Glycol Groups Research Articles

Toxicity-Attenuated Glycol Chitosan Adhesive Inspired by Mussel Adhesion Mechanisms.

Chitosan-catechol, inspired from mussel-adhesive-proteins, is characterized by the formation of an adhesive membrane complex through instant bonding with serum proteins not found in chitosan. Using this intrinsic property, chitosan-catechol is widely applied for hemostatic needles, general hemostatic materials, nanoparticle composites, and 3D printing. Despite its versatility, the practical use of chitosan-catechol in the clinic is limited due to its undesired immune responses. Herein, a catechol-conjugated glycol chitosan is proposed as an alternative hemostatic hydrogel with negligible immune responses enabling the replacement of chitosan-catechol. Comparative cellular toxicity and in vivo skin irritation between chitosan-catechol and glycol chitosan-catechol are evaluated. Their immune responses are also assessed using histological analysis after subcutaneous implantation into mice. The results show that glycol chitosan-catechol significantly attenuates the immune response compared with chitosan-catechol; this finding is likely due to the antibiofouling effect of ethylene glycol groups and the reduced adhesion of immune cells. Finally, the tissue adhesion and hemostatic ability of glycol chitosan-catechol hydrogels reveal that these ethylene glycol groups do not dramatically modify the adhesiveness and hemostatic ability compared with nonglycol chitosan-catechol. This study suggests that glycol chitosan-catechol can be a promising alternative to chitosan-catechol in various biomedical fields such as hemostatic agents.

Highly-branched amphiphilic organometallic dendronized diblock copolymer: ROMP synthesis, self-assembly and long-term Au and Ag nanoparticle stabilizer for high-efficiency catalysis

Dendronized polymers (DPs) are an increasing field at the interfaces between organic chemistry, polymer synthesis, and materials science, and in particular DPs are expected to provide designed applications as nanoparticle (NP) sensors and catalysts. Herein, we report a new highly-branched amphiphilic dendronized diblock copolymer containing bulky hydrophilic triethylene glycol (TEG) and hydrophobic ferrocenyl (Fc) groups via the living and controlled ring-opening metathesis polymerization. The amphiphilicity drives the self-assembly of the resulting DP into spherical nanoscale micelles in water using THF or DMSO as cosolvents. AuNPs and AgNPs of various sizes depending on the presence of NaBH4 are successfully prepared using the DP as stabilizers or reductants and used as excellent catalysts for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol by NaBH4. The obtained AuNPs about 2.1 nm show TONs up to 25 000 and TOFs of 26 400 h−1 and remain stable and efficient for this catalysis after two months.

Synergy between Synthetic Antimicrobial Polymer and Antibiotics: A Promising Platform To Combat Multidrug-Resistant Bacteria.

The failure of many antibiotics in the treatment of chronic infections caused by multidrug-resistant (MDR) bacteria necessitates the development of effective strategies to combat this global healthcare issue. Here, we report an antimicrobial platform based on the synergistic action between commercially available antibiotics and a potent synthetic antimicrobial polymer that consists of three key functionalities: low-fouling oligoethylene glycol, hydrophobic ethylhexyl, and cationic primary amine groups. Checkerboard assays with Pseudomonas aeruginosa (P.aeruginosa) and Escherichia coli demonstrated synergy between our synthetic antimicrobial polymer and two antibiotics, doxycycline and colistin. Coadministration of these compounds significantly improved the bacteriostatic efficacy especially against MDR P.aeruginosa strains PA32 and PA37, where the minimal inhibitory concentrations (MICs) of polymer and antibiotics were reduced by at least 4-fold. A synergistic killing activity was observed when the antimicrobial polymer was used in combination with doxycycline, killing >99.999% of planktonic and biofilm P.aeruginosa PAO1 upon a 20 min treatment at a polymer concentration of 128 μg mL-1 (4.6 μM) and doxycycline concentration of 64 μg mL-1 (133.1 μM). In addition, this synergistic combination reduced the rate of resistance development in P.aeruginosa compared to individual compounds and was also capable of reviving susceptibility to treatment in the resistant strains.

