Trimix Vial validity

[roy123]

Hello All

my trimix vial comes from the pharmacy that does not require freezing. it only requires refrigeration. each vial when it opens is valid for 28 days. the end date (28th day) is clearly marked on the vial.

my questions are:

1) can i use the vial on the 29th day and still get the same results?
2) are these dates only for legal reasons and one can use trimix beyond expiration date?
3) does the vial loses its efficacy as it approaches its ending date or does it work with same efficacy throughout the 28 day period?

please advise