5

A 3 months stability study was performed on the various solid vaccine forms (nasal and oral powders, sublingual tablets) stored under three different temperatures and relative humidity (RH) conditions: 4 °C (black line), 25 °C/65% RH (gray dot line), and 40 °C/75% RH (gray line). At each indicated month time point (M0–M3), samples were reconstituted with water and the mean virosome particle size (nm) was determined. Due to specific excipient interference during particle size analysis and different equipment available at different manufacturing sites, different methods were selected for particle analysis during stability study: DLS for nasal and oral powder and NTA for sublingual tablets. Note that for the sublingual virosomes, the mean particle size (101 nm) is about 10% smaller after lyophilization at M0, respective to the liquid virosomes (116 nm), but it is closer to the starting size after 3 months storage (120 nm at 4 °C and 124 nm at 40 °C). The higher residual moisture content in sublingual tablets (about 4%) and nasal powder (about 3%), respective to the oral powder (about 2.5%) may have contributed to bring back the virosome size closer to the original liquid virosome size over time. Data shown are from representative DLS and NTA measures.

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