[Study on Extraction Conditions of Water-Soluble Substances­Purity Test (4) for Polyvinylpolypyrrolidone Listed in Japan's Specifications and Standards for Food Additives].

The food additive polyvinylpolypyrrolidone is approved for use as a filter aid. The water-soluble substances test of polyvinylpolypyrrolidone often shows poor reproducibility. The instruction "boil gently while stirring using a stirrer" was considered critical, and so this issue was examined. The results showed that the use of a combination of both an oil bath and a stirrer provided good reproducibility without decomposition or other problems.

Removing polyvinylpyrrolidone from catalytic Pt nanoparticles without modification of superficial order.

Herein, we report a simple methodology for cleaning Pt nanoparticles, prepared by a colloidal synthesis and coated with polyvinylpyrrolidone, without loss of crystalline surface structure. To prove the removal of the polyvinylpirrolidone from a Pt surface without disturbing the superficial order, a cleaning method using a solution of H(2)O(2)/H(2)SO(4) was tested successfully for a Pt(111) single-crystal electrode. The decontamination method was then tested for two different types of nanoparticles by mixing the suspension of nanoparticles with H(2)O(2)/H(2)SO(4) and subsequent centrifugation. The resulting voltammetric profiles of platinum particles synthesized by the colloidal method employing PVP show a marked presence of the adsorption-state characteristic of (111) ordered surface domains. The presence of the well-ordered domains present on the surface of the nanoparticles was confirmed by using the irreversible adsorption of bismuth, tellurium and germanium.

Removal of polyvinylpyrrolidone from wastewater using different methods.

Polyvinylpyrrolidone (PVP) is a frequently used polymer in the pharmaceutical and foodstuff industries. Because it is not subject to metabolic changes and is virtually nondegradable, trace concentrations of PVP are often found in community wastewaters. The literature finds that the partial removal of PVP in wastewater treatment plants probably occurs through sorption. The primary objective of this study was to find an effective method to remove PVP from wastewaters. In this regard, the literature indicates the theoretical potential to use specific enzymes (e.g., gamma-lactamases, amidases) to gradually degrade PVP molecules. Polyvinylpyrrolidone biodegradability tests were conducted using suitable heterogeneous cultures (activated sludge) collected from a conventional wastewater treatment plant, treatment plants connected to a pharmaceutical factory, and using select enzymes. Aerobic biodegradation of PVP in a conventional wastewater environment was ineffective, even after adaptation of activated sludge using the nearly identical monomer 1-methyl-2-pyrrolidone. Another potential method for PVP removal involves pretreating the polymer prior to biological degradation. Based on the results (approximately 10 to 15% biodegradation), pretreatment was partially effective, realistically, it could only be applied with difficulty at wastewater treatment plants. Sorption of PVP to an active carbon sorbent (Chezacarb S), which corresponded to the Langmuir isotherm, and sorption to activated sludge, which corresponded to the Freundlich isotherm, were also evaluated. From these sorption tests, it can be concluded that the considerable adsorption of PVP to activated sludge occurred primarily at low PVP concentrations. Based on the test results, the authors recommend the following methods for PVP removal from wastewater: (1) sorption; (2) application of specific microorganisms; and (3) alkaline hydrolysis, which is the least suitable of the three for use in wastewater treatment plants.

Removal of pesticides from white wine by the use of fining agents and filtration.

The effects of four clarification agents (bentonite, charcoal, PVPP and potassium caseinate) on the removal of residues of three fungicides (famoxadone, fluquinconazole and trifloxystrobin) applied directly to a racked white wine, elaborated from Airen variety grapes from the D.O. Region of Jumilla (Murcia, Spain) are studied. The clarified wines were filtered with 0.45 microm nylon filters to determine the influence of this winemaking process in the disappearance of fungicide residues. Hydro-alcoholic solutions with the three fungicides at concentrations of 1 and 2 ppm were then added through intense stirring to each of the containers. Two hours later, the corresponding clarifying agent was added with intense stirring for some minutes. The containers were then sealed and left to settle for five days. Once the clean wines had been racked, they were filtered through nylon 0.45 microm pore filters. All assays were performed three times. Analytical determination of fluquinconazole and trifloxystrobin was performed by gas chromatography with an electron captor detector (ECD), while that of famoxadone was made using an HPLC-DAD. For the three fungicides, the highest elimination is produced with the clarification by charcoal, reaching Levels of removal of 100% in all cases. For the four clarifying agents, the highest elimination is produced for the fluquinconazole residues. The fungicide which is retained most in the lees is famoxadone, since it has the lowest solubility of the three pesticides studied. The highest percentage of residues in the lees is obtained for the assay with charcoal. The filtration process of the clarified wines using the four agents studied is not effective, since the elimination percentage is generally lower than 10% of the initial residues in the non-clarified wines.

