Can't Dissolve Synthesized Compounds! - issues with cytotoxicity assays (Apr/09/2007 )
[b]Okay I am at witt's end on this one.....please rescue me
I am testing the anticancer activity of several newly synthesized compounds. I used Dmso in attempts to dissolve them, and it was ineffective....I then opted for DMF....DMF dissolved the compounds readily however I'm faced with several problems
1. the compounds dissolved in the cell in vitro assay are crystallizing out of the media during incubation (despite the fact that the humidity is high, so the media is not evaporating)
2. some compounds fall out of solution as soon as I pipette them into media
3. I've tried doing higher dilutions with DMF to reduce the concentration of solute in my stock solutions, but I end up having
too high of a percentage of DMF ( I was aiming at 0.1 % because this is the % of DMSO that is non-toxic to the cells)
4. One of the compounds crystallized out of the stock solution (despite dilution w/ DMF) and I had to use high temp. to get it to re-dissolve...
and once the solution assumed room temp, the crystals reformed instantly.
I searched the literature and some papers don;t even report the solvent they used....I cannot use any type of alcohol because
of toxicity on the cells....
what can I do to test these cmpds in vitro????? Suggestions/Solution pls.
Solubility is a big issue. Many drug cadidates can not make to the next phase because of poor solubility.
If your compound is more lipophilic, you can try emulsion or liposomes. But yours dont sound likely just lipophilic problem, because the rapid crystal formation.
Try CM-cellulose, 2-(hydroxypropyl)-beta-cyclodextrin, low MW PEG with or without alcohol or detergent to see if that will help. You may want to dissolve your drug in DMF, add to CMC or PEG/detergent mixture before add to water.
For HP-cyclodextrin, try to dissolve drug in DMF or chloroform/methanol mixture, add HP-C, in roughly 1:1 mole ratio, dry the solvent with a rotovaper and a pump, then suspend in water.
I dont have a detailed protocol for you, you can go check out some pharmaceutical preparation books. There is no univeral method when you deal with drug solubility issue.
Also, do you have the structures? If the drug is an acid (COOH?), try adding small amount of diluted (0.1 M) NaOH, and if it is a base (any N, NH, NH2 groups?), try HCl. Hope that will help.
Thanks genehunter....I am not familiar with the chemicals that you mentioned above...I'm doing some inquiry on that...the compounds cannot dissolve in the presence of a base...they may dissolve in an acid....are you currently working with cell culture? If I were to try methanol, do you know what % will be safe for thr cells?