Novel axially-substituted silicon phthalocyanines with pH-modulated fluorescence ON/OFF switching properties

Two novel axially-substituted asymmetric silicon (IV) phthalocyanines, the first one substituted with both polyethylene glycol and indomethacin groups (Pc1) and second one substituted with both polyethylene glycol and mefenamic acid groups (Pc2) have been designed and synthesized for the purpose of pH sensing examinations. Their absorption and fluorescence emission-based spectral properties were investigated in chloroform, tetrahydrofuran and toluene. The pH-sensing properties of Pc1 and Pc2 were examined in detail by using UV-vis absorption and fluorescence spectroscopies in tetrahydrofuran. The effects of the substituents on the spectroscopic properties and pH-sensing behavior of these silicon phthalocyanines were revealed. Pc1 didn’t show a pH response; however, Pc2 exhibited a signal increase from pH 5.40 to 0.37 (turn on) and a drastic quenching when pH went from 0.37 to 5.40 (turn off). The protonation/deprotonation stage of the NH group of Pc2 presented fluorescence-based “on-off” type molecular switch properties.

Induction of periodic nanostructures in polythiophene films through block copolymer templating

ABSTRACTA new class of periodically nanostructured polythiophene materials with high regularity and numerous morphologies is prepared through the cooperative self‐assembly of polythiophene derivatives with a templating block copolymer (BCP) and poly(1,4‐isoprene)‐block‐poly(methacrylic acid) (PMA). The selection of the hydrophilic and aprotic triethylene glycol (TEG) group as side chains on polythiophene and the use of hydrophilic and protic PMA are crucial to producing well‐ordered nanostructures in polythiophene films, as it enables selective coassembly within the hydrophilic domain through hydrogen bonding. The composite films are shown to have formed hexagonally packed cylinders with 28 nm periodicities based on small‐angle X‐ray scattering and transmission electron microscopy. The formation of hydrogen bonding is revealed by a shift in the carbonyl peak of PMA in the Fourier transform infrared spectra of the composite film relative to the neat film. This suggests that the TEG‐functionalized polythiophene selectively incorporates into PMA. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1105–1112

Antimicrobial AgNPs composites of gelatin hydrogels crosslinked by ferrocene-containing tetrablock terpolymer

Redox-responsive ferrocene (Fc)-containing hydrogels have attracted increasing interest for their potential applications in materials science, biomedicine and catalysis. Herein, we report the synthesis of a novel polynorbornene-based tetrablock terpolymer containing consecutively aldehyde, Fc, and dentritic triethylene glycol and aldehyde groups in the side chain by the ring-opening metathesis polymerization with the aid of the 3rd generation Grubbs catalyst. Owing to the presence of Fc and triazole groups, this copolymer could be used as both reducing and stabilizing agents for the formation of silver nanoparticles (AgNPs). Also, this copolymer could be used as a crosslinking agent to fabricate gelatin hydrogels based on the Schiff's base reaction between the aldehyde groups and the side-chain amino groups of gelatin. Based on the above properties, the AgNPs composites of gelatin hydrogels were further successfully fabricated by blending this copolymer, gelatin and AgNO3 together or soaking this Fc-containing gelatin hydrogels into the AgNO3 solution, in which the AgI was in situ reduced into Ag0 by the Fc groups. Results of inhibition zone experiments confirmed the antibacterial activities of the obtained composites against both Escherichia coli and Staphylococcal aureus.

