Gravity influences bevacizumab distribution in an undisturbed balanced salt solution in vitro

• Published in: PloS one Vol. 14; no. 10; p. e0223418
• Main Authors: Kim, Rae Young, Kwon, Soonil, Ra, Ho
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 04.10.2019; Public Library of Science (PLoS)
• Subjects: Angiogenesis inhibitors; Antineoplastic agents; Antineoplastic Agents, Immunological - chemistry; Antineoplastic Agents, Immunological - pharmacokinetics; Bevacizumab; Bevacizumab - chemistry; Bevacizumab - pharmacokinetics; Biology and Life Sciences; Cell proliferation; Diabetes; Diabetic retinopathy; Enzyme-linked immunosorbent assay; Enzymes; Gravitation; Gravitational effects; Gravity (Force); Gravity effects; Hemorrhage; Humans; Immunotherapy; In Vitro Techniques; Influence; Injection; Medicine and Health Sciences; Monoclonal antibodies; Pharmaceutical Solutions - chemistry; Physical Sciences; Research and Analysis Methods; Retina; Saline solutions; Statistical analysis; Test procedures; Time Factors; Tubes; United States > US; San Francisco California; South Korea
• DOI: 10.1371/journal.pone.0223418
• ISSN: 1932-6203

The effects of gravity on bevacizumab or the recommended head position after intraocular bevacizumab injection have not been reported. To evaluate the effect of gravity on bevacizumab in vitro, we added bevacizumab to the upper part of a test tube filled with balanced salt solution (BSS) and examined its distribution over time. Sixty-four test tubes were divided equally into two groups; group 1 (32, collected from upper part of the tube) and group 2 (32, collected from lower part of the tube). Each test tube was filled with 5 mL BSS before bevacizumab (1.25 mg/0.05 mL) was added, and then stored at 36°C. Bevacizumab concentration in 8 test tubes from each group was measured at 12, 24, 48, and 168 h using an enzyme-linked immunosorbent analysis (ELISA) kit. Mann-Whitney and Jonckheere-Terpstra tests were used for statistical analysis. Bevacizumab concentration was significantly higher in Group 2 than in Group 1 at 12, 24, 48, and 168 h (12, 24, 48, and 168 h; P < 0.01 each; Mann-Whitney test). The mean change in bevacizumab concentration over time tended to increase in Group 1 (P < 0.01; Jonckheere-Terpstra test), but tended to decrease in Group 2 (P < 0.01; Jonckheere-Terpstra test). The significant differences in concentration between the upper and lower parts even after a considerable amount of storage time showed that bevacizumab did not dissolve immediately and diffused evenly throughout the solution. It appeared that more bevacizumab settled in the lower part of the tube than in the upper part because of gravitational force. However, the concentration difference between the upper and lower parts decreased as bevacizumab gradually diffused over time, indicating that the difference in concentration due to gravity was more significant at the beginning of bevacizumab injection.