hydroxypropylmethylcellulose
Also known as: Hydroxypropyl Methylcellulose, HPMC, Hypromellose, Hydroxypropyl Methyl Cellulose
Overview
Hydroxypropyl methylcellulose (HPMC), also known as hypromellose, is a semisynthetic cellulose ether derivative. It is produced by chemically modifying cellulose with hydroxypropyl and methyl groups. HPMC is not naturally occurring but synthesized from plant cellulose. It is widely used as a nonfermentable dietary fiber supplement, a pharmaceutical excipient, and an ophthalmic lubricant in artificial tears for dry eye disease (DED). It is also used in food manufacturing as a thickener and stabilizer. HPMC is a water-soluble fiber with viscous, gel-forming properties and is classified as Generally Recognized As Safe (GRAS) up to 20 g/day in the US. Research indicates its efficacy and safety in ophthalmology and metabolic modulation, with promising data on microbiota interactions.
Benefits
HPMC has demonstrated benefits in treating dry eye disease and improving metabolic health. As an ophthalmic solution, a 2% HPMC solution significantly improves symptoms and signs of dry eye disease after cataract surgery, with statistically significant reductions in Ocular Surface Disease Index (OSDI) scores and improvements in tear meniscus height (TMH) compared to controls (p < 0.05). Systematic reviews confirm its efficacy and safety as an artificial tear component for DED. In rodent models, dietary supplementation with 10% HPMC reduced weight gain, decreased plasma cholesterol, and lowered liver triglycerides. Human studies corroborate cholesterol-lowering and postprandial insulin reduction effects, supporting metabolic benefits. HPMC also modulates intestinal microbiota composition, with decreased microbial alpha-diversity and altered bacterial populations linked to metabolic improvements in animal models.
How it works
HPMC functions through different mechanisms depending on its application. In ophthalmic use, HPMC acts as a viscous lubricant, stabilizing the tear film and protecting the ocular surface. Metabolically, it functions as a nonfermentable dietary fiber that alters intestinal microbiota composition, leading to improved lipid metabolism and insulin sensitivity. HPMC enhances tear film stability and reduces ocular surface inflammation. In the gastrointestinal tract, it modulates gut microbiota and metabolic signaling pathways. HPMC is poorly absorbed systemically, acting locally in the gut or on the ocular surface.
Side effects
HPMC has an excellent safety profile and is generally well-tolerated. It has GRAS status for dietary use up to 20 g/day and is considered safe for ophthalmic applications. Common side effects are minimal, with rare reports of mild ocular irritation with topical use. Uncommon side effects include rare gastrointestinal discomfort when ingested in high amounts. Serious adverse events are rare in controlled trials. No significant drug interactions have been documented. Contraindications include hypersensitivity to cellulose derivatives. It is considered safe for use in postoperative eye patients and the general population, but caution is advised for individuals with cellulose allergies.
Dosage
For ophthalmic use, a 2% HPMC solution is typically applied as per clinical protocols, such as 1-2 drops 3-4 times daily. For dietary supplementation, effective doses in humans range up to 20 g/day, while animal studies have used 10% dietary supplementation. An optimal dietary dosage is between 5-20 g/day, depending on metabolic goals. The maximum safe oral dose is up to 20 g/day (GRAS limit). For dry eye, regular dosing throughout the day is recommended. For metabolic effects, daily dietary intake is advised. Ophthalmic formulations are available as sterile eye drops, and dietary forms are available as powders or capsules. HPMC is not absorbed, so its efficacy depends on local action or microbiota interaction.
FAQs
Is HPMC safe for long-term use?
Yes, both topical and dietary uses have demonstrated safety over extended periods in clinical studies and trials.
Can HPMC cause allergic reactions?
Rarely; hypersensitivity to cellulose derivatives is uncommon, but possible. Discontinue use if any allergic symptoms arise.
How quickly does HPMC work for dry eye?
Improvements in dry eye symptoms can be seen within 30 days post-treatment with regular use of HPMC eye drops.
Does HPMC affect gut microbiota?
Yes, it modulates microbiota composition, contributing to metabolic benefits by altering bacterial populations.
Is HPMC a fermentable fiber?
No, HPMC is a nonfermentable fiber, meaning it is not broken down by bacteria in the gut.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC10853018/ – This prospective randomized controlled trial evaluated the efficacy of 2% HPMC eye drops in post-cataract surgery patients with dry eye. The study found that HPMC significantly improved dry eye symptoms (OSDI scores) and tear meniscus height compared to control groups after 30 days. Additionally, corneal dendritic cell density decreased, indicating reduced inflammation.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC3545536/ – This controlled feeding study in mice examined the metabolic effects of HPMC supplementation. The study found that HPMC reduced weight gain, lowered plasma cholesterol, and decreased liver triglycerides in mice fed a high-fat diet. These metabolic improvements were correlated with alterations in gut microbiota diversity and composition.
- https://onlinelibrary.wiley.com/doi/10.1111/aos.16753 – This systematic review and meta-analysis assessed the efficacy and safety of HPMC in treating dry eye disease. The review concluded that there is consistent evidence supporting HPMC's role in improving dry eye symptoms and tear film stability with minimal adverse effects. However, the authors noted heterogeneity in formulations and study designs.
- https://onlinelibrary.wiley.com/doi/abs/10.1111/aos.16753 – This abstract summarizes a systematic review on the use of HPMC in artificial tears for dry eye disease. The review highlights the consistent evidence supporting HPMC's effectiveness in improving dry eye symptoms and tear film stability, while also noting the minimal adverse effects associated with its use. The review acknowledges the heterogeneity in formulations and study designs as a limitation.
