Hydroxypropyl methylcellulose applications

Fig. 27 Infiuence of the type of polymer application on film properties (top and side view). HP55 (HPMCP)-coated pellet, prepared from a micronized film dispersion (A). HP55 [hydroxypropyl methylcellulose (HPMCP)]-coated pellet, prepared from an organic solution (B).

Dimethyl phthalate is used in pharmaceutical applications as a solvent and plasticizer for film-coatings such as hydroxypropyl methylcellulose, cellulose acetate and cellulose acetate-butyrate mixtures. ... 

Chen R, Sekulic S, Zelesky T. Development and validation of a cost-effective, efficient, and robust liquid chromatographic method for the simultaneous determination of the acetyl and succinoyl content in hydroxypropyl methylcellulose acetate succinate polymer. J AOAC Int 2002 85(4) 824-831. Correction 85(6), 125A. Onda Y, Muto H, Maruyama K. Ether-ester derivatives of cellulose and their applications. United States Patent No. 4,226,981 1980. Final report on the safety assessment of hydroxyethylcellulose, methylcellulose, hydroxypropyl methylcellulose and cellulose gum. J Am Coll Toxicol 1986 5 1-59. 

In 1940, Eastman Kodak Company published a U.S. patent that provided one of the earliest de.scriptions of enteric coating of medicaments. The patent claimed the use of a cellulose derivative containing free carboxyl groups as an enteric film forming polymer. Specifically, the claimed enteric polymer was cellulose acetate phthalate (CAP) (34). Numerous enteric cellulose derivatives have been developed since this early account and these polymers remain as some of the most widely used for enteric coating applications. In addition to CAP these derivatives include cellulose acetate trimellitate (CAT), cellulose acetate succinate (CAS), hydroxypropyl methylcellulose phthalate (HPMCP), and hydroxypropyl methylcellulose acetate succinate (HPMCAS). The molecular structure of these polymers is depicted in Figure 1 with their respective substituent groups listed in the caption. 

For all cIEF methods, polymer solutions are added into the samples, including methyl cellulose (MC) and (hydroxypropyl)methylcellulose (HPMC). These polymers modify the capillary surface [10-12] and enhance separation resolution. The existence of the polymer in the sample solution reduces diffusion coefficients of the proteins, thus, as described in Section 19.3.3, enhancing the separation resolution. In all cIEF applications described in this chapter, 0.35-0.5% of MC are added to the samples. 

Stamper RL, DiLoreto D, Schacknow P. Effect of intraocular aspiration of sodium hyaluronate on postoperative intraocular pressure. Ophthalmic Surg 1990 21 486-491 Steele ADM. Viscoelastic materials in keratoplasty. Trans Ophthalmol Soc UK 1983 103 268-269 Steele EA. Hydroxypropyl methylcellulose used as a viscoelastic fluid in ocular surgery, in Rosen ES (ed) Viscoelastic Materials Basic Science and Clinical Applications. New York, Pergamon Press, 1989,S. 161-163... 

The mechanism of separation with linear polymers is as follows. At a certain polymer concentration known as the entanglement threshold, the individual polymer strands begin to interact with each other, leading to a meshlike structure within the capillary. This allows DNA separation to take place. Many of the common polymers are cellulose derivatives, such as hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, and methylcellulose. Other applicable polymers include linear polyacrylamide, polyethylene oxide, agarose, polyvinyl pyrrolidone, and poly-N. Ar-dimethylacrylamide. High-resolution separation up to 12,000 bp has been reported using entangled polymer solutions. 

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