Depolymerization Methods Research Articles

Direct Depolymerization Coupled to Liquid Extraction Surface Analysis-High-Resolution Mass Spectrometry for the Characterization of the Surface of Plant Tissues.

The cuticle, the outermost layer covering the epidermis of most aerial organs of land plants, can have a heterogeneous composition even on the surface of the same organ. The main cuticle component is the polymer cutin which, depending on its chemical composition and structure, can have different biophysical properties. In this study, we introduce a new on-surface depolymerization method coupled to liquid extraction surface analysis (LESA) high-resolution mass spectrometry (HRMS) for a fast and spatially resolved chemical characterization of the cuticle of plant tissues. The method is composed of an on-surface saponification, followed by extraction with LESA using a chloroform–acetonitrile–water (49:49:2) mixture and direct HRMS detection. The method is also compared with LESA-HRMS without prior depolymerization for the analysis of the surface of the petals of Hibiscus richardsonii flowers, which have a ridged cuticle in the proximal region and a smooth cuticle in the distal region. We found that on-surface saponification is effective enough to depolymerize the cutin into its monomeric constituents thus allowing detection of compounds that were not otherwise accessible without a depolymerization step. The effect of the depolymerization procedure was more pronounced for the ridged/proximal cuticle, which is thicker and richer in epicuticular waxes compared with the cuticle in the smooth/distal region of the petal.

Ovine Mucosal Enoxaparin Exhibit Comparable Pharmacokinetic Profiles to Porcine Mucosal Enoxaparin

BackgroundLow Molecular Weight Heparins (LMWH) such as Enoxaparin are currently derived from porcine mucosal heparin (PMH), the same depolymerization methods can be used to obtain enoxaparin from unfractionated heparin from other sources. The purpose of this study is to compare the pharmacokinetics of ovine mucosal enoxaparin (OME) with that of porcine mucosal enoxaparin (PME).Materials and MethodsBranded Enoxaparin (Lovenox, Sanofi‐Aventis, Bridgewater, NJ) and three batches of OME (Suzhou Ronnsi Pharma, Suzhou, China) were used. Following anesthesia, a baseline blood sample was collected from primates (Macaca mulatta; n=4). LMWH was administered subcutaneously (SC) at a dose of 1 mg/kg. Additional blood samples were collected at various times (2,4,6 hours). Anti‐Xa and anti‐thrombin assays were used to calculate pharmacokinetic parameters. Tissue factor pathway inhibitor antigen levels were also measured using an ELISA method.ResultsIn the samples collected at 2, 4, and 6 hours, comparable levels of branded PME and the three batches of OME were observed using both anti‐Xa and anti‐thrombin assays. The pharmacokinetic parameters such as biologic half‐life, Cmax, volume of distribution, and clearance were comparable for both the ovine and porcine enoxaparin. Tissue Factor Pathway Inhibitor levels returned to baseline levels by 6 hours in OME, but remained slightly elevated with PME.DiscussionAt a 1 mg/kg SC dosage, three OME preparations produced comparable anti‐Xa and anti‐IIa effects which were similar to the ones observed with PME. The PK parameters calculated based on this data were also comparable for both groups. It is concluded that the SC pharmacokinetics of the three batches of OME were not only comparable between batches, but were also similar to the branded product.Support or Funding InformationNone.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

A Comparison of GMP Manufactured Ovine Mucosal Enoxaparin and Branded Porcine Enoxaparin

