We frequently get requests regarding protocols for putting CNO in the drinking water for long-term studies.
Here is our protocol:
1. Dissolve the CNO in a small volume of DMSO 2. Diluted the dissolved CNO in drinking water (e.g., 5mg/200ml) 3. Give mice with CNO drinking water and protect from light using foil-wrapped bottles 4. The mice will receive 5mg/kg/day CNO (assume that mice weight 30g and consume 6ml water per day) 5. Prepare fresh daily. 6. A small amount of saccharine in the drinking water will mask the slightly bitter taste of CNO
"My question is with regard to the use of CNO in drinking water (in mouse studies). Your recipe calls for the addition of a small amount of DMSO to dissolve CNO at a concentration of 5 mg in 200 mL. As we and others routinely dissolve CNO in 0.9% saline (no DMSO) at concentrations up to four times this amount, I am curious whether the addition of DMSO to CNO solutions for H2O drinking is critical, or whether the properties of CNO permit it's direct dissolution in H2O at concentrations from 5-20 mg per 200 mL. There appears to be no difficulty dissolving such concentrations in H2O in my hands, but I would prefer to hear your perspective. Is there a published reference for the solubility profile of CNO in H2O or 0.9% saline?"
It basically depends upon the source of the CNO. CNO via the NIH RAID program (which is what we use) is not readily soluble in H20 while commercial CNO is. Although we've verified that both sources are …