Views: 272 Author: Vickey Publish Time: 2023-08-14 Origin: Site
As a short form of hydroxypropyl methylcellulose (HPMC), hypromellose (INN), also known as hydroxypropyl methylcellulose, is a semi-synthetic, inert, viscoelastic polymer utilized in eye drops as well as an excipient and controlled-delivery component in oral medications. As a food ingredient, hypromellose functions as a thickening, suspending, and emulsifying agent as well as a substitute for animal gelatin. Its E464 Codex Alimentarius code identifies it.
There are many fields of application for hypromellose, including:
Scientists from the Agricultural Research Service are examining the possibility of replacing gluten in all-oat and other grain breads with HPMC, a substance generated from plants. The gluten found in wheat, rye, and barley is missing (or only small amounts of gluten are present) in oats and other grains. Similar to gluten, HPMC may also act as a trap for yeast-created air bubbles in bread dough, enabling the loaf to rise.
Typically, HPMC is utilized as a rheology modifier and water retention agent in building materials like tile adhesives and renders.
HPMC (hydro ethyl methyl cellulose) and HEMC (hydroxy ethyl methyl cellulose) are quite comparable in terms of functionality.
As an alternative to tear film that is semi-synthetic, hypromellose solutions were patented. Its molecular structure is based on a very water-soluble basic celluloid compound. According to reports, the good water solubility of celluloid contributes to optical clarity after application. A hypromellose solution operates to swell and absorb water when applied, increasing the tear film's thickness. Therefore, hypromellose augmentation prolongs the lubricant's stay on the cornea, which should reduce eye discomfort, particularly in dry situations like the home or workplace.
Hypromellose has also been employed as an excipient in oral tablet and capsule formulations, where, depending on the grade, it serves as a controlled release agent to delay the release of a medicinal component into the digestive system. Hypromellose has also been utilized in ocular solutions.It is also used as a binder and as a component of tablet coatings.
Various benchmark tests are used to qualify hypromellose:
There are several test techniques available for hypromellose solution since it is a non-Newtonian solution and shows pseudoplastic, notably thixotropic behavior. However, the outcomes of various test methods and viscosimeters may not always agree. Additionally, viscosity is frequently expressed as a mean or as a range due to the allowed ranges of error for viscometers.
The average level of methoxy substitution along the cellulose chain is measured as the degree of substitution. This average value is a real number between 0 and 3, as each cellulose molecule has a maximum of three potential sites of replacement. However, percentages are frequently used to describe the degree of replacement.
The average degree of hydroxypropoxy substitution along the cellulose chain is known as molar substitution. This number may be greater than 3 due to the fact that hydroxypropoxy bases can be joined together on side chains and do not individually need a base substitution site on the cellulose molecule.However, molar substitution is also often expressed in percentages.
All cellulose ethers are hygroscopic; therefore, if they are kept out of their original packaging, they will collect moisture from the air. To guarantee that a suitable amount of dry active material is apportioned for use, moisture must be measured and weight must be corrected. A sample of X grams is weighed on an analytical scale to determine its moisture content. The sample is then dried at 105 °C for two hours before being reweighed on the same scale.
