Poly Ethyl Cyanoacrylate Research Articles

N-doped MWCNTs from catalyst-free, direct pyrolysis of commercial glue

We report a unique, catalyst-free, direct pyrolysis process to obtain nitrogen-doped multiwall carbon nanotubes (N-MWCNTs). The process includes the polymerization of ethyl cyanoacrylate (ECA) based commercial super glue with aqueous NaCl solution. The resultant poly-ethyl cyanoacrylate (PECA)-NaCl composite was washed to remove NaCl and subsequently calcined at 1000 °C in an inert atmosphere to obtain carbon nanotubes. The field emission scanning electron microscopy and high-resolution transmission electron microscopy studies confirm that these are nitrogen-doped multiwall carbon nanotubes (N-MWCNTs) with diameters in the range of 80–110 nm. Compared to conventional MWCNTs, these nanotubes exhibit distinct multilayer stacking of carbon with short-range ordering with interlayer spacing slightly larger than graphitic carbon. XPS studies reveal the presence of doped nitrogen substituting for carbon atoms, whereas Raman spectroscopy data shows that these nitrogen-doped nanotubes exhibit nanocrystalline, graphitic carbon. Washing of PECA-NaCl composite results in the removal of NaCl leading to the unique porous PECA intermediate structure. These unique morphological changes and structural transformations of PECA in DI water along with the peculiar degradation behavior of PECA during the heat treatment process may be responsible for the formation of N-MWCNTs.

Properties of polyethylcyanoacrylate/modified Mt composites with highly exfoliated montmorillonite

The surface mineral modification of montmorillonite (Mt) layers was carried out by removing some of the exchangeable cations and anions (salts) using dimethylformamide as a chelating agent. The rest unremoved exchangeable cations were balanced by the permanent negative charges in the Mt layers. The modified Mt layers were characterized by X-ray fluorescence, high-resolution scanning electron microscopy (HR-SEM), dynamic light scattering (DLS), and high-resolution transmission electron microscopy. The completely exfoliated modified Mt layers were composed of polyethylcyanoacrylate (PECA) at different ratios 1, 3, 5, 7, 10, and 15% (wt/wt). The obtained composites were investigated by molar mass, FTIR, small-angle X-ray diffraction, wide-angle X-ray diffraction, HR-SEM, DLS, and TGA. The results showed that the exchangeable cations and anions (salts) were removed from the surfaces of Mt layers, and all the percentages of loaded Mt layers were completely exfoliated in the bulk of PECA. TEM morphology exhibited clearly separated modified Mt layers due to removing the salts. SEM morphology showed highly exfoliated modified Mt layers in PECA bulk. TGA and nanoindentation data were showed increases in both thermal stability and mechanical properties of prepared composites by increasing the ratios of modified Mt layers in the bulk of PECA.

Andrographolide Loaded in Micro- and Nano-Formulations: Improved Bioavailability, Target-Tissue Distribution, and Efficacy of the “King of Bitters”

Abstract Andrographolide (AG) is the characteristic constituent of Andrographis paniculata, of the Acanthaceae family. This plant is a well-known Asian medicinal plant that is widely used in India, China, and Thailand. A monograph of Herba Andrographidis (Chuanxinlian) is included in the Chinese Pharmacopoeia, which reports that this decoction can “remove heat, counteract toxicity, and reduce swellings.” The numerous potential activities of AG range from anti-inflammatory to anti-diabetic action, from neuroprotection to antitumor activity, and from hepatoprotective to anti-obesity properties. However, AG has low bioavailability and poor water solubility, which can limit its distribution and accumulation in the body after administration. In addition, AG is not stable in gastrointestinal alkaline and acidic environments, and has been reported to have a very short half-life. Among the diverse strategies that have been adopted to increase AG water solubility and permeability, the technological approach is the most useful way to develop appropriate delivery systems. This review reports on published studies related to microparticles (MPs) and nanoparticles (NPs) loaded with AG. MPs based on polylactic-glycolic acid (PLGA), alginic acid, and glucan derivatives have been developed for parenteral oral and pulmonary administration, respectively. NPs include vesicles (both liposomes and niosomes); polymeric NPs (based on polyvinyl alcohol, polymerized phenylboronic acid, PLGA, human serum albumin, poly ethylcyanoacrylate, and polymeric micelles); solid lipid NPs; microemulsions and nanoemulsions; gold NPs; nanocrystals; and nanosuspensions. Improved bioavailability, target-tissue distribution, and efficacy of AG loaded in the described drug delivery systems have been reported.

