A company asks me for Fluoride intoxication a solution 4% Ca-gluconate for INW. Use. I've already made it, but she gives a precipitation after some time. How can I improve the solubility??

Because of the limited supply of raw materials, a solution to your problem is not easy. That you get precipitation is not surprising because 4% is above the saturation concentration. After all, cagluconate is much better soluble at higher than at room temperature. Several methods are described to increase the solubility of cagluconate.

1. a complex form with boric acid or borax for the formation of Although used in veterinary medicine, this method is more likely to be regarded as dangerous in humans.
2. adding Ca saccharinate according to USP
3. adding cysteine HCl

possibility n ° 2 can not be used there is nowhere casacharinate emerging in the product lists of Belgian suppliers. However, possibility 3 is feasible. I can't tell you exactly how much cysteineHCl should be added. According to the publication, a small amount seems to me sufficient. I suggest 100 mg per 100 ml.

If this does not succeed then two possibilities remain:

1. you deliver a saturated solution (about 3%)
2. you will deliver a solution of Caglycerophospas, which is better soluble.

I suspect that the reaction Ca + F is aimed at forming the insoluble CaF. This can also be tested with Caglycerophosphate for inspection!