Aqueous Solutions Of Polyvinylpyrrolidone Research Articles

Hydrogen-bonded structure of hydrated water in polyvinyl pyrrolidone aqueous solution investigated by X-ray absorption and emission spectroscopy

Polyvinylpyrrolidone (PVP) is a hydrophilic polymer that is widely used in various biomedical applications owing to its excellent biocompatibility. It has been suggested that water-polymer interactions play a key role in controlling biocompatibility, although the molecular-level consequences of these interactions remain unknown. In this study, the hydrogen-bonded structures of water molecules hydrating PVP were investigated using X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES). XAS spectral profiles revealed that the CO bonds in highly concentrated PVP aqueous solutions have at least two states: one where hydrogen bonds are formed with water molecules and the other where they are not. In the XES profile of water extracted from a solution with a stoichiometric ratio of nw = 1.0, increased hydrogen bonding and hydrogen bond distortion were identified from the enhancement of 1b1′ and 3a1 peaks, respectively. Because it is difficult for water molecules to form strong hydrogen-bonded structures in tetrahedral coordination at nw = 1.0, these findings suggest that the presence of strong hydrogen bonds between the CO sites and water prevents the formation of tetrahedrally coordinated hydrogen-bonded structures among water molecules.

The Influence of Wet Granulation Parameters on the Compaction Behavior and Tablet Strength of a Hydralazine Powder Mixture.

The aim of this paper was to describe the influence of high-shear wet granulation process parameters on tablet tensile strength and compaction behavior of a powder mixture and granules containing hydralazine. The hydralazine powder mixture and eight types of granules were compacted into tablets and evaluated using the Heckel, Kawakita and Adams analyses. The granules were created using two types of granulation liquid (distilled water and aqueous solution of polyvinylpyrrolidone), at different impeller speeds (500 and 700 rpm) and with different wet massing times (without wet massing and for 2 min). Granulation resulted in improved compressibility, reduced dustiness and narrower particle-size distribution. A significant influence of wet massing time on parameters from the Kawakita and Adams analysis was found. Wet massing time had an equally significant effect on tablet tensile strength, regardless of the granulation liquid used. Granules formed with the same wet massing time showed the same trends in tabletability graphs. Tablets created using a single-tablet press (batch compaction) and an eccentric tablet press showed opposite values of tensile strength. Tablets from granules with a higher bulk density showed lower strength during batch compaction and, conversely, higher strength during eccentric tableting.

Вольт-амперні характеристики діодів Шотткі на основі гетероструктури графен/n-Si

The authors investigated the electrical properties of graphene/n-Si Schottky diode heterostructures obtained by mechanical exfoliation of graphite to thin-layer graphene in an aqueous solution of polyvinylpyrrolidone as a result of the dynamics of the dispersed graphite mixture under the action of a mechanical blender. The graphene/n-Si structures differed in terms of duration of applying graphene films on n-Si substrates: 5, 10 and 15 min. The temperature of the substrates did not exceed 250°C. The formation of graphene layers was confirmed by the study of Raman scattering spectra in the frequency range of 1000—3250 cm–1, which show G and 2D bands with the features characteristic of low-layer graphene. The dependence of the electrical properties of the investigated surface-barrier graphene/n-Si structures on the duration of sputtering of graphene films was established. It was found that the value of the contact potential difference φk was 1.35, 1.32 and 1.27 V and the series resistance at room temperature was 3.4•106, 3.4•103 and 3.7•103 Ω for structures with the duration of graphene layer deposition 5, 10 and 15 min, respectively. The formation of both forward and reverse currents was dominated by the tunneling of charge carriers through the potential barrier.

