Polyvinylpyrrolidone preparations

G 3 — Weight average molecular weight of polyvinylpyrrolidone preparations as determinated by light scattering. J. Phann. and Pharmacol. 9,230 (1957). 

Table 5. Physicochemical data of the most important polyvinylpyrrolidone preparations discussed in the literature. (Gruber 1969)...

The compounds 12,14 and 15 can be prepared from parent lysergic acid amides by bromination with NBS or PHT, but not the compounds of the type 12. The latter structure is very sensitive and under these circumstances only degradation products were obtained. Besides it was necessary to use much milder reagent, e.g. bromine bonded onto polymeric matrix with polyvinylpyrrolidone or polyvinylpyridine structure (29) ... 

Protective Colloids. Another approach in preparing and stabilizing metal colloids is by adsorption of macromolecules on their surfaces. A wide variety of materials have been used including gummy gelatinous liquids,(J 0) albumin,(27) Icelandic moss,(28) latex,(22) polyvinylpyrrolidone, (29) antibodies, ( 30 ) carbowax 20M, ( 31 ) polyvinylpyridine, (31 ) and various polymer-water/oil-water mixtures.( 2) These studies clearly indicate that "steric stabilization of metal colloids is also important (along with electronic stabilization).(33)... 

Ffirai and Toshima have published several reports on the synthesis of transition-metal nanoparticles by alcoholic reduction of metal salts in the presence of a polymer such as polyvinylalcohol (PVA) or polyvinylpyrrolidone (PVP). This simple and reproducible process can be applied for the preparation of monometallic [32, 33] or bimetallic [34—39] nanoparticles. In this series of articles, the nanoparticles are characterized by different techniques such as transmission electronic microscopy (TEM), UV-visible spectroscopy, electron diffraction (EDX), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) or extended X-ray absorption fine structure (EXAFS, bimetallic systems). The great majority of the particles have a uniform size between 1 and 3 nm. These nanomaterials are efficient catalysts for olefin or diene hydrogenation under mild conditions (30°C, Ph2 = 1 bar)- In the case of bimetallic catalysts, the catalytic activity was seen to depend on their metal composition, and this may also have an influence on the selectivity of the partial hydrogenation of dienes. 

As reported, by polycondensation of dicarboxylic acids with diamines or by polycondensation of aminoacids in the presence of polyvinylpyrrolidone, polymers with very high molecular weight were obtained. The viscosities of poly(terephthalamides) prepared by template polymerization in the presence of polyvinylpyrrolidone from p-phenylenediamine and 4,4 -diaminodiphenylosulfone and of poly(m-benzamid) are very high. Also, polypeptides with molecular weight of 20-30 thousands were obtained by template polymerization in the presence of polyvinylpyrrolidone ... 

Lenaerts et al. (2) prepared a biphasic drug delivery device for tramadol consisting of polyvinyl acetate and polyvinylpyrrolidone having a sustained release for 24 hours. Polyvinylpyrrolidone was also used by Midha et al. (3) in the trans-dermal delivery of atomoxetine. 

Tachibana T, Nakamura A. A method for preparing an aqueous colloidal dispersion of organic materials by using water-soluble polymers dispersion of beta-carotene by polyvinylpyrrolidone. Kolloid-Z Polym 1965 203 130-133. 

Similar grafting experiments by the emulsion technique were described (34) in the system vinyl chloride/copolymer butyl methacrylate-methacrylic acid and in the reverse system, and also in the system styrene/polyvinyl chloride. In this last case again as in homogenous medium, the inverse process failed (vinyl chloride on polystyrene). Grafted acrylonitrile copolymers were also prepared in order to improve their dyeability, by polymerizing acrylonitrile in emulsion in the presence of many different polymers as polyvinyl alcohol, polymethacrylamide and polyvinylpyrrolidone (119, 120, 121), polyvinyl acetate and polyacrylic acid (115), wool (224,225), proteins (136), etc. 

Ronnau AC, Wulferink M, Gleichmann E, Unver E, Ruzicka T, Krutmann J, Grewe M. Anaphylaxis to polyvinylpyrrolidone in an analgesic preparation. Br J Dermatol 2000 143 1055-8. 