ObjectiveLow Molecular Weight Heparins (LMWH) such as Enoxaparin are currently derived from porcine mucosal heparin (PMH). The same depolymerization methods that retrieve this enoxaparin from unfractionated heparin can be used from other sources, including from sheep, resulting in ovine enoxaparin. Previous studies have compared non‐good manufacturing practice (GMP) batches of ovine enoxaparin and comparing them to porcine mucosal enoxaparin. The purpose of this study is to compare the pharmacokinetics of GMP ovine mucosal enoxaparin (OME) with that of porcine mucosal enoxaparin (PME).Materials and MethodsBranded Enoxaparin (Lovenox, Sanofi‐Aventis, Bridgewater, NJ) and three batches of GMP OME were used. Individual batches of GMP or branded Lovenox were administered subcutaneously (SC) to groups of primates (macaca mulatta) at a dose of 1 mg/kg. Blood samples were collected at baseline and post‐injection times of 2,4, and 6 hours. Plasma samples were frozen for batch analysis. aPTT was measured using clot‐based methods and amidolytic anti‐Xa and anti‐thrombin assays were used to calculate circulating levels of heparin. Individual calibration curves for each the GMP product and branded product were constructed, and the concentrations of drugs were measured at time points in terms of micrograms per milliliter. Drug levels and PK parameters were determined using anti‐Xa and anti‐thrombin assays. The batches of the GMP products were compared among each other and grouped means of all batches were compared with the branded Enoxaparin.ResultsIn the in‐vitro calibration studies, using the aPTT, anti‐Xa and, anti‐IIa assays, despite minor variations, the GMP batches composite values compared well with that of the branded Lovenox. In the PK/PD studies, the three batches of GMP‐produced ovine enoxaparin compared well within the group and the composite mean was similar to that of the branded Lovenox.DiscussionAt a 1 mg/kg SC dosage, three GMP OME preparations produced comparable anti‐Xa and anti‐IIa effects which were similar to the ones observed with PME. The PK parameters calculated based on this data were also comparable for both groups. It is concluded that the SC pharmacokinetics of the three batches of OME were not only comparable between batches but were also similar to the branded Lovenox.Support or Funding InformationNone.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Sequential Extraction and Characterization of Lignin-Derived Compounds from Thermochemically Processed Biorefinery Lignins

As the most abundant source of renewable aromatic compounds on the planet, lignin is an attractive feedstock for producing a range of chemicals and products that are currently derived from petroleum. Despite its great potential, separation of lignin depolymerization products remains one of the main obstacles toward cost-effective lignin valorization. Two lignin-rich streams, residues from enzymatic hydrolysis of the dilute acid and alkaline-pretreated corn stover, were depolymerized via pyrolysis using induction heating and catalytic transfer hydrogenolysis (CTH), respectively. Differences in phenolic compounds from gas chromatography–mass spectrometry and gel permeation chromatography analyses suggest that both pretreatment conditions and lignin depolymerization methods affected the product distribution. CTH lignin oils contain less polar compounds as compared to pyrolysis lignin oils, probably due to saturation of the derived compounds as a result of the reductive chemistry. The resulting liquid oils we...

Precise Structure and Anticoagulant Activity of Fucosylated Glycosaminoglycan from Apostichopus japonicus: Analysis of Its Depolymerized Fragments.

Apostichopus japonicus is one of the most economically important species in sea cucumber aquaculture in China. Fucosylated glycosaminoglycan from A. japonicus (AjFG) has shown multiple pharmacological activities. However, results from studies on the structure of AjFG are still controversial. In this study, the deaminative depolymerization method that is glycosidic bond-selective was used to prepare the depolymerized products from AjFG (dAjFG), and then a series of purified oligosaccharide fragments such as tri-, hexa-, nona-, and dodecasaccharides were obtained from dAjFG by gel permeation chromatography. The 1D/2D NMR and ESI-MS spectrometry analyses showed that these oligosaccharides had the structural formula of l-FucS-α1,3-d-GlcA-β1,3-{d-GalNAc4S6S-β1,4-[l-FucS-α1,3-]d-GlcA-β1,3-}n-d-anTal-diol4S6S (n = 0, 1, 2, 3; FucS represents Fuc2S4S, Fuc3S4S, or Fuc4S). Thus, the unambiguous structure of native AjFG can be rationally deduced: it had the backbone of {-4-d-GlcA-β1,3-d-GalNAc4S6S-β1-}n, which is similar to chondroitin sulfate E, and each d-GlcA residue in the backbone was branched with a l-FucS monosaccharide at O-3. Bioactivity assays confirmed that dAjFG and nonasaccharides and dodecasaccharides from AjFG had potent anticoagulant activity by intrinsic FXase inhibition while avoiding side effects such as FXII activation and platelet aggregation.

