Multifunctional Role of Polyvinylpyrrolidone in Pharmaceutical Formulations

Design and Preparation of Lifetime-Based Dual Fluorescent/Phosphorescent Sensor of pH and Oxygen and its Exploration in Model Physiological Solutions and Cells

In the present report, a novel dual pH-O2 sensor based on covalent conjugate of rhodamine 6G and cyclometalated iridium complex with poly(vinylpyrrolidone-block-vinyltetrazole) copolymer is reported. In model physiological solutions the sensor chromophores display independent phosphorescent and fluorescent lifetime responses onto variations in oxygen concentration and pH, respectively. Colocalization studies on Chinese hamster ovary cells demonstrate the preferential localization in endosomes and lysosomes. The fluorescent lifetime imaging microscopy-phosphorescent lifetime imaging microscopy (FLIM-PLIM) experiments show that the phosphorescent O2 sensor provides unambiguous information onto hypoxia versus normoxia cell status as well as semi-quantitative data on the oxygen concentration in cells in between these two states. However, the results of FLIM measurements indicate that dynamic lifetime interval of the sensor (≈0.5 ns between pH values 5.0 and 8.0) is insufficient even for qualitative estimation of pH in living cells because half-width of lifetime distribution in the studied samples is higher than the sensor dynamic interval. Nevertheless, the variations in rhodamine emission intensity are much higher and allow rough discrimination of acidic and neutral cell conditions. Thus, the results of this study indicate that the suggested approach to the design of dual pH-O2 sensors makes possible to prepare the biocompatible and water-soluble conjugate with fast cellular uptake.

PEGose Block Poly(lactic acid) Nanoparticles for Cargo Delivery

Hydrophilic polymers have found ubiquitous use in drug delivery and novel polymer materials to advance drug delivery systems are highly sought after. Herein, an amylose mimic (PEGose) was combined with poly(lactic acid) (PLA) in an amphiphilic block copolymer to form PEG-free nanoparticles as an alternative to PEG-based nanomedicines. The block copolymer self-assembled into 150-200 nm particles with a narrow dispersity in aqueous environment. The formed nanoparticles were capable of encapsulation, the sustained release of both hydrophilic and hydrophobic dyes. Moreover, the nanoparticles were found to be remarkably stable and had a very low cytotoxicity and a high propensity to penetrate cells. These results highlight the potential of PEGose-b-PLA to be used in drug delivery with a new hydrophilic building block.

Physical Unclonable Functions with Hyperspectral Imaging System for Ultrafast Storage and Authentication Enabled by Random Structural Color Domains

Physical unclonable function (PUF) is attractive in modern encryption technologies. Addressing the disadvantage of slow data storage/authentication in optical PUF is paramount for practical applications but remains an on-going challenge. Here, a highly efficient PUF strategy based on random structural color domains (SCDs) of cellulose nanocrystal (CNC) is proposed for the first time, combing with hyperspectral imaging system (HIS) for ultrafast storage and authentication. By controlling the growth and fusion behavior of the tactoids of CNC, the SCDs display an irregular and random distribution of colors, shapes, sizes, and reflectance spectra, which grant unique and inherent fingerprint-like characteristics that are non-duplicated. Based on images and spectra, these fingerprint features are used to develop two sets of PUF key generation methods, which can be respectively authenticated at the user-end and the manufacturer-front-end that achieving a high coding capacity of at least 22304. Notably, the use of HIS greatly shortens the time of key reading and generation (≈5 s for recording, 0.5-0.7 s for authentication). This new optical PUF labels can not only solve slow data storage and complicated authentication in optical PUF, but also impulse the development of CNC in industrial applications by reducing color uniformity requirement.

Injectable chitosan-polyvinylpyrrolidone composite thermosensitive hydrogels with sustained submucosal lifting for endoscopic submucosal dissection

To develop a submucosal injection material with sustained submucosal lifting for endoscopic submucosal dissection (ESD), this study designed and prepared a novel composite thermosensitive hydrogel system with high pH chitosan-polyvinylpyrrolidone-β-glycerophosphate (HpHCS-PVP-GP). HpHCS improved the injectability of the hydrogels and retained the rapid gelation ability at low concentrations. The modification of PVP significantly improved the stability of low-temperature hydrogel precursor solutions and the integrity of hydrogels formed at 37 °C through hydrogen bonds between PVP and HpHCS. A mathematical model was established using response surface methodology (RSM) to evaluate the synergistic effect of HpHCS, GP, and PVP concentrations on gelation time. This RSM model and submucosal lifting evaluation using in vitro pig esophageal models were used to determine the optimal formula of HpHCS-PVP-GP hydrogels. Although the higher PVP concentration (5 % (w/v)) prolonged gelation time, it improved hydrogel mechanical strength, resulting in better submucosal lifting performance. The experiments of Bama mini pigs showed that the heights of the cushions elevated by the HpHCS-5%PVP-GP hydrogel remained about 80 % 1 h after injection. Repeated injections were avoided, and the hydrogel had no cytotoxicity after electric cutting. Therefore, the HpHCS-PVP-GP thermosensitive hydrogel might be a promising submucosal injection material for ESD.

Water-compatible cross-linked pyrrolidone acrylate pressure-sensitive adhesives with persistent adhesion for transdermal delivery: Synergistic effect of hydrogen bonding and electrostatic force

Poor skin adhesion and mechanical properties are common problems of pressure-sensitive adhesive (PSA) in transdermal drug delivery system (TDDS). Its poor water compatibility also causes the patch to fall off after sweating or soaking in the application site. To solve this problem, poly (2-Ethylhexyl acrylate-co-N-Vinyl-2-pyrrolidone-co-N-(2-Hydroxyethyl)acrylamide) (PENH), a cross-linked pyrrolidone polyacrylate PSA, was designed to improve the adhesion and water resistance of PSA through electrostatic force and hydrogen bonding system. The structure of PENH was characterized by 1H NMR, FTIR, DSC, and other methods. The mechanism was studied by FTIR, rheological test, and molecular simulation. The results showed that the PENH patch could adhere to human skin for more than 10 days without cold flow, and it could still adhere after sweating or water contact. In contrast, the commercial PSA Duro-Tak® 87-4098 and Duro-Tak® 87-2852 fell off completely on the 3rd and 6th day, respectively, and Duro-Tak® 87-2510 showed a significant dark ring on the second day. Mechanism studies have shown that the hydrogen bond formed by 2-ethylhexyl acrylate (2-EHA), N-vinyl-2-pyrrolidinone (NVP), and N-(2-Hydroxyethyl)acrylamide (HEAA) enhances cohesion, the interaction with skin improves skin adhesion, and the electrostatic interaction with water or drug molecules enhances the ability of water absorption and drug loading. Due to the synergistic effect of hydrogen bonds and electrostatic force, PENH can maintain high cohesion after drug loading or water absorption. PENH provides a choice for the development of water-compatible patches with long-lasting adhesion. STATEMENT OF SIGNIFICANCE: Based on the synergistic effect of hydrogen bonding and electrostatic force, a hydrogen-bonded, cross-linked pyrrolidone acrylate pressure-sensitive adhesive for transdermal drug delivery was designed and synthesized, which has high adhesion and cohesive strength and is non-irritating to the skin. The patch can be applied on the skin surface continuously for more than 10 days without the phenomenon of "dark ring", and the patch can remain adherent after the patient sweats or bathes. This provides a good strategy for choosing a matrix for patches that require prolonged administration.

Potential Biosafety of Mxenes: Stability, Biodegradability, Toxicity and Biocompatibility

MXenes are two-dimensional nanomaterials with unique properties that are widely used in various fields of research, mostly in the field of energy. Fewer publications are devoted to MXene application in biomedicine and the question is: are MXenes safe for use in biological systems? The sharp edges of MXenes provide the structure of "nanoknives" which cause damage in direct physical contact with cells. This is effectively used for antibacterial research. However, on the other hand, most studies in cultured cells and rodents report that they do not cause obvious signs of cytotoxicity and are fully biocompatible. The aim of our review was to consider whether MXenes can really be considered non-toxic and biocompatible. Often the last two concepts are confused. We first reviewed aspects such as the stability and biodegradation of MXenes, and then analyzed the mechanisms of toxicity and their consequences for bacteria, cultured cells, and rodents, with subsequent conclusions regarding their biocompatibility.