Highly Transparent Polyethylcyanoacrylates from Approved Eco-Friendly Fragrance Materials Demonstrating Excellent Fog-Harvesting and Anti-Wear Properties.

Superglue monomers belong to a family of cyanoacrylates that are known for their very rapid polymerization upon contact with moist surfaces. Their biodegradation and low toxicity make them attractive as medical and veterinary adhesives. Although the fast-acting polymerization characteristics have been successfully utilized to design nanoscale polymeric particles that can carry drugs or other inorganic nanoparticles, it constitutes a significant drawback if one desires to produce other forms of functional biodegradable acrylics, such as coatings, sheets, or nanocomposites. This is because rapid polymerization in air creates highly porous and brittle structures. Here, we address this drawback by reporting a simple and inexpensive method of fabricating highly transparent (>92%) polyethylcyanoacrylate (PECA) coatings by dispersing the monomer in a fragrance-classified green liquid, cyclopentanone. The resulting transparent coatings were hydrophilic but with slippery wetting characteristics, suitable as efficient fog-harvesting templates. Furthermore, another fragrance liquid, benzyl alcohol, is introduced as a plasticizer and co-solvent to overcome its brittleness while retaining its transparency. The same plasticized monomer solutions, dispersing low concentrations of graphene (<0.5 wt %), were allowed to self-assemble on stainless steel surfaces, forming low-friction and anti-wear dry lubricants by decreasing the steel friction coefficient and wear rate by 6- and 10-fold, respectively.

Vacuum pyrolysis of polymeric wastes containing hazardous cyano groups

Vacuum pyrolysis of polymeric wastes containing hazardous cyano groups was studied using low temperature pyrolysis mass spectrometry. Specifically, the study analyzed the presence of toxic compounds among the pyrolysis products. The polymers were pyrolyzed directly in the solid probe of a quadruple mass spectrometer within an ion source at a pressure of 10−6 Torr and then sorted by quadrupole mass analyzer. Polyethyl cyanoacrylate degrades by depolymerization, mostly into the ethyl cyanoacrylate monomer units. The degradation of polyurethane produces nonpolymeric urethane, isocyanates, amines and ethers. Polyacrylonitrile degrades via a depolymerization pathway into oligonitriles, acrylonitrile, ammonia and hydrogen cyanide.

Synthesis and characterization of polyethyl cyanoacrylate nanoparticles loaded with capreomycin sulfate

Some aspects of the synthesis and characterization of polyethyl cyanoacrylate nanoparticles loaded with the antituberculosis drug capreomycin sulfate are considered in this work. Polyethyl cyanoacrylate nanoparticles containing capreomycin sulfate have been synthesized using anionic polymerization in emulsion. Optimum conditions of immobilization of the drug into the polymeric matrix have been found. It was determined that to increase the loading efficiency of the drug, it has to be added into the reaction medium after polymerization has started.

Pharmacokinetics of ketorolac loaded to polyethylcyanoacrylate nanoparticles using UPLC MS/MS for its determination in rats

Polyethylcyanoacrylate (PECA) nanoparticles (NPs) have been employed as biodegradable polymeric carriers for oral (PO) delivery of ketorolac. The nanoparticles were prepared by polymerization technique at room temperature in a continuous aqueous phase at pH 2.5. This polymerization technique was able to hold 76–96% of ketorolac and the drug loading was a monomer concentration dependent. The feasibility of PECA NPs as PO controlled drug delivery systems of ketorolac was investigated in two groups of rats which were given orally either ketorolac tromethamine solution (1.5 mg/kg) or the selected ketorolac NPs aqueous dispersion (1.6 mg/kg). Ketorolac plasma concentrations were measured by a new fully validated specific, precise and accurate ultra-performance liquid chromatography tandem mass spectrometry (UPLC MS/MS) assay. The detection was performed on Waters TQ detector via negative electrospray ionization in a multiple reaction monitoring mode. Linear response ( r 2 ≥ 0.995) was observed over the range of 10–10,000 ng/ml of ketorolac, with the lower limit of quantification of 5 ng/ml with 1 μl injection volume. The intra- and inter-day precision (relative standard deviation, R.S.D.) values were <10% and the accuracy (relative error) was ≤8 for ketorolac concentrations. The drug solution is rapidly absorbed, distributed, and eliminated and shows a monophasic elimination phase. The assay was sensitive to follow pharmacokinetics of ketorolac in rats up to 24 h after a PO dose of its aqueous solution or NPs suspension. After NPs administration the mean Cmax, 5.0 ± 1.3 mg/l, was attained at 1 h. The drug was successfully maintained around this elevated plasma drug concentration up to 6 h (>2 t 1/2), in rats. The AUC was significantly higher after the NPs suspension than the solution of ketorolac. This present study provides evidence that the sorption of ketorolac to PECA NPs could control the drug release/elimination in rats.