A comparative study of secondary depolymerization methods on oxidized lignins

DDQ oxidized lignins were used as substrates to assess the effectiveness of secondary depolymerization methods for the production of aromatics.

Comparison of product distribution, content and fermentability of biomass in a hybrid thermochemical/biological processing platform

Thermochemical processing is a promising method for the rapid depolymerization of biomass. This study investigated switchgrass, corn stover, red oak, hybrid poplar, and loblolly pine in terms of heteropolymer and elemental composition, and the distribution and composition of the fast pyrolysis products. Corn stover differed from other biomass types in that less of the biomass was recovered as sugar or phenolic oil (PO) and more of the biomass was recovered as bio-char and bio-gas. The sugar-rich aqueous stream recovered from the bio-oil heavy fraction was characterized in terms of sugar content and distribution, inhibitor content, and ability to support production of ethanol by Escherichia coli KO11 + lgk as a model biorenewable product. Levoglucosan was the most abundant sugar from each type of biomass, followed by either xylose or cellobiosan. For hybrid poplar, cellobiosan accounted for 30 wt% of the total sugar pool. Each of the sugar streams also contained a variety of inhibitors, particularly 5-hydroxymethylfurfural (5-HMF) and methylcyclopentenolone. Methylcyclopentenolone, maple lactone, was found to decrease the specific growth rate of E. coli by 50% when present at 0.72 wt%, indicating that it is less toxic than furfural, acetic acid and guaiacol. Sugars produced from switchgrass contained 4-fold less contaminants on a per-sugar basis than those from poplar and pine. All of the sugar streams contained too many inhibitors to be used at an industrially feasible concentration without additional detoxification. The poplar-derived pyrolytic sugar syrup was particularly inhibitory, possibly due to the high abundance of aromatic hydrocarbons, such as xylenes, and anisoles.

Comparison between solid and liquid acids for production of low molecular weight chitosan using systematic DOE-based approach

Chitosan is an abundantly available biodegradable polymer with diverse applications in various chemical and biomedical industries. However, it has remained underutilized due to its bulky and intractable nature, limiting its application in various fields. The major drawback, however, is poor aqueous solubility and thus preparation of low molecular weight derivatives of chitosan (LMWC) is an ideal solution to overcome the drawbacks associated with the parent polymer. The present study reports a sustainable method to produce LMWC, using H-β Zeolite as a green catalyst in comparison to the traditional depolymerization methods, based on nitrous acid. Successful decrease in molecular weight from 1157 to 175 kDa was achieved as studied by gel permeation chromatography. Furthermore, spray drying assisted in achieving uniform sized particles of LMWC of size less than 100 µm. Integration of response surface methodology for process optimization led to the negligible formation of by-products like 5-hydroxymethylfurfural. Comparative investigations confirmed the consistency of the developed method, simultaneously presenting additional advantages such as catalyst reusability, process reproducibility and process safety. Our findings demonstrate a greener approach for preparation of consistent quality LMWC, by implementing systemic stratagem of design of experiments.

Alternatives for Chemical and Biochemical Lignin Valorization: Hot Topics from a Bibliometric Analysis of the Research Published During the 2000–2016 Period

A complete bibliometric analysis of the Scopus database was performed to identify the research trends related to lignin valorization from 2000 to 2016. The results from this analysis revealed an exponentially increasing number of publications and a high relevance of interdisciplinary collaboration. The simultaneous valorization of the three main components of lignocellulosic biomass (cellulose, hemicellulose, and lignin) has been revealed as a key aspect and optimal pretreatment is required for the subsequent lignin valorization. Research covers the determination of the lignin structure, isolation, and characterization; depolymerization by thermal and thermochemical methods; chemical, biochemical and biological conversion of depolymerized lignin; and lignin applications. Most methods for lignin depolymerization are focused on the selective cleavage of the β-O-4 linkage. Although many depolymerization methods have been developed, depolymerization with sodium hydroxide is the dominant process at industrial scale. Oxidative conversion of lignin is the most used method for the chemical lignin upgrading. Lignin uses can be classified according to its structure into lignin-derived aromatic compounds, lignin-derived carbon materials and lignin-derived polymeric materials. There are many advances in all approaches, but lignin-derived polymeric materials appear as a promising option.

