2-acrylamido-2-methylpropane Sulfonic Acid Research Articles

β-cyclodextrin modification by cross-linking polymerization as highly porous nanomatrices for olanzapine solubility improvement; synthesis, characterization and bio-compatibility evaluation

Herein, we report highly porous and amorphous nanomatrices developed by cross-linking polymerization with subsequent condensation technique for solubility, dissolution and ultimately bioavailability enhancement of poorly soluble drug olanzapine (OLN). β-cyclodextrin was chemically cross-linked with monomer 2-acrylamido 2-methylpropane sulfonic acid (AMPS) by using methylene bis acrylamide (MBA) as cross-linking agent. Developed nanomatrices were characterized by zetasizer, FTIR, XRD, SEM, DSC, swelling, sol-gel, drug loading, stability, porosity (%), solubility, and in-vitro dissolution analysis. The developed porous nanomatrices are intended for oral administration of poorly soluble drugs therefore, to determine the biocompatibility of the system to the biological environment, in-vivo cytotoxicity study was also conducted using rabbit model which endorsed the safety of the nanomatrices with biological system. The particle size of nanomatrices were found 152.30 ± 07.46 d.nm. XRD analysis depicted the highly amorphous nature of nanomatrices while. To evaluate the pharmacokinetic profile of olanzapine, in-vivo studies were also conducted. The in-vivo and dissolution experiments revealed that drug release characteristics were significantly improved by nanomatrices as compared with the reference product (OLANZIA®). The solubility of olanzapine by the developed nanomatrices was enhanced noticeably up to 40.11 times which is higher than previously reported β-cyclodextrin formulations. The efficient method of preparation, improved solubility, rapid and high dissolution and non-toxic βCD-co-poly (AMPS) nanomatrices may be a promising approach for oral delivery of poorly soluble drugs.

Characterization and oil recovery enhancement by a polymeric nanogel combined with surfactant for sandstone reservoirs

The characterization and enhanced oil recovery mechanisms of a nanosized polymeric cross-linked gel are presented herein. A negatively charged nanogel was synthesized using a typical free radical suspension polymerization process by employing 2-acrylamido 2-methyl propane sulfonic acid monomer. The synthesized nanogel showed a narrow size distribution with one peak pointing to a predominant homogeneous droplet size. The charged nanogels were also able to adsorb at the oil–water interfaces to reduce interfacial tension and stabilize oil-in-water emulsions, which ultimately improved the recovered oil from hydrocarbon reservoirs. In addition, a fixed concentration of negatively charged surfactant (sodium dodecyl sulfate or SDS) was combined with different concentrations of the nanogel. The effect of the nanogels combined with surfactant on sandstone core plugs was examined by running a series of core flooding experiments using multiple flow patterns. The results show that combining nanogel and SDS was able to reduce the interfacial tension to a value of 6 Nm/m. The core flooding experiments suggest the ability of the nanogel, both alone and combined with SDS, to improve the oil recovery by a factor of 15% after initial seawater flooding.

Preparation of antibacterial polyester–cotton absorbents; the effects of star-shaped functional oligomers

Antibacterial absorbent fabrics were prepared through by the immersion of polyester polyester–cotton fabrics in a soaking media, containing novel functional acrylic monomers and various antibacterial agents. 2-acrylamido 2-methyl propane sulfonic acid (AMPS) and a novel functional star-shaped oligomer (FSO) were used as monomers for inducing the absorbency and compatibility to the fabric. FSO in two steps and employing condensation reaction between glycerol and lactic acid via multi-step microwave irradiation was synthesized. Bio-based materials, such as gallic acid and tannic acid, were used as antibacterial agents to induce antibacterial activity to the cotton fabric. ATR-FTIR, H NMR, SEM, contact angle, as well as antibacterial activity, absorbency in distilled water and saline solution have been employed for further evaluation. The swelling capacity of the modified absorbent fabric H1 (AMPS/FSO: 50:/50 wt%) was up to 21.1 g/g−1 in distilled water, and 6.1 g/g−1 in saline solution. Antibacterial properties tests of these absorbent fabrics showed a good antibacterial behavior, against Staphylococcus aureus.

