Why don't you start with WIKI for individual compound, or with searching 'solubility drug' on the internet, in combination with Physical Pharmacy.

Or try the online pharmacopoeias like EurPh or USP

You can find the solubility profile and other chemical properties of most substances by searching "chemical name" + "material safety data sheet".

Alternatively, try Chemspider;

http://www.chemspider.com/Default.aspx

Type the drug name into the search bar, then click on the 'Properties' button.

If solubility isn't listed under 'Experimental data', it will probably be under 'Predicted-EPI Suite'.

Pharmacopoeia