Freebase vs. salt MIT extract: how to choose
Freebase MIT extract keeps mitragynine in its neutral form, which dissolves in ethanol and organic solvents. Salt extract is converted with an acid, which makes it water-soluble and usually more stable as a dry powder. Salt grades read lower in mitragynine percentage because the counter-ion adds mass.
The chemistry in one paragraph
Mitragynine is an alkaloid, a weak base. In its freebase form it is neutral and lipophilic. Reacting it with an acid produces a salt, an ionic form that dissolves readily in water. Both forms carry the same alkaloid; they differ in how they behave during processing.
Side by side
| Property | Freebase | Salt |
|---|---|---|
| Solubility | Ethanol, organic solvents | Water |
| Dry-powder stability | Good when protected from heat, light and air | Generally better |
| Labeled mitragynine % | Higher for the same alkaloid content | Lower, because the counter-ion adds mass |
| Typical use | Further processing in non-aqueous systems | Water-based processing |
Compare lots on the same basis
A 50% salt grade and a 60% freebase grade can carry similar amounts of mitragynine. Ask for mitragynine reported as freebase-equivalent on every COA, and compare cost per gram of freebase-equivalent mitragynine rather than cost per kilogram of powder.
Both forms must meet the same 7-OH limits
The proposed federal threshold applies to the finished material whatever its form. See the DEA 7-OH threshold guide for the two tests every lot must pass.