Engineered Nanocomposite Coatings: From Water-Soluble Polymer to Advanced Hydrophobic Performances

In this work, a water-soluble (hydrophilic) polymer was used to form a hydrophobic coating on silicon substrates (Si) in a two-step process comprising (i) the transformation of the polymer into an insoluble material and (ii) the structuring of this coating at nanometric and micrometric scales to achieve the desired hydrophobic behavior. Polyvinylpyrrolidone (PVP), a water-soluble commodity polymer, was crosslinked using benzophenone and UV irradiation to produce a water-insoluble PVP coating. The nanometric scale roughness of the coating was achieved by the addition of silica nanoparticles (NPs) in the coating. The micrometric scale roughness was achieved by forming vertical pillars of PVP/NP coating. To prepare these pillars, a perforated polystyrene (PS) template was filled with a PVP/NP suspension. Micrometer scale vertical pillars of PVP/silica NPs were produced by this method, which allowed us to tune the wettability of the surface, by combining the micrometric scale roughness of the pillars to the nanometric scale roughness provided by the nanoparticles at the surface. By adjusting the various experimental parameters, a hydrophobic PVP coating was prepared with a water contact angle of 110°, resulting in an improvement of more than 80% compared to the bare flat film with an equal amount of nanoparticles. This study paves the way for the development of a more simplified experimental approach, relying on a blend of polymers containing PVP and NPs, to form the micro/nano-structured PVP pillars directly after the deposition step and the selective etching of the sacrificial major phase.

Wichterle hydron for breast augmentation - case reports and brief review

During the period of 1960s and 1970s, a new alloplastic material - Wichterle gel - was introduced in the field of plastic surgery. In 1961, a Czech scientist, prof. Otto Wichterle, had developed, along with his research team, a hydrophilic gel made of polymers, which fulfilled the high standards for prosthetic materials due to its hydrophilic, chemical, thermal and shape stability that provided a better tolerance in the body compared with other hydrophobic gels. Plastic surgeons had started to use the gel for breast augmentations and reconstructions. Success of the gel had been reinforced due to its easy preoperative preparation. The material had been implanted during general anaesthesia via submammary approach over the muscle fixed with a stitch to the fascia. Fixing corset bandage was applied after the surgery. The implanted material had proved to be suitable for postoperative processes with a minimum of complications. In the later postoperative period, however, serious complications occurred - mainly infections and calcifications. Long-term results are presented by case reports. Today, this material is no longer used and it is replaced by more modern implants.

Livedo racemosa associated with central venous catheter use in a newborn

Livedo racemosa (LRac) refers to violaceous, red, or blue netlike mottling of the skin in an irregular pattern caused by circulatory abnormalities. Central venous catheters (CVC) are widely used in neonates who require intensive care to offer steady intravenous access. CVCs are covered with a hydrophilic polymer gel that reduces friction between the sheath and the vessel wall, thereby minimizing vascular spasm, irritation, and aneurysm formation. However, the introduction of foreign material into the vein carries a risk of embolization. Recently, LRac was reported as a cutaneous manifestation of hydrophilic polymer gel embolization (HPE) in adults. We present a case of LRac in a newborn that developed following CVC insertion and resolved spontaneously after the catheter was removed.

Hot-Melt Extrusion-Based Fused Deposition Modeling 3D Printing of Atorvastatin Calcium Tablets: Impact of Shape and Infill Density on Printability and Performance

The main objective of the current research was to investigate the effect of tablet shapes (heart-shaped and round tablets) and infill densities (50% and 100%) on the drug release profiles of 3D printed tablets prepared by hot-melt extrusion paired with fused deposition modeling techniques. Drug-loaded filaments of 1.5 mm and 2.5 mm diameters were extruded using a Process 11 mm hot-melt extruder employing atorvastatin calcium as a model drug and Kollicoat® IR, Kollidon® VA64, Kollidon® 12PF, and Kolliphor® P407 as hydrophilic polymers. Filaments of Kollicoat® IR in combination with Kollidon® VA64/Kollidon® 12PF has resulted in successful printing of immediate release tablets. The mechanical properties of drug-loaded filaments were evaluated using a 3-point bend test and stiffness test. The transformation of a crystalline drug to an amorphous form and the absence of drug-polymer interactions were confirmed by differential scanning calorimetry and Fourier transform infrared spectroscopy, respectively. The effect of infill density on drug release profiles was greater than that of tablet shape. The stability of 3D printed tablets was preserved even after storage under accelerated conditions (40 ± 2°C and 75 ± 5% RH) for 6 months. Thus, the 3D printing process of hot-melt extrusion paired with fused deposition modeling serves as an alternative manufacturing approach for developing patient-focused doses.

