There is an excellent throat spray that lubricates with glycerin and is made specifically for singers and speakers. It is called ENTERTAINER'S SECRET. It is made in the US by Kli Corp, Carmel, IN (Indiana) 46032. The phone number is 800-308-7452. You can get it on the internet at
http://www.entertainers-secret.com/.

If you can't get something like Entertainer's Secret in your location, maybe a Mudcatter can order for you and send it on to your address.
I use it and it works. You need to stay away from sprays that are made with anesthetics or decongestants when you are close to a performance. Use nothing that will dry the tissues or numb your throat.

Stilly, I used to use alot of mints, mainly because I like the taste, but recently I found out that mint does cause acid reflux, which causes damage to the larynx/vocal cords.

From a site on VOCAL CORD DISFUNCTION (VCD):
http://cantbreathesuspectvcd.com/page5.html
People having gastric reflux (which can cause
               VCD) should avoid MINT(in all forms, including toothpaste, tooth powder, mouthwash, tea,
               candy, etc.--at least until no more VCD attacks for 3 months). Also avoid scented and
               chemical products. (Ref.17,21, and see "links" page: (E) about avoiding mint, etc.)

Alice