Pharmacopeial Specifications for Methylcellulose
| Test | JP 2001 | PhEur 2005 | USP 28 |
|---|---|---|---|
| Identification | ✔✔✔ | ✔ | ✔✔✔ |
| pH | 5.0–8.0 | 5.5–8.0 | — |
| Loss on Drying | ≤5.0% | ≤10.0% | ≤5.0% |
| Residue on Ignition | ≤1.0% | ≤1.0% | ≤1.5% |
| Chlorides | ≤0.284% | ≤0.5% | — |
| Heavy Metals | ≤10 ppm | ≤20 ppm | ≤0.001% |
| Methoxyl Assay | 26.0–33.0% | — | 27.5–31.5% |
Applications in Pharmaceutical Formulation or Technology
Methylcellulose is widely used in pharmaceutical formulations as a binder, disintegrant, emulsifier, thickener, and sustained-release agent. It is commonly used in tablets, suspensions, topical products, and ophthalmic preparations. Therapeutically, it serves as a bulk laxative and has been explored for appetite control.
Comments
Methylcellulose’s gelation temperature and viscosity are influenced by concentration, additives, and drugs. It dissolves best by mixing with hot water (70°C) and cooling below 20°C. Alternative methods include dry blending or pre-wetting with ethanol. Its solutions exhibit pseudoplastic flow and remain stable when frozen. Some cellulose ethers contain hydroxypropyl substitutions and should not be mistaken for pure methylcellulose.