Investigation of Optical and Electrical Properties of 2-acrylamido-2-methyl Propane Sulfonic Acid/2-Hydroxy Ethyl Methacrylate (AMPS/HEMA) Hydrogel Prepared by Gamma Irradiation

Hydrogels from either 2-acrylamido-2-methylpropane sulfonic acid (AMPS) or 2-hydroxyl ethyl methacrylate (HEMA) have been prepared by gamma radiation at irradiation dose of 10 kGy. Different volume ratio (v/v) of the starting materials were used to obtain crosslinked hydrogels of variable compositions and crosslink density. UV-VIS absorption spectra indicated that there is a variation in intensity as well as in optical energy gap with different doping levels. Therefore, values of direct and indirect energy gaps were calculated and discussed. The reflectance and transmittance were collected for the as-prepared hydrogels and analyzed in the incident photon energy range from 0.1 to 1.6 eV at a temperature range 300 to 500 K. The optical investigation revealed that the optical transition is directly allowed.

A new less toxic polymer gel dosimeter: Radiological characteristics and dosimetry properties

PurposeA new polymer gel dosimeter recipe was investigated that may be more suitable for widespread applications than polyacrylamide gel dosimeters, since the extremely toxic acrylamide has been replaced with the less harmful monomer 2-Acrylamido 2-Methyl Propane Sulfonic acid (AMPS). MethodsThe new formulation was named PAMPSGAT. The MRI response (R2) of the dosimeters was analyzed for conditions of varying dose, dose rate, and temperature during scanning. Radiological properties of the PAMPSGAT polymer gel dosimeter were investigated. ResultsThe dose-response (R2) of AMPS/Bis appears to be linear over a dose range 10–40 Gy. The percentage of difference between the R2 values for imaging at 15 °C and MRI room temperature is about 4.6% for vial with 40 Gy absorbed dose which decreased to less than 1% for imaging at 20 °C. The percentage difference of Zeff of PAMPSGAT gel and soft tissue was less than 1% in the practical energy range (100 KeV–100 MeV). The electron density of the PAMPSGAT polymer gel was 2.9% higher than that of muscle. Results showed that the sensitivity of PAMPSGAT polymer gel dosimeter irradiated by 60Co (energy = 1.25 MeV) is about 27.7% higher than that of irradiated using a 6 MeV Linac system. ConclusionsTemperature during MRI scanning has a small effect on the R2 response of the PAMPSGAT polymer gel dosimeter. Results confirmed tissue equivalency of the PAMPSGAT polymer gel dosimeter in most practical energy range. The PAMPSGAT polymer gel dosimeter response depends on energy and dose rate.

Coloring–decoloring behavior of fluoroalkyl end‐capped 2‐acrylamido‐2‐methylpropanesulfonic acid oligomer/acetone composite in methanol

ABSTRACTA reddish‐brown fluoroalkyl end‐capped 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS) oligomer/acetone composite was prepared by heating the white oligomer powder with acetone at 80 °C for 3 h. The color was not observed in the corresponding non‐fluorinated AMPS oligomer/acetone composite, which was prepared under similar conditions. The coloring was probably caused by the formation of acetone polyaldol condensation products in the fluorinated oligomeric gel network cores. The colored RF‐(AMPS)n‐RF/acetone composite powders were stable and did not exhibit any color change after 2 years in natural light at room temperature. The colored composite powders dissolved in methanol to give a reddish‐brown solution at room temperature. However, the retro‐polyaldol condensation decolored the solution after 1 day at room temperature. This is the first example of the retro‐aldol polycondensation of acetone under mild conditions. The decoloration increased by between 38‐ and 70‐fold under UV irradiation, compared with that in dark conditions. The coloring–decoloring behavior was consistent and repeatable; therefore our fluorinated oligomer/acetone composites are promising candidates for new fluorinated coloring materials. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2555–2564

Nanodiamond based sponges with entrapped enzyme: A novel electrochemical probe for hydrogen peroxide

A “modular approach” has been demonstrated for the preparation of nanodiamond (ND) based sponges (NS) with entrapped enzyme (horseradish peroxidase, HRP) (ND-NS(HRP)) and utilization as an electrochemical probe for detection of hydrogen peroxide (H2O2). ND-NS comprises ND, porous poly(aniline)–poly(2-acrylamido 2-methyl propane sulfonic acid) (PANI–PAMPSA) network and entrapped HRP. Field emission scanning electron microscope image of ND-NS(HRP) reveals sponge like suprastructure comprising interconnected nanospheres with numerous openings/pinholes/cavities. The entrapped HRP in ND-NS exhibits effective direct electron transfer with an electron transfer rate constant of 1.85s−1. ND-NS(HRP) exhibited excellent bioelectrocatalytic reduction of hydrogen peroxide (H2O2) with a wide linear concentration range (1–45mM), quick response (5s), high sensitivity (129.6μAM−1) and low detection limit 59μM (S/N=3).