Lactide Production from Polymer Waste

The method of thermal depolymerization of polylactide wastes and products from it has been studied. At a temperature of 200-250 °C and a pressure of 5-10 mbar the maximum yield of crude lactide and pure lactide is 40 and 5.5 % by weight accordingly. The addition of catalysts (Zn, ZnO, SnO, C16H30O4Sn, Sb2O3) in an amount from 0.5 to 2.0 % by weight make it possible to intensify the process and increase the monomer yield by 3-10 times. The maximum amount of lactide (~60 wt %) is achieved by using of tin octoate (1.5 % wt) as the catalyst. The findings product is a mixture that consist of D-, L-lactide (~80 wt %) and m-lactide (~4 wt %) isomers, lactic acid (~2 wt %), oligomer of lactic acid (~14 wt %), water (<1 wt %), and has a melting point 92-96 °C.

Microwave-assisted Depolymerization of Lignin with Metal Chloride in a Hydrochloric Acid and Formic Acid System

A microwave-assisted depolymerization method of lignin with various metal chloride catalysts (MgCl2, AlCl3, FeCl3, ZnCl2, and MnCl2) in a formic acid and hydrochloric acid system under mild conditions (160 °C for 30 min) was studied. The resulting bio-oil was identified by a gas chromatography-mass spectrometer, and the solid residue was analyzed by Fourier transform infrared spectroscopy (FT-IR). Furthermore, the molecular weight change of lignin after the reaction was measured by gel permeation chromatography. The MnCl2 catalyzed lignin to produce most aromatic monomers, including approximately 23.0% G-type, 11.9% S-type, and 14.8% H-type monomer compounds. Different metal chloride catalysts had different effects on the depolymerization of lignin, which were embodied in the type and content of the products. It was also worth noting that the catalytic effects of transition metal chlorides on lignin may have been related to each chloride’s cation radius.

CuI‐Mediated Degradation of Polysaccharides Leads to Fragments with Narrow Polydispersities

Biomass derived oligo‐ and polysaccharides are important compounds for various applications, including biomedicine and material science. Their use, however, is often limited by inherent structural inhomogeneity of the starting materials. Here, a method for depolymerization of naturally occurring polysaccharides, including dextran, starch, xylan and galactoglucomannan, into well‐defined fragments of narrow polydispersities is described, based on the use of in situ generated CuI species under the commonly employed CuAAC reaction conditions. The main strength of the reported method is its high versatility, both in terms of substrate scope and operational simplicity.

Synthesis and evaluation of antibacterial and anti-oxidant activity of small molecular chitosan–fucoidan conjugate nanoparticles

Low-molecular weight chitosan (LMWC) and low-molecular weight fucoidan (LMWF) have been reported to possess diverse biological activity. In this study, LMWC and LMWF of different molecular weights were prepared by a H2O2-involved oxidative depolymerization method. Covalently linked LMWC–LMWF conjugates were synthesized through the activation of carboxyl groups of LMWF and an amidation reaction between the activated LMWF and LMWC. Light transmittance assay and TEM analysis showed that the LMWC–LMWF conjugates gradually form colloidal nanoparticles during the amidation reaction. The LMWC–LMWF conjugates prepared from lower-molecular weight (depolymerized in a longer degradation time) LMWC and LMWF have larger particle sizes and lower zeta potentials. The LMWC–LMWF conjugates were investigated for their ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and superoxide anion radicals. The DPPH and superoxide anion radical scavenging activities of the LMWC–LMWF conjugates were higher than that of LMWC alone and generally increased with a decrease in degradation time during the preparation of LMWF and LMWC. LMWC has superior hydroxyl radical scavenging activity, thus the hydroxyl radical scavenging activity of LMWC–LMWF conjugates were higher than that of LMWF alone. Bacterial inhibition assay of the conjugates against Escherichia coli and Staphylococcus aureus indicated that the conjugation of LMWC with LMWF improved the antibacterial activity of LMWF.

