Sodium polyvinyl alcohol

FIGURE 1.9 Plot of )sp/c versus c for the sodium salt of partially sulfuric acid-esterified sodium polyvinyl alcohol (degree of substitution a = 0.31, and degree of polymerization = 2500) in water with added molar concentrations of NaCl as indicated. (Adapted from Nishidaetal. [2002].)... 

Capryloamphoglycinate, cocoamphodiacetate, disodium cocoamphodiacetate, lauroamphoacetate, sodium capryloamphohydroxypropyl sulfonate, sodium mixed Cg amphocarboxylate, and alkylamphohydroxypropyl sulfonate Polyvinylpyrrolidone, polyvinyl alcohol, starches, cellulosic material, or partially hydrolyzed polyacrylamide, and polypropylene glycol, or a betaine [43]... 

Note PEO = polyethylene oxide PVA = polyvinyl alcohol SDS = sodium dodecyl sulfate CTAB = cetyl trimethyl ammonium bromide. 

Adsorbents for biomacromolecules such as proteins have special properties. First, they need to have large pore sizes. A ratio of pore radius to molecule radius larger than 5 is desirable to prevent excessive diffusional hindrance (see Intraparticle Mass Transfer in this section). Thus, for typical proteins, pore radii need to be in excess of 10-15 nm. Second, functional groups for interactions with the protein are usually attached to the adsorbent backbone via a spacer arm to provide accessibility. Third, adsorbents based on hydrophilic structures are preferred to limit nonspecific interactions with the adsorbent backbone and prevent global unfolding or denaturation of the protein. Thus, if hydrophobic supports are used, their surfaces are usually rendered hydrophilic by incorporating hydrophilic coatings such as dextran or polyvinyl alcohol. Finally, materials stable in sodium hydroxide solutions (used for clean-in-place) are... 

Stabilization in water (surface tension 72 mN/m) can be achieved through the use of surfactants [77] such as SDBS [78] or sodium cholate [79], or long chain polymers such as polyvinyl alcohol. While this allows a non-toxic and easily removed solvent to be used, the presence of the surfactant or polymer molecules can be detrimental to the subsequent applications [80]. 

When heated, polyvinyl chloride (PVC) and polyvinyl alcohol (PVA) lose HC1 and H20, respectively, to produce dark-colored conductive polyacetylene. Superior polymers of acetylene can be made by the polymerization of acetylene with Ziegler-Natta catalysts. The conductivity of polyacetylene is increased by the addition of dopants, such as arsenic pentafluoride or sodium naphthenide. 

Carbomer, carmellose, microcrystalline cellulose, sodium carboxymethylcellulose, povidone, sodium alginate, tragacanth, and xanthan gum Acacia and methylcellulose, glycerol esters, polysorbates and sorbitan esters, fatty acids, sodium stearate, carbomer Macrogol esters, polyvinyl alcohol, and glycerides... 

Sugars, including glucose, sucrose syrup, and honey, sorbitol, mannitol, and xylitol, sodium and calcium salts of saccharin, aspartame, potassium thaumatin Sugars and polyvinyl alcohol, povidone, and cellulose Electrolytes, polymers, starch, sodium alginate, and carbomer... 

Superabsorbent polymers are now commonly made from the polymerization of acrylic acid blended with sodium hydroxide in the presence of an initiator to form a polyacrylic acid, sodium salt (sometimes referred to as cross-linked sodium polyacrylate). Some of the polymers include polyacrylamide copolymer, ethylene maleic anhydride copolymer, cross-linked carboxy-methyl-cellulose, polyvinyl alcohol copolymers, cross-linked polyethylene oxide, and starch grafted copolymer of polyacrylonitrile to name a few. The latter is one of the oldest SAP forms created. 

Thioridazine, U.S.P. was obtained at Sandoz Pharmaceuticals Corporation, East Hanover, NJ. Sodium oleate (Purified Grade) was obtained from Fisher Scientific Company, Springfield, NJ. Polyvinyl alcohol (Type III, Hot Water Soluble, P 1763) was obtained from Sigma Chemical Company, St. Louis, MO. Poly(L-lactide) was prepared by Sandoz Ltd. (Basle, Switzerland) and poly(DL-lactide) by Battelle Columbus Laboratories (Columbus, OH). Other materials were of reagent grade unless otherwise specified. 