Engineering molecular interaction in polymeric hybrids: Effect of thermal linker and polymer chain structure on thermal conduction

In past decades, more research efforts have been devoted to the processing of thermally conductive polymer composite and less on fundamental aspects of heat conduction in polymeric materials. Here we presented a polymeric hybrid system comprising of polymer chain and short thermal linkers that show promising thermal conductivity and optical transparency. This was achieved by engineering their intermolecular interactions without incorporating traditional fillers (carbon, ceramic and metal). Polyvinyl alcohol (PVA) with different degrees of hydrolysis has been engineered to achieve enhanced thermal conduction by using small organic linkers (OL) having symmetric terminal groups such as ethylene diamine (ED) and ethylene glycol (EG) and hybrid terminal groups like ethanolamine (EA). Comparing with ED and EG, EA has been demonstrated more effective in enhancing thermal conductivity for both PVAs with different degrees of hydrolysis (88% and 99+%). Presence of bulkier acetate group in PVA (88% hydrolysis) restricted the efficient thermal connections by steric hindrance. Optimized pairing of terminal groups of OLs was thus found to provide an interesting handle to manipulate the thermal conductivity. Additionally, degree of hydrolysis of polymer matrix is another crucial factor to effectively engineer thermal conductivity. In summary, impact of functional group, molecular structure, side groups of backbone polymer and organic linkers were found to have substantial impact on overall thermal conductivity of PVA/OL and can be manipulated for efficient thermal management.

Bortezomib Dendrimer Prodrug‐Based Nanoparticle System

AbstractBortezomib (BTZ) is mainly used to treat hematologic tumors, such as multiple myeloma and small cell lymphoma. However, its usefulness for solid tumor therapy is limited owing to its poor stability and toxicity in vivo. In the present study, an amphiphilic PEGylated dendrimer with dopamine molecule is synthesized from azide group–functionalized polyethylene glycol and alkyne group–functionalized dendrimer, which is produced from 1,1‐dimethylolpropionic acid and dopamine. The amphiphilic PEGylated dendrimer with dopamine molecule reacts with BTZ to construct a BTZ prodrug‐based nanoparticle through a ultrasonic emulsification method. The BTZ prodrug‐based nanoparticles have greater serum stability than BTZ alone and release the prototype drug in acidic environments. The BTZ prodrug‐based nanoparticle is more effective against subcutaneous tumors than BTZ itself. Furthermore, c(RGDyK) modification significantly improves the antitumor efficacy of the BTZ prodrug‐based nanoparticle with regard to subcutaneous and intracranial tumors. Moreover, the BTZ prodrug‐based nanoparticle significantly reduces the toxicity of BTZ in vivo. Therefore, the PEGylated BTZ dendrimer prodrug‐based nanoparticles have great potential for the treatment of solid tumors in vivo.

Metformin prevents nephrolithiasis formation by inhibiting the expression of OPN and MCP-1 invitro and invivo.

Treatment targeting osteopontin (OPN) and monocyte chemoattractant protein 1 (MCP-1) has been recognized as a novel approach in renal crystal formation. The present study was designed to investigate the suppressive effects of metformin on nephrolithiasis formation and its potential mechanism. The cytotoxicity of metformin on MDCK and HK-2 cells was determined using a Cell Counting Kit-8 assay in vitro. Subsequently, the mRNA transcription and protein expression levels of MCP-1 and OPN were detected by reverse transcription-quantitative-polymerase chain reaction analysis, western blot analysis and ELISA. Male Sprague-Dawley rats were divided into a control group, ethylene glycol (EG) group and EG + metformin group. The expression levels of MCP-1 and OPN and crystal formations were evaluated in renal tissues following an 8-week treatment period. In vitro, metformin significantly inhibited the production of MCP-1 and OPN induced by oxalate at the mRNA and protein expression levels. In vivo, increased expression levels of MCP-1 and OPN were detected in the EG group compared with the controls, and this upregulation was reversed in the EG + metformin group. Renal crystal deposition in the EG + metformin group was markedly decreased compared with that in the EG group. Therefore, the results of the study suggest that metformin suppressed urinary crystal deposit formation, possibly by mediating the expression of inflammatory mediators OPN and MCP-1.

Effect of exogenous spastin combined with polyethylene glycol on sciatic nerve injury.