Engineering Matrix-Free Drug Protein Nanoparticles with Promising Penetration through Biobarriers for Treating Corneal Neovascularization

Protein drugs have been widely used in treating various clinical diseases because of their high specificity, fewer side effects, and favorable therapeutic effect, but they greatly suffer from their weak permeability through tissue barriers, high sensitivity to microenvironments, degradation by proteases, and rapid clearance by the immune system. Herein, we disrupted the standard protocol where protein drugs must be delivered as the cargo via a delivery system and innovatively developed a free entrapping matrix strategy by simply mixing bevacizumab (Beva) with zinc ions to generate Beva-NPs (Beva-Zn2+), where Beva is coordinatively cross-linked by zinc ions with a loading efficiency as high as 99.2% ± 0.41%. This strategy was universal to generating various protein NPs, with different metal ions (Cu2+, Fe3+, Mg2+, Sr2+). The synthetic conditions of Beva-NPs were optimized, and the generated mechanism was investigated in detail. The entrapment, releasing profile, and the bioactivities of released Beva were thoroughly studied. By using in situ doping of the fourth-generation polyamindoamine dendrimer (G4), the Beva-G4-NPs exhibited extended ocular retention and penetration through biobarriers in the anterior segment through transcellular and paracellular pathways, effectively inhibiting corneal neovascularization (CNV) from 91.6 ± 2.03% to 13.5 ± 1.87% in a rat model of CNV. This study contributes to engineering of protein NPs by using a facile strategy for overcoming the weaknesses of protein drugs and protein NPs, such as weak tissue barrier permeability, low encapsulation efficiency, poor loading capacity, and susceptibility to inactivation.

A novel cationic β-cyclodextrin decorated with a choline-like pendant exhibits Iodophor, Mucoadhesive and bactericidal properties

Iodine is a vital microelement and a powerful antiseptic with a rapid and broad spectrum of action. The development of iodophor compounds to improve the solubility and stability of iodine is still challenging. Here, we report the synthesis of a novel cationic β-cyclodextrin bearing a choline-like pendant (β-CD-Chol) designed to complex and deliver iodine to bacterial cells. The characterization of β-CD-Chol and the investigation of the inclusion complex with iodine were performed by NMR spectroscopy, mass spectrometry, UV-vis spectrophotometry, isothermal titration calorimetry, and dynamic light scattering. The functionalization with the positively charged unit conferred improved water-solubility, mucoadhesivity, and iodine complexation efficiency to the β-CD scaffold. The water-soluble β-CD-Chol/iodine complex efficiently formed both in solution and by solid-vapor reaction. The solid complex exhibited a significant stability for months. Iodine release from the inclusion complex was satisfactory and the bactericidal activity was proved against a Staphylococcus epidermidis strain. The absence of cytotoxicity tested on human keratinocytes and the improved mucoadhesivity make β-CD-Chol a promising drug delivery system and an appealing iodophor candidate for iodine-based antisepsis including mucosa disinfection.

Poly(N-methyl-N-vinylacetamide): A Strong Alternative to PEG for Lipid-Based Nanocarriers Delivering siRNA

Lipid-based nanocarriers have demonstrated high interest in delivering genetic material, exemplified by the success of Onpattro and COVID-19 vaccines. While PEGylation imparts stealth properties, it hampers cellular uptake and endosomal escape, and may trigger adverse reactions like accelerated blood clearance (ABC) and hypersensitivity reactions (HSR). This work highlights the great potential of amphiphilic poly(N-methyl-N-vinylacetamide) (PNMVA) derivatives as alternatives to lipid-PEG for siRNA delivery. PNMVA compounds with different degrees of polymerization and hydrophobic segments, are synthesized. Among them, DSPE (1,2-distearoyl-sn-glycero-3-phosphoethanolamine)-PNMVA efficiently integrates into lipoplexes and LNP membranes and prevents protein corona formation around these lipid carriers, exhibiting stealth properties comparable to DSPE-PEG. However, unlike DSPE-PEG, DSPE-PNMVA24 shows no adverse impact on lipoplexes cell uptake and endosomal escape. In in vivo study with mice, DSPE-PNMVA24 lipoplexes demonstrate no liver accumulation, indicating good stealth properties, extended circulation time after a second dose, reduced immunological reaction, and no systemic pro-inflammatory response. Safety of DSPE-PNMVA24 is confirmed at the cellular level and in animal models of zebrafish and mice. Overall, DSPE-PNMVA is an advantageous substitute to DSPE-PEG for siRNA delivery, offering comparable stealth and toxicity properties while improving efficacy of the lipid-based carriers by minimizing the dilemma effect and reducing immunological reactions, meaning no ABC or HSR effects.

Polyvinylpyrrolidone as a primer for resin-dentin bonding

OBJECTIVE

This study aimed to investigate the effects of polyvinylpyrrolidone (PVP)-containing primer (PCP) on dentin bonding.

METHODS

PVP and anhydrous ethanol were used to prepare the PCPs, which were prepared at concentrations of 0.5%, 1%, and 2% (w/v). These PCPs were subsequently applied to the dentin surface, denoted as E1, E2, and E3, respectively. In the control group, no primer was applied. Following the treatment, the dentin surfaces were subjected to analysis using Fourier-transform infrared spectroscopy (FTIR), and the micro-tensile bond strength (MTBS) was evaluated. The failure mode, nanoleakage, and bonding longitudinal section were observed utilizing scanning electron microscopy (SEM). Additionally, the effect of PCPs on matrix metalloproteinases (MMPs) activity was analyzed through an in situ zymography test. Data were subjected to statistical analysis using ANOVA tests (α = 0.05).

RESULTS

Significant alterations in the infrared resonances associated with collagen cross-linking within the collagen matrix were observed across all PCP groups. The application of PCP demonstrated a noteworthy enhancement in micro-tensile bond strength (MTBS) compared to group C (p < 0.05). Notably, group C exhibited the lowest MTBS (41 ± 7.7 MPa), whereas group E2 demonstrated the highest MTBS (66 ± 11.9 MPa). Even after undergoing aging, the MTBS of the PCP groups remained superior to that of group C (p < 0.05). The resin tag length in the PCP groups was found to be greater than that of group C, and the occurrence of nanoleakage was comparatively lower in the PCP groups, both before and after aging. Additionally, PCP exhibited a dose-dependent inhibition of matrix metalloproteinases (MMPs) activity, which was statistically significant (p < 0.05).

CONCLUSIONS

The utilization of PCP Primer exhibits notable enhancements in bond strength, mitigates nano-leakage, and suppresses enzyme activity within the hybrid layer.

Biomedical applications of natural and synthetic polymer based nanocomposites

Various nanomaterials have been studied for their biomedical application in recent years. Among them, nanocomposites have a prominent medical application in the prevention, diagnosis, and treatment of various diseases. Nanocomposites are made up of polymeric matrix layers composed of synthetic or natural polymers like chitosan, polyethylene glycol, etc. Polymer nanocomposites are inorganic nanoparticles dispersed in a polymer matrix. There are two types of polymeric nanocomposites which include natural and synthetic polymer nanocomposites. These nanocomposites have various biomedical applications, such as medical implants, wound healing, wound dressing, bone repair and replacement, and dental filling. Polymeric nanocomposites have a wide range of biomedical applications due to their high stability, non-immunogenic nature, sustained drug delivery, non-toxic, and can escape reticuloendothelial system uptake along with drug bioavailability improvement. In this review, we have discussed various types of natural and synthetic polymer nanocomposites and their biomedical applications.