UV irradiation- $$\hbox {H}_{2} \hbox {O}_{2}$$ H 2 O 2 system as an effective combined depolymerization technique to produce oligosaccharides from chitosan

UV irradiation hydrogen peroxide ( $$\hbox {H}_{2} \hbox {O}_{2}$$ ) system is used as an effective, easy and low-cost combined depolymerization technique to produce oligosaccharides from chitosan. UV–Vis spectroscopic studies explained that with increasing treatment time, the absorption of the depolymerized chitosan solution has increased, indicating the increase in the carbonyl and amino groups in their structure. Fourier transform infrared spectroscopy and nuclear magnetic resonance (1H NMR) analysis showed that the 1,4- $$\beta $$ -d-glucoside linkages of chitosan are degraded without important changes in chemical structure of decomposed samples. X-ray diffraction patterns verified the polymerization of chitosan to produce oligomers, changing in structure from crystalline to amorphous. Viscosity-average molecular weight measurements of fragmented chitosan samples and Mark–Houwink equation are used to demonstrate the efficiency of this depolymerization method. Finally, the obtained results ascertained that this combined method could produce water soluble chitosan with significant efficiency and no essential change in its chemical structure.

Understanding the relationship between the structure and depolymerization behavior of lignin

Various lignin depolymerization methods have been proposed. Nevertheless, the relationship between the structure of lignin and its depolymerization behavior has not been widely investigated. Herein, six types of lignin samples were produced from oakwood (OW, hardwood) and pinewood (PW, softwood) using three different delignification techniques (ethanolsolv, formasolv, and Klason). The content of ether linkages in the OW-derived lignins was approximately three times higher than that in the PW-derived lignins because of the presence of the sinapyl alcohol unit in the former. The contents of ether linkages in the lignin isolated via the different methods followed the order: formasolv > ethanolsolv > Klason. The lignin samples were depolymerized in a mixture of supercritical ethanol (scEtOH) and formic acid at temperatures of 250–350 °C. At 350 °C, regardless of the lignin type, high conversion (>95%) and a high bio-oil yield (>81 wt%) could be achieved, demonstrating that the combined use of scEtOH-HCOOH was very effective for the depolymerization of various types of lignin. At the low temperatures of 250–300 °C, the lignin conversion and bio-oil yield were highly dependent on the amount of ether linkages; for example, at 300 °C, the use of OW-derived formasolv lignin resulted in a high bio-oil yield (86.2 wt%), whereas the use of OW-derived Klason lignin resulted in a very low bio-oil yield (27.9 wt%). The properties of the bio-oils produced from the different types of lignin were discussed.

Catalytic depolymerization of a typical lignite for improving tar yield by Co and Zn catalyst

A novel process for improving tar yield through catalytic depolymerization of a typical lignite was put forward. The catalytic depolymerization of the lignite over CoCl2 and ZnCl2 catalyst in different concentrations were investigated by a Gray-King apparatus. The optimal catalyst concentrations of CoCl2 and ZnCl2 catalyst that could obtain the highest tar yield was achieved, by which the tar yield increased about 20.3% and 6.6% compared with that of the raw coal, respectively. Different with the traditional catalytic pyrolysis process for which the tar yield decreased, more tar was produced by the catalytic depolymerization method. The GC × GC-MS analysis showed that the components of alkanes and two-ring aromatics in tar increased dramatically with the addition of the optimal CoCl2 and ZnCl2 catalyst. The Raman measurement revealed that more large aromatic ring systems ( > 6 rings) were formed in the char from depolymerization with catalyst and the elemental analysis showed that the hydrogen content decreased slightly. The gas products analysis reflected the contents of methane showed an obvious decrease. All of this reflects that more fragments and small free radicals cracked were enhanced by catalysis in the catalytic depolymerization process, thereby leading to an enhancement of the tar formation possibilities.