The Influence on Proton Conductivity and Methanol Permeability of SiO<sub>2</sub>/PVA-PAMPS Composite Membrane

Polyvinyl alcohol(PVA) modified by SiO2/poly 2-acrylamido 2-methylpropane sulfonic acid (PAMPS) electrolyte membrane (SiO2/PVA-PAMPS ) was prepared by a Sol-gel synthesis in situ technique for DMFC. The influence of the different ratio of AMPS and SiCl4 on the proton conductivity and methanol permeability of these membranes was studied using an impedance analyzer and a gas chromatograph. The results showed that with increasing of the content of silicon dioxide, the SiO2 was homogeneously distributed in the membrane. As the AMPS content increased, the proton conductivity of the SiO2/PVA-PAMPS membranes also increased. The swelling degree of the SiO2/PVA-PAMPS membrane with 30wt% SiCl4 and 20wt% AMPS was 28.79% at 25°C. The membranes possess a methanol permeability of around 10-7 cm2•S-1, which is about one order of magnitude lower than that of Nafion115. These membranes have high selectivity and are promising for use in direct methanol fuel cells (DMFC).

PERFORMANCE OF POLYMERIC AND NON-POLYMERIC ADDITIVES AS DISPERSANTS FOR CALCIUM HYDROXYAPATITE IN AQUEOUS SYSTEMS

The influence of polymeric and non-polymeric additives as dispersants for calcium hydropxyapatite, HAP, was investigated in an aqueous system. The polymeric additives tested include: homo-polymers of acrylic acid (AA), maleic acid, methacrylic acid, 2-acrylamido 2-methylpropane sulfonic acid, (SA); co-polymer of AA:SA and ter-polymers of AA:SA:t-bAM (tertiary butyl acrylamide) and AA:SA:SS (sulfonated styrene). It was found that polymer architecture i.e., monomer type, monomer content, molecular weight, and polymerization solvent, strongly influences the performance of polymer as HAP dispersant. The non-polymeric additives investigated include: phosphonates and surfactants. The dispersancy data reveal that non-polymeric additives are inferior to polymeric additives in dispersing HAP.

Immobilization of yeast cells with ionic hydrogel carriers by adhesion-multiplication.

The mixture of an ionic monomer, 2-acrylamido 2-methylpropanesulfonic acid (TBAS), and a series of poly(ethylene glycol) dimethacrylate (nG) monomers were copolymerized with 60Co gamma-rays, and the produced ionic hydrogel polymers were used for immobilization of yeast cells. The cells were adhered onto the surface of the hydrogel polymers and intruded into the interior of the polymers with growing. The immobilized yeast cells with these hydrogel polymers had higher ethanol productivity than that of free cells. The yield of ethanol with poly(TBAS-14G) carrier was the highest and increased by 3.5 times compared to the free cells. It was found that the ethanol yield increased with the increase of glycol number in poly(ethylene glycol) dimethacrylate. The state of the immobilized cells was observed with microscope, and it was also found that the difference in the ethanol productivity is mainly due to the difference in the internal structure and properties of polymer carrier, such as surface charge, hydrophilicity, and swelling ability of polymer carrier.

Designing new thermoreversible gels by molecular tailoring of hydrophilic-hydrophobic interactions

We have shown that the lattice fluid hydrogen bond (LFHB) model can successfully quantify the first-order volume transition in hydrogels. The model predicts that a critical balance of hydrophilic and hydrophobic interactions is required for a gel to exhibit a discontinuous volume transition. In this work we will report the swelling behavior of a new thermoreversible copolymer hydrogel, which has been synthesized from two monomers, whose homopolymers do not show any volume transition in water in the observable range of temperatures. The discontinuous volume transition phenomenon in the copolymer gel was observed only at a critical balance of hydrophilic-hydrophobic interactions. The discontinuous nature of the volume transition is lost with a subtle change in the hydrophilic-hydrophobic balance. The copolymer gel was synthesized from 2-acrylamido 2-methyl propane sulfonic acid (AMPS), which is a hydrophilic monomer, and N-tertiary butylacrylamide (N-t-BAm), which is a hydrophobic monomer. The hydrophilic-hydrophobic balance in the gel was altered by either changing the composition of the co-monomers or by substituting the N-t-BAm with another hydrophobic monomer, N-isopropylacrylamide (NIPAm).