Advancing Drug Delivery Paradigms: Polyvinyl Pyrolidone (PVP)-Based Amorphous Solid Dispersion for Enhanced Physicochemical Properties and Therapeutic Efficacy

BACKGROUND

The current challenge in drug development lies in addressing the physicochemical issues that lead to low drug effectiveness. Solubility, a crucial physicochemical parameter, greatly influences various biopharmaceutical aspects of a drug, including dissolution rate, absorption, and bioavailability. Amorphous solid dispersion (ASD) has emerged as a widely explored approach to enhance drug solubility.

OBJECTIVE

The objective of this review is to discuss and summarize the development of polyvinylpyrrolidone (PVP)-based amorphous solid dispersion in improving the physicochemical properties of drugs, with a focus on the use of PVP as a novel approach.

METHODOLOGY

This review was conducted by examining relevant journals obtained from databases such as Scopus, PubMed, and Google Scholar, since 2018. The inclusion and exclusion criteria were applied to select suitable articles.

RESULTS

This study demonstrated the versatility and efficacy of PVP in enhancing the solubility and bioavailability of poorly soluble drugs. Diverse preparation methods, including solvent evaporation, melt quenching, electrospinning, coprecipitation, and ball milling are discussed for the production of ASDs with tailored characteristics.

CONCLUSION

PVP-based ASDs could offer significant advantages in the formulation strategies, stability, and performance of poorly soluble drugs to enhance their overall bioavailability. The diverse methodologies and findings presented in this review will pave the way for further advancements in the development of effective and tailored amorphous solid dispersions.

In vitro culture of sheep early-antral follicles: Milestones, challenges and future perspectives

Early antral follicles (EAFs) represent the transitional stage between pre-antral and antral follicles, containing oocytes that have completed most of their growth phase. Therefore, they offer an easily exploitable reserve for producing mature oocytes and preserving genetic resources, given their higher abundance compared to antral follicles (AFs) and shorter culture period than other pre-antral follicles (PAFs). Despite these advantages, the culture of EAFs remains challenging, and the success rates of in vitro embryo production (IVEP) from EAF-derived oocytes are still far below the standard achieved with fully grown oocytes in ruminant species. The difficulty is related to developing suitable in vitro culture systems tailored with nutrients, growth factors, and other signaling molecules to support oocyte growth. In this review, we focus on the in vitro development of sheep EAFs to provide an informative reference to current research progress. We also summarize the basic aspect of folliculogenesis in sheep and the main achievements and limitations of the current methods for EAF isolation, in vitro culture systems, and medium supplementation. Finally, we highlight future perspectives and challenges for improving EAF culture outcomes.

Crystallization-induced thickness tuning of carbon nanosheets for fast potassium storage

Carbon nanosheets (CNS) have garnered significant interest as anode materials for potassium-ion batteries (PIBs) due to the excellent potassium storage kinetics and rate performance. Moreover, tuning the thickness of CNS can enhance the potassium storage performance by exposing abundant surface active sites and shortening the K+ migration path. Herein, crystallization-induced thickness tuning of carbon nanosheets in polyvinyl pyrrolidone-potassium chloride (PVP-KCl) solution is reported to enhance the fast potassium storage. PVP with varying molecular weights is employed to induce the crystallization behavior of KCl, leading to the formation of KCl grains with controllable sizes. Concurrently, these KCl grains act as hard templates for dispersing the PVP molecules to fabricate carbon nanosheets on the surface during annealing. PVP with high molecular weight is beneficial for hindering ion migration to reduce crystal sizes, which can decrease the thickness of carbon nanosheets. The ultrathin structure exposes abundant potassium storage sites, endowing CNS with high reversible capacity (359.0 mAh/g at 100 mA/g). The reduction in the migration path of K+ ions facilitate rapid ion and electron transport kinetics, resulting in rate performance with a capacity of 181.9 mAh/g at 1 A/g. Our work extends the application of the crystallization-induced strategy for controllable designing carbon nanosheets, and puts forward some conceptions on improving the potassium storage performance of carbon anode materials.

Evaluation of dermal toxicity and toxicokinetics of povidone‑iodine in Göttingen minipigs

BACKGROUND

Povidone‑iodine (PVP-I) is an effective and commonly used broad-spectrum antiseptic; limited information exists around its long-term safety and impact on endocrine disruption. We assessed the dermal toxicity and toxicokinetics following a once-daily application of 7.5% (w/v) and 10% (w/v) PVP-I in Göttingen Minipigs® for up to 39 weeks.

METHODS

An in vivo study was conducted in male (n = 27) and female (n = 27) minipigs. Animals were randomized into untreated control, 7.5% and 10% PVP-I, and matching vehicle treatment groups. Animals were assessed for general in-life measurements, including skin irritation and organ weights. Serum samples were analyzed for PVP, total iodine, triiodothyronine [T3], thyroxine [T4], thyroid stimulating hormone [TSH], and toxicokinetic parameters.

RESULTS

Neither 7.5% nor 10% PVP-I affected general in-life measurements. Increased mean thyroid gland absolute weights were noted with 7.5% and 10% PVP-I. Serum levels of PVP, T3, T4, and TSH in the 7.5% and 10% PVP-I treatment group animals were similar to those in vehicle treatment group animals. Mean total serum iodine concentration was 52- and 13-fold higher with 7.5% and 10% PVP-I, respectively, vs respective vehicle treatments. There was no dose-dependent increase in mean maximum serum concentration and area under the curve from 0 to 24 h for PVP, T3, T4, and TSH, nor accumulation of PVP, T3, T4, or TSH in the study.

CONCLUSION

Once-daily dermal application of 7.5% and 10% PVP-I for up to 39 weeks was safe and well tolerated in Göttingen Minipigs® and was not associated with skin irritation, thyroid dysfunction, or endocrine disruption. As the anatomy and physiology of the minipig skin closely resembles that of human skin, the findings of this study suggest that 7.5% and 10% PVP-I may be translated into antimicrobial benefits for humans without the risk of endocrine disruption.

Kinetically Limited Bulk Polymerization of Polymer Thin Films by Initiated Chemical Vapor Deposition

An experimental study and kinetic model analysis of the initiated chemical vapor deposition (iCVD) of polymer thin films have been performed at saturated monomer vapor conditions. Previous iCVD kinetic studies have focused on subsaturated monomer conditions where polymer deposition kinetics is known to be limited by monomer adsorption. However, iCVD kinetics at saturated conditions have so far not been systematically investigated, and it remains unclear whether the adsorption-limited phenomenon would still apply at saturation, given the abundance of monomer for reaction. To probe this question, a series of depositions of poly(vinylpyrrolidone) (PVP) thin films as a model system were performed by iCVD at substrate temperatures from 10 to 25 °C at both fully saturated (100%) and subsaturated (50%) conditions. While the deposition rates at subsaturated conditions exhibit the expected adsorption-limited behavior, the deposition rates at saturated conditions unexpectedly show two distinct deposition regimes with reaction time: an initial adsorption-limited regime followed by a kinetically limited steady-state regime. In the steady-state regime, the deposition kinetics is found to be thermally activated by raising substrate temperature with an overall activation energy of +86 kJ/mol, which agrees reasonably well with the experimentally determined value of +89 kJ/mol in the literature for bulk PVP polymerization and a mechanistically derived value of +91 kJ/mol based on the bulk free radical polymerization mechanism of PVP. These findings open new operating windows for iCVD polymerization and thin-film growth in which fast polymer deposition can be achieved without substrate cooling that can greatly simplify the iCVD scale-up to roll-to-roll processing and enable iCVD polymerization of highly volatile monomers relevant for diverse applications in biomedicine, smart wearables, and renewable energy.