Nakano and Fujishige prepared a colloidal nickel boride catalyst by reducing nickel chloride with sodium borohydride in ethanol in the presence of polyvinylpyrrolidone) as a protective colloid.83 Catalytic activity of the colloidal catalyst was higher than P-2 Ni boride for the hydrogenation of acrylamide and markedly enhanced by the addition of sodium hydroxide in the hydrogenation of acetone.84... 

The experimental samples of the magnetic films were prepared using mentioned above hydrosol of magnetite and water-soluble polyvinylpyrrolidone (PVP). Nanoparticles from ferrofluid have been embedded into solid diamagnetic PVP matrix. Ferrofilms of PVP have been dried in air for several hours with and without external MF of 1500 G intensity. 

Swan [3] prepared a benzene 1,3-disulfonic acid derivative, (III), as a surface coating agent for polyvinylpyrrolidone for subsequent use as a surface modifier on polyvinylchloride urinary catheters. 

Most research into the study of dispersion polymerization involves common vinyl monomers such as styrene, (meth)acrylates, and their copolymers with stabilizers like polyvinylpyrrolidone (PVP) [33-40], poly(acrylic acid) (PAA) [18,41],poly(methacrylicacid) [42],or hydroxypropylcellulose (HPC) [43,44] in polar media (usually alcohols). However, dispersion polymerization is also used widely to prepare functional microspheres in different media [45, 46]. Some recent examples of these preparations include the (co-)polymerization of 2-hydroxyethyl methacrylate (HEMA) [47,48],4-vinylpyridine (4VP) [49], glycidyl methacrylate (GMA) [50-53], acrylamide (AAm) [54, 55], chloro-methylstyrene (CMS) [56, 57], vinylpyrrolidone (VPy) [58], Boc-p-amino-styrene (Boc-AMST) [59],andAT-vinylcarbazole (NVC) [60] (Table 1). Dispersion polymerization is usually carried out in organic liquids such as alcohols and cyclohexane, or mixed solvent-nonsolvents such as 2-butanol-toluene, alcohol-toluene, DMF-toluene, DMF-methanol, and ethanol-DMSO. In addition to conventional PVP, PAA, and PHC as dispersant, poly(vinyl methyl ether) (PVME) [54], partially hydrolyzed poly(vinyl alcohol) (hydrolysis=35%) [61], and poly(2-(dimethylamino)ethyl methacrylate-fo-butyl methacrylate)... 

Suzuki and Sunada " also prepared solid dispersions of nifedipine with other combined carriers using a fusion (melt) method. The combined carriers were nicotinamide and four different water-soluble polymers hydroypropyl methylcellulose (HPMC), polyvinylpyrrolidone (PVP), partially hydrolyzed polyvinyl alcohol (PVA), and pullulan. HPMC, PVP, and PVA dissolved in the melt of nicotinamide and were effective in the amorphous formation of nifedipine in solid dispersions. In dissolution studies, the drug concentration... 

Van den Mooter et al. prepared solid dispersions of tamazepam in PEG 6000 and polyvinylpyrrolidone K30 (PVP K30) by the fusion (melting) and cooling process. In contrast to the very slow dissolution rate of pure temazepam, the dispersion of the drug in the polymers enhanced the dissolution rate considerably. This can be attributed to improved wettability and dispersibility and a decrease of the crystalline fraction of the drug. 

Kumar V, Yang T, Yang Y. Interpolymer complexation I preparation and characterization of a polyvinyl acetate phtha-late-polyvinylpyrrolidone (PVAP-PVP) complex. Int J Pharm 1999 188 221-232. 

Christensen M, Johansen P, Hau C. Storage of polyvinylpyrrolidone (PVP) in tissues following long-term treatment with a PVP containing vasopressin preparation. Acta Med Scand 1978 204 295-298. 

Sonication and liquid chromatography are a rapid pair of techniques for extraction and fractionation of plant material. The method combines extraction by sonication with a mixture of nonmiscible solvents, rapid preseparation of the crude extract by vacuum-liquid chromatography (silica gel 60H), and separation by preparative, reversed-phase HPLC or classical liquid chromatography with polyvinylpyrrolidone. 

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