Polyvinyl pyrollidone

Chemically it is a l-Ethenyl-2-pyrrolidinone homopolymer. It is categorized as nonionic polymer. 

Povidone occurs as a fine, white to creamy-white colored, odorless or almost odorless, hygroscopic powder. Povidones with K-values equal to or lower than 30 are manufactured by spray-drying and occur as spheres. Povidone K-90 and higher K-value povidones are manufactured by drum-drying and occur as plates. It softens at 150°C. 

Though povidone is used in a variety of pharmaceutical formulations, it is primarily used in solid-dosage forms. In tableting, povidone solutions are used as binders in wet-granulation processes. Povidone is also added to powder blends in the dry form and granulated in situ by the addition of water, alcohol, or hydroalcoholic solutions. Povidone is used as a solubilizer in oral and parenteral formulations, and has been shown to enhance dissolution of poorly soluble drugs from solid-dosage forms. 

K-Value Approximate Molecular Weight K-Value Approximate Molecular Weight 

Povidone is manufactured by the Reppe process. Acetylene and formaldehyde are reacted in the presence of a highly active copper acetylide catalyst to form butynediol, which is hydrogenated to butanediol and then cyclodehydrogenated to form butyro-lactone. Pyrrolidone is produced by reacting butyrolactone with ammonia. This is followed by a vinylation reaction in which pyrrolidone and acetylene are reacted under pressure. The monomer, vinylpyrrolidone, is then polymerized in the presence of a combination of catalysts to produce povidone. 

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In the other two studies, selenosulphate was used. In one, a formamide complex of Hg, made by dissolving HgO in formamide, was used [154]. The solution was made ca. 0.5 M in NaOH, and a trace of polyvinyl pyroUidone was added. The deposition was carried out at room temperature. The polyvinyl pyrollidone slowed the deposition somewhat and apparently improved fihn uniformity and adherence as well as slightly increased terminal thickness (500 mn). It was noted that films were not obtained with the usual complexants, such as ammonia, triethanolamine, and cyanide. It is not mentioned in which way these complexants were unsuitable ammonia and triethanolamine might be too weak, resulting in immediate precipitation in solution. Also, addition of ammonia to some mercuric salts tends to lead to precipitation of insoluble products. Cyanide, however, is a very strong com-plexant and would be expected to control such bulk precipitation better than formamide. Iodide, a strong complex for Hg (and successfully used to deposit HgS, as described earlier), resulted in film deposition but with poor reproducibility. 

PVP separation. The remaining pigment was removed from the polyamide water fractions by chromatography on a 2.4 cm x 15 cm column containing 50 g polyvinyl pyrollidone (Polyclar AT, GAF Corp., Wayne, N. J.) as shown in Figure 4. The PVP was rinsed first with 1 column volume of water followed by 1 column volume methanol. The p-damascenone charm of each fraction was then determined. The water rinses were concentrated on a 1 cm x 20 cm column containing 40 g of 40 mm C18 reversed phase adsorbant and eluted with 2 volumes of 50% methanol/water. The p-damascenone charm of the eluate was determined. 

Polyvinyl pyrollidone n. (C6H9NO) . White free-flowing amorphous polymer. It is soluble in water and organic solvents, and is compatible with a wide range of hydrophilic and hydrophobic resins. Abbreviation PVR... 

Polymeric Systems in Quick Dissolving Novel Films 153 5.4.5 Polyvinyl Pyrollidone... 

Polyvinyl pyrollidone is also known as E1201 Kollidon (Scheme 5.5) Plasdone poly[l-(2-0X0-l-pyrrolidinyl)ethylene] polyvidone polyvinylpyrrolidone povidonum Povipharm PVP and l-vinyl-2-pyrrolidinone polymer. 

Polyvinyl pyrollidone has been accepted for use in Europe as a food additive. It is also included in the FDA Inactive Ingredients Database in non-parenteral medicines licensed in the UK and in the Canadian List of Acceptable Non-medicinal Ingredients. 

Another example of this method is the synthesis of dual Au/Pt composites-the aqueous solutions of polyvinyl alcohol and poly-(JV>vinyl-2-pyrollidone) have been used [39] with polymerization in the solution after colloid particle formation. The aggregation of nanoparticles in this case does not usually take place however the polymerization conditions affect the homogeneity of the composite obtained. They show some catalytic propertks, characteristic of bimetallic catalysts. There were some reports on semiconductor composites with metal coatings such as CdS/Rh 40 A composites [44] and CdSe/Ag SO A composites [45]. The former system exhibits enhanced photochemical properties, the latter was used for investigation of Raman scattering of nanocomposites. 

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