Toxicity Evaluation and Controlled-Release of Curcumin-Loaded Amphiphilic Poly-N-vinylpyrrolidone Nanoparticles: In Vitro and In Vivo Models

Curcumin attracts huge attention because of its biological properties: it is antiproliferative, antioxidant, anti-inflammatory, immunomodulatory and so on. However, its usage has been limited by poor water solubility and low bioavailability. Herein, to solve these problems, we developed curcumin-loaded nanoparticles based on end-capped amphiphilic poly(N-vinylpyrrolidone). Nanoparticles were obtained using the solvent evaporation method and were characterized by dynamic and electrophoretic light scattering, transmission electron (TEM) and atomic force (AFM) microscopy. The average particle size was 200 nm, and the ζ-potential was -4 mV. Curcumin-release studies showed that nanoparticles are stable in aqueous solutions. An in vitro release study showed prolonged action in gastric, intestinal and colonic fluids, consistently, and in PBS. In vitro studies on epidermoid carcinoma and human embryonic kidney cells showed that the cells absorbed more curcumin in nanoparticles compared to free curcumin. Nanoparticles are safe for healthy cells and show high cytotoxicity for glioblastoma cells in cytotoxicity studies in vitro. The median lethal dose was determined in an acute toxicity assay on zebrafish and was 23 μM. Overall, the curcumin-loaded nanoparticles seem promising for cancer treatment.

Drug Extended-Release System Utilizing Micelle Formation of Highly Water-Soluble Drugs and a Counter Polymer

The objective of this study is to clarify the mechanism of extending release of highly water-soluble drugs via counter polymer (CP) utilization in poly(ethylene oxide) (PEO)/polyethylene glycol (PEG) matrix tablets. Carbomer, poly(acrylic acid), was used as a CP, which has the opposite charges to the drugs. The in vitro release of several highly water-soluble drugs from PEO/PEG tablet with or without CP were tested, the relationship between the sustained release effect by a CP (SRE) and the physicochemical properties of the drugs was investigated. The results demonstrated that the utilization of CP can extend the release of some highly water-soluble drugs by effectively controlling the drug diffusion through matrices. On the other hand, the effectiveness of CP was different depending on the drugs applied. There were not statistical correlations between SRE and physicochemical properties such as solubility, molecular weight, and charge intensity of the drugs, while a micelle forming property of the drugs played an important role in SRE by CP. It was concluded that CP, Carbomer, having negative charges could effectively interact with opposite charges on the surface of stable drug micelles, which could result in a significant decrease in drug diffusion leading to extended drug release. It is considered that the system utilizing CP is a promising approach to achieve extended release of highly water-soluble drugs with a reasonable tablet size, especially in the case of large drug loading.

Formulation and Investigation of CK2 Inhibitor-Loaded Alginate Microbeads with Different Excipients

The aim of this study was to formulate and characterize CK2 inhibitor-loaded alginate microbeads via the polymerization method. Different excipients were used in the formulation to improve the penetration of an active agent and to stabilize our preparations. Transcutol® HP was added to the drug-sodium alginate mixture and polyvinylpyrrolidone (PVP) was added to the hardening solution, alone and in combination. To characterize the formulations, mean particle size, scanning electron microscopy analysis, encapsulation efficiency, swelling behavior, an enzymatic stability test and an in vitro dissolution study were performed. The cell viability assay and permeability test were also carried out on the Caco-2 cell line. The anti-oxidant and anti-inflammatory effects of the formulations were finally evaluated. The combination of Transcutol® HP and PVP in the formulation of sodium alginate microbeads could improve the stability, in vitro permeability, anti-oxidant and anti-inflammatory effects of the CK2 inhibitor.

Engineering of PVA/PVP Hydrogels for Agricultural Applications

Hydrogels have gained significant popularity in agricultural applications in terms of minimizing waste and mitigating the negative environmental impact of agrochemicals. This review specifically examines the utilization of environmentally friendly, shapable hydrogels composed of polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) in various casings for crop protection against different pests, fertilizing, and watering. To activate their effectiveness, PVA/PVP hydrogels were loaded with both hydrophilic and hydrophobic environmentally friendly pesticides, namely hydrogen peroxide (HP), the essential oil thymol, and urea as a fertilizer, either separately or in combination. This review covers various physical and chemical approaches used for loading, shaping, and controlling the release profiles of pesticides and fertilizers. Additionally, it explores the evaluation of the chemical composition, structure, classification, rheology, and morphology of the hydrogels as well as their impact on the thermal stability of the encapsulated pesticides and fertilizer, followed by biological tests. These hydrogels significantly contribute to the stabilization and controlled release of essential nutrients and biocides for plants, while maintaining excellent biocidal and fertilizing properties as well as sustainability characteristics. By shedding light on the latest insights into the concepts, applications, and results of these hydrogels, this review demonstrates their immense potential for widespread future use in agriculture.

Facile preparation of biocompatible and antibacterial water-soluble films using polyvinyl alcohol/carboxymethyl chitosan blend fibers via centrifugal spinning

Water-soluble polyvinyl alcohol/carboxymethyl chitosan (PVA/CMCS) blend fiber films were successfully prepared using a plane-collection centrifugal spinning machine. The addition of CMCS significantly increased the shear viscosity of the PVA/CMCS blend solution. The effects of spinning temperature on the shear viscosity and the centrifugal spinnability of PVA/CMCS blend solution were discussed. The PVA/CMCS blend fibers were uniform, and their average diameters ranged from 1.23 μm to 29.01 μm. It was found that the CMCS was distributed evenly in the PVA matrix and increased the crystallinity of PVA/CMCS blend fiber films. The hydrogen bonds between the hydroxyl group of PVA and the carboxymethyl group of CMCS were also detected. An in vitro cell study of human skin fibroblast cells on the PVA/CMCS blend fiber films confirmed biocompatibility. The maximum tensile strength and elongation at break of PVA/CMCS blend fiber films could reach 3.28 MPa and 29.52 %, respectively. The colony-plate-count tests indicated that the PVA16-CMCS2 presented 72.05 % and 21.36 % antibacterial rates against Staphylococcus aureus (10⁴ CFU/mL) and Escherichia coli (10³ CFU/mL), respectively. These values indicated that the newly prepared PVA/CMCS blend fiber films are promising materials for cosmetic and dermatological applications.

Hydroxypropyl Methylcellulose Bioadhesive Hydrogels for Topical Application and Sustained Drug Release: The Effect of Polyvinylpyrrolidone on the Physicomechanical Properties of Hydrogel

Hydrogels are homogeneous three-dimensional polymeric networks capable of holding large amounts of water and are widely used in topical formulations. Herein, the physicomechanical, rheological, bioadhesive, and drug-release properties of hydrogels containing hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) were examined, and the intermolecular interactions between the polymers were explored. A three-level factorial design was used to form HPMC-PVP binary hydrogels. The physicomechanical properties of the binary hydrogels alongside the homopolymeric HPMC hydrogels were characterized using a texture analyzer. Rheological properties of the gels were studied using a cone and plate rheometer. The bioadhesiveness of selected binary hydrogels was tested on porcine skin. Hydrophilic benzophenone-4 was loaded into both homopolymeric and binary gels, and drug-release profiles were investigated over 24 h at 33 °C. Fourier transform infrared spectroscopy (FTIR) was used to understand the inter-molecular drug-gel interactions. Factorial design analysis supported the dominant role of the HPMC in determining the gel properties, rather than the PVP, with the effect of both polymer concentrations being non-linear. The addition of PVP to the HPMC gels improved adhesiveness without significantly affecting other properties such as hardness, shear-thinning feature, and viscosity, thereby improving bioadhesiveness for sustained skin retention without negatively impacting cosmetic acceptability or ease of use. The release of benzophenone-4 in the HPMC hydrogels followed zero-order kinetics, with benzophenone-4 release being significantly retarded by the presence of PVP, likely due to intermolecular interactions between the drug and the PVP polymer, as confirmed by the FTIR. The HPMC-PVP binary hydrogels demonstrate strong bioadhesiveness resulting from the addition of PVP with desirable shear-thinning properties that allow the formulation to have extended skin-retention times. The developed HPMC-PVP binary hydrogel is a promising sustained-release platform for topical drug delivery.