Polyethylene glycol can connect the distal and proximal ends of an injured nerve at the cellular level through axonal fusion to avoid Wallerian degeneration of the injured distal nerve and promote peripheral nerve regeneration. However, this method can only prevent Wallerian degeneration in 10% of axons because the cytoskeleton is not repaired in a timely fashion. Reconstruction of the cytoskeletal trunk and microtubule network has been suggested to be the key for improving the efficiency of axonal fusion. As a microtubule-severing protein, spastin has been used to enhance cytoskeletal reconstruction. Therefore, we hypothesized that spastin combined with polyethylene glycol can more effectively promote peripheral nerve regeneration. A total of 120 male Sprague-Dawley rats were randomly divided into sham, suture, polyethylene glycol, and polyethylene glycol + spastin groups. In suture group rats, only traditional nerve anastomosis of the end-to-end suture was performed after transection of the sciatic nerve. In polyethylene glycol and polyethylene glycol + spastin groups, 50 μL of polyethylene glycol or 25 μL of polyethylene glycol + 25 μL of spastin, respectively, were injected immediately under the epineurium of the distal suture. Sensory fiber regeneration distance, which was used to assess early nerve regeneration at 1 week after surgery, was shortest in the suture group, followed by polyethylene glycol group and greatest in the polyethylene glycol + spastin group. Behavioral assessment of motor function recovery in rats showed that limb function was restored in polyethylene glycol and polyethylene glycol + spastin groups at 8 weeks after surgery. At 1, 2, 4 and 8 weeks after surgery, sciatic functional index values and percentages of gastrocnemius muscle wet weight were highest in the sham group, followed by polyethylene glycol + spastin and polyethylene glycol groups, and lowest in the suture group. Masson staining was utilized to assess the morphology of muscle tissue. Morphological changes in skeletal muscle were detectable in suture, polyethylene glycol, and polyethylene glycol + spastin groups at 1, 2, 4, and 8 weeks after surgery. Among them, muscular atrophy of the suture group was most serious, followed by polyethylene glycol and polyethylene glycol + spastin groups. Ultrastructure of distal sciatic nerve tissue, as detected by transmission electron microscopy, showed a pattern of initial destruction, subsequent disintegration, and gradual repair in suture, polyethylene glycol, and polyethylene glycol + spastin groups at 1, 2, 4, and 8 weeks after surgery. As time proceeded, axonal ultrastructure gradually recovered. Indeed, the polyethylene glycol + spastin group was similar to the sham group at 8 weeks after surgery. Our findings indicate that the combination of polyethylene glycol and spastin can promote peripheral nerve regeneration. Moreover, the effect of this combination was better than that of polyethylene glycol alone, and both were superior to the traditional neurorrhaphy. This study was approved by the Animal Ethics Committee of the Second Military Medical University, China (approval No. CZ20170216) on March 16, 2017.

Study of the Stability of Functionalized Gold Nanoparticles for the Colorimetric Detection of Dipeptidyl Peptidase IV

In this report, we investigated three stabilization strategies of gold nanoparticles and their practical application for the visual detection of dipeptidyl peptidase IV (DPP-IV). Citrate-capped gold nanoparticles (Au NPs) are generally unstable in high-ionic-strength samples. Au NPs are easily tagged with various proteins and biomolecules rich in amino acids, leading to important biomedical applications including targeted drug delivery, cellular imaging, and biosensing. The investigated assays were based on different modes of stabilization, such as the incorporation of polyethylene glycol (PEG) groups, stabilizer peptide, and bifunctionalization. Although all approaches provided highly stable Au NP platforms demonstrated by zeta potential measurements and resistance to aggregation in a high-ionic-strength saline solution, we found that the Au NPs modified with a separate stabilizer ligand provided the highest stability and was the only platform that demonstrated sensitivity to the addition of DPP-IV, whilst PEGylated and peptide-stabilized Au NPs showed no significant response.

A Targeted and pH-Responsive Bortezomib Nanomedicine in the Treatment of Metastatic Bone Tumors.