Amoxicillin-loaded polyethylcyanoacrylate nanoparticles: Influence of PEG coating on the particle size, drug release rate and phagocytic uptake

Polyethyleneglycol (PEG)-coated polyethylcyanoacrylate (PECA) nanoparticles loaded with amoxicillin were prepared and the influence of the PEG coating on the particle size, zeta potential, drug release rate and phagocytic uptake by murine macrophages was studied. Experimental results show that this colloidal drug delivery system could be useful for intravenous or oral administration. The profile of amoxicillin release from PECA nanoparticles system was studied under various conditions similar to those of some corporeal fluids. In all these experiments, amoxicillin release in the free form was studied by HPLC analysis. Experimental results showed that at pH 7.4 drug release rises when molecular weight of PEG added to polymerization medium increases; in human plasma on the contrary drug release is reduced as molecular weight of PEG rises. Phagocytosis was evaluated by incubating amoxicillin-loaded PECA nanoparticles with murine macrophages and determining the amount of phagocytized nanoparticles by dosing the amoxicillin present inside the macrophages. The results of this study showed significative differences between nanoparticles prepared in the presence or in the absence of PEG and demonstrated that the PEG coating reduces the macrophages uptake. These results suggest that nanoparticles prepared in the presence of PEG are stealth carriers, which could be an injectable colloidal system able to avoid MPS recognition after intravenous injection. Experimental data of drug release at pH 1.1 and in the presence of urease, taking into account the mucoadhesive properties of polyalkylcyanoacrylate nanoparticles and the activity of the amoxicillin versus Helicobacter pylori, suggest moreover that the colloidal drug delivery system obtained in our laboratory could be useful for the treatment of diseases caused by H. pylori by peroral administration.

Preparation, characterization and in vitro antimicrobial activity of ampicillin-loaded polyethylcyanoacrylate nanoparticles

In this paper, the experimental conditions for preparing ampicillin-loaded polyethylcyanoacrylate (PECA) nanoparticles are described. The effects of drug concentration and surfactant type in the polymerization medium on the particle size distribution and loading capacity were studied. The results of these studies show that only the type of surfactant has an impact on the nanoparticle dimensions. The release rate of ampicillin from PECA nanoparticles at pH 7.4 (extracellular value pH) performed either with and without esterases, show that the drug release is considerably increased in the presence of these exzymes. The results of drug release study at pH 1.1 (simulated gastric juice) are very interesting. This study has evidenced that the 70% of ampicillin is released quickly, while the remaining fraction is firmly incorporated in nanoparticles. The released ampicillin is quickly degraded in acid medium while the entrapped fraction is protected from acid degradation and afterwards, when nanoparticles reach the small intestine, can be readily released in the presence of esterases. This result could be exploited for the oral administration of the ampicillin-PECA system. Finally, studies of antimicrobial activity of prepared systems evidenced that ampicillin-loaded PECA nanoparticles exhibit an activity equal or higher than the free drug.

Ocular disposition of nanoencapsulated acyclovir and ganciclovir via intravitreal injection in rabbit's eye

AbstractGanciclovir nanoparticles were prepared using biodegradable polymers to evaluate a possible treatment for cytomegalovirus (CMV) retinitis. Bovine serum albumin (BSA), polyethylcyanoacrylate (PEC), and chitosan were utilized as drug carriers. The three products were evaluated for drug-loading capacity, particle size, and drug release. Spherical nanoparticles ranging between 0.3 and 1.2 μm in diameter were obtained, with those of PEC being the smallest. Loading capacity was in the range of 62.5–66.9%. Drug release studies revealed decreasing release rates in the following order: BSA > PEC ≥ chitosan. PEC nanoparticles containing ganciclovir (measured spectrophotometrically) and radioactive acyclovir (measured by liquid scintillation) showed essentially the same release patterns. The PEC nanoparticles containing [3H]acyclovir and ganciclovir together were selected for in vivo drug level studies. Following an intravitreal injection in rabbit eyes, drug levels in different eye tissues were used to comp...