Poly(vinyl pyrrolidone) derivatives as PEG alternatives for stealth, non-toxic and less immunogenic siRNA-containing lipoplex delivery

The recent approval of Onpattro® and COVID-19 vaccines has highlighted the value of lipid nanoparticles (LNPs) for the delivery of genetic material. If it is known that PEGylation is crucial to confer stealth properties to LNPs, it is also known that PEGylation is responsible for the decrease of the cellular uptake and endosomal escape and for the production of anti-PEG antibodies inducing accelerated blood clearance (ABC) and hypersensitivity reactions. Today, the development of PEG alternatives is crucial. Poly(N-vinyl pyrrolidone) (PNVP) has shown promising results for liposome decoration but has never been tested for the delivery of nucleic acids. Our aim is to develop a series of amphiphilic PNVP compounds to replace lipids-PEG for the post-insertion of lipoplexes dedicated to siRNA delivery. PNVP compounds with different degrees of polymerization and hydrophobic segments, such as octadecyl, dioctadecyl and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE), were generated. Based on the physicochemical properties and the efficiency to reduce protein corona formation, we showed that the DSPE segment is essential for the integration into the lipoplexes. Lipoplexes post-grafted with 15% DSPE-PNVP30 resulted in gene silencing efficiency close to that of lipoplexes grafted with 15% DSPE-PEG. Finally, an in vivo study in mice confirmed the stealth properties of DSPE-PNVP30 lipoplexes as well as a lower immune response ABC effect compared to DSPE-PEG lipoplexes. Furthermore, we showed a lower immune response after the second injection with DSPE-PNVP30 lipoplexes compared to DSPE-PEG lipoplexes. All these observations suggest that DSPE-PNVP30 appears to be a promising alternative to PEG, with no toxicity, good stealth properties and lower immunological response.

Perspectives on recent advancements in energy harvesting, sensing and bio-medical applications of piezoelectric gels

The development of next-generation bioelectronics, as well as the powering of consumer and medical devices, require power sources that are soft, flexible, extensible, and even biocompatible. Traditional energy storage devices (typically, batteries and supercapacitors) are rigid, unrecyclable, offer short-lifetime, contain hazardous chemicals and possess poor biocompatibility, hindering their utilization in wearable electronics. Therefore, there is a genuine unmet need for a new generation of innovative energy-harvesting materials that are soft, flexible, bio-compatible, and bio-degradable. Piezoelectric gels or PiezoGels are a smart crystalline form of gels with polar ordered structures that belongs to the broader family of piezoelectric material, which generate electricity in response to mechanical stress or deformation. Given that PiezoGels are structurally similar to hydrogels, they offer several advantages including intrinsic chirality, crystallinity, degree of ordered structures, mechanical flexibility, biocompatibility, and biodegradability, emphasizing their potential applications ranging from power generation to bio-medical applications. Herein, we describe recent examples of new functional PiezoGel materials employed for energy harvesting, sensing, and wound dressing applications. First, this review focuses on the principles of piezoelectric generators (PEGs) and the advantages of using hydrogels as PiezoGels in energy and biomedical applications. Next, we provide a detailed discussion on the preparation, functionalization, and fabrication of PiezoGel-PEGs (P-PEGs) for the applications of energy harvesting, sensing and wound healing/dressing. Finally, this review concludes with a discussion of the current challenges and future directions of P-PEGs.

Polyvinylpyrrolidone-Alginate Film Barriers for Abdominal Surgery: Anti-Adhesion Effect in Murine Model

Surgical operations on the peritoneum are often associated with the formation of adhesions, which can interfere with the normal functioning of the internal organs. The effectiveness of existing barrier materials is relatively low. In this work, the effectiveness of soluble alginate-polyvinylpyrrolidone (PVP-Alg) and non-soluble Ca ion cross-linked (PVP-Alg-Ca) films in preventing these adhesions was evaluated. Experiments in vivo were performed on mice via mechanical injury to the adjacent peritoneum wall and the caecum, followed by the application of PVP-Alg or PVP-Alg-Ca films to the injured area. After 7 days, samples from the peritoneal wall and caecum were analyzed using histology and quantitative polymerase chain reaction (qPCR). It was shown that the expression of genes responsible for adhesion formation in the caecum in the PVP-Alg group was comparable to that in the control group, while in the PVP-Alg-Ca group, it increased by 5-10 times. These results were consistent with the histology: in the PVP-Alg group, the adhesions did not form, while in the PVP-Alg-Ca group, the adhesions corresponded to five points on the adhesion scale. Therefore, the formation of intraperitoneal adhesions can be effectively prevented by non-crosslinked, biodegradable PVP-Alg films, whereas cross-linked, not biodegradable PVP-Alg-Ca films cause inflammation and adhesion formation.

Electron-Poor Butenolides: The Missing Link between Acrylates and Maleic Anhydride in Radical Polymerization

Butenolides are a class of 5-membered lactones that hold great potential as bio-based monomers to replace oil-derived acrylates, of which they are cyclic analogues. Despite this structural resemblance, the reactivity of the unsaturated ester moiety of electron-poor butenolides leans toward that of maleic anhydride, another essential monomer that does not homopolymerize but copolymerizes in a highly alternating fashion with polarized electron-rich comonomers. By studying the reactivity of 5-methoxy and 5-acyloxy butenolides through a combination of kinetics and density functional theory (DFT) experiments, we explain why electron-poor butenolides constitute a missing link between acrylates and maleic anhydride in radical polymerization.

The high-throughput atomization of polymer solutions for fiber synthesis in a single step aided with corona ionizers

Polymer microfibers are ubiquitous structures across virtually all technological fields. Their applications include, for instance, filter media, tissue regeneration, wound healing and dressing, and reinforcement materials. The most effective methods for fabrication of fibrous micro and nanomaterials rely on electric fields to spin a liquid jet into an ultrafine thread that rapidly dries up forming a fiber. Continuous spinning and collection leads to formation of fiber mats. Here we report a robust yet simple approach for the massive production of liquid threads, which upon acquiring electrical charges in-flight are collected downstream in the form of fibers. The entire process takes place on-line in a single step. The liquid threads are produced through the fragmentation of a polymer solution bulk due to a turbulent interaction of a gas-liquid interface in the interior of an engineered device, a so-called Flow Blurring atomizer. The particularity of this approach consists precisely in such vigorous interaction, at the micrometer scale, which triggers a bubbly motion in the interior of the device, that is a "micro-mixing". Subsequently, the threads are passed through ionized air currents, at ambient conditions, and then stretched to sub-micrometer dimensions by electric fields. Polyvinylpyrrolidone (PVP) as well as carbon nanotubes (CNTs) or graphene oxide sheets (GOSs)-containing PVP fibers, with diameters in the range 100-900 nm, were synthesized via this approach. In the cases studied herein the method was operated at liquid flow rates (i.e. production rates) of 0.2 mL/min but it could be readily increased up to a few tens of mL/min. The method requires further improvement and optimization, nevertheless it is a promising alternative for mass production of polymer fibers.

Activated Carbon-Enriched Electrospun-Produced Scaffolds for Drug Delivery/Release in Biological Systems

To vectorize drug delivery from electrospun-produced scaffolds, we introduce a thin outer drug retention layer produced by electrospinning from activated carbon nanoparticles (ACNs)-enriched polycaprolacton (PCL) suspension. Homogeneous or coaxial fibers filled with ACNs were produced by electrospinning from different PCL-based suspensions. Stable ACN suspensions were selected by sorting through solvents, stabilizers and auxiliary components. The ACN-enriched scaffolds produced were characterized for fiber diameter, porosity, pore size and mechanical properties. The scaffold structure was analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy. It was found that ACNs were mainly coated with a polymer layer for both homogeneous and coaxial fibers. Drug binding and release from the scaffolds were tested using tritium-labeled sirolimus. We showed that the kinetics of sirolimus binding/release by ACN-enriched scaffolds was determined by the fiber composition and differed from that obtained with a free ACN. ACN-enriched scaffolds with coaxial and homogeneous fibers had a biocompatibility close to scaffold-free AC, as was shown by the cultivation of human gingival fibroblasts and umbilical vein cells on scaffolds. The data obtained demonstrated that ACN-enriched scaffolds had good physico-chemical properties and biocompatibility and, thus, could be used as a retaining layer for vectored drug delivery.