Bortezomib is a boronate proteasome inhibitor widely used as an efficient anticancer drug; however, the clinical use of bortezomib is hampered by its adverse effects such as hematotoxicity and peripheral neuropathy, and low efficacy on solid tumors due to unfavorable pharmacokinetics and poor penetration in the solid tumors. In this study, we developed a tripeptide Arg-Gly-Asp (RGD)-targeted dendrimer conjugated with catechol and poly(ethylene glycol) groups for the targeted delivery of bortezomib to metastatic bone tumors. Bortezomib was loaded on the dendrimer via a boronate-catechol linkage with pH-responsive property, which plays an essential role in the control of bortezomib loading and release. The nontargeted bortezomib nanomedicine showed minimal cytotoxicity at pH 7.4, but significantly increased anticancer activity when cyclic RGD (cRGD) moieties were anchored on the dendrimer surface. The ligand cRGD enabled efficient internalization of the bortezomib complex by breast cancer cells such as MDA-MB-231 cells. The targeted nanomedicine efficiently depressed the progression of metastatic bone tumors and significantly inhibited the tumor-associated osteolysis in a model of bone tumors. This study provided an insight into the development of nanomedicine for metastatic bone tumors.

Booster medication to achieve capsule excretion in colon capsule endoscopy: a randomized controlled trial of three regimens.

Background and study aims To achieve a complete colon capsule endoscopy, the entire colon must be visualized, clean and filled with clear fluids. The primary aim was to compare three booster regimens in colon capsule endoscopy in achieving capsule excretion within recording time. Secondary aims were quality of bowel cleansing and completion rate (both adequate cleansing and capsule excretion). Patients and methods Patients scheduled for follow-up colonoscopy due to previous neoplastic findings or familial history of colorectal cancer aged 18 to 70 years were eligible. Bowel preparation was 2-L split doses of polyethylene glycol. Patients were randomized to three booster regimens of either polyethylene glycol (Group A), sulfate-based solution (Group B) or polyethylene glycol with iodine oral contrast (Group C). Results One hundred eighty participants were included and randomized into three groups of 60. Capsule excretion was 70 % (95 % CI: 58 – 80) in Group A, 73 % (95 % CI: 61 – 83) in Group B and in 68 % (95 % CI: 56 – 79) in Group C, no statistically significant differences. Bowel cleansing grade was statistically significant better in Group B compared to Group A ( P = 0.03), but there were no statistically significant differences between Groups C and A ( P = 0.40). Complete examination rate was 65 % (95 % CI: 53 – 77), 72 % (95 % CI: 61 – 83) and 62 % (95 % CI: 50 – 74) in Group A, B and C respectively, not statistically significant different. Conclusions Sulfate-based solution resulted in statistically significant better bowel cleansing compared to polyethylene glycol. Overall the excretion and completion rate was suboptimal. Achieving a high completion rate using patient-tolerable and low-risk compounds is still a challenge.

Oligomers in polyethylene furanoate - identification and quantification approach via LC-UV LC-MS response ratio

ABSTRACTPolyethylene furanoate polymer is intended to be used as a food contact material. A PEF polymer sample was investigated for its oligomer composition by solvent extraction and using HRLC-MS. The 20 oligomers found were divided into four groups: group I contains cyclic oligomers consisting of furandicarboxylic acid and monoethylene glycol units, group II comprises cyclic oligomers consisting of furandicarboxylic acid, monoethylene glycol units and one diethylene glycol unit, group III are cyclic oligomers were two monoethylene glycol units are substituted by diethylene glycol units and group IV are linear oligomers consisting of furandicarboxylic acid and monoethylene glycol units. Oligomers of group I account for around 87% of the total oligomer content, group II oligomers 12% and group III oligomers 1%. The contribution of group IV oligomers is very small: less than 0.05%. MS-MS experiments showed similar fragmentation patterns for all oligomers. The results of this study demonstrate that oligomers are abundant in the PEF material and are potential migrants to foods that are in contact with the polymer. Oligomers of group I and group II have the same absorption maxima in UV detection which was used to develop a quantification approach for these oligomers using dimethyl 2,5-furandicarboxylate as external standard.

