we are supplier of camptothecin and its derivates,especially the 2 products:10-hydroxy-camptothecin,7-ethyl-10-hydroxy-CPT,we have a new way of production of the 2 goods,so the cost is much lower than the market,we can provid topotecan hydrochloride, 7-ethyl-CPT and Irinotecan hydrochloride as well.If interest,pleast feel free to contact us to ask for prices,or samples.we will give you our reply immediately.