Фармакокинетика антагониста брадикинина производного 1,4-бензодиазепин-2-она в эксперименте

Introduction. The 1,4-benzodiazepin-2-one derivative (codenamed – PAV-0056), in a wide range of low doses 0.1–10 mg/kg has a pronounced analgesic effect as bradykinin receptor type 1 antagonist. Preclinical study of the pharmacokinetics of a new potential analgesic with different routes of administration in appropriate doses seems to be relevant. Aim. To evaluate the pharmacokinetic parameters, bioavailability and transmembrane transport of the 1,4-benzodiazepin-2-one derivative PAV-0056. Materials and methods. PAV-0056 at doses of 0.1, 1 and 10 mg/kg was administered in a 1% aqueous solution of polyvinylpyrrolidone into the stomach and vein of male Sprague Dawley rats (age 1.5–3 months) weighing 250–300 g. We determined the plasma concentration of PAV-0056 in the blood of rats at discrete time intervals using mass spectrometry. The pharmacokinetic parameters and absolute bioavailability of PAV-0056 were studied. The permeability of PAV-0056 through a cell monolayer was studied on a 21-day cell culture originated from of colorectal carcinoma (CaCO-2). Results. The absolute bioavailability of the 1,4-benzodiazepin-2-one derivative PAV-0056 after administration into the stomach of rats at a dose of 0.1 mg/kg is 10.1 ± 6.1%, at a dose of 1 mg/kg – 2.2 ± 0.1%, at a dose of 10 mg/kg – 6.4 ± 0.8%. Systemic exposure AUC and maximum plasma concentration Cmax change linearly with increasing dose of PAV-0056 from 0.1 to 10 mg/kg (coefficients of determination R2 are 0.9767 and 0.9976, respectively). PAV-0056 is absorbed from the small intestine within 1 h and eliminated from plasma within 5 h (the lower limit of quantification of PAV-0056 in plasma is 0.1 ng/ml). After intravenous administration, PAV-0056 is eliminated within 0.5 h. The analgesic has a total clearance (ClT) of 83.16 l/kg/h and is not a P-glycoprotein substrate. Conclusion. The lipophilic derivative of 1,4-benzodiazepin-2-one, PAV-0056 after administration into the stomach is absorbed from the small intestine by passive diffusion with a bioavailability of no more than 10.1 ± 6.1%. Linear pharmacokinetics and no interaction with P-glycoprotein allow PAV-0056 to be positioned as a non-opioid analgesic with a good safety profile.

Влияние поливинилпирролидона на эффект самоконсервации гидрата пропана

Experimental data on the dissociation of propane hydrate samples obtained from the bulk samples of ice and frozen aqueous solutions of polyvinylpyrrolidone are presented. It was revealed that propane hydrate exhibits a self-preservation effect, with a meager dissociation rate when subjected to a sudden drop in pressure in the presence of polyvinylpyrrolidone . This phenomenon occursat temperatures below 271 K. The results of the experiments made it possible to establish the range of polyvinylpyrrolidone concentration in frozen aqueous solutions, as well as estimate the thickness of the ice crust formed on the gas hydrate surface during dissociation,at which the self-preservation effect of propane hydrate is realized. It has been experimentally established that the shielding effect of the ice crust of preserved propane hydrate is retained up to a temperature of 272 K and completely disappears near 273 K.

Effect of quenching in aqueous polyvinylpyrrolidone solutions on the microstructure and pitting corrosion resistance of AISI 1045 carbon steel

AbstractCarbon steels are widely used as infrastructure components owing to their high strength, ductility, and weldability. However, as corrosion degrades critical infrastructure components, exploring the relationship between the microstructure and corrosion resistance of carbon steel is of particular interest in engineering. To analyze this relationship, it is first essential to evaluate the corrosion resistance of each microstructure in a carbon steel specimen with a single chemical composition to eliminate the effects of alloying elements. In this study, we compared the pitting corrosion resistance of four microstructures (water‐quenched martensite, tempered martensite, bainite and degenerate pearlite, and ferrite–pearlite) of an AISI 1045 medium‐carbon steel. The pitting corrosion resistances of the microstructures in near‐neutral pH solutions containing NaCl were ordered as follows: (high) water‐quenched martensite > bainite and degenerate pearlite > tempered martensite > ferrite–pearlite (low). Elucidating the effect of the microstructure on the pitting corrosion resistance may contribute to the development of corrosion‐resistant carbon steels with excellent mechanical properties.