Elaboration and study of a PANI/PAMPS/WO 3 all solid-state electrochromic device

An all solid-state electrochromic device (ECD) was formed by anodically colored polyaniline (PANI) and cathodically colored tungstic acid, WO 3, 2H 2O, separated by a protonic conductor solid electrolyte: poly 2-acrylamido 2-methylpropane sulfonic acid, (PAMPS). PANI as well as tungstic acid films were electrochemically deposited on SnO 2. The transmission spectra of ECD were displayed using near IR/visible/near UV spectroscopy as well as optical multichannel analysis which allows, in addition, to obtain the kinetics of coloration/bleaching. They were checked after up to 2·10 4 electrochromic cycles extending from −1.2 to +1.2 V; the change of optical density, ΔOD, the coloration yield and the stability during the cycling were determined. The influence of the experimental parameters (electrolyte pH in the range 0.65–7.65, coloration potential) was studied; good coloration reversibility and memory effect can be obtained up to pH=7.65. A typical device presented a coloration time of ≈30 s and a shorter (<10 s) bleaching time, with ΔOD=0.4 at 2.23 eV (human eye maximum sensitivity), falling to 0.25 after 2·10 4 cycles. The choice of PAMPS as a solid electrolyte has many advantages: its pH can be set to the best value, rather high, and the structure of the PANI/PAMPS interface allows to explain the presence of conductivity even at high pH. The excellent reversibility of ECD is associated to the presence of an optical free-carriers tail.

Reversible Thermoassociation of Water-Soluble Polymers

In various industrial fields, water soluble polymers are commonly used as thickening agents to control the reology of aqueous fluids. Nevertheless, their properties are weakened as the temperature increases. In order to overcome this problem, the concept of thermoassociativewater soluble polymers was developed. Such new amphilic systems can be obtained by grafting on an hydrophilic backbone, side chains which become non water soluble above a Lower Critical Solution Temperature (LCST). Semidilute solutions of these copolymers present reversible thickening properties as the temperature increases and reaches a critical value, close to the side chains LCST. This behaviour can be related to the agregation of the grafts above their LCST, into hydrophobic microdomains , inducing the formation of a three dimensional network. At higher temperature, the viscosity of the solution sheared at a constant rate reaches a maximum value. This can be interpreted in terms of the reorganisation of the physical network under shear, from a structure with mainly intermolecular associationsto a system with an increasing number of intramolecular associations . Owing to the diversity of water soluble polymers exhibiting a phase separation on heating (LCST), different thermoassociativecopolymers were realized [1] and [2], using either polyelectrolyte or neutral hydrophilic backbone. In the aim of applications of such systems in the oilfield industry, copolymers containing 2-acrylamido 2-methyl propane sulfonic acid (AMPS) were developed, using polyethylene oxide (PEO) as LCST grafts. A general description of their rheological behaviour will be given here. Their properties can be controlled either by varying the solution characteristic (polymer concentration, salinity, etc. ) or by modifying the chemical structure of the copolymer (grafting ratio, molecular weight of the backbone, etc. ). This rheological study showed the potentiality of the thermoassociativesystem, particularly towards the oilfield industry [3]. It is now possible to have thin cement slurries at ambient temperature and still viscous slurries at bottom hole temperature, as desired. The reversibility of the phenomenon joint to the shear thinning properties of the polymer solution are adding a plus for cement slurries and drilling fluids designs. The thermoassociative phenomenon was also studied by Small Angle Neutrons Scattering (SANS) using copolymers composed by a deuterated polyacrylate backbone and protonated polyethylene oxide grafts. The scattering properties of our system were studied by varying the temperature, the salinity and the polymer concentration of the solution. A good agreement between the microscopic characteristics of the solutions and their rheological properties was found.