proving to be a valuable adjunct in the treatment of refractory detmsor hyper-reflexia. However, certain issues are yet to be resolved especially the storage and stability of stock solutions. Researchers have reported degradation of RTX solution stored in various plastic containers. Therefore, we investigated the stability of stock solutions stored in a comlnonly used plastic material and in glass, under differing conditions of temperature, light and dark. MATERIAL & METHODS: RTX 1 mg was dissolved in 1 ml of absolute ethanol and diluted (10 fold) in ethanol/water (50150), so that we had RTX 1 mg in 10 ml of equal parts ethanol/water solvent as our stock solution(s). The solution was distributed in eight aliquots of 250 ml and stored in glass containers or high grade polypropylene (plastic) containers and subjected to different temperatures and light/dark conditions over times ranging from O-144 hours. 10 ml of samples were loaded for HPLC analysis. Results were normalized by taking the value at time 0 as 100%. RESULTS: Normalized results are shown in the Table. From the analysis of the data, it clearly emerges that: (a) both room temperature and light exposure affect RTX stability and the combined effect of these factors is additive; (b) RTX degradation, if present, falls to a nadir at 48 hours; (c)At low temperatures, in the dark, plastic storage affords better stability than glass. CONCLUSIONS: RTX stock solutions should be stored at temperature 4” C in the dark. The material comprising the container for RTX is of secondary importance.
Stability of Resiniferatoxin stock solutions
GIANNANTONI, Antonella;
2004
Abstract
proving to be a valuable adjunct in the treatment of refractory detmsor hyper-reflexia. However, certain issues are yet to be resolved especially the storage and stability of stock solutions. Researchers have reported degradation of RTX solution stored in various plastic containers. Therefore, we investigated the stability of stock solutions stored in a comlnonly used plastic material and in glass, under differing conditions of temperature, light and dark. MATERIAL & METHODS: RTX 1 mg was dissolved in 1 ml of absolute ethanol and diluted (10 fold) in ethanol/water (50150), so that we had RTX 1 mg in 10 ml of equal parts ethanol/water solvent as our stock solution(s). The solution was distributed in eight aliquots of 250 ml and stored in glass containers or high grade polypropylene (plastic) containers and subjected to different temperatures and light/dark conditions over times ranging from O-144 hours. 10 ml of samples were loaded for HPLC analysis. Results were normalized by taking the value at time 0 as 100%. RESULTS: Normalized results are shown in the Table. From the analysis of the data, it clearly emerges that: (a) both room temperature and light exposure affect RTX stability and the combined effect of these factors is additive; (b) RTX degradation, if present, falls to a nadir at 48 hours; (c)At low temperatures, in the dark, plastic storage affords better stability than glass. CONCLUSIONS: RTX stock solutions should be stored at temperature 4” C in the dark. The material comprising the container for RTX is of secondary importance.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