Water-Absorbing Bioadhesive Poly(Acrylic Acid)/Polyvinylpyrrolidone Complex Sponge for Hemostatic Agents.

Poly(acrylic acid) (PAA) is a water-soluble synthetic polymer with tissue-adhesive properties. When PAA is mixed with polyvinylpyrrolidone (PVP) in water, it forms a water-insoluble precipitate that neither swells nor adheres to tissues. We developed a novel solid/solution interface complexation method to obtain a water-swellable PAA/PVP complex. First, PAA solution was dried up in a vessel to form a film. The PAA film was then immersed in an aqueous PVP solution to obtain a highly swollen PAA/PVP hydrogel. Heat drying of the hydrogel yielded a transparent film, while freeze-drying the hydrogel provided a soft sponge. Both the PAA/PVP film and sponge could be re-swelled by water to obtain a bioadhesive gel. A relatively larger specific surface area of the sponge than that of the film led to a more rapid swelling and water absorption behavior and quick adhesion to tissues. The addition of hyaluronic acid (HA) improved the mechanical characteristics of the sponges. PAA/PVP/HA sponges had low cytotoxicity, and they exhibited high hemostatic efficiency in clinical studies after dialysis treatment or tooth extraction, even in patients on antithrombotic drugs. Such bioadhesive materials consisting of low-toxicity polymers have a high potential for use in medical hemostatic devices.

Rheological characterization and flow reconstruction of polyvinylpyrrolidone aqueous solutions by means of velocity profiling-based rheometry

Rheological characterization and flow reconstruction of polyvinylpyrrolidone aqueous solutions by means of velocity profiling-based rheometry

Synthesis of Ni/Y2O3 Nanocomposite through USP and Lyophilisation for Possible Use as Coating.

The Ni/Y2O3 catalyst showed high catalytic activity. Based on this, the aim of this study was to create Ni/Y2O3 nanocomposites powder with two innovative technologies, Ultrasonic Spray Pyrolysis (USP) and lyophilisation. In the USP process, thermal decomposition of the generated aerosols in an N2/H2 reduction atmosphere caused a complete decomposition of the nickel (II) nitrate to elemental Ni, which became trapped on the formed Y2O3 nanoparticles. The Ni/Y2O3 nanocomposite particles were captured via gas washing in an aqueous solution of polyvinylpyrrolidone (PVP) in collection bottles. PVP was chosen for its ability to stabilise nano-suspensions and as an effective cryoprotectant. Consequently, there was no loss or agglomeration of Ni/Y2O3 nanocomposite material during the lyophilisation process. The Ni/Y2O3 nanocomposite powder was analysed using ICP-MS, SEM-EDX, and XPS, which showed the impact of different precursor concentrations on the final Ni/Y2O3 nanocomposite particle composition. In a final step, highly concentrated Ni/Y2O3 nanocomposite ink (Ni/Y2O3 > 0.140 g/mL) and test coatings from this ink were prepared by applying them on a white matte photo paper sheet. The reflection curve of the prepared Ni/Y2O3 nanocomposite coating showed a local maximum at 440 nm with a value of 39% reflection. Given that Ni is located on the surface of the Ni/Y2O3 nanocomposite in the elemental state and according to the identified properties, tests of the catalytic properties of this coating will be performed in the future.

