Thanks for using Healthcaremagic,
It is not clear why you want to make it alkaline if you have any burning or discharge it may be due to infection bacterial,fungal or mixed.
In fact naturally weak acidic .
Relieving minor vaginal irritation
It may also be used to cleanse and deodorize the vaginal area.Betadine
douche is an antiseptic combination. It works by killing sensitive bacteria.
you are allergic to any ingredient in Betadine .
you are pregnant or breast-feeding.
If you are doubtful then please visit a Gynecologist first and follow her advise.
Hope this helps.
Dr.Akhilesh Dubey M.D.