7OH Solubility Data for Research-Grade Lab Use
- 7OHyea
- Jul 24
- 4 min read
What researchers need to know about 7OH solubility data
7-hydroxymitragynine (7OH) is poorly soluble in water but dissolves at 5 mg/mL in ethanol and 10 mg/mL in methanol. These figures are the practical starting point for any analytical protocol involving this alkaloid. Aqueous buffers simply cannot maintain 7OH in stable solution, which means organic solvents are the default vehicle for laboratory work.
7OH is a semi-synthetic alkaloid. Its natural leaf concentration in kratom is typically at or below 0.1%, making direct extraction economically impractical. Researchers work with material derived by adding a hydroxyl group to the 7-position of mitragynine, a well-characterized semi-synthetic conversion performed under controlled laboratory conditions.
In silico ADMET modeling places 7OH’s water solubility at log mol/L of -3.911, classifying it as moderately low. That figure aligns with observed bench behavior: 7OH precipitates or remains suspended in plain aqueous systems without co-solvents or emulsifiers.
Key physicochemical properties at a glance:
Water solubility: Negligible under standard conditions (log mol/L = -3.911)
Ethanol solubility: 5 mg/mL
Methanol solubility: 10 mg/mL
Physical form: Crystalline solid
Predicted pKa: 12.20 ± 0.60
Predicted density: 1.29 ± 0.1 g/cm³
Predicted boiling point: 567.4 ± 50.0 °C
Recommended storage: -20°C freezer
Solvent | Solubility | Notes |
Water | Negligible | Precipitates without co-solvents |
Ethanol | 5 mg/mL | Preferred for tincture-type preparations |
Methanol | 10 mg/mL | Standard for HPLC stock solutions |
Lipid carriers | Variable | Preferred for stable oral formulations |
Table of Contents
How does temperature and pH affect 7OH solubility?
Direct temperature-dependent solubility curves for 7OH are not publicly listed in the peer-reviewed literature as of 2026. However, pH behavior for the structurally related parent alkaloid mitragynine is well characterized and provides a useful reference frame. Mitragynine solubility rises sharply under acidic conditions, reaching 3.5 mg/mL at pH 4, while dropping to 64.6 µg/mL in neutral water and 18.7 µg/mL at pH 9. Because 7OH shares the same indole alkaloid scaffold and weak-base character, researchers can reasonably expect analogous pH-dependent behavior, though direct experimental confirmation for 7OH specifically remains an open gap in the published data.
Warm temperatures modestly improve apparent mixing of 7OH in partially aqueous systems, but this reflects physical dispersion rather than true dissolution. Stable, reproducible concentrations require organic solvents regardless of temperature.
How does 7OH solubility compare with related alkaloids?
Mitragynine, the parent compound, has an intermediate lipophilicity with a logP of 1.70 and shows measurable aqueous solubility under acidic conditions. 7OH is consistently more hydrophobic than mitragynine, reflected in its lower aqueous solubility log value. Mitragynine pseudoindoxyl, a downstream metabolite of 7OH, is more potent at µ-opioid receptors but its solubility profile has not been characterized as thoroughly in published sources.
The practical takeaway for researchers: 7OH requires organic solvents where mitragynine can sometimes be handled in acidic aqueous buffers. Designing parallel assays with both alkaloids means maintaining separate solvent systems rather than a shared aqueous stock.
Stability and degradation of 7OH in solution
7OH is acid labile, degrading in strongly acidic environments such as simulated gastric fluid. This has direct implications for solution preparation: stock solutions in acidic buffers will lose concentration over time, compromising assay reproducibility. Neutral to mildly basic pH buffers offer better stability, though aqueous solubility at those pH values is low enough to limit practical working concentrations.
Methanol and ethanol stocks stored at -20°C are the most reliable format for maintaining concentration integrity between experiments. Lipid-based carriers, including self-emulsifying systems, protect 7OH from acid degradation and are the preferred vehicle when aqueous delivery is required. Researchers should also note that oral bioavailability of 7OH is only 2.7% ± 0.3% in rat models, largely due to first-pass metabolism, which affects how pharmacokinetic data from oral dosing studies should be interpreted.
Pro Tip: Prepare 7OH stock solutions in methanol at 10 mg/mL, then dilute into the target buffer immediately before use. Never pre-dilute into aqueous systems and store, as concentration loss is rapid and difficult to quantify without re-assay.
Research-grade 7OH is available in Canada through 7ohyea
Canadian researchers working with 7-hydroxymitragynine need a domestic supplier that matches the purity demands of analytical work. 7ohyea sources and manufactures research-grade 7OH powder in British Columbia, with purity options ranging from 43% to 93% and tablet dosage strengths of 15mg, 30mg, and 50mg. Every batch is supported by Certificates of Analysis from third-party laboratories, giving your team the documentation needed for experimental records and institutional compliance.
The domestic supply chain means faster delivery than international chemical distributors, and the customizable dosage formats let you match material specifications to your protocol rather than reformulating around what is available. Researchers can review the full product range and place orders directly at 7ohyea.ca.
Key Takeaways
7OH is hydrophobic with negligible water solubility, dissolving reliably only in organic solvents like methanol (10 mg/mL) or ethanol (5 mg/mL), which must guide every formulation and analytical protocol.
Point | Details |
Water solubility | Negligible; log mol/L = -3.911, requiring organic solvents for stable stock solutions. |
Organic solvent values | Methanol: 10 mg/mL; ethanol: 5 mg/mL — the standard vehicles for analytical work. |
Acid lability | 7OH degrades in strongly acidic conditions; store stocks in methanol at -20°C. |
Oral bioavailability | Only 2.7% ± 0.3% in rat models due to first-pass metabolism, affecting pharmacokinetic study design. |
7ohyea sourcing | Canada-based supplier offering 43%–93% purity powders and 15mg, 30mg, 50mg tablets with third-party Certificates of Analysis. |
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