Octanoyl Chloride Research Articles

Development of novel pyrimidine nucleoside analogs as potential anticancer agents: Synthesis, characterization, and In-vitro evaluation against pancreatic cancer

The present study proposed modification of 5-FU by conjugation with an acyl chloride and a 5-membered heterocyclic ring to improve its in-vitro cytotoxicity and metabolic stability. XYZ-I-71 and XYZ-I-73 were synthesized by introducing a tetrahydrofuran ring on 5-fluorocytosine (a precursor of 5-FU) and conjugation with octanoyl chloride and lauroyl chloride, respectively. The structure of the synthesized compounds was validated using NMR and micro-elemental analysis. The antiproliferative activity of the analogs was determined against MiaPaCa-2, PANC-1, and BxPC-3 pancreatic cancer cells. The analog's stability in human liver microsomes was quantified by HPLC. We found that the XYZ-I-73 (IC50 3.6 ± 0.4 μM) analog was most effective against MiaPaCa-2 cells compared to XYZ-I-71(IC50 12.3 ± 1.7 μM), GemHCl (IC50 24.2 ± 1.3 μM), Irinotecan (IC50 10.1 ± 1.5 μM) and 5-FU (IC50 13.2 ± 1.1 μM). The antiproliferative effects of this analog in Miapaca-2 cells is evident based on it having a 7-fold,3-fold, and 4-fold increased cytotoxic effect over Gem-HCl, Irinotecan, and 5-FU, respectively. On the other hand, XYZ-I-71 exhibited a 2-fold increased cytotoxic effect over Gem-HCl but a comparable cytotoxic effect to 5-FU and Irinotecan in MiaPaCa-2 cells. A similar trend of higher XYZ-I-73 inhibition was observed in PANC-1 and BxPC-3 cultures. For 48-h MiaPaCa-2 cell migration studies, XYZ-I-73 (5 μM) significantly reduced migration (# of migrated cells, 168 ± 2.9), followed by XYZ-I-71(315±2.1), Gem-HCl (762±3.1) and 5-FU (710 ± 3.2). PARP absorbance studies demonstrated significant inhibition of PARP expression of XYZ-I-73 treated cells compared to 5-FU, GemHCl, and XYZ-I-71. Further, BAX and p53 expressions were significantly increased in cells treated with XYZ-I-73 compared to 5-FU, GemHCl, and XYZ-I-71. In-vitro, metabolic stability studies showed that 80 ± 5.9% of XYZ-I-71 and XYZ-I-73 remained intact after 2 h exposure in liver microsomal solution compared to 5-FU. The XYZ-I-73 analog demonstrated a remarkable cytotoxic effect and improved in-vitro metabolic stability over the selected standard drugs and may have potential anticancer activity against pancreatic cancer.

Abstract 1825: Synthesis and biological evaluation of novel 5-FU analogs against pancreatic cