Product overview
Hydroxypropyl methyl cellulose acetate succinate (HPMCAS) is an enteric polymer and a common carrier for amorphous solid dispersions made by spray drying or hot-melt extrusion. Its dissolution pH depends on the ratio of acetyl to succinoyl groups.
Specification
| Property | Value |
|---|---|
| Appearance | White to off-white powder |
| Methoxyl | 20.0–24.0% |
| Hydroxypropoxyl | 5.0–9.0% |
| Viscosity, 10% in acetone | 2.4–3.6 mPa·s |
| Loss on drying | ≤ 5.0% |
| Residue on ignition | ≤ 0.20% |
| Heavy metals | ≤ 10 ppm |
| Content, % | LG | MG | HG |
|---|---|---|---|
| Acetyl | 5.0–9.0 | 7–11 | 10–14 |
| Succinoyl | 14–18 | 10–14 | 4–8 |
Values are from our current product data. Confirm the exact grade and limits with the TDS and the COA of the lot you test.
Applications
- Solid dispersions: carrier for poorly soluble drugs (spray drying, hot-melt extrusion)
- Enteric coating: tablets and pellets
HPMCAS solubility by grade
| Grade | Acetyl / succinoyl | Dissolves above about |
|---|---|---|
| LG (L type) | Low acetyl, high succinoyl | pH 5.5 |
| MG (M type) | Medium / medium | pH 6.0 |
| HG (H type) | High acetyl, low succinoyl | pH 6.8 |
HPMCAS is insoluble in water at acidic pH and dissolves once the succinic acid groups are ionised above the grade threshold. It dissolves in acetone, methanol and acetone/water mixtures, which are used for spray drying.
Structure
HPMCAS is hypromellose (HPMC) whose free hydroxyl groups are partly esterified with acetic and succinic acid. The acetyl groups make it more hydrophobic; the succinoyl groups provide the pH-dependent solubility. The balance between them defines the L, M and H types.
How to choose a grade
L grades dissolve at the lowest pH and H grades at the highest; pick by where release should start and by drug-polymer miscibility in your dispersion.
Packing and documents
25 kg multi-wall paper bags with an inner PE liner. Other packing is agreed per order. TDS, SDS and a representative COA are available for every grade, and each lot ships with its COA. Request documents or a sample.
Download (2026 revision): Technical data sheet (TDS, PDF) · Safety data sheet (SDS, PDF)
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FAQ
Which grade for spray-dried dispersions?
M and H grades are often screened first; the best grade depends on the drug. Screen at small scale.
Why is HPMCAS used in amorphous solid dispersions?
It keeps poorly soluble drugs in an amorphous form and slows their recrystallisation in solution, which raises the dissolved drug concentration in the intestine.
Is HPMCAS the same as HPMC-AS?
Yes. HPMC-AS, HPMCAS and hypromellose acetate succinate are names for the same polymer.