Dear colleagues

I need the help for the antiurolithiatic activity, first I have three questions:

1-      My problem is in choosing the standard, Cystone, it is not sold by Sigma Aldrich, Can I use the Cystone sold by the market (Amazon)?

2-      My second question is about the second part of the activity (Aggregation assay): the Calcium oxalate is not soluble in the buffer solution, are that I can use directly in continuous agitation during the realization of the activity.

3-      My last question that I can use sodium citrate as standard for antiurolithiatic activity

With my best regards