Polyvinylpyrrolidone as co-inhibitor of crystallization of nifedipine in paper tablets

Techniques to maintain drugs amorphous that would otherwise crystallize is an extensively studied approach to enhance the dissolution characteristics of poorly soluble drugs. However, their performance is limited by the low physical stability of the amorphous phase which can lead to recrystallization which in turn results in decreased solubility and bioavailability of the drug. In this work, the crystallinity of nifedipine loaded into a cellulose-based paper matrix, so called smartFilms, was determined by terahertz time-domain spectroscopy. By adding polyvinylpyrrolidone as an extra carrier, the capability of smartFilms to transfer nifedipine into its amorphous state improved. Moreover, the performance of the formulation to inhibit recrystallization of the amorphous drug over a period of six months increased. For formulations containing up to 10 w% drug loading and additional polyvinylpyrrolidone (nifedipine/polyvinylpyrrolidone: 4:1 mass ratio), nifedipine was found to be completely amorphous after six months of storage.

CuF2/DMAP-Catalyzed N-Vinylation: Scope and Mechanistic Study

CuF₂/DMAP has been established as an excellent catalytic system for vinylsilane-promoted N-vinylation of amides and azoles at room temperature without an external fluoride source. A mechanism has been proposed on the basis of the isolation of reactive intermediate [Cu(DMAP)₄Cl₂], fluoride ion-assisted transmetalation, and ultraviolet-visible spectroscopic studies. The catalytic efficiency of the synthesized and structurally characterized [Cu(DMAP)₄Cl₂] complex has been demonstrated. The valuable monomers for water-soluble polymers, viz., NVP, NVC, and NVIBA, were synthesized on a gram scale.

Assemblies of poly(N-vinyl-2-pyrrolidone)-based double hydrophilic block copolymers triggered by lanthanide ions: characterization and evaluation of their properties as MRI contrast agents

Because of the formation of specific antibodies to poly(ethylene glycol) (PEG) leading to life-threatening side effects, there is an increasing need to develop alternatives to treatments and diagnostic methods based on PEGylated copolymers. Block copolymers comprising a poly(N-vinyl-2-pyrrolidone) (PVP) segment can be used for the design of such vectors without any PEG block. As an example, a poly(acrylic acid)-block-poly(N-vinyl-2-pyrrolidone) (PAA-b-PVP) copolymer with controlled composition and molar mass is synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Mixing this copolymer with lanthanide cations (Gd³⁺, Eu³⁺, Y³⁺) leads to the formation of hybrid polyion complexes with increased stability, preventing the lanthanide cytotoxicity and in vitro cell penetration. These new nanocarriers exhibit enhanced T₁ MRI contrast, when intravenously administered into mice. No leaching of gadolinium ions is detected from such hybrid complexes.

Fabrication of Celecoxib PVP Microparticles Stabilized by Gelucire 48/16 via Electrospraying for Enhanced Anti-Inflammatory Action

Electrospraying (ES) technology is considered an efficient micro/nanoparticle fabrication technique with controlled dimensions and diverse morphology. Gelurice® 48/16 (GLR) has been employed to stabilize the aqueous dispersion of Celecoxib (CXB) for enhancing its solubility and oral bioavailability. Our formula is composed of CXB loaded in polyvinylpyllodine (PVP) stabilized with GLR to formulate microparticles (MPs) (CXB-GLR-PVP MPs). CXB-GLR-PVP MPs display excellent in vitro properties regarding particle size (548 ± 10.23 nm), zeta potential (−20.21 ± 2.45 mV), and drug loading (DL, 1.98 ± 0.059 mg per 10 mg MPs). CXB-GLR-PVP MPs showed a significant (p < 0.05) higher % cumulative release after ten minutes (50.31 ± 4.36) compared to free CXB (10.63 ± 2.89). CXB exhibited good dispersibility, proved by X-ray diffractometry (XRD), adequate compatibility of all components, confirmed by Fourier-Transform Infrared Spectroscopy (FTIR), and spherical geometry as revealed in scanning electron microscopy (SEM). Concerning our anti-inflammatory study, there was a significant decrease in the scores of the inflammatory markers’ immunostaining in the CXB-GLR-PVP MPs treated group. Also, the amounts of the oxidative stress biomarkers, as well as mRNA expression of interleukins (IL-1β and IL-6), considerably declined (p < 0.05) in CXB-GLR-PVP MPs treated group alongside an enhancement in the histological features was revealed. CXB-GLR-PVP MPs is an up-and-coming delivery system that could be elucidated in future clinical investigations.

Rhenium(I) Block Copolymers Based on Polyvinylpyrrolidone: A Successful Strategy to Water-Solubility and Biocompatibility

A series of diphosphine Re(I) complexes Re1-Re4 have been designed via decoration of the archetypal core {Re(CO)₂(N^N)} through the installations of the phosphines P⁰ and P¹ bearing the terminal double bond, where N^N = 2,2'-bipyridine (N^N1), 4,4'-di-tert-butyl-2,2'-bipyridine (N^N2) or 2,9-dimethyl-1,10-phenanthroline (N^N3) and P⁰ = diphenylvinylphosphine, and P¹ = 4-(diphenylphosphino)styrene. These complexes were copolymerized with the corresponding N-vinylpyrrolidone-based Macro-RAFT agents of different polymer chain lengths to give water-soluble copolymers of low-molecular p(VP-l-Re) and high-molecular p(VP-h-Re) block-copolymers containing rhenium complexes. Compounds Re1-Re4, as well as the copolymers p(VP-l-Re) and p(VP-h-Re), demonstrate phosphorescence from a ³MLCT excited state typical for this type of chromophores. The copolymers p(VP-l-Re#) and p(VP-h-Re#) display weak sensitivity to molecular oxygen in aqueous and buffered media, which becomes almost negligible in the model physiological media. In cell experiments with CHO-K1 cell line, p(VP-l-Re2) and p(VP-h-Re2) displayed significantly reduced toxicity compared to the initial Re2 complex and internalized into cells presumably by endocytic pathways, being eventually accumulated in endosomes. The sensitivity of the copolymers to oxygen examined in CHO-K1 cells via phosphorescence lifetime imaging microscopy (PLIM) proved to be inessential.

Nanofiber formation as a promising technology for preservation and easy storage of extracellular vesicles

Extracellular vesicles (EVs) are cell-derived, membrane-enclosed particles with the potential for a wide range of future therapeutic applications. However, EVs have almost always been administered by direct injection, likely hindering their efficacy because of rapid clearance from the injection site. The present study aimed to incorporate medium-sized extracellular vesicles (mEVs) into fast-dissolving electrospun polyvinylpyrrolidone-based nanofibers to explore the storage-dependent structure-activity relationship of the resulting nanofibrous formulations. Aqueous polyvinylpyrrolidone-based precursor solutions were selected for the electrospinning process. The presence of EVs in the electrospun samples was confirmed by transmission electron microscopy, flow cytometry, and confocal laser scanning microscope. The results indicate that the fibrous structure of the samples was preserved until the end of the 12-week storage period. Furthermore, regardless of the storage temperature (4 °C or room temperature), nanofibers and nanofiber-associated EVs were present throughout the experimental period. Incorporating EVs into a stable solid polymeric delivery base could preserve their stability; meanwhile, according to the characteristics of the polymer, their targeted and controlled release can be achieved.

