STABILITY OF BOTHROPIC ANTIVENOMS UNDER DIFFERENT CONDITIONS OF TEMPERATURE

Silva, D.G., Clemente, C.A., Barbosa, C.F., Lima, S.L., Velarde, D.T.

Fundação Ezequiel Dias, Belo Horizonte, MG, Brazil.

OBJECTIVE: To evaluate the stability of the bothropic antivenoms produced in the Fundação Ezequiel Dias, providing data of their behavior through time, under different storage temperatures

METHODOLOGY:

Four conditions of study of stability were delineated with different storage temperatures and sampling periods: study of shelf life (5+3° C) for 36 months, intermediate study (25+3°C) for 30 months, accelerated study (37+2° C) for eight months and stress study (45+2°C) for eighteen months. The first condition seeks to validate the stability of the product, confirming the expiry period and in the last two conditions we intend to study the chemical degradation or physical modification of the product. Three lots of bothropic antivenoms were used in this study, and the following characteristics were evaluated: aspect, pH, protein content, concentration and efficiency of the preservative (phenol), in vivo and in vitro activities and electrophoretic and chromatographic analyses.

RESULTS AND CONCLUSIONS:

After twelve months of the study the results indicated that the appearance was the first factor to be altered by drastic temperatures (37 and 45° C). The pH, protein content, phenol concentration and electrophoretic pattern did not change during the study, even under the most drastic conditions for twelve months. As was anticipated, the in vivo and in vitro activities showed a reduction at the end of the accelerated and stress studies. No significant modification was observed in these activities with the lower temperatures used in the study. This indicates the stability of the products for twelve months. A variability should be considered in the results of those activities, that it is inherent to the biological and immunochemical assays. Antivenoms kept at 45° C for twelve months showed variations in Superose12 chromatograms.

CORRESPONDENCE TO:

Velarde, D.T., Fundação Ezequiel Dias, Belo Horizonte, 31000-000, MG, Brasil, Email: celia@funed.mg.gov.br