A solution of 1.0 g of thioridazine free base and 1.0 g of poly(DL-lactide) or poly(L-lactide) in 10 mL of methylene chloride was emulsified with 100 mL of an aqueous solution containing 0.4 g of sodium oleate or polyvinyl alcohol and 0-15 mL of 0.1 N NaOH (0-0.14 mole NaOH/mole lactic acid). After the emulsion was magnetically stirred for 10-15 minutes, the organic solvent was removed by rotary evaporation, 150 rpm, 375 mm Hg, at 40°C for 2 hours. The product was filtered, washed with water and vacuum dried at 30°C. 

The effect of NaOH on drug release was examined with microspheres prepared with thioridazine and two biodegradable polymers. The wall-forming polymers were poly(DL-lactide) and poly(L-lactide). Sodium oleate was used as the emulsifier, with the exception of one set of experiments where the emulsions were stabilized with polyvinyl alcohol. 

In order to determine whether the effect of NaOH was specific to the use of sodium oleate as the emulsifier, microspheres were also prepared using polyvinyl alcohol to stabilize the emulsion. Figure 3 indicates that there was only a moderate increase in drug release by the addition of NaOH to the emulsion. 

To recapitulate, thioridazine release from microspheres was enhanced when NaOH was added to the emulsion prior to the solvent evaporation step. This was observed for both poly(DL-lactide) and poly(L-lactide) and also for two emulsifier systems, sodium oleate and polyvinyl alcohol. It should be pointed out that NaOH is added only to the aqueous phase of the emulsion. It is not incorporated into the microspheres by this process. 

PVA is further modified to obtain polyvinylacetatephthalate (PVAcP), which is used in enteric coatings. PVAcP is prepared from the reaction of partially hydrolyzed polyvinyl alcohol, sodium acetate and phthalic anhydride. It consists of 55 to 62% of phthalyl groups. The PVA used is a low molecular weight grade with 87 to 89 mole% hydrolyzed. Since only vinyl alcohol portions of the partially hydrolyzed PVA are phthalated, the acetyl content remains constant before and after the reaction. 

The polyvinyl alcohol is soluble in hot water, and the solution is wet-spun into a coagulating bath consisting of a concentrated solution of sodium sulfate. The fibers are heat-treated to provide temporary stability so that they may be converted to the formal derivative by treatment with an aqueous solution of formaldehyde and sulfuric acid. This final product resists hydrolysis up to the boiling point of water. It seems reasonable to assume that it contains hemiacetal groups and some unreacted hydroxyls on the polymer chain as... 

Monomer droplets are suspended in the water through the use of agitation and stabilizers, such as methyl cellulose, gelatin, polyvinyl alcohol, and sodium polyacrylate.32 Typical droplet sizes are 0.01-0.5 cm. A monomer soluble initiator is added to begin the polymerization. The kinetics of suspension polymerization are the same as for bulk polymerization, but suspension polymerization offers the advantage of good heat transfer. Polymers such as polystyrene, PVC, and polymethyl methacrylate are prepared by suspension polymerization. 

Higher hydrolytic stability is exhibited by capillaries based on vinyl coatings as primary anchor group, where, in the second step, vinyl acetate is polymerized and subsequently hydrolyzed with sodium methylate in methanol [6]. Such capillaries are stable up to a pH value of 10. Polyvinyl alcohol has also been thermally immobilized onto the capillary surface [7]. With such stable layers in the acidic and neutral region no measurable EOF is present and the stability of the capillaries is very good. 

A method for determination of sodium isoascorbate (see 2) in boiler feed water, where it is used for deoxygenation, consists of following the reaction kinetics of Rhodamine B (13) in the presence of KBrOs, measuring at 555 nm. A linear correlation exists between the catalytic effect of the analyte on the reaction rate and its concentration Fe(III), Ca(II) and Mg(II) in the 5-200 ppm range interfere with the analysis . The effects of solvents, pH, surfactants, metal ions and other food additives on the absorbance were studied for the micelle-enhanced UV spectrophotometric determination of the food preservative sodium D-isoascorbate. The optimal conditions were using water at pH 7-8 as solvent and polyvinyl alcohol as surfactant, which causes an up to 3-fold increase of the UV absorbance. ... 

Nelson JD, Farris RL. Sodium hyaluronate and polyvinyl alcohol artificial tear preparations. Arch Ophthalmol 1988 106 484-487. 

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