Catalytic Oxidation and Depolymerization of Lignin in Aqueous Ionic Liquid

Lignin is an integral part of the plant cell wall which provides rigidity to plants, also contributes to the recalcitrance of the lignocellulosic biomass to biochemical and biological deconstruction. Lignin is a promising renewable feedstock for aromatic chemicals; however, an efficient and economic lignin depolymerization method needs to be developed to enable the conversion. In this study, we investigated the depolymerization of alkaline lignin in aqueous 1-ethyl-3-methylimidazolium acetate [C2C1Im][OAc] under oxidizing conditions. Seven different transition metal catalysts were screened in presence of H2O2 as oxidizing agent in a batch reactor. CoCl2 and Nb2O5 proved to be the most effective catalysts in degrading lignin to aromatic compounds. A central composite design was used to optimize the catalyst loading, H2O2 concentration and temperature for product formation. Results show that lignin was depolymerized and the major degradation products found in the extracted oil were guaiacol, syringol, vanillin, acetovanillone, and homovanillic acid. Lignin streams were characterized by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC) to determine the effects of the experimental parameters on lignin depolymerization. The weight average molecular weight (Mw) of liquid stream lignin after oxidation, for CoCl2 and Nb2O5 catalysts were 1202 and 1520 g·mol-1, lower than that of Kraft lignin. Polydispersity index of the liquid stream lignin increased as compared with Kraft lignin, indicating wide span of the molecular weight distribution as a result of lignin depolymerization. Results from this study provide insights into the role of aqueous ionic liquid in presence of the oxidant and transition metal catalysts and the oxidative degradation reaction sequence of lignin towards product formation.

Low-Power Microwave Radiation-assisted Depolymerization of Ethanol Organosolv Lignin in Ethanol/Formic Acid Mixtures

Ethanol organosolv lignin separated from bamboo was depolymerized by low-power microwave radiation (~80 W) using ethanol as a swelling agent and formic acid as a hydrogen donor solvent. After increasing the temperature from 100 to 200 °C, the total amount of phenolic compounds in the products increased from 8.1% to 40.8%, and both the weight average molecular weight (Mw) and number average molecular weight (Mn) of the products from the lignin depolymerization decreased. With extended reaction time from 20 to 60 min, the total amount of phenolic compounds and molecular weight did not remarkably change. In addition, Fourier transform infrared (FT-IR) spectroscopy showed that oxidative fracture was the primary way that lignin depolymerized. The severity factor played an important role in converting lignin into small molecular substances, and the evaluation showed that the microwave temperature was more influential on the lignin depolymerization than the reaction time. Because depolymerization and repolymerization of fragments both occurred during the microwave radiation process, it is critical to inhibit repolymerization of degraded fragments for the efficient degradation of lignin. This study not only provides a theoretical basis for studying the mechanism of microwave-assisted lignin degradation but is also important for the determination of a cost-effective lignin depolymerization method.

Anticoagulant profiling of a Generic Enoxaparin and its comparison with its Branded version

