Vinyl acetate-vinylpyrrolidone

Poly( 1 -vinyl pyrrolidone- vinylpyrrolidinone) vinyl acetate-vinylpyrrolidone copolymer 136445-69-7... 

Rhodium precipitation in solubilized rhodium-phosphite complex catalyzed liquid recycle hydroformylation may be minimized or prevented by carrying out product recovery in the presence of an organic polymer containing polar functional groups such as amides, ketones, carbamates, ureas and carbonates.[20] Patent examples include the use of polyvinylpyrrolidone and vinylpyrrolidone-vinyl acetate copolymer with diorganophosphite-modified rhodium catalysts. 

Applying this method to the system polystyrene/methyl methacrylate, block copolymers containing 20—30% styrene have been prepared the systems polyvinyl acetate/styrene and polyvinyl acetate/ethyl chloroacrylate afford block copolymers containing respectively 40 and 82% vinyl acetate 204). In contrast, the polystyrene prepared using phthalyl polyperoxide was unable to initiate the polymerization of vinyl acetate or vinylpyrrolidone, likely on account of the difference in stability of the concerned radicals. 

Similar results are reported in the literature when Kollidon VA 64 is compared to povidone (Kollidon K 25, K 30, and 90 F). Copovidone absorbs about three times less water than the other soluble Kollidon K 25, 30, and 90F after seven days at 25 °C up to 80% relative humidity [62], Kollidon VA 64 is manufactured by free-radical polymetization of 6 parts of vinylpyrrolidone and 4 parts of vinyl acetate in 2-propanol. A water-soluble copolymer with a chain structure is obtained. In contrast to the soluble grades of Kollidon, the number 64 is not a K value but the mass ratio of the two monomers, vinylpyrrolidone and vinyl acetate. The K value of Kollidon VA 64 is of the same order of magnitude as that of Kollidon 30. Synonyms for Kollidon VA 64 are copovidone, copovidonum, copolyvidone, copovidon, and PVP-VAc-copolymer [Eur. Ph., Japanese Pharmaceutical Excipients, and USP National Formulary (NF)] [63],... 

Acrylamide, 2-methyl-5-vinylpyridine and /V-vinylpyrrolidone can be polymerized under similar conditions, and also after decomposition of a monomer-peroxide complex. On the other hand, styrene, methyl methacrylate, isoprene, methyl acrylate, vinyl acetate and ascorbic acid do not polymerize under these conditions. Complex formation between persulphate and these monomer donors is more favourable energetically [165]. The complex is more stable, it is not decomposed into initiating radicals and polymerization does not occur. 

Some other interesting copolymers having properties of PVC thermal stabUizers, like poly[Af-(a-benzothiazolonylmethyl)methacrylate-co-methyl methacrylate] [45], of flame retardants like a terpolymer of styrene, acrylonitrile and a polymerizable perbrominated phenol [76] or poly[4-methacryloyloxy-2,3,5,6-tetrabromobenzyldi-phenyl phosphonate-co-methyl methacrylate] [104] (93), bioddes, mostly copolymers of monomers containing tris(n-butyl tin) or triphenyl tin moieties and alkyl acrylates, methacrylates, vinyl acetate, acrylonitrile, styrene or A-vinylpyrrolidone [105], e.g. a terpolymer of styrene, MMA and tri(n-butyl tin) itaconate [106] (94),... 

Linear polystyrene can be functionalized by various methods . The functional group capacity in these polymers diould not be too high otherwise, steric complications may arise. Poly(ethylene ycol) has been found to be most suitable for liquid-phase synthesis. This linear polyether and the block copolymers with functional groups at defined distances are chemically stable and soluble in a large number of solvents including water and can be precipitated selectively. Partially hydrolyzed poly(vinylpyrrolidone) and its copolymers with vinyl acetate were successfully applied in peptide synthesis. Poly(acrylic acid), poly(vinyl alcdiol), and poly-(ethylenimine) are less suitable for the sequential type synthesis because of the... 

