Evaluation of the stability of Vigabatrin in hospitalar extemporaneous formulations

Abstract

The aim of this study was to analyze the chemical stability of the anticonvulsant vigabatrin extemporaneous formulation from tablets in storage conditions of different temperatures and types of packaging used. The analysis of vigabatrin extemporaneous formulations were performed by high-performance liquid chromatography (HPLC). The method described in British Pharmacopoeia was co-validated for specificity, linearity, precision and accuracy. Vigabatrin extemporaneous solutions were prepared in triplicate and placed in amber glass and PET bottles, which were stored under three different conditions: at room temperature (15 to 30 °C), under refrigeration (2 to 8 °C), and oven (40 °C). Samples of solutions stored at room temperature and refrigeration were collected every 7 days along 35 days. The same was done for solutions kept at 40 °C, but for a period of 28 days. It was also analyzed the solutions pH in each sampling time. Vigabatrin extemporaneous solutions showed variations within the limits of British Pharmacopoeia 2016 up to 21 days in amber PET and glass bottles at room and refrigerated temperatures. Vigabatrin content for formulations kept in oven decreased above 10% after 7 days of study. The lowest pH change occurred in amber glass bottle stored under refrigeration. Results of this study will be applied as a reference for vigabatrin extemporaneous formulation in hospital, once it was demonstrated the reliability of storage time interval and proper conditions for the use. Thus, pediatric patients with fractionated doses or use of nasogastric probe will have adequately prepared extemporaneous formulations, reducing the risk of dilution errors and microbiological contamination, improving the efficacy and safety, and enabling more time for nursing assistance.