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Hello,

I need technical information about Ag cortisol-BSA Fitzgerald ref: 80-IC20. According to the record "data sheet", must reconstitute the product in methanol or DMSO and store at -20 ° C. Organic solvents are not compatible with my technique.
What proportion of solvent / aqueous solution can I use to dissolve the product? What is the solubility limit of the product in aqueous medium? How long the product remains stable at -20 ° C?

Thanks,
Tara

Hello Tara,

Should you want to have them in a water based solution, we suggest that they be dissolved in an organic solvent that is also water miscible. DMSO, THF, Acetone, Acetonitrile or an alcohol (Methanol, Ethanol, isoPropanol are options). One needs to consider the toxicity of the solvent. DMSO and Ethanol are the most frequently used.
Most steroids will not dissolve in water unless they are a sodium salt or an acid. If one wants them to be dissolved in oil (mineral, vegetable) or if one needs them in a solution for cell culture, you are recommended to use an organic solvent first, and then dilute the solution.
Water has both organic and inorganic properties. If one is using buffer salts in the cell culture, you will tend to enhance the inorganic properties of water, thus reducing the organic properties, and hence reducing the solubility of the steroid.

Hi girls,

For "solubilizing" steroids, me, I prepare a solution of 25% of endotoxin free 2-hydroxylpropyl-\-cyclodextrin in water, sterile saline or buffer. Finely ground steroid is added to the cyclodextrin solution which is then sonicated until a clear solution is obtained, requiring 5-20 minutes. The solubility tends to parallel the solubility in pure Ethanol, ie about 5-10mgm/ml.
When prepared under sterile conditions, the solution can be stored at room temperature in the dark for at least a week without detectable decomposition. The exceptions are catechol estrogens which require the presence of 1mg/ml ascorbic acid to minimize the oxidation, and phenolic estrogen sulfates which require neutral pH buffer to minimize the hydrolysis; both solutions should be used immediately.
When diluted and stored at -20C, Ag cortisol-BSA Fitzgerald should be stable for at least six months.

Salomé

Thank you girls