Physicochemical Properties of Water-Based Copolymer and Zeolite Composite Sustained-Release Membrane Materials

A nitrogen fertilizer slow-release membrane was proposed using polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), epoxy resin, and zeolite as raw materials. The effects of the water-based copolymer (PVA:PVP) solution ratio A (A1−A4) and zeolite amount B (B1−B4) on the water absorption rate (XS), water permeability (TS), fertilizer permeability (TF), tensile strength (KL), elongation at break (DSL), and viscosity (ND) of the membrane were explored using the swelling method, a self-made device, and a universal testing machine. The optimal combination of the water-based copolymer and zeolite amount was determined by the coefficient-of-variation method. The results show that the effects of the decrease in A on KL and the increase in B on KL and DSL are promoted first and then inhibited. DSL and ND showed a negative response to the A decrease, whereas XS, TS, and TF showed a positive response. The effect of increasing B on ND, TS, and TF showed a zigzag fluctuation. In the condition of A1−A3, XS showed a negative response to the B increase, whereas in the condition of A4, XS was promoted first and then inhibited. Adding PVP and zeolite caused the hydroxyl stretching vibration peak of PVA at 3300 cm−1 to widen; the former caused the vibration peak to move to low frequencies, and the latter caused it to move to high frequencies. The XRD pattern shows that the highest peak of zeolite is located at 2θ = 7.18° and the crystallization peak of the composite membrane increases with the rise in the proportion of zeolite. Adding PVP made the surface of the membrane smooth and flat, and adding a small amount of zeolite improved the mechanical properties of the membrane and exhibited good compatibility with water-based copolymers. In the evaluation model of the physicochemical properties of sustained-release membrane materials, the weight of all indicators was in the following order: TF > ND > TS > KL > XL > DSL. The optimal membrane material for comprehensive performance was determined to be A2B3.

Surface Modifiers on Composite Particles for Direct Compaction

Direct compaction (DC) is considered to be the most effective method of tablet production. However, only a small number of the active pharmaceutical ingredients (APIs) can be successfully manufactured into tablets using DC since most APIs lack adequate functional properties to meet DC requirements. The use of suitable modifiers and appropriate co-processing technologies can provide a promising approach for the preparation of composite particles with high functional properties. The purpose of this review is to provide an overview and classification of different modifiers and their multiple combinations that may improve API tableting properties or prepare composite excipients with appropriate co-processed technology, as well as discuss the corresponding modification mechanism. Moreover, it provides solutions for selecting appropriate modifiers and co-processing technologies to prepare composite particles with improved properties.

Immediate release 3D printed oral dosage forms: How different polymers have been explored to reach suitable drug release behaviour

Three-dimensional (3D) printing has been gaining attention as a new technological approach to obtain immediate release (IR) dosage forms. The versatility conferred by 3D printing techniques arises from the suitability of using different polymeric materials in the production of solids with different porosities, geometries, sizes, and infill patterns. The appropriate choice of polymer can facilitate in reaching IR specifications and afford other specific properties to 3D printed solid dosage forms. This review aims to provide an overview of the polymers that have been employed in the development of IR 3D printed dosage forms, mainly considering their in vitro drug release behaviour. The physicochemical and mechanical properties of the IR 3D printed dosage forms will also be discussed, together with the manufacturing process strategies. Up to now, methacrylic polymers, cellulosic polymers, vinyl derivatives, glycols and different polymeric blends have been explored to produce IR 3D printed dosage forms. Their effects on drug release profiles are critically discussed here, giving a complete overview to drive formulators towards a rational choice of polymeric material and thus contributing to future studies in 3D printing of pharmaceuticals.

Activated Carbon for Drug Delivery from Composite Biomaterials: The Effect of Grinding on Sirolimus Binding and Release

Activated carbon (AC) could be potentially useful as a drug carrier in fiber polymer scaffolds destined for prolonged drug delivery. To be introduced, AC must be ground into smaller-sized particles to be introduced in scaffolds, as most biocompatible scaffolds consist of fibers with a diameter of less than 1 µm. In this study, the adsorption of sirolimus (SRL) from phosphate-buffered saline (PBS) solution and blood plasma (BP) onto AC of AX-21 type, as well as the release of SRL from AC depending on its fragmentation, were studied. Two-stage grinding of the AC, first with a ball mill, and then with a bead mill, was performed. Grinding with a bead mill was performed either in water or in polyvinylpyrrolidone to prevent aggregation of AC particles. Dynamic light scattering and scanning electron microscopy (SEM) demonstrated that the size of the particles obtained after grinding with a ball mill was 100–10,000 nm, and after grinding with a bead mill, 100–300 nm. Adsorption in PBS was significantly higher than in BP for all fractions, and depended on SRL concentration. The fraction obtained after grinding with a ball mill showed maximal SRL adsorption, both in PBS and BP, and slow SRL release, in comparison with other fractions. The 100–300 nm AC fractions were able to adsorb and completely release SRL into BP, in contrast to other fractions, which strongly bound a significant amount of SRL. The data obtained are to be used for controlled SRL delivery, and thus in the modification of drug delivery in biological media.

Immunomodulation of Telmisartan-Loaded PCL/PVP Scaffolds on Macrophages Promotes Endogenous Bone Regeneration

Biomaterial-immune system interactions play an important role in postimplantation osseointegration to retain the functionality of healthy and intact bones. Therefore, appropriate osteoimmunomodulation of implants has been considered and validated as an efficient strategy to alleviate inflammation and enhance new bone formation. Here, we fabricated a nanostructured PCL/PVP (polycaprolactone/polyvinylpyrrolidone) electrospinning scaffold for cell adhesion, tissue ingrowth, and bone defect padding. In addition, telmisartan, an angiotensin 2 receptor blocker with distinct immune bioactivity, was doped into PCL-/PVP-electrospun scaffolds at different proportions [1% (TPP-1), 5% (TPP-5), and 10% (TPP-10)] to investigate its immunomodulatory effects and osteoinductivity/conductivity. Telmisartan-loaded scaffolds displayed in vitro anti-inflammatory bioactivity on lipopolysaccharide-induced M1 macrophages by polarizing them to an M2-like phenotype and exhibited pro-osteogenic properties on bone marrow-derived mesenchymal stem cells (BMSCs). Histological analysis and micro-CT results of a rat skull defect model also showed that the telmisartan-loaded scaffolds induced a higher M2/M1 ratio, less inflammatory infiltration, and better bone regenerative patterns. Furthermore, activation of the BMP2 (bone morphogenetic protein-2)-Smad signaling pathway was found to be dominant in telmisartan-loaded scaffold-mediated macrophage-BMSC interactions. These findings indicate that telmisartan incorporation with PCL/PVP nanofibrous scaffolds is a potential therapeutic strategy for promoting bone healing by modulating M1 macrophages to a more M2 phenotype at early stages of postimplantation.

Wound Dressing: Combination of Acacia Gum/PVP/Cyclic Dextrin in Bioadhesive Patches Loaded with Grape Seed Extract

The success of wound treatment is conditioned by the combination of both suitable active ingredients and formulation. Grape seed extract (GSE), a waste by-product obtained by grape processing, is a natural source rich in many phenolic compounds responsible for antioxidant, anti-inflammatory, and antimicrobial activities and for this reason useful to be used in a wound care product. Bioadhesive polymeric patches have been realized by combining acacia gum (AG) and polyvinylpyrrolidone (PVP). Prototypes were prepared by considering different AG/PVP ratios and the most suitable in terms of mechanical and bioadhesion properties resulted in the 9.5/1.0 ratio. This patch was loaded with GSE combined with cyclic dextrin (CD) to obtain the molecular dispersion of the active ingredient in the dried formulation. The loaded patch resulted mechanically resistant and able to release GSE by a sustained mechanism reaching concentrations able to stimulate keratinocytes’ growth, to exert both antibacterial and antioxidant activities.