Hydrophilic Crosslinked TEMPO-Methacrylate Copolymers - a Straight Forward Approach towards Aqueous Semi-Organic Batteries

Crosslinked hydrophilic poly(2,2,6,6-tetramethylpiperidinyl-N-oxyl-co-[2-(methacryloyloxy)-ethyl]trimethyl ammonium chloride) [poly(TEMPO-co-METAC)] polymers with different monomer ratios are synthesized and characterized regarding a utilization as electrode material in organic batteries. These polymers can be synthesized rapidly utilizing commercial starting materials and reveal an increased hydrophilicity compared to the state-of-the-art poly(2,2,6,6-tetramethylpiperidinyl-N-oxyl-4-methacrylate) (PTMA). By increasing the hydrophilicity of the polymer, a preparation of cathode composites is enabled, which can be used for aqueous semi-organic batteries. Detailed battery testing confirms that the additional METAC groups do not impair the battery behavior while enabling straight-forward zinc-TEMPO batteries.

Characterization of Hydrophilic Polymers as a Syringe Extrusion 3D Printing Material for Orodispersible Film

The application of hydrophilic polymers in designing and three-dimensional (3D) printing of pharmaceutical products in various dosage forms has recently been paid much attention. Use of hydrophilic polymers and syringe extrusion 3D printing technology in the fabrication of orodispersible films (ODFs) might hold great potential in rapid drug delivery, personalized medicine, and manufacturing time savings. In this study, the feasibility of 3D-printed ODFs fabrication through a syringe extrusion 3D printing technique and using five different hydrophilic polymers (e.g., hydroxypropyl methylcellulose E15, hydroxypropyl methylcellulose E50, high methoxyl pectin, sodium carboxymethylcellulose, and hydroxyethylcellulose) as film-forming polymers and printing materials has been investigated. Rheology properties and printability of printing gels and physicochemical and mechanical properties of 3D-printed ODFs were evaluated. Amongst the investigated hydrophilic polymers, sodium carboxymethylcellulose at a concentration of 5% w/v (SCMC-5) showed promising results with a good printing resolution and accurate dimensions of the 3D-printed ODFs. In addition, SCMC-5 3D-printed ODFs exhibited the fastest disintegration time within 3 s due to high wettability, roughness and porosity on the surface. However, the results of the mechanical properties study showed that SCMC-5 3D printed ODFs were rigid and brittle, thus requiring special packaging to prevent them from any damage before practical use.

Celecoxib Crystallized from Hydrophilic Polymeric Solutions Showed Modified Crystalline Behavior with an Improved Dissolution Profile

The crystallization technique has been established as a cost-effective and simple approach to improve the dissolution rate and oral bioavailability of poorly soluble drugs. This study was carried out to study the effect of some selected hydrophilic polymers such as methyl cellulose, hydroxypropyl methylcellulose (HPMC), polyvinyl alcohol, and carboxymethyl cellulose on the crystal behavior and dissolution properties of celecoxib (CLX), a common nonsteroidal anti-inflammatory drug. Structural and spectral characteristics of crystallized CLX have been studied by Fourier transform infrared (FTIR) spectroscopy, diffraction scanning calorimetry (DSC), and X-ray diffraction (XRD) analysis. From FTIR and DSC analysis, no significant shifting of peaks or appearance of any new peaks (for polymers) were observed, which indicated the absence of any major interaction between drug and polymers as well as the absence of polymers in the final crystallized product of CLX. The XRD analysis showed a change in crystalline morphology to some extent. The dissolution rate of crystallized CLX in the presence of polymers (particularly with HPMC) was significantly improved compared with plain CLX. The improved dissolution profile of the experimental CLX crystal products could be an indication of improved bioavailability of CLX for better clinical outcome.