Effect of polymer size and cosolutes on phase separation of poly(vinylpyrrolidone) (PVP) and dextran in frozen solutions.

The aim of this study was to elucidate the effect of the molecular weight of polymers on their miscibility in frozen solutions to model the physical properties of freeze-dried pharmaceutical formulations. Thermal analysis of frozen solutions containing poly(vinylpyrrolidone) (PVP) and dextran of various molecular weights was performed at polymer concentrations below the binodal curve at room temperature. Frozen solutions containing PVP 29,000 and dextran 10,200 showed two thermal transitions (glass transition temperature of maximally freeze-concentrated solution: Tg') representing two freeze-concentrated amorphous phases, each containing predominantly one of the polymers. A combination of smaller polymers (PVP 10,000 and dextran 1,060) was freeze-concentrated into an amorphous mixture phase across a wide range of concentration ratios. Combinations of intermediate size polymers separated into two freeze-concentrated phases only at certain concentration ratios. Addition of NaCl prevented the phase separation of PVP and dextran in the aqueous and frozen solutions. Higher concentrations of NaCl were required to retain the miscibility of larger polymer combinations in the freeze-concentrate. The molecular weights of the component polymers, polymer concentration ratio, and cosolute composition are the important factors that determine component miscibility in frozen solutions.

Freeze-concentration separates proteins and polymer excipients into different amorphous phases.

PURPOSE: To study the miscibility of proteins and polymer excipients in frozen solutions and freeze-dried solids as protein formulation models. METHODS: Thermal profiles of frozen solutions and freeze-dried solids containing various proteins (lysozyme, ovalbumin, BSA), nonionic polymers (Ficoll, polyvinylpyrrolidone [PVP]), and salts were analyzed by differential scanning calorimetry (DSC). The polymer miscibility was determined from the glass transition temperature of maximally freeze-concentrated solute (Tg') and the glass transition temperature of freeze-dried solid (Tg). RESULTS: Frozen Ficoll or PVP 40k solutions showed Tg' at -22 degrees C, while protein solutions did not show an apparent Tg'. All the protein and nonionic polymer combinations (5% w/w, each) were miscible in frozen solutions and presented single Tg's that rose with increases in the protein ratio. Various salts concentration-dependently lowered the single Tg's of the proteins and Ficoll combinations maintaining the mixed amorphous phase. In contrast, some salts induced the separation of the proteins and PVP combinations into protein-rich and PVP-rich phases among ice crystals. The Tg's of these polymer combinations were jump-shifted to PVP's intrinsic Tg' at certain salt concentrations. Freeze-dried solids showed varied polymer miscibilities identical to those in frozen solutions. CONCLUSIONS: Freeze-concentration separates some combinations of proteins and nonionic polymers into different amorphous phases in a frozen solution. Controlling the polymer miscibility is important in designing protein formulations.

Removal of percoll from microsomal vesicles by gel filtration on sephacryl-S-1000 superfine.

A microsomal vesicle fraction was prepared from rat liver homogenate by centrifugation in gradients of Percoll. The microsomes were subjected to gel filtration on Sephacryl S-1000 Superfine, which resolved the microsomes from Percoll. The elution pattern of the microsomal marker enzyme NADPH-cytochrome c reductase showed that the main part of the enzyme was present in a peak at Kav about 0.1, while Percoll eluted in a broad peak at Kav about 0.7. The total yield of eluted enzyme activity was 85%. The gel filtration had to be carried out in the presence of 10 mM tris or NaCl. At lower ionic strength or in 0.25 M sucrose alone, anomalous behaviour of the Percoll particles and microsomes on the gel was observed. Electron microscopy of samples from the void volume fraction of the Sephacryl S-1000 Superfine column showed an almost complete removal of Percoll from the microsomes. Furthermore, the vesicle preparation was essentially free of membrane fragments.