What is the the market size for such lubricants? in the USA and the
rest of the world. What is the epidemiology of such vaginal dryness
and who are the main users

Dear eint, 

Your question is about to expire without having been answered, and you
might be disappointed. 

One possible reason is that you've asked three different questions in
one posting. If a researcher does not find one component of the answer
(or figures that the amount you're willing to pay for an answer does
nto justify the effort in looking for one of those three components),
your question might remain unanswered. If I may, I suggest that you'll
repost the questions separately (if you're still interested in an
answer).

In addition, here is a link to guidelines about pricing your question,
in the pricing guide:
https://answers.google.com/answers/pricing.html - I hope this would
help you price your next questions on Google Answers.