18 mg/L

Use databases such as:

https://scifinder.cas.org/scifinder/view/scifinder/scifinderExplore.jsf

http://chem.sis.nlm.nih.gov/chemidplus/

Check also the summary tables of physicochemical properties in my trace organic contaminant related research papers (uploaded to ResearchGate)

But there is a paper (link given below) which says the solubility of CBZ is 125 mg/L

http://www.sciencedirect.com/science/article/pii/S1385894713002118

https://www.researchgate.net/publication/257567162_Degradation_of_the_antiepileptic_drug_carbamazepine_upon_different_UV-based_advanced_oxidation_processes_in_water

Please tell that what is the time of dissolution, Have the time of stirring increses the sollubilty, or 18 mg/L is the saturation level of carbamazepine above which it can not be dissolved

Article Degradation of the antiepileptic drug carbamazepine upon dif...

Faisal Hai is right!

You can simply check it by preparing a solution.

Yongjun Zhang's review paper is a must read before you design your biodegradation tests.

Carbamazepine and diclofenac: Removal in wastewater treatment plants and occurrence in water bodies

http://www.sciencedirect.com/science/article/pii/S004565350800996X

Carbamazrpine is a hard nut to crack! See Yongjun's and my publications for fungal degradation

Carbamazepine solubility in water is about 125 mg/L. You may look at our data (and at the literature data provided there):

"Enhancement effect of water associated with natural organic matter (NOM) on organic compound-NOM interactions: a case study with carbamazepine.: - Borisover M, Sela M, Chefetz B.Chemosphere. 2011 82(10):1454-60.

Be careful to distinguish from the estimated solubility of carbamazepine which is often provided as about 15 mg/L. This is the wrong value. Finally, carbamazepine equilibrated with aqueous solution is actually digydrate.

I have dissolved pure carbamazepine Sigma Aldrich @ 100 mg/L in water . Then after complete dissolution I have quantified it using HPLC with standard calibration curve. The concentration is found to be 98 mg/L. It means that carbamazepine is soluble upto 100 ppm or even more. I am not getting the concept of dihydrate formation.??

Thank you, Milkhail and Kshitiz for correcting our knowledge.

CBZ's solubility is much higher than 15 mg/L.

Mikhail's data: 126 mg/L, ~23 °C

http://www.sciencedirect.com/science/article/pii/S0045653510013421

another study: 236 mg/L, 25 °C.

http://www.sciencedirect.com/science/article/pii/S0378381213006857

Yes, interesting. The value I quoted was from the databases mentioned above. According to Mikhail, this is "estimated" solubility.

For our work we are only concerned with nano to microgram level of concentrations, so haven't made any aqueous solution of over 1 mg/L. We make stock solution in methanol and add an aliquot to the test solution to obtain nano to microgram level of concentrations.

Dear friends, there are several studies reporting the carbamazepine solubility as about 120-125 mg/L. This value is, to my understanding, the aqueous solubility of CBZ being equilibrated with its solid dihydrate (fromed from a dry CBZ during equilibration)! That is what we will get if we will wait enough and equilibrate the aqueous solution. The value about 230 mg/L and above is, to my memory, the experimental estimate, given for a hypothetical case when CBZ is equilibrated with its solution but did not convert to dihydrate. This value was experimentally estimated from the initial rate of CBZ dissolution. In some papers, we have quoted, this issue was explained. Of course, when the issue is about below ppm level, it is not important.

Exactly, as per my experimental knowledge and knowledge of databases the solubility of carbamazepine should be somewhat around 120-125 ppm, becauce this is a trace pollutant also. Moreover, the increase in solubility can be explained due to formation of dyhydrate. This is but obvious that the solubility may increase by adding polar solvents to the aqueous solution.

Dear Samarth Thakore,

since it is about ywo-phase equilibrium in a two-component system, in order to form a dihidrate, it is enough you will have quite minimal amount of water in the system. Basically, most probably, if you enough water to form a dihydrate of a given mass of CBZ, and a little bit of extra-water to dissolved 125 mg/L, you wll get this two-phase equilibrium. By the way, some sources report the CBZ solubility as 17 mg/L but not always indicate that it was the calculated value. In addition, this story teaches that very often we do NOT consider that a solid state may be a hydrate. This is especially true for pharmaceuticals. Most probably, pharmaceutical scientists know that well but environmental scioentists using solubility as a solite predictor are not necessarily aware of that 

The minimal amount of water  is to form dihydrate with all the CBZ sample mass, plus any extra-amount, to contain dissolved 125 mg/L and to maintain water activity needed. 

125 mg/L is the equilibrium solubility of dihydrate. 250 mg/L is not measured at equilibrium; I know these values as estimates based on the rate of initial dissolution. If by chance it is what you got, then, somehow the rate of duhydrate formation in a solid state is slow. This measurement may do by two ways: by slowly saturating aqueous solution with CBZ, till formation the soilid state which will be certainly dihydrate, or cooling down the CBZ solution (which may result in formation of oversaturated solutions). Equilibrating the solid CBZ phase (taken in excess) with water needs time to hydrate all CBZ in this solid phase. It may be relatively slow process

@Kshitiz Dwivedi .... Hi , i want to know how you have dissolved  carbamazepine in water only. Because you have mentioned that you have make 100ppm solution of carbamazepine. I am unable to dissolve carbamazepine in water.    

@Kuldeep.....Hello, which grade CBZ you are trying to dissolve, is it sigma grade or you are using industrial CBZ??

Dear friends

i agree with you Carbamyzipine is practicaly insoluble in water.

from my practicle experince , to disolve carbamyzipine in water. first dissolve it in methanol then complite the volume by water. For example to prepair 30mg/l. first disolve 30mg in 80 ml methanol and compilte then add 920 ml water.

best regards and wishes

Ayoup Ghrair

Royal Scientific Society

Jordan

Yes Sir, I am agree with you.

I also wish to thank you for sharing your practical experience with solubility of CBZ in water. I have also mentioned the same thing in my previous comments that the solubility of carbamazepine can be increased by adding polar solvents to the aqueous solution.

Best regards

@Kshitiz Dwivedi ... It is from Sigma.