Preparation and characterization of polyethyl-2-cyanoacrylate nanocapsules containing antiepileptic drugs

Biocompatible and biodegradable colloidal drug delivery systems can be obtained by means of in situ polymerization of alkylcyanoacrylate. In particular, nanocapsules of polyethylcyanoacrylate (PECA) were prepared by adding the monomer to an organic phase, consisting of Miglyol 812 ® and an organic solvent (ethanol, acetone or acetonitrile), and subsequently mixing the organic phase with an aqueous phase containing Pluronic F68 ® at different concentrations. The possible mechanism of formation and the influence of preparation conditions on the quality of nanocapsule formulations were investigated by freeze-fracture electron microscopy and laser light scattering using both the inverse Laplace transform and the standard cumulant analysis for data fitting. High-quality nanocapsule systems were obtained using an aprotic fully water-miscible organic solvent such as acetone. The presence of ethanol led to the formation of both nanospheres and nanocapsules. The concentrations of nonionic surfactant in the aqueous phase of monomer in the organic phase did not influence the kind of colloidal suspension obtained. The oil simply plays the role of monomer support. The diameter of PECA nanoparticles (nanospheres and nanocapsules) ranged from 100 to 400 nm. Three antiepileptic drugs (Ethosuximide, 5,5-diphenyl hydantoin and carbamazepine) were entrapped in PECA nanocapsules. The loading capacity of PECA nanocapsules, prepared using acetone as organic solvent, varied from 1% to 11% (drug/dried material) as a function of the solubility (affinity) of the different drugs with the oil core. This parameter also influenced the release from PECA nanocapsules, which was slower for drugs with a higher affinity for Miglyol 812. By encapsulating the three antiepileptic drugs in the PECA nanocapsules, it was possible to achieve controlled drug release. The mechanism of drug release from PECA nanocapsules was mainly diffusion from the oil core through the intact polymer barrier.

Entrapment of β-lactams antibiotics in polyethylcyanoacrylate nanoparticles: Studies on the possible in vivo application of this colloidal delivery system

Polyethylcyanoacrylate (PECA) nanoparticles were prepared in the presence of three different non-ionic surfactants: Triton X-100, Tween 80 and Pluronic F68. The influence of the surfactant, employed during the nanoparticle preparation process, on drug loading, size and storage stability was evaluated. The amount of Cefaclor (CFR) and Cefsulodin (CFN) entrapped in the colloidal system was not influenced by the presence of the three different surfactants, achieving a mean loading value of about 1.6% (w/w). PECA nanoparticles prepared in the presence of Tween 80 and Pluronic F68 and entrapping the two drugs showed showed no dependence of the mean particle size on the various components present in the polymerization medium. Only the system obtained in the presence of Triton X-100 showed an increase in particle size compared to the nanoparticles prepared in the absence of the active compound. Storage at room temperature, as dried powder, caused a drastic increase in size and polydispersity index values of the PECA nanoparticles containing CFN or CFR. The PECA nanoparticle colloidal suspensions prepared in the presence of Pluronic F68 provided much greater values of the retention capability for CFN and CFR, followed by the systems prepared in the presence of Tween 80 and Triton X-100, respectively. For each nanoparticle formulation, the retention of CFR was higher than that of CFN. The permeability through a biological membrane model was greater for CFN loaded nanoparticles than for the free drug. In contrast, no noticeable difference was observed between free CFR and that loaded in PECA nanoparticles, prepared with Pluronic F68 or Triton X-100. Only the system prepared in the presence of Tween 80 showed a high diffusion rate of CFR compared to the free drug.

An interpretative analysis of the effect of the surfactants used for the preparation of polyalkylcyanoacrylate nanoparticles on the release process.

The release of fluorescein from polyethylcyanoacrylate (PECA) or polyisobutylcyanoacrylate (PICA) nanoparticles was affected by the surfactants used for the preparation. The different surfactants also modified the molecular weight, size and loading of the nanoparticles. However, these factors were not be responsible for the different release. According to the release profiles and the Baker-Lonsdale model, a portion of fluorescein was concentrated near the nanoparticle surface. Thus, a non-homogeneous distribution of the fluorescent probe inside the nanoparticles was hypothesized. This distribution could reflect the fluorescein position inside the micella during the polymerization stage, or could be reached during the washing stage as the consequence of a different effect of the surfactants on the porosity of the nanoparticle structure.