BMA butyl methacrylate, EA ethyl acrylate, DAEMA dimethylaminoethyl methacrylate, MAA methacrylic acid, MMA methyl methacrylate, TAMCl trimethylammonioethyl methacrylate chloride, VA vinyl acetate, VP vinylpyrrolidone. 

Acetic acid vinyl ester, polymer with 1-vinyl-2-pyrrolidinone copolymer of 1-vinyl-2-pyrrolidone and vinyl acetate in a ratio of 3 2 by mass copolyvidone KolUdon VA 64-, Luviskol VA Plasdone S-630-, poly(l-vinylpyrrolidone-co-vinyl acetate) polyvinylpyrrolidone-vinyl acetate copolymer PVPAA. PVP/ VA copolymer. 

Copovidone is manufactured by free-radical polymerization of vinylpyrrolidone and vinyl acetate in a ratio of 6 4. The synthesis is conducted in an organic solvent owing to the insolubility of vinyl acetate in water. 

Matsumoto T, Zografi G. Physical properties of solid molecular dispersions of indomethacin with poly(vinylpyrrolidone) and poly(vinylpyirolidone-co-vinyl-acetate) in relation to indomethacin crystallization. Pharm Res 1999 16 1722-8. 

Fig. 5. Free-radical polymerization of vinylpyrrolidone-vinyl acetate copolymer (n+1) m = 6 4...

HPLC method for the determination of free N-vinylpyrrolidone, 2-pyrrolidone and vinyl acetate in povidone and copovidone... 

The determination limits are 2 mg/kg N-vinylpyrrolidone, 200 mg/kg 2-pyrro-lidone and 10 mg/kg vinyl acetate. 

Dissolve reference substances (50 mg of N-vinylpyrrolidone, about 300 mg of 2-pyrrolidone and 50 mg of vinyl acetate in the case of copovidone) in methanol and dilute with the same solvent. Further dilutions are done with eluent A. 

Calculation of 2-pyrrolidone resp. N-vinylpyrrolidone resp. vinyl acetate in the sample ... 

FP = Peak area of 2-pyrrolidone resp. N-vinylpyrrolidone resp. vinyl acetate in the sample chromatogram [mV s] fi(P) = calculated concentration of the sample solution [mg/io ml]... 

The calibration curves given in Fig. 29,30 and 31 were obtained with the reference substances 2-pyrrolidone, N-vinylpyrrolidone and vinyl acetate. 

Two commercial products of the vinylpyrrolidone-vinyl acetate copolymer are available in the market having the pharmaceutical quality required by the Pharmacopoeias. Table 151 mentions the tradenames and producers of these copovidone products. 

Table 151. Vinylpyrrolidone-vinyl acetate copolymer 6+4 of pharmaceutical quality (= copovidone) in the market...

Table 152. Official names and abbreviations for the vinylpyrrolidone-vinyl acetate copolymer 6 + 4 ...

The CAS number of the vinylpyrrolidone-vinyl acetate copolymer 6+4 is 25086-89-9. It has the synonyms and abreviations given in Table 152. 

As an alternative to the iodometric titration given in the pharmacopoeias, the monomers vinylpyrrolidone and vinyl acetate can be determined by HPLC (see Section 2.3.3.2 or 4.3.2.2). The two commercial products mentioned in Table 151 fulfill the requirement of max. 10 ppm of each monomer. The microbial status can... 

Because of the ratio of vinylpyrrolidone to vinyl acetate in copovidone is almost as universally soluble as povidone. It dissolves in extremely hydrophilic liquids such as water as well as in more hydrophobic solvents such as butanol. 

Some of the pharmacopoeia methods are not always entirely relevant. This applies particularly to the titration test for the N-vinylpyrrolidone and vinyl acetate monomers, as the method is not very specific and relatively inaccurate and therefore no longer do justice to the purity of copovidone. 

As copovidone almost always contains levels of N-vinylpyrrolidone and vinyl acetate that are much lower than the detection limits of pharmacopoeia titration methods, it is recommended to use a more sensitive method such as high performance liquid chromatography (HPLC). 

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