Functional Polyamides: A Sustainable Access via Lysine Cyclization and Organocatalytic Ring-Opening Polymerization

Functional polyamides are very important polymers that have a variety of valuable applications. However, the effective synthesis of these polymers is still a long-going challenge. Herein, the efficient cyclization of lysine derivative was presented as a universal approach to synthesize e-lactam monomers bearing pendant benzyl-protected hydroxyl, allyloxy, and oligo-ethylene glycol groups. Superbase t-BuP4-catalyzed polymerization could proceed under very mild conditions (e.g., 25 °C) compatible with a wide range of functional pendants, affording high molecular weight (up to 47.7 kg/mol) functional polyamides with high monomer conversion (up to 99%). Of importance, the allyloxy groups were stable toward the initiating and propagating species under mild polymerization conditions. Such an allyloxy-functionalized e-lactam and organocatalytic polymerization to well-defined allylated polyamide has not been reported in the literature and allows further incorporation of an unprecedented range of functional groups...

Critical Coalescence Concentration (CCC) for Surfactants in Aqueous Solutions

This paper presents results of tests performed to determine the minimum concentration of a surfactant used at which the probability of occurrence of coalescence of air bubbles during flotation is low. Tests of the coalescence phenomenon were carried out using selected flotation frothing agents such as poly(ethylene glycol) butyl ethers, which are the ingredients of industrial flotation frothers known under the brand name of CORFLOT. Studies were carried out for three successive butyl ethers in the homologous series: ethylene glycol butyl ether (C4E1), diethylene glycol butyl ether (C4E2), triethylene glycol butyl ether (C4E3). Critical coalescence concentration (CCC) surfactant values were determined using the linear regression method. The investigation proved the existence of a clear relationship between the number of ethylene glycol groups in the ether molecule CnH2n+2(OC2O5)nOH and the value of the CCC. The results obtained show a correlation between the CCC values and the molecular weights (MW) of the tested frothers. This article shows the relationship between CCC value and hydrophilic–lipophilic balance (HLB)/MW for the family of polyglycol ethers. Results show the correlation between the critical coalescence concentration and the value of HLB index, being the measure of hydrophilic–lipophilic balance of surfactants (such as flotation frothers), expressed by the weight ratio of hydrophilic portion of the surfactant molecule and its molecular weight. Histograms of air bubbles created a distribution curve similar to the Gauss distribution pattern. The average diameter of air bubbles tends to decrease along with increasing concentration of the tested surfactants. Two characteristic zones that may be distinguished on the graphs show the relationship between Sauter mean diameter and frother concentration. The tests carried out demonstrate that the critical coalescence concentration may be used to characterize the flotation process, as, knowing the CCC values of the frothers used, we are able to control the consumption of foaming agents during mineral processing.

Fabrication and biological imaging of hydrazine hydrate cross-linked AIE-active fluorescent polymeric nanoparticles

Amphiphilic copolymers play a paramount role in the fabrication of fluorescent polymeric nanoparticles (FPNs) through the self-assembly procedure. In this work, novel hydrazine hydrate cross-linked amphiphilic poly(PEG‑co‑FHMA) copolymers were constructed via reversible addition-fragmentation chain transfer (RAFT) polymerization, containing an aggregation-induced emission (AIE) active hydrophobic moiety and a hydrophilic poly(ethylene glycol) (PEG) group. Different characterization techniques have been employed to confirm their successful synthesis. Due to their amphiphilic property, the resulting poly(PEG‑co‑FHMA) copolymers can self-assemble into FPNs in aqueous solution and form poly(PEG‑co‑FHMA) FPNs with size ranging from 100 to 200 nm. The investigation of photophysical properties demonstrated poly(PEG‑co‑FHMA) FPNs possess strong fluorescence, large Stokes shift, excellent AIE characteristic, low critical micelle concentration and remarkable photostability. Biological assay results suggested that these cross-linked AIE-active FPNs are of low toxicity and excellent cell dyeing performances. All of these features make them promising candidates for biomedical applications. As compared with typical AIE-active FPNs based on the synthetic AIE-active compounds, the novel cross-linked AIE-active FPNs based on the Schiff base is rather simple, good designable and universal. More importantly, this strategy could also be adopted for preparation of a large number of AIE-active FPNs because of the well designability of copolymers and salicylaldehyde derivatives. Thus this work will provide a novel route for preparation of multifunctional AIE-active FPNs in a rather facile manner.

