I have ordered some from the Zhengzhou Debao Fine Chemical Co, and received it in a total of about 2 weeks total (counting response times from him to me and I to him). I created a money order through Western Union, and the cost for 100 gm of Vardenafil was $115 with $35 of handling and shipping charges.
There were a few options for other forms (all powdered) that were a lot more money - I considered whether I might be sacrificing purity for what I ordered but have no way of knowing. If the purity is not good, that is OK - the usual “impurities” are normal breakdown products of the chemical and are non-toxic (see ref 1 below).
But the greater concern is manufacturing technique and the possibility of toxic heavy metals as impurities (ie arsenic). I will have to decide if I want to have that looked at. I am uncertain if it is feasible (if I do, I will post results here), but several analytic chemists can do this - I should have enough to mail them plenty of milligrams and still have enough for me. ;)
Assuming it is OK, then the remaining question I have here is this:
How to mix it for consumption?
I have taken liquid tadalafil from aquachem for years and it has worked (but I am almost out) and it was mixed into an ethanol base (I think). Though mixed in an alcohol, the tadalafil chem profile says it is soluble in water or ethanol at < 1 mg/ml at 25 °C. Neither sounds very soluble. In fact, solubility is overrated (it is not the same as creating an emulsion or mix - soluble means the chemical is actually dissolved). If it mixes evenly, and you shake it up, you should get a pretty good dose (that is, the same dose each time).
Powdered sildenafil is said to not solubilize in water at all, and ethanol may not be that good either.
However, Vardenafil doesn’t seem any better for mixing. Water seems to decrease the bioavailability, and if one could, simply getting a small dose into the mouth for direct buccal membrane absorption seems better yet (avoids “first pass” elimination in gut). I can sacrifice about 30% of bioavailability (mouth versus gut) since I have so much, and it might be easy to buy a commercial inert powder, mix it all up and make capsules (I have all the tools for this already), but that is a bit of an effort!
Any help that anyone can provide would be very gratefully appreciated!
Tim
1 (American Journal of Analytical Chemistry, 2012, 3, 59-66 - “A Validated Rapid Stability-Indicating Method for the Determination of Related Substances in Vardenafil Hydrochloride by Ultra-Performance Liquid Chromatography”)