Safety Assessment of Methylcellulose

Chemical Properties and Sources

Methylcellulose (CAS 9004-67-5) is a non-ionic water-soluble polymer obtained by methyl etherification of natural cellulose. Its molecular structure is highly hydrophilic, soluble in cold water to form a transparent colloidal solution, and does not participate in human metabolism. The raw materials are derived from plant fibers (such as wood and cotton pulp), which meet the requirements of vegetarian and non-animal sources.

Application Fields

Food Industry: As a thickener (INS 461), emulsifier stabilizer and dietary fiber supplement, it is used in low-fat foods, ice cream, baked goods, etc., which can improve the texture and delay water migration.

Medical Field:

Sustained-release preparations: As tablet binders and controlled-release coating materials.

Clinical Uses: Core component of artificial tears for dry eyes, intestinal bulk laxatives (through physical promotion of intestinal peristalsis).

Other Industries: Cosmetic thickening, coating rheology modification and special adhesive preparation.

Metabolic characteristics and biosafety

Methylcellulose is chemically inert in the gastrointestinal tract:

No metabolic transformation: Resistant to gastric acid and digestive enzymatic hydrolysis, not absorbed or decomposed by the intestine.

Zero caloric value contribution: Excreted in feces in its original form, no risk of energy release or fat accumulation.

Toxicological data: LD₅₀ (rat oral)>5g/kg, a practically non-toxic substance; no teratogenic, carcinogenic or cumulative toxicity was found in long-term feeding experiments.

Health benefits

Intestinal function regulation: Increase fecal volume and improve transmission efficiency through hydration (especially suitable for senile constipation).

Metabolic regulation:

Delay gastric emptying rate, enhance satiety and assist weight management.

Inhibit postprandial blood sugar fluctuations and cholesterol enterohepatic circulation.

Mucosal protection: Form a bionic lubricating film on the ocular surface or wound surface to reduce mechanical friction damage.

Risk control recommendations

Dose-related reactions:

Excessive intake (>15g/d) may cause osmotic diarrhea symptoms such as abdominal distension and bowel sounds. It is recommended to increase the dosage in steps to adapt to the intestinal flora.

Drug interactions:

May physically adsorb some oral drugs (such as digoxin and levothyroxine), and need to be taken 2 hours apart.

Necessity of hydration: Intake at least 1.5L of water per day to avoid the risk of intestinal obstruction due to excessive water absorption of colloids.

Safety conclusions of international authoritative organizations

FDA: GRAS (Generally Recognized as Safe) certification, allowed as a food additive and pharmaceutical excipient.

EFSA/JECFA: The acceptable daily intake (ADI) is "not specified", confirming its safety for long-term use.

ICH: Listed in the Manual of Pharmaceutical Excipients (IPEC), no biocompatibility risk under GMP standards.

Conclusion

Methylcellulose, as a highly purified semisynthetic cellulose derivative, has excellent biosafety within regulatory limits (food grade ≤2%, pharmaceutical grade ≤45%). Its risks are only due to its physical properties, not chemical toxicity, and it poses no health threat under standardized use. Special populations (such as those with a history of intestinal obstruction) need to follow clinical guidance.