Characterization of Betulinic Acid-Multiwalled Carbon Nanotubes Modified with Hydrophilic Biopolymer for Improved Biocompatibility on NIH/3T3 Cell Line

The biocompatibility of carbon nanotubes (CNT) is fairly a challenging task for their applications in nanomedicine. Therefore, the objective of this research was to formulate four types of highly biocompatible betulinic acid-loaded biopolymer nanocomposites, namely chitosan-multiwalled carbon nanotubes (MWBA-CS), polyethylene glycol-multiwalled carbon nanotubes (MWBA-PG), Tween 20-multiwalled carbon nanotubes (MWBA-T2) and Tween 80-multiwalled carbon nanotubes (MWBA-T8). The physico-chemical properties of the modified nanocomposites were determined by Fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA) and Raman spectroscopy, while the surface morphology of the resulting nanocomposites was studied using field emission scanning electron microscopy (FESEM). All data revealed that the external surface of MWBA nanocomposites was successfully coated with the respective polymer molecules through hydrophobic and electrostatic interactions with improved thermal profiles. The cell viability assay, which was performed on cultured normal embryonic mouse fibroblast cells, confirmed their excellent biocompatibility in phosphate-buffered saline aqueous media. Overall, our findings herein suggest that the synthesized biopolymer-coated MWBA nanocomposites are promising nanomaterials for drug delivery applications as they enhance the solubility and dispersibility of CNT with significantly reduced cytotoxic effect, especially in normal cells.

Folic acid-hydrophilic polymer coated mesoporous silica nanoparticles target doxorubicin delivery

Mesoporous silica nanoparticles (MSNs) gained significant attention, particularly in the pharmaceutical field. Folic acid (FA) shows marked promise as a targeting agent for its specific interaction with the folate receptor. This receptor is over-expressed on the cell surface of several cancerous cells like breast cancer. Polyethylene glycol (PE), as well as polypropylene glycol (PEG), is used to decorate nanoparticles to improve their biodistribution. Moreover, carboxymethyl beta-cyclodextrin (CM-β-CD), is used as a complexation molecule. In this study, we described the chemical synthesis, in vitro drug release and antiproliferative activity of doxorubicin-loaded/decorated MSNs further coupled with FA in two conditions: chemically bound or as a complex with CM-β-CD. Fourier Transform Infrared Spectroscopy with Transmission Electron Microscopy confirmed the successful surface change. Dynamic Light Scattering confirmed the change in surface characters like zeta potential, polydispersity index (PI), and size. PI improved from 0.58 to 0.23 while the size enlarged from 200 to 348 and 532 nm. Functionalized nanoparticles demonstrated more significant drug entrapment with (97%) while undecorated MSNs only showed (63%). Accordingly, we effectively synthesized FA-PEG2000-MSNs with IC₅₀: 0.015 mg/mL targeting HeLa cells. This approach may allow potential applications as a drug delivery system in cancer chemotherapy.HighlightsMesoporous silica nanoparticles (MSNs) with a carboxylic acid or amine surface group can be successfully decorated with long-chain hydrophilic polymer via an amide bond.Carboxymethyl-β-cyclodextrin coupled with long-chain polymer as host to form a complex with targeting molecule folic acid.Folic acid can be anchored directly to a polymer coat.TEM; DLS and FTIR confirmed the surface modification.The drug encapsulation efficiency; cytotoxicity and selectivity of functionalized nanoparticles with PEG and conjugated with FA were the best.Chemical modification has improved cytotoxicity of doxorubicin and selectivity against Hela cells.