Versatile thiolactone-based conjugation strategies to polymer stabilizers for multifunctional upconverting nanoparticles aqueous dispersions

We describe here a new methodology for the synthesis of well-defined phosphonic acid-terminated poly(ethylene glycol) (PEG) and RAFT-derived poly(N-vinylpyrrolidone) (PVP) and poly(N-vinylcaprolactam) (PVCL) by amine-thiol-ene and amine-thiol-thiosulfonate conjugation strategies using a phosphonated thiolactone and their use to prepare stable, water-dispersible multifunctional upconverting luminescent nanohybrids.

New Insights on Solvent Implications in the Design of Materials Based on Cellulose Derivatives Using Experimental and Theoretical Approaches

The current paper presents a strategic way to design and develop materials with properties adapted for various applications from biomedicine to environmental applications. In this context, blends of (hydroxypropyl)methyl cellulose (HPMC) and poly(vinylpyrrolidone) (PVP) were obtained to create new materials that can modulate the membrane properties in various fields. Thus, to explore the possibility of using the HPMC/PVP system in practical applications, the solubility parameters in various solvents were initially evaluated using experimental and theoretical approaches. In this frame, the study is aimed at presenting the background and steps of preliminary studies to validate the blends behavior for targeted application before being designed. Subsequently, the analysis of the behavior in aqueous dilute solution of HPMC/PVP blend offers information about the conformational modifications and interactions manifested in system depending on the structural characteristics of polymers (hydrophilicity, flexibility), polymer mixtures composition, and used solvent. Given this background, based on experimental and theoretical studies, knowledge of hydrodynamic parameters and analysis of the optimal compositions of polymer mixtures are essential for establishing the behavior of obtained materials and validation for most suitable applications. Additionally, to guarantee the quality and functionality of these composite materials in the targeted applications, e.g., biomedical or environmental, the choice of a suitable solvent played an important role.

Towards a better understanding of thermally treated polycarbophil matrix tablets for controlled release

Polycarbophil (POL), a polyacrylic acid cross-linked with divinyl glycol, is widely used in semisolid and solid dosage forms. When undergoing a thermal treatment in the range 120–160 °C, POL shows interesting morphological modifications, related to changes in physical properties, such as swelling of the powder granules, or hardening and matrix formation if included in the composition of a tablet. Thermal analysis conducted on POL highlighted a thermal event (Z) that can be correlated both to the shrinking of the powder granules and to the matrix formation in compacted POL powder. Modulated differential scanning calorimetry (MDSC) allowed to distinguish, inside event Z, an irreversible process overlapping with a reversible glass transition, attributable to the volatilization of residual solvents identified, through a complex TGA-FTIR-GC–MS interface, as acetate esters used for the polymer production as very fine powder. A specific interaction between acetates and POL, capable of stabilizing the polymer chains in a given conformation, was highlighted. The molecular rearrangement of the POL chains, following the volatilization of the solvent-stabilizers, is therefore ascribable to a loss of energetic stability of this material, which justifies the shrinking phenomena in the granules of the powder and the matrix formation when POL is compacted.

Effect of N-Vinyl-2-Pyrrolidone (NVP), a Bromodomain-Binding Small Chemical, on Osteoblast and Osteoclast Differentiation and Its Potential Application for Bone Regeneration

The human skeleton is a dynamic and remarkably organized organ system that provides mechanical support and performs a variety of additional functions. Bone tissue undergoes constant remodeling; an essential process to adapt architecture/resistance to growth and mechanical needs, but also to repair fractures and micro-damages. Despite bone's ability to heal spontaneously, certain situations require an additional stimulation of bone regeneration, such as non-union fractures or after tumor resection. Among the growth factors used to increase bone regeneration, bone morphogenetic protein-2 (BMP2) is certainly the best described and studied. If clinically used in high quantities, BMP2 is associated with various adverse events, including fibrosis, overshooting bone formation, induction of inflammation and swelling. In previous studies, we have shown that it was possible to reduce BMP2 doses significantly, by increasing the response and sensitivity to it with small molecules called "BMP2 enhancers". In the present study, we investigated the effect of N-Vinyl-2-pyrrolidone (NVP) on osteoblast and osteoclast differentiation in vitro and guided bone regeneration in vivo. We showed that NVP increases BMP2-induced osteoblast differentiation and decreases RANKL-induced osteoclast differentiation in a dose-dependent manner. Moreover, in a rabbit calvarial defect model, the histomorphometric analysis revealed that bony bridging and bony regenerated area achieved with NVP-loaded poly (lactic-co-glycolic acid (PLGA) membranes were significantly higher compared to unloaded membranes. Taken together, our results suggest that NVP sensitizes BMP2-dependent pathways, enhances BMP2 effect, and inhibits osteoclast differentiation. Thus, NVP could prove useful as "osteopromotive substance" in situations where a high rate of bone regeneration is required, and in the management of bone diseases associated with excessive bone resorption, like osteoporosis.

Polyvinyl-Pyrrolidone-Coated Silver Nanoparticles-The Colloidal, Chemical, and Biological Consequences of Steric Stabilization under Biorelevant Conditions

(1) Background: Several properties of silver nanoparticles (AgNPs), such as cytotoxic, anticancer, and antimicrobial activities, have been subjects of intense research; however, important aspects such as nanoparticle aggregation are generally neglected, although a decline in colloidal stability leads to a loss of the desired biological activities. Colloidal stability is affected by pH, ionic strength, or a plethora of biomolecules that interact with AgNPs under biorelevant conditions. (2) Methods: As only a few studies have focused on the relationship between aggregation behavior and the biological properties of AgNPs, here, we have systematically evaluated this issue by completing a thorough analysis of sterically (via polyvinyl-pyrrolidone (PVP)) stabilized AgNPs that were subjected to different circumstances. We assessed ultraviolet-visible light absorption, dynamic light scattering, zeta potential measurements, in vitro cell viability, and microdilution assays to screen both colloidal stability as well as bioactivity. (3) Results: The results revealed that although PVP provided outstanding biorelevant colloidal stability, the chemical stability of AgNPs could not be maintained completely with this capping material. (4) Conclusion: These unexpected findings led to the realization that stabilizing materials have more profound importance in association with biorelevant applications of nanomaterials than just being simple colloidal stabilizers.

Probing the Interactions of Porphyrins with Macromolecules Using NMR Spectroscopy Techniques

Porphyrinic compounds are widespread in nature and play key roles in biological processes such as oxygen transport in blood, enzymatic redox reactions or photosynthesis. In addition, both naturally derived as well as synthetic porphyrinic compounds are extensively explored for biomedical and technical applications such as photodynamic therapy (PDT) or photovoltaic systems, respectively. Their unique electronic structures and photophysical properties make this class of compounds so interesting for the multiple functions encountered. It is therefore not surprising that optical methods are typically the prevalent analytical tool applied in characterization and processes involving porphyrinic compounds. However, a wealth of complementary information can be obtained from NMR spectroscopic techniques. Based on the advantage of providing structural and dynamic information with atomic resolution simultaneously, NMR spectroscopy is a powerful method for studying molecular interactions between porphyrinic compounds and macromolecules. Such interactions are of special interest in medical applications of porphyrinic photosensitizers that are mostly combined with macromolecular carrier systems. The macromolecular surrounding typically stabilizes the encapsulated drug and may also modify its physical properties. Moreover, the interaction with macromolecular physiological components needs to be explored to understand and control mechanisms of action and therapeutic efficacy. This review focuses on such non-covalent interactions of porphyrinic drugs with synthetic polymers as well as with biomolecules such as phospholipids or proteins. A brief introduction into various NMR spectroscopic techniques is given including chemical shift perturbation methods, NOE enhancement spectroscopy, relaxation time measurements and diffusion-ordered spectroscopy. How these NMR tools are used to address porphyrin-macromolecule interactions with respect to their function in biomedical applications is the central point of the current review.