Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Cellulose hydroxypropylmethyl

Hydroxy propyl cellulose, like methyl cellulose, is soluble in cold water but not in hot, precipitating above 38°C. It was introduced by Hercules in 1968 (Klucel) for such uses as adhesive thickeners, binders, cosmetics and as protective colloids for suspension polymerisation. The Dow company market the related hydroxypropylmethyl cellulose (Methocel) and also produce in small quantities a hydroxyethylmethyl cellulose. [Pg.632]

Hydroxypropylmethyl cellulose phthalate (HPMCP) Poly(methacrylates)... [Pg.308]

In the absence of gluten some other system must be used to cause the bread to rise. One possibility is to use hydroxypropylmethyl cellulose, which forms a film with the rice flour and water that traps the gases and acts as a substitute for gluten. [Pg.190]

CIEF analysis of rtPA in the presence of urea was also carried out in an uncoated capillary using pressure mobilization.114 The final urea concentration used was 4 M, and EOF was reduced by adding polymers to the reagents and sample (0.4% hydroxypropylmethyl cellulose produced better results than polyethylene glycol). A one-step CIEF method described by Moorhouse et al.115 for the analysis of rtPA produced a constant residual EOF in a neutral capillary. The sample was prepared by dilution to 125 to 250 pg of protein per milliliter in 3% ampholytes 3 to 10 and 5 to 8 (1 1) containing 7.5% TEMED and 4 M urea. Results obtained by CIEF correlated well with those generated by IEF, and the analysis was completed in less than 10 min. [Pg.205]

Among the gelling agents used are synthetic macromolecules as acrylic acid polymers such as Carbomer 934, cellulose derivatives such as carboxymethyl cellulose or hydroxypropylmethyl cellulose, and natural gums such as xanthan gum. Appendix IV shows the commonly used gelling agents in commercially available pharmaceutical gels. [Pg.204]

Protective Film Coating with Hydroxypropylmethyl Cellulose + Kollidon VA 64 page 2... [Pg.351]

FIGURE 18.10 Inhibitory effect of polymers on recrystallization of nifedipine (NP) from a supersaturated solution at pH 6.8. HPMCAS, hydroxypropylmethyl cellulose acetate succinate HPMC, hydroxypropylmethyl cellulose HPMCP, hydroxypropylmethyl pthate PVP, polyvinyl pyrrolidone MAEA, methacrylic acid ethyl acrylate copolymer. (From Tanno, F., Y. Nishiyama, H. Kokubo, S. Obara. ZWMjDev Ind Pharm30 13. [Pg.517]

Suitable materials for a flow-promoting layer include hydroxypropyl, hydroxyethyl, or hydroxypropylmethyl celluloses povidone polyethylene glycols (PEGs) or their mixtures [18]. [Pg.219]

Yong et ah [175] developed an effective omeprazole buccal adhesive tablet with excellent bioadhesive force and good drug stability in human saliva. The omeprazole buccal adhesive tablets were prepared with various bioadhesive polymers, alkali materials, and croscarmellose sodium. Their physicochemical properties, such as bioadhesive force and drug stability in human saliva, were investigated. The release and bioavailability of omeprazole delivered by the buccal adhesive tablets were studied. As bioadhesive additives for omeprazole tablet, a mixture of sodium alginate and hydroxypropylmethyl cellulose was selected. The omeprazole tablets prepared with bioadhesive polymers alone had bioadhesive forces suitable for a buccal adhesive tablet, but the stability of omeprazole in human saliva was not satisfactory. Magnesium oxide is an alkali stabilizer for omeprazole buccal adhesive tablets. Croscarmellose sodium enhanced the release of omeprazole from the tablets but it decreased the bioadhesive forces and stability of omeprazole tablets in human saliva. [Pg.254]

Schulze et al. [135] developed fused-silica chips dynamically coated with hydroxypropylmethyl cellulose and utilized them for the separation of aromatic low molecular weight compounds such as serotonin, propranolol, a diol, and tryptophan. The authors used deep UV laser-induced fluorescence detection for these compounds. Schuchert-Shi et al. [136] identified ethanol, glucose, ethyl acetate, and ethyl butyrate, byproducts obtained in enzymatic conversions using hexokinase, glucose oxidase, alcohol dehydrogenase, and esterase. The authors reported that the quantification for ethyl acetate was possible using contactless conductivity detection. Hu et al. [137] described the separation of reaction products of (3-thalassemia in a multiplex primer-extension reaction using NCE. The method developed was used for patient samples and the results coincided with those of a detection kit. [Pg.214]

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. [Pg.366]