Foreign body reaction toward hydrophilic polymer at the site of endovascular procedure: A report of two cases

Hydrophilic polymer-coated devices have been increasingly utilized for various endovascular procedures, however not been without adverse effects. We report two cases of subacute cutaneous lesions on the neck encountered in our dermatology clinic. Histopathologic findings were significant for a nodular aggregate of epithelioid histiocytes and lymphocytes with numerous foreign body giant cells in the dermis. The granulomatous infiltrate was associated with an amorphous basophilic non-polarizable material. Further chart review reveals both patients receiving a central venous procedure in the past, thus attributing the hydrophilic polymers as the likely source of the foreign material found at the insertion site. Our cases contrast to the more commonly reported distal embolization by these hydrophilic polymer layers. We suspect the incidence of retained hydrophilic polymer at the site of prior endovascular procedures may be underreported in the literature with the more inconspicuous presentations. Therefore, retained foreign material should be considered by both treating physicians and dermatopathologists in presenting cases of lesions that occur at common sites of endovascular procedures.

Hydrophilic Polymer in Thrombus Specimens Obtained During Thrombus Aspiration in the Setting of Percutaneous Interventions in Japan

Although hydrophilic polymer (HP) is used on vascular catheters to prevent medical device-related complications, HP emboli are well established as a potentially fatal iatrogenic phenomenon. HP embolus is thromboembolism by HP, which is mechanically disrupted from catheter during procedure. We reviewed 119 thrombus specimens obtained by percutaneous interventions from the coronary artery, vessels of inferior and superior limbs, cerebral artery, carotid artery, and renal vein. The frequency of HP was 28.6% (34/119 cases); 26.4% (24/91 cases), coronary artery; 50% (6/12 cases), artery of the lower limb; 28.6% (2/7 cases), vein of the lower limb; 0% (0/2), artery of the upper limb; 33.3% (1/3 cases), cerebral artery; 50% (1/2 cases), pulmonary artery; 0% (0/1 case), carotid artery; and 0% (0/1 case), renal vein. The range of numbers and diameter of HP was 1 to 127 per case and 10 to 934 µm, respectively. This is the first study concerning HP in thrombus specimens in Japan. We think that this study is significant because HP in thrombus specimens obtained from coronary artery in Japan seems to be of lower frequency than that of Europe. Although we suspect that the difference was caused by types of catheter, protocol, and procedure time of percutaneous interventions, we could not investigate correlation of HP in thrombus specimens with these factors. For future investigation, we should accumulate thrombus specimens obtained by routine procedure and device to clarify specific device-associated risk of disruption of HP.

Application of Super Absorbent Polymer and Plant Mucilage Improved Essential Oil Quantity and Quality of Ocimum basilicum var. Keshkeni Luvelou

One of the major factors limiting the production of medicinal plants in arid and semi-arid areas is water deficit or drought stress. One-third of the land in the world is arid and semi-arid and is inhabited by nearly 4 × 10⁸ people. Ocimum basilicum (sweet basil) is a valuable medicinal plant that is sensitive to water deficit, and water shortage negatively affects sweet basil yield and quality. Water availability in the root zone of basil could ameliorate the negative effects of water shortage. To the best of our knowledge, although the effects of hydrophilic polymers (HPs) have been studied in different agricultural crops, the effects of HP application in medicinal plants have not been previously investigated. This investigation was conducted to explore the effects on water use efficiency when using Stockosorb^® (STS) and psyllium seed mucilage (PSM) as hydrophilic polymers (HPs) and the effects of these HPs on essential oil quality, quantity, and yield. The research was set up in a factorial experiment on the basis of completely randomized block design with three replications. We used two HPs, STS (industrial) and PSM (herbal), with two methods of application (mixed with soil, mixed with soil + root) at four concentrations (0%, 0.1%, 0.2%, and 0.3% (w/w)). Results showed that the STS and PSM significantly increased the dry herb yield (both shoot and root) in comparison to the control, and the improving effect was higher when these HPs were mixed with soil + root. The highest dry herb yield (6.74 and 3.68 g/plant for shoot and root, respectively) was detected in the PSM at 0.1% mixed with soil + root. There was not any significant difference in dry herb yield among PSM (0.1%), PSM (0.2%), and STS (0.2%) when mixed with soil + root. Soil application of PSM and soil + root application of STS at a concentration of 0.3% increased the Essential Oil (EO) content almost three-fold in comparison to the control (0.5% and 0.52% to 0.18% v/w, respectively). The maximum essential oil yield was recorded in plants treated with STS (0.2% in) or PSM (0.1%) by soil + root application (0.21 and 0.19 mL/plant, respectively). PSM at concentrations of 0.1% and 0.2% (mixed with soil + root) showed the highest water use efficiency (1.91 and 1.82 g dry weight (DW)/L H₂O, respectively). STS mixed with soil also significantly improved water use efficiency (WUE) in comparison to the control. The application of these HPs improved the quality of sweet basil essential oil by increasing the linalool and decreasing the eugenol, epi-α-cadinol, and trans-α-bergamotene content.