Remarkable stability of dye in polymer-clay nanocomposite film

The immobilization of rhodamine 6G and polyvinylpyrrolidone in a purified bentonite was investigated. Hybrid films were prepared by mixing an aqueous rhodamine 6G-bentonite suspension with aqueous solution of polyvinylpyrrolidone and subsequent casting on the solid substrate. The successful intercalation of the dyes and the polymer into the interlayer space of the bentonite was confirmed by the systematic expansion of the interlayer space. The stability of the rhodamine 6G adsorbed on the purified bentonite with polyvinylpyyrolidone was examined by following the appearance and the spectroscopic characteristics to find superior stabilities upon heating at 300 °C and sunlight irradiation at 150 °C in air if compared with the dye on the purified bentonite (without polymer) and that in the polymer (without bentonite).

Противовоспалительное и анальгетическое действие ингибитора индуцируемой синтазы оксида азота в эксперименте

Introduction. Nitric oxide plays a key role in the development of inflammation. In this regard, it is promising to create a drug that reduces the production of nitric oxide in the focus of inflammation. Aim. To study experimentally the anti-inflammatory and analgesic effects of an inducible nitric oxide synthase inhibitor of an aminoguanidine derivative (LIS-M). Materials and methods. The compound LIS-M in 1% aqueous solution of polyvinylpyrrolidone was administered intramuscularly at doses of 5, 10 and 20 mg/kg to 150 male Sprague Dawley rats and 50 male CD-1 mice with experimental models of inflammation and pain. The animals of the comparison group received diclofenac at a dose of 10 mg/kg, the animals of the control group received 1% aqueous solution of polyvinylpyrrolidone in an equivalent volume. The effect of the LIS-M compound on the course of experimental pathology and its analgesic potential ulcerogenic effect were evaluated. Results. In male Sprague Dawley rats, the LIS-M compound reduces acute exudative inflammation caused by injection of carrageenan, histamine or serotonin in plantar aponeurosis, inhibits the proliferation of granulation tissue and exudation around a cotton swab implanted under the skin, does not have an ulcerogenic effect. In male CD-1 mice, it weakens the pain reaction and increases the time before it occurs. Conclusion. The LIS-M compound at doses ranging from of 5 to 20 mg/kg has a pronounced antiexudative, antiproliferative and analgesic effect, not inferior to the action of diclofenac at a dose of 10 mg/kg, and does not have an ulcerogenic effect.

In situ generated Ligand-Free gold nanoparticles in polyvinylpyrrolidone solution assisted laser in liquid method for green oxidation of cyclohexane to adipic acid with high yield

Here in we report a very simple method to create gold nanoparticles coated-double silica shells by using a three step process containing pulse laser ablation (PLAL) of metallic gold target in aqueous solution of polyvinylpyrrolidone, well-known stober process and calcination at high temperature respectively for achieving of Au@SiO2@SiO2 nanoparticles with narrow size distribution. Final structure was characterized by techniques such STEM, FESEM, BET, XPS, XRD, TGA, ICP-OES and FT-IR and shows the activity of 26 % conversion in aerobic oxidation of cyclohexane to adipic acid with the 92 % selectivity in mild conditions. More over the catalyst has saved its activity until 6 cycles without any dominant losing.

Prediction of quality attributes (mechanical strength, disintegration behavior and drug release) of tablets on the basis of characteristics of granules prepared by high shear wet granulation.