Figure 5.12 Electrophoretic separation of Figure 5.12 Electrophoretic separation of <I X 174RF DNA HaeIII digest using monointercalating dye (ethidium bromide). Conditions buffer, 89 mM Tris, 89 mM boric acid, and 2 mM EDTA with 0.4% (w/v) (hydroxypropylmethyl)cellulose electric field strength, 180 V/cm injection, electromigration, 4 kV for 4 sec. (Reprinted from Ref. 29 with permission.)...
Methyl cellulose Ethyl cellulose Hydroxyethyl cellulose Hydroxypropyl cellulose Hydroxyethylmethyl cellulose Hydroxypropylmethyl cellulose Carboxymethyl cellulose sodium Cellulose acetate Cellulose acetate butyrate Cellulose acetate propionate Cellulose acetate phthalate Hydroxypropylmethyl cellulose phthalate... [Pg.418]

Water-soluble hydroxypropylmethyl cellulose and water-insoluble cellulose acetate are further treated with phthalic anhydride or succinic anhydride to yield hydroxypropyl methylcellulose phthalate, cellulose acetate phthalate, and hydroxypropyl-methylcellulose acetate succinate. These polymers are used as enteric materials and are water soluble or insoluble above or below a specific pH, respectively. [Pg.491]

Methyl cellulose (0.5-5% aqueous suspension) Carboxymethyl cellulose Hydroxypropylmethyl cellulose... [Pg.919]

Hydroxypropyl cellulose Hydroxypropylmethyl cellulose Magnesium aluminum silicate 50.000- 1250,000 10.000- 1 00,000... [Pg.294]

Research on nasal powder drug delivery has employed polymers such as starch, dextrans, polyacrylic acid derivatives (e.g., carbopol, polycarbophil), cellulose derivatives (microcrystalline cellulose, semicrystalline cellulose, hydroxypropylmethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose), chitosan, sodium alginate, hyaluronans, and polyanhydrides such as poly(methyl vinyl ether-co-maleic anhydride) (PVM/MA). Many of these polymers have already been used as excipients in pharmaceutical formulations and are often referred to as first-generation bioadhesives [38-45], In nasal dry powder a single bioadhesive polymer or a... [Pg.655]

Cellulose derivatives Sodium carboxymethyl cellulose Methylcellulose Hydroxyethylcellulose Hydroxypropylmethyl cellulose Other derivatives Modified starches Low-Methoxyl pectins Propylene glycoalginates... [Pg.154]

Excipients like dibutyl phthalate were used as plasticizers for controlled-release microspheres of theophylline and sulfamethazine prepared by spray-drying. Likewise, citric acid was used as plasticizer for spray-dried sodium carboxymethyl cellulose and hydroxypropylmethyl cellulose microspheres containing theophylline.Excipients were found to affect the release rate of theophylline with citric acid and triethylene citrate giving the slowest and fastest rate, respectively, as compared with polyethylene glycol and glycerin excipients. [Pg.1651]

Hypromellose acetate succinate is a mixture of acetic acid and monosuccinic acid esters of hydroxypropylmethyl cellulose. It is available in several grades, which vary in extent of substitution, mainly of acetyl and succinoyl groups, and in particle size (fine or granular). When dried at 105°C for one hour, it contains 12.0-28.0% of methoxy groups 4.0-23.0% of hydroxypropoxy groups 2.0-16.0% of acetyl groups and 4.0-28.0% of succinoyl groups. [Pg.350]

Hoshi N, Ueno K, Yano H, Hirashima K, Kitagawa H. General pharmacological studies of hydroxypropylmethyl cellulose acetate succinate in experimental animals. / Toxicol Sci 1985 10 129-146. [Pg.353]


See other pages where Cellulose hydroxypropylmethyl is mentioned: [Pg.22]    [Pg.298]    [Pg.125]    [Pg.176]    [Pg.510]    [Pg.245]    [Pg.251]    [Pg.154]    [Pg.298]    [Pg.302]    [Pg.753]    [Pg.92]    [Pg.244]    [Pg.248]    [Pg.221]    [Pg.418]    [Pg.778]    [Pg.827]    [Pg.827]    [Pg.1245]    [Pg.1676]    [Pg.1776]    [Pg.2125]    [Pg.2825]    [Pg.3564]    [Pg.3658]   
See also in sourсe #XX -- [ Pg.632 ]

See also in sourсe #XX -- [ Pg.298 ]

See also in sourсe #XX -- [ Pg.632 ]

See also in sourсe #XX -- [ Pg.221 ]

See also in sourсe #XX -- [ Pg.437 ]

See also in sourсe #XX -- [ Pg.632 ]

See also in sourсe #XX -- [ Pg.2 , Pg.126 ]




SEARCH



Hydroxypropylmethyl

© 2024 chempedia.info