Keif' Richard's Ole' Fashioned Guide to Buying Liquid Methadone
It is almost universal i.e. perhaps it is done differently in Uzbekistan, for Methadone liquid to be dispensed in a sealed container from the clinic. Different clinics have different methods, but you're typically going to see a medicine bottle with a heat-sealed, tamper-evident top.
By law, the clinic must be able to determine if you have abused your medication. The only time you break that seal is when it is time for you to consume that dose.
Clinics will call people randomly to have them report with their bottles for inspection. If anything is amiss or the seal is broken, you won't be getting any take home Methadone for a while. You would then be reporting every morning for your dose until you are reinstated.
So, it is a pretty well-known rule, that for someone to sell you authentic Methadone, it would have to come with the seal still intact. These heat seals are difficult to replicate without the proper equipment.
So when I go and buy a bottle of Methadone, I inspect the seal, the color and the taste. This gives you some fairly good insurance against bullshit, but it is not perfect.
You receive each dose in it's own bottle for each day. There shouldn't be a good reason for a maintenance patient to just have some lying around in a syringe.
Most often, I've found that when people use alternate containers, they aren't completely ripping you off, but they usually are trying to sell you a significantly diluted tincture.
Methadone tincture is typically dispensed as a 10mg per Ml ratio. Some places like the UK for instance, tend to use 1mg to 1ml solutions, but in the states, the former is almost always the case.
Does this answer most of your questions?