Pretty much a certainty, Hari. I have a 4 oz bottle sitting right beside me that is expiry dated Aug 93. Came out of a First Aid Kit, Individual I stripped out to make a custom kit for a client.
This ia actually Scrub as opposed to solution. Scrub contains sudsing agents whereas Solution does not.
The bottle is seperated into two distinct layers, lighter at the top, much darker on the bottom. Approximately 40/60, light vs. dark.
Iodine outgases at ambient temperatures. Once opened and exposed to air it begins to deteriorate. it is important to keep Iodine solutions tightly capped until needed for this reason. Chemically Iodine is a Element, atomic number 53, symbol *I*. It is highly reactive and has some metallic properties in its pure form.
Iodine is dissolved in a solvent such as alcohol. It dissolves poorly in water. The seperation indicates that the elemental Iodine et al are seperating out of solution, thus the concentration is no longer viable. Normal 10% solution contains 1% elemental Iodine evenly distributed. When it seperates it is no longer well distrubuted and can be concentrated to a very undesirable level.
The normal shelf live given by most manufacturers is 2 years. Please note that stated and actual practical shelf lives are two different animals.
The following info on the actions of Iodine are copied from:
Povidone-iodine is a broad spectrum topical microbicide. Its mode of action involves the release of free iodine from the povidone-iodine complex in response to microbial challenge. The free iodine is released at a sufficiently low concentration to minimise the usual side effects associated with conventional iodine preparations (Iodine Tincture and Lugol's Solution), while
retaining the nonselective antimicrobial properties of iodine. Povidone-iodine is rapidly cidal for all classes of microorganisms including bacteria, fungi, viruses and protozoa, in vitro.
Please note the *in vitro * caveat. in vitro means outside the body. in vivo means internal. The actions in one do not always equal the actual under the other condition.