Hydroxypropyl methylcellulose (Hypromellose) (HPMC)

Hydroxypropyl methylcellulose (HPMC), also known as hypromellose, is a semi-synthetic, inert, viscoelastic polymer derived from cellulose (PubChem CID 21239). It is widely utilized in the pharmaceutical industry as both an active ingredient in ophthalmic lubricants and a versatile excipient in oral drug delivery systems (FDA Inactive Ingredient Database). As a topical lubricant, it serves as a tear substitute to treat dry eye syndrome by increasing the residence time of moisture on the ocular surface and forming a protective film (StatPearls, Dry Eye Syndrome). In oral formulations, it acts as a binder, film-coater, and hydrophilic matrix for controlled-release medications, modulating drug dissolution through its gel-forming properties (ScienceDirect, Hydroxypropyl Methylcellulose). Because its therapeutic effects are mediated through physical and mechanical actions rather than binding to a specific protein or signaling pathway, it is not considered a molecular target in the traditional pharmacological sense. Its primary value lies in its ability to modify the rheological properties of solutions and provide a physical barrier or delivery vehicle for other active pharmaceutical ingredients.

Other names

HypromelloseHPMCCellulose hydroxypropyl methyl etherMethyl hydroxypropyl celluloseE464

Hypromellose acts as a physical lubricant and viscosity-increasing agent. In ophthalmic applications, it stabilizes the precorneal tear film and increases tear residence time by forming a transparent, lubricating, and protective film on the corneal surface (PubChem CID 21239). In oral drug delivery, it forms a hydrophilic gel matrix upon contact with water, which controls the rate of drug release through diffusion and erosion (ScienceDirect, Hydroxypropyl Methylcellulose).