High shear wet granulation is commonly applied technique for commercial manufacturing of tablets. Granulation process for tablets manufacturing is generally optimized by hit and trial which involves preparation of granules under different processing parameters, compression of granules and evaluation of the resultant tablets; and adjustment is made in granulation process on the basis of characteristics of tablets. Objective of the study was to optimize the process of high shear wet granulation and prediction of characteristics of tablets on the basis of properties of granules. Atenolol granules were prepared by high shear wet granulation method, using aqueous solution of polyvinyl pyrrolidone (PVP k-30) as binder. Concentration of binder solution and granulation time were taken as process variables, both studied at three levels. Different combinations of process variables were determined by Design Expert software. Granules were evaluated for different parameters on the basis of SeDeM-ODT (Sediment Delivery Model-Oro Dispersible Tablets) expert system. Granules from all the trials were compressed using round (10.5 mm) flat faced punches at compression weight of 250 mg/tablet. Tablets were evaluated of different quality control parameters as per USP. Results showed that both the process variables had positive effect on mechanical strength of tablets and negative effect on disintegration and dissolution rate. Granule prepared with highest level of binder concentration (15%) and highest granulation time (60 sec) resulted in tablets with highest crushing strength (11.8 kg), specific crushing strength (0.328 kg/mm2), tensile strength (0.208 kg/mm2), lowest value of friability (0.19%) and highest disintegration time (10.9 min), as predicted from granules characteristics on the basis of SeDeM-ODT expert system. Drug release from Trial-13 (processed under highest level of both process parameters) was also lower than rest of the trials. It is concluded from the study that quality characteristics of tablets can be predicted from granules characteristics using SeDeM-ODT expert system. Furthermore, SeDeM-ODT expert system can also be used for optimization of the process of high shear wet granulation.

A novel composite binder design for direct ink writing alumina-based ceramics with enhanced strength at low sintering temperature

Direct ink writing (DIW), an extrusion-based additive manufacturing method, has been proposed as a versatile process for preparing ceramics for structural and functional applications. However, controlling the strength of ceramics during processing remains a challenge. In this study, a novel composite binder system consisting of aqueous polyvinylpyrrolidone solution and Al(H2PO4)3 gel was adopted for the DIW of alumina ceramics. Throughout the process, the mechanical performance, dimensional shrinkage, phase compositions and microstructure of samples were evaluated. The results indicate that the composite binder improves green strength by generating hydrogen bonding, which considerably enhances the strength of alumina ceramics under low-temperature sintering due to the reaction between Al(H2PO4)3 gel and nanosized clay particles. This also promotes the high-temperature sintering performance of Al2O3-based ceramics. Overall, the current composite binder is anticipated to be promising for DIW of alumina ceramics, providing sufficient strength for post-processing and greatly improving strength after low-temperature sintering.

DEVELOPMENT OF A TECHNOLOGY FOR PRODUCING A STABLE INJECTABLE DOSAGE FORM OF A HYDROPHOBIC INDOLOCARBAZOLE DERIVATIVE

Objective: Development of a technology for the production of a stable injectable dosage form (IDF) of indolocarbazole derivative LHS-1269. Methods: LHS-1269 is an active pharmaceutical ingredient that was synthesized in the N. N. Blokhin National Medical Research Center of Oncology of the Ministry of Health of the Russian Federation. The IDF includes dimethyl sulfoxide (DMSO), 95% ethanol, Kollidon® 17PF and water for injection. Magnetic stirrer and overhead stirrer with a propeller stirring element were used to prepare the model solution of the IDF of LHS-1269. Sterilizing filtration of the solution was performed with 0.2−0.22 um polycarbonate, cellulose, polyvinylidene fluoride, polyethersulfone and nylon membrane filters. The aqueous solution of LHS-1269 was lyophilized in Edwards Minifast DO.2 freeze dryer. Assay of LHS-1269 was performed by spectrophotometry at 320±3 nm. Potentiometry was used to measure pH, a viscosimetry method was used to measure the viscosity of the solutions. The average weight was estimated by weighing a sample of 10 vials with the concentrate. Results: 0.5% aqueous solution of LHS-1269 was produced by mixing the solution of the active substance in DMSO and ethanol with an aqueous solution of polyvinylpyrrolidone gradually at the ratio of LHS-1269/DMSO/ethanol/Kollidon® of 1/11/32/40 by weight. The aqueous solution of the study substance cannot be lyophilized, so a sequence of technological operations was presented to produce an anhydrous concentrate “LHS-1269, concentrate for solution for injection and infusion 25 mg”. Conclusion: A technology was developed to produce a stable IDF of a hydrophobic indolocarbazole derivative LHS-1269, a high-potential antitumor drug.