High-Performance Green Light-Emitting Diodes Based on MAPbBr3 with π-Conjugated Ligand

The morphology, crystal size, and trap density of perovskite films significantly affect the luminescent properties of perovskite light-emitting diodes (PeLEDs). Recently, numerous studies have been conducted on ligands that surround the surface of perovskite crystals and passivate the trap sites to improve the performance of PeLEDs. In this study, a 4-aminobenzonitrile (ABN) ligand improved the performance of methylammonium lead bromide (MAPbBr₃)-based PeLEDs by reducing the MAPbBr₃ crystal size to the nanoscale and reducing the trap density. Moreover, the properties of PeLEDs with ABN were further improved using a surface-modified hole-transport layer (HTL) with a hydrophilic polymer. Finally, a bright green PeLED was fabricated, which exhibited the maximum luminance of 3350 cd/m² with an external quantum efficiency of 8.85%. Therefore, it is believed that the use of proper ligands for the perovskite layer and the optimization of the charge-transport layer have great potential for the development of high-performance PeLEDs.

Metallo-Supramolecular Hydrogels from the Copolymers of Acrylic Acid and 4-(2,2':6',2″-terpyridin-4'-yl)styrene

Hydrophilic copolymers containing 2,2′:6′,2″-terpyridine moieties and acrylic acid (AA) units poly (acrylic acid-co-4-(2,2′:6′,2″-terpyridin-4′-yl)styrene) (P(AA-co-TPY)) were synthesized and characterized. Coordinated with different transition metal ions, the dilute aqueous solution of the copolymers exhibited red-shifted UV-vis absorption peaks of π-π* transition from 317 to 340 nm. Further, interacting with iron ions, the copolymer showed new absorption peaks at a longer wavelength region (570 nm) and the absorption intensity enhanced with increase of the ion concentration. When enough ions were added to coordinate with the 2,2′:6′,2″-terpyridine moieties, novel metallo-supramolecular hydrogels were obtained due to the formation of metal coordination bonds between polymer back bones and transition metal ions (Ni²⁺, Zn²⁺, Cd²⁺, Fe²⁺ and Cu²⁺), which acted as self-assembly crosslinking structures. The mechanical strength and morphology of the resulting metallo-supramolecular hydrogels have been investigated.

Solubility and Permeability Improvement of Quercetin by an Interaction Between α-Glucosyl Stevia Nanoaggregates and Hydrophilic Polymer

The effect of composite formation between α-glucosyl stevia (Stevia-G) and hydrophilic polymers on solubility and permeability enhancement of quercetin hydrate (QUE) was evaluated. Polyvinylpyrrolidone K-30 (PVP), hydroxypropyl methylcellulose 2910-E (HPMC), and hydroxypropyl cellulose SSL (HPC) were selected as candidate hydrophilic polymers. Fluorescence studies with pyrene and curcumin suggested composite formation occurs between Stevia-G aggregate and polymers. Furthermore, the strength of interaction between Stevia-G aggregate and polymers was as follows: PVP > HPMC > HPC. Evaporated particles (EVPs) of QUE with Stevia-G and polymers showed synergic QUE solubility enhancement. Solubility of QUE from the EVPs was enhanced in the following order: Stevia-G/PVP > Stevia-G/HPMC > Stevia-G/HPC, in accordance with the degree of interaction. Enhanced membrane permeability of QUE from the EVPs of Stevia-G/PVP was confirmed using Caco-2 cells. The amount of QUE that permeated Caco-2 cells from the EVPs of Stevia-G/PVP was 13.7-, 4.7-, and 2.1-fold higher than that of the untreated QUE powder, EVPs of Stevia-G, and EVPs of PVP, respectively. These results indicated that the composite formed by Stevia-G and PVP can dramatically enhance the solubility and membrane permeability of QUE.

