Physicochemical Characterization of Polyvinyl Pyrrolidone: A Tale of Two Polyvinyl Pyrrolidones

Abstract

Of several samples of polyvinyl pyrrolidone (PVP) used to coat and stabilize freshly manufactured aqueous dispersions of silver nanoparticles, one batch gave anomalous results: the dispersion maintained continued stability, even on extensive dilution. Our efforts to understand this desirable feature concluded that the generally used spectral method of PVP purity verification, Fourier transform infrared (FTIR) spectroscopy, was incapable of answering our inquiry. This led to the employment of several other methods, including X-ray photoelectron and nuclear magnetic resonance spectroscopies, which ultimately revealed several possible reasons for the dilution stability, including incomplete PVP hydrolysis during manufacture and the presence of hydroperoxide contaminants. It led, as well, to explanations for the shortcomings of FTIR spectroscopy as a verification method for PVP purity.

Impurities in polyvinylpyrrolidone: the key factor in the synthesis of gold nanostars

“…As described by Straub et al , 33 the synthesis of commercial PVP often relies on hydrogen peroxide as an initiator, and this leads to the introduction of hydroxyl end groups, which may oxidize into aldehyde groups. 18 In our study, the presence of aldehyde end groups, as suggested by the 1 H-NMR data discussed above, was further confirmed by (1) reducing the purified PVP-TCI-10k with NaBH 4 forming a hydroxyl end-terminated PVP (PVP-TCI-OH), and (2) reacting the purified PVP-TCI-10k with 4-aminopyridine (PVP-TCI-pyridine), respectively. As shown in the 1 H-NMR spectra and more clearly by DOSY, the treatment of purified PVP-TCI-10k ( Fig.…”

“…The authors found that aldehyde PVP end-groups (PVP-CHO) lead to the formation of silver nanocubes, whereas PVP-OH and PVP-H yield a mixture of particles having different shapes. Warned by colleagues who observed that only one of the two PVP grades used during their experiments prevented the aggregation of Ag NPs upon dilution, Sacher et al 18 characterized the two PVPs purchased from the same supplier. The authors concluded that the commercial PVP used in the study contained 2-pyrrolidone and hydroperoxides as contaminants.…”

The Synthesis and Properties of a New Carrier for Paclitaxel and Doxorubicin Based on the Amphiphilic Copolymer of N‐vinyl‐2‐pyrrolidone and Acrylic Acid

“…Since the copolymerization was carried out in a large excess of N ‐vinyl‐2‐pyrrolidone in order to prevent the formation of the low water‐soluble interpolymer complexes, the FT‐IR ( Figure A) and 1 H NMR spectra (Figure 2B) of the obtained copolymer show all the signals characteristic of poly( N ‐vinyl‐2‐pyrrolidone). [ 32–34 ] A broad intense 3440 cm −1 signal can be seen in the FT‐IR spectrum of the amphiphilic copolymer of N ‐vinyl‐2‐pyrrolidone and acrylic acid (Figure 2A), which is related to the stretch of the O─H‐bonds in the carboxy groups of the acrylic acid residues that participate in hydrogen bond formation with the amide carbonyl of the N ‐vinyl‐2‐pyrrolidone residues. The 2955.7 and 2925.4 cm −1 absorption bands pertain to the C─H‐bonds’ stretch, while the 1462.7, 1436.7, 1374.1, 1082.1, and 844.3 cm −1 bands correspond to the bending of the C─H‐bonds.…”

Formulation and Bioavailability of Novel Mucoadhesive Buccal Films for Candesartan Cilexetil in Rats

“…It is an anionic polymer that gives the highest bio-adhesive force. The addition of PVP to the mucoadhesive film increases its bioadhesive strength due to the ability of PVP to form hydrogen bonding and Van der Waals forces with the mucous membrane [ 28 , 45 ]. Besides, the presence of PVP in the prepared mucoadhesive film enhances its swellability because of its water solubility and hygroscopic character [ 38 ].…”