The Influence of the Strength of Drug-Polymer Interactions on the Dissolution of Amorphous Solid Dispersions.

In an earlier report, ionic interactions between ketoconazole (KTZ), a weakly basic drug, and poly(acrylic acid) (PAA), an anionic polymer, resulted in a dramatic decrease in molecular mobility as well as reduced crystallization propensity of amorphous solid dispersion (ASD) in the solid state. On the other hand, weaker dipole-dipole interactions between KTZ and polyvinylpyrrolidone (PVP) resulted in ASDs with higher crystallization propensity (Mistry Mol Pharm., 2015, 12 (9), 3339-3350). In this work, we investigated the behavior of the ketoconazole (KTZ) solid dispersions in aqueous media. In vitro dissolution tests showed that the PAA ASD maintained the level of supersaturation for a longer duration than the PVP ASD at low polymer contents (4-20% w/w polymer). Additionally, the PAA ASDs were more resistant to drug crystallization in aqueous medium when measured with synchrotron X-ray diffractometry. Two-dimensional 1H nuclear Overhauser effect spectroscopy (NOESY) NMR cross peaks between ketoconazole and PAA confirmed the existence of drug-polymer interactions in D2O. The interaction was accompanied by a reduced drug diffusivity as monitored by 2D diffusion ordered spectroscopy (DOSY) NMR and enthalpy-driven when characterized by isothermal titration calorimetry (ITC). On the other hand, drug-polymer interactions were not detected between ketoconazole and PVP in aqueous solution, with NOESY, DOSY, or ITC. The results suggest that interactions that stabilize ASDs in the solid state can also be relevant and important in sustaining supersaturation in solution.

Rapid separation of nanodiamond particles by viscosity gradient centrifugation

The nanodiamond (ND) particles have several potential applications including tribology, drug delivery, bioimaging, etc. However, the severe colloidal aggregation tendency of ND particles strictly limits its exploitation. Moreover, due to NDs rich surface chemistry and relatively small size, it is still difficult to separate these large ND particles using conventional separation methods. Herein, we develop an efficient and straightforward strategy to separate the colloidal aminated nanodiamonds (ND-NH2) into small size nanoparticles by viscosity gradient centrifugation method in a polyvinylpyrrolidone (PVP) aqueous solution. Prior to and after separation, the pristine ND and ND-NH2 particles size and morphology were characterized by DLS (dynamic light scattering analyzer) and TEM (transmission electron microscopic), which show that ND particles with narrow size distribution and uniform morphology can be easily separated by the viscosity gradient of PVP aqueous solution. This simple, rapid and effective separation method could be extended to separate other functionalized NDs with different sizes.

Insights into kinetic inhibition effects of MEG, PVP, and L-tyrosine aqueous solutions on natural gas hydrate formation

It is necessary to understand all the prerequisites, which result in gas hydrate formation for safe design and control of a variety of processes in petroleum industry. Thermodynamic hydrate inhibitors (THIs) are normally used to preclude gas hydrate formation by shifting hydrate stability region to lower temperatures and higher pressures. Sometimes, it is difficult to avoid hydrate formation and hydrates will form anyway. In this situation, kinetic hydrate inhibitors (KHIs) can be used to postpone formation of gas hydrates by retarding hydrate nucleation and growth rate. In this study, two kinetic parameters including natural gas hydrate formation induction time and the rate of gas consumption were experimentally investigated in the presence of monoethylene glycol (MEG), L-tyrosine, and polyvinylpyrrolidone (PVP) at various concentrations in aqueous solutions. Since hydrate formation is a stochastic phenomenon, the repeatability of each kinetic parameter was evaluated several times and the average values for the hydrate formation induction times and the rates of gas consumption are reported. The results indicate that from the view point of hydrate formation induction time, 2 wt% PVP and 20 wt% MEG aqueous solutions have the highest values and are the best choices. It is also interpreted from the results that from the view point of the rate of gas consumption, 20 wt% MEG aqueous solution yields the lowest value and is the best choice. Finally, it is concluded that the combination of PVP and MEG in an aqueous solution has a simultaneous synergistic impact on natural gas hydrate formation induction time and the rate of gas consumption. Furthermore, a semi-empirical model based on chemical kinetic theory is applied to evaluate the hydrate formation induction time data. A good agreement between the experimental and calculated hydrate formation induction time data is observed.