Therapeutic effects of aerial parts of Smyrnium cordifolium ethanolic extract on ethylene glycol-induced kidney calculi in rats

Introduction: In this study, the effects of the ethanolic extract of aerial parts (stem and leaves) of Smyrnium cordifolium (S. cordifolium) Boiss on the ethylene glycol(EG)-induced kidney calculi in rats was investigated. Materials and methods: Thirty-six male Wistar albino rats were randomly divided in 6 groups. Group I (normal control), Groups II (control of EG) to VI received EG 1% v/v in water for 28 days. Animals in Groups III and IV (preventive groups) received ethanolic extract of stem and leaves of S. cordifolium in 200 mg/kg and 400 mg/kg orally in water for 28 days, respectively. Groups V and VI (treatment groups) received extract in 200 mg/kg and 400 mg/kg orally in water from 15th to 28th day, respectively. Results: Results showed that the level of urine oxalate, blood urea and creatinine in EG group vs. normal control significantly increased (P<0.001). Extract did not show significant effect on urinary oxalate, urine volume and other blood biochemical parameters in the treatment groups (V and VI). Provision of extract resulted in significantly lower levels of urine oxalate and higher level of volume, serum creatinine and blood urea in III and IV groups as compared with Group II (P<0.05). Conclusion: These observations enable us to conclude that the ethanolic extract of aerial parts of S. cordifolium Boiss is effective against EG induced urinary calculi in rats.

In situ Crosslinkable Thiol-ene Hydrogels Based on PEGylated Chitosan and β-Cyclodextrin

Novel β-Cyclodextrin incorporated injectable hydrogels employing PEGylated chitosan as bio-based hydrophilic matrix have been fabricated via thiol-ene reaction. As thiol bearing polymer counterpart of hydrogel precursors, native chitosan was firstly modified with polyethylene glycol groups to increase its water solubility and bioinertness and then decorated with thiol groups to facilitate thiol-ene crosslinking with acryloyl-modified β-cyclodextrin. A series of hydrogels with varying amounts of acryloyl β-CD and PEGylated chitosan feed were synthesized with high efficiency under mild aqueous conditions. The resulting hydrogels were characterized by equilibrium swelling, structural morphology and rheology. These materials were investigated as controlled drug release platforms by employing a poorly water soluble anti-inflammatory drug diclofenac as model compound. Benefiting from the inclusion complex formation of the drug with β-CD groups in gel interior, prolonged release profiles were maintained. The total drug absorption and release of hydrogels were shown to be dependent on the amount of β-CD in gel matrix. These hydrogels combined efficient crosslinking and β-CD incorporation into clinically important chitosan scaffold and might have potential applications as injectable drug reservoirs such as in regenerative tissue engineering.

N-hexanoyl-O-glycol chitosan as a carrier agent for water-insoluble herbicide

The objective of this study was to assess the potential of an amphiphilic chitosan derivative, namely N-hexanoyl-O-glycol chitosan (HGC) as a carrier agent for herbicide atrazine. The physicochemical properties of HGC were characterised using several analytical instruments. The critical micelle concentration (CMC) of HGC was determined using a Fluorescence Spectrometer. A High Performance Liquid Chromatography (HPLC) was used to determine encapsulation efficiency and loading capacity of atrazine in the amphiphilic chitosan derivative. Research findings found that the addition of hexanoyl and glycol groups to the chitosan backbone has improved the thermal stability of chitosan. TEM observation confirmed that HGC can form self-aggregation in the solution with spherical shape. The CMC values determined for HGC was 0.008 mg/mL. HGC also exhibited excellent encapsulation efficiency and loading capacity. The release profiles of atrazine loaded in HGC showed that it has different release behaviour than the pure herbicide in solution. In conclusion, the results from the study suggest that the amphiphilic chitosan derivative is applicable to be utilised as carrier agent for herbicide atrazine in pesticide formulation.