http://img.hisupplier.com/var/userImages/old/anhuik/anhuik$101816424.jpgRe: length of IM 4-AcO-DMT: Roughly 60 - 70 percent of the length of an oral trip, but will likely differ by person as people report widely varying durations for 4-AcO.
Of every tryptamine I've IMd, aMT HCl has shown both the most radical increase in potency and decrease in duration (which I consider a vast improvement). 20 mgs IM'd is roughly equivalent to 50 mgs oral aMT HCl
in my experience. If you can get an HCl solution (as in some muriatic acid pool cleaners containing ONLY HCl and water, which you'll have to buy at the store as I don't think it can be shipped to private residences -- though proper lab grade solution is of course vastly preferred), you can easily make aMT HCl from the freebase. It requires no molar calculations, either. Just slowly add the HCl solution to freebase until it's all dissolved, and evaporate off. Any excess HCl will evaporate at room temperature so you'll just be left with aMT HCl and nothing else.
Re: storage of 4-subs in solution: A friend of mine kept 4-AcO-MiPT in solution for many months. At the end of the time it turned black and was inactive. The 4-AcO-MiPT was highly hydoscopic, and may have sped up its degradation relative to something like 4-AcO-DMT. I personally wouldn't keep any compounds in solution for long, even if I was confident the solution was thoroughly sterilized and sealed.
Re cotton filtering: I'm not sure how much cotton filtering near pure compounds is going to reduce risks. As I understand the cotton filters out insoluble particulate matter in dirty heroin. Substances like that should never be IMd. Only a micron filter will remove bacteria. Those require a needless syringe with a screw top to attach the filter to.
You fill the needle-less syringe with the pre-filtered solution and push it through the filter into a sterile vile, then you're good to go. I suck out any solution held up in the exit nozzle of the filter using the needle of the syringe I'm using for injection, then I add additional sterile water into the needle-less syringe, and use it to push through the remaining solution that's held up in the filter/tip of the syringe so as to not waste any. A good way to figure out how much extra water to use is to fill the needle-less syringe with your solution, attach the dry filter, then push the solution through slowly until you see the first little drop of it exit the other side of the filter. The change in volume from the beginning to the sight of the first drop is the volume of your tryptamine solution that will be stuck in the filter if you don't flush with water. Don't use any more water than necessary, as if you do you'll end up with a greater volume to IM than you may like. You could also just use air, but I don't think it works as well as water because it may bubble through the liquid in the filter -- maybe if you force a lot of air through quickly it would clear the remaining solution more effectively.
Sterile water: in a pinch a cheap and convenient source of sterile saline is preservative-free sterile contact lens cleaning solution (used for heat cleaning contacts). Unisol brand contains only sterile saline and some harmless acids to make the pH the same as tears.
The smallest syringes are best for working with just a few doses because changes in volume are easier to see.