Gaining thermochromic property of quartz lamel surface and functionalization

The aim of this study was to obtain functional features by coating the quartz lamella with a sol-gel technique. Smart functional material was developed by including microencapsulated thermochromic pigments in coatings. Using anatase powder titanium (IV) oxide with additions in different ratios, the coatings were applied to the quartz lamel surfaces by dip-coating technique. The sol formulation was made using the initial precursors Tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES). Tetraethoxysilane was added to the structure of the coatings to increase the adhesion of the coatings to the substrate. Thermochromic coatings were synthesized by reacting polyvinylpyrrolidone in aqueous solution with tetraethoxysilane. The structural and thermochromic performance of coatings prepared with the sol-gel dip-coating method was systematically characterized and its functionality was determined. In this study, the effects of the addition of titanium (IV) oxide on the phase composition, transition temperature, and surface morphology of the coatings were investigated. The result obtained showed that the formed anatase phase increased as the titanium (IV) oxide content increased. Exothermic and endothermic transition temperatures for the undoped sample ranged from 34.6 °C to 26.5 °C, while 3 g titanium (IV) oxide doped sample these temperatures varied from 34.6 °C to 26.7 °C. Smooth surface coatings were prepared using polyethylene glycol. The results demonstrated that the colors of the obtained thermochromic coatings could be reversibly changed between green and white.

Structural and dynamical characterisation of intermediate water interacting polyvinyl pyrrolidone

Polyvinyl pyrrolidone (PVP) is well known as a biocompatible polymer used in the fields of medical devices and pharmaceuticals, and is associated with intermediate water, which is said to play an important role in developing the biocompatibility of medical materials. The states of water molecules interacting with PVP, i.e., the non-freezing water, slow and fast intermediate water are classified using 2H NMR. The non-freezing water is directly hydrogen-bonded to ca. 1.5 amide groups of PVP. The slow intermediate water interacts with PVP indirectly through non-freezing water. It then shows slow diffusion dynamics and forms cubic-form ice during cold crystallisation, while the fast intermediate water can diffuse as fast as free water, and can freeze to form normal hexagonal-form ice. Statement of significanceFor many of the medical materials, including artificial organs such as dialysis membranes and artificial blood vessels, polymers are used. Biocompatibility of polymer is an important property for materials used in medical devices and medicine. Although there are lots of studies about surface design of materials in terms of hydrophilicity, charge, or morphology, the unified expression factor of biocompatibility have not been clear. Recently, it is suggested that water molecules, especially intermediate water, on materials surface play important roles in the development of biocompatibility. However, the characteristics of the intermediate water have not been understood. It is important issues to be solved in the development of new and high-performance biocompatible polymer materials based on the concept of intermediate water.In present study, we have investigated the intermediate water on polyvinyl pyrrolidone (PVP), which is biocompatible polymer widely used in medical device and medicine. Differential scanning calorimeter (DSC), X-ray diffraction (XRD), and various nuclear magnetic resonance (NMR) methods for PVP aqueous solutions were performed in order to clarify the physical properties of the intermediate water. We found that the intermediate water has structural order and diffusive mobility just between free water and non-freezing water. These features of intermediate water are induced by structural interaction with polymer. The knowledge from present study expected to provide guidance for the design of biocompatible materials.