A Brief Note On Microcrystalline Cellulose

1.2.2.Microcrystalline Cellulose30
Microcrystalline Cellulose is basically cellulose and is derived from high quality wood pulp. Slightly soluble in 5% w/v sodium hydroxide solution; practically insoluble in water, dilute acids, and most organic solvents. It is comprised of glucose units connected by a 1-4 beta glycosidic bond. It is also called as Avicel PH, Celex, cellulose gel, Celphere,
Emocel,Crystalline cellulose,Fibrocel,Pharmacel. It is used as an Adsorbent, suspending agent, tablet and capsule diluent, tablet disintegrant. .

It is Microcrystalline cellulose is purified, partially depolymerized cellulose that occurs as a white, odorless, tasteless, crystalline powder composed of porous particles. It is commercially

Methyl cellulose occurs as a white, fibrous powder or granules. It is practically odorless and tasteless. It is uesd as coating agent; emulsifying agent; suspending agent tablet and capsule disintegrant; tablet binder; viscosity-increasing agent. It is practically insoluble in acetone, methanol chloroform, ethanol (95%). Ether, saturated salt solution and hot water. Soluble in glacial acetic acid and in a mixture of equal volumes of ethanol and chloroform. In cold water, methyl cellulose swells and disperses slowly to form a clear to opalascent,viscous,colloidal dispersion.

It is a stable, slightly hygroscopic material. It is chemically resistant to alkalis, both dilute and concentrated, and to salt solution, although it is more sensitive to acidic materials than are cellulose esters. Ethyl cellulose is subject to oxidative degradation in the presence of sunlight or UV light at elevated temperature. This may be prevented by the use of antioxidant and chemical additives that absorb light in the range 230-340 nm range. Ethyl cellulose should be stored at a temperature not exceeding 320C (900F) in a dry area away from all sources of heat. It should not be stored next to peroxide or other oxidizing

It should not be stored next to peroxide or other oxidizing agents.
Losartan microspheres were prepared and evaluated using ethyl cellulose, alginate and acrylic polymers by solvent evaporation and W/O emulsion solvent evaporation methods. The microspheres were found to be discrete, spherical with free flowing properties. Solvent evaporation method was better with respective release, yield, micro encapsulation efficiency and particle size (40-50 μm) than that of W/O emulsion solvent evaporation method. Microspheres found to be sustained over 8 hrs.11

Propranolol hydrochloride bilayer matrix tablet was developed and it contain as the fast release layer (sodium starch glycolate) and sustaining layer (EC, Eudragit RLPO and Eudragit RSPO) by direct compression technique. The formulation gave an initial burst effect to provide the loading dose of the drug fallowed by the sustained release for 12 h from the sustained layer of matrix embedded tablets. In vitro dissolution kinetics followed the Higuchi model via a non-Fickian diffusion controlled release mechanism after the initial burst release. Statistical analysis (ANOVA) showed no significant difference in the cumulative amount of drug release after 15 min, but significant difference (p < 0.05) in the amount of drug released after 12 h from the optimized formulation was