Effect of hydrophilic and hydrophobic polymers on permeation of S-amlodipine besylate through intercalated polymeric transdermal matrix: 3(2) designing, optimization and characterization

OBJECTIVE

Innovation in material science has made it possible to fabricate a pharmaceutical material of modifiable characteristics and utility, in delivering therapeutics at a sustained/controlled rate. The objective of this study is to design and optimize the controlled release transdermal films of S-Amlodipine besylate by intercalating hydrophilic and hydrophobic polymers.

METHODS

3(2) factorial design and response surface methodology was utilized to prepare formulations by intercalating the varied concentration of polymers(A) and penetration enhancer(B) in solvent. The effect of these independent factors on drug release and flux was investigated to substantiate the ex-vivo, stability and histological findings of the study.

RESULTS

FTIR, DSC revealed the compatibility of drug with polymers; however, the semicrystallinity in drug was observed under PXRD. SEM micrographs showed homogeneous dispersion and entanglement of drug throughout the matrix. Results from the permeation study suggested the significant effect of factors on the ex vivo permeation of drug. It was observed that drug release was found to be increased with an increase in hydrophilic polymer concentration and PE. The formulations having polymers (EC:PVPK-30) at 7:3 showed maximum drug release with highest flux (102.60 ± 1.12 µg/cm²/h) and permeability coefficient (32.78 ± 1.38 cm/h). Significant effect of PE on lipid and protein framework of the skin was also observed which is responsible for increased permeation. The optimized formulation was found to be stable and showed no-sign of localized reactions, indicating safety and compatibility with the skin.

CONCLUSION

Thus, results indicated that the prepared intercalated transdermal matrix can be a promising nonoral carrier to deliver effective amounts of drug.

Fatal Case of Hydrophilic Polymer Emboli

Hydrophilic polymers are used to coat catheters and other intravascular devices. In general, these polymers have many salutary properties; however, in some instances, fragmentation of hydrophilic polymers coating intravascular devices can occur with fatal consequences. This report details the histopathologic changes in the lung seen following polymer fragmentation and embolization from a central venous catheter. Polymer emboli detected microscopically are intravascular and consist of basophilic, lamellated, and nonrefractile elements. Typically, an inflammatory response is present to a variable degree. Embolization can result in severe tissue injury with ischemia and infarction.

Improved oral bioavailability of poorly water-soluble indirubin by a supersaturatable self-microemulsifying drug delivery system

BACKGROUND

Indirubin, isolated from the leaves of the Chinese herb Isatis tinctoria L, is a protein kinase inhibitor and promising antitumor agent. However, the poor water solubility of indirubin has limited its application. In this study, a supersaturatable self-microemulsifying drug delivery system (S-SMEDDS) was developed to improve the oral bioavailability of indirubin.

METHODS

A prototype S-SMEDDS was designed using solubility studies and phase diagram construction. Precipitation inhibitors were selected from hydrophilic polymers according to their crystallization-inhibiting capacity through in vitro precipitation tests. In vitro release of indirubin from S-SMEDDS was examined to investigate its likely release behavior in vivo. The in vivo bioavailability of indirubin from S-SMEDDS and from SMEDDS was compared in rats.

RESULTS

The prototype formulation of S-SMEDDS comprised Maisine™ 35-1:Cremophor(®) EL:Transcutol(®) P (15:40:45, w/w/w). Polyvinylpyrrolidone K17, a hydrophilic polymer, was used as a precipitation inhibitor based on its better crystallization-inhibiting capacity compared with polyethylene glycol 4000 and hydroxypropyl methylcellulose. In vitro release analysis showed more rapid drug release from S-SMEDDS than from SMEDDS. In vivo bioavailability analysis in rats indicated that improved oral absorption was achieved and that the relative bioavailability of S-SMEDDS was 129.5% compared with SMEDDS.

CONCLUSION

The novel S-SMEDDS developed in this study increased the dissolution rate and improved the oral bioavailability of indirubin in rats. The results suggest that S-SMEDDS is a superior means of oral delivery of indirubin.