INTRODUCTIONLow Molecular Weight Heparins (LMWHs) have been used parallel to Unfractionated Heparin (UFH) for the prophylaxis and treatment of venous thrombosis. Currently, the resourcing of LMWHs includes bovine (BE), ovine (OE) and porcine mucosal (PE) tissues. The relative potency of these drugs not only depends upon the inherent properties of the particular drug but also depends on the type of assays used. In our study we compared the potencies calculated from different anticoagulant/anti‐protease methods for Generic LMWHs with Branded LMWH.MATERIAL AND METHODSFour Generic LMWHs prepared from the porcine heparin of US origin and one Branded LMWH were compared. Blood was drawn from healthy volunteers (n=5) and supplemented with each of the individual LMWHs to obtain final concentrations of 10‐0 ug/mL. These samples were analyzed for anticoagulant assays: aPTT (2 reagents) and Thrombin Time (TT) assays immediately on ST4 instrument. The remaining blood was centrifuged (3000rpm, room temperature for 20minutes) for retrieved plasma. The retrieved plasma samples were analyzed for assays: aPTT (2 reagents), TT, Anti‐Xa and Anti‐IIa on ACL elite instrument. The results were tabulated, potencies were calculated and graphed were made accordingly.RESULTSIn whole Blood system; in the aPTT (TriniClot), Branded LMWH had 80.8‐44.1 seconds (secs) and Generic LMWHs had 75.3±2.7 to 43.7±3.1 secs. In the aPTT (Actin FSL), Branded LMWH had 151.6‐65.8 secs and Generic LMWHs had 88.9±5.3 to 46.8±0.8 secs. In the TT, Branded LMWH had 183.3‐15.1 secs and Generic LMWHs had 140±31.6 to 18.9±3.1 secs.In retrieved plasma system; aPTT (TriniClot), Branded LMWH had 105‐29.5 secs and Generic LMWHs had 69±3.2 to 26.3±0.4 secs. On aPTT (Actin FSL), Branded LMWH had 224.3‐53.1 secs and Generic LMWHs had 119.5±11.4 to 37.4±0.3 secs. On TT, Branded LMWH had 300‐10.9 secs and Generic LMWHs had of 300±0.0 to 13.5±0.7 secs. On anti‐Xa assay, the % inhibition for Branded LMWH was 88.9‐20.1 % and Generic LMWHs had 74.9±1.5 to 15.2±2.6 %. While on anti‐IIa assay, the % inhibition for Branded LMWH was 90.3‐27.7 % and Generic LMWHs had 80.3±1.4 to 22.3±6.1 %.The USP potency calculated in whole Blood system from aPTT (TriniClot), Branded LMWH had 109 U/mg and Generic LMWHs had 106.1±5.4 U/mg, from aPTT (Actin FSL), Branded LMWH had 136 U/mg and Generic LMWHs had 95±5.0 U/mg. The potency calculated in retrieved plasma system from aPTT (TriniClot), Branded LMWH had 186 U/mg and Generic LMWHs had 110.3±4.6 U/mg, from aPTT (Actin FSL), Branded LMWH had 187 U/mg and Generic LMWHs had 108.8±3.9 U/mg. The AXa potency calculated for Branded LMWH was 132 U/mg and Generic LMWHs had 107.6±7.6 U/mg while AIIa potency calculated for Branded LMWH was 45 U/mg and Generic LMWHs had 35.8±2.0 U/mgCONCLUSIONThe results showed variable potencies for the four batches of Generic enoxaparin in different assays. Branded LMWH showed stronger response, suggesting that the depolymerization method used to obtain these LMWHs may differ and therefore effect their anticoagulant and anti‐protease activities. Furthermore, it was also noticed that all agents showed lower potencies on whole blood suggesting that binding/uptake of these drugs by the blood cellular components which maybe responsible for the decreased potencies. The remarkably higher potencies in the retrived plasmas for the branded enoxaparin may also be due to differential uptake and binding of the components by blood cells.

The Effect of Liquid Natural Rubber as Toughening Agent in Epoxy/LNR/CB Composite

Liquid natural rubber (LNR) was used as the toughening agent to overcome the brittleness of epoxy thermoset matrix. The LNR were prepared by using depolymerization method. The experiment was consist of two parts of study, first, epoxy filled with carbon black to get the optimun 15 vol.% content of carbon black (CB). Second, epoxy with various amount LNR and at 15vol.% CB content. This can be seen from the result of flexural properties testing, fracture toughness testing and SEM morphology . The best properties of LNR as toughening as 4 phr because it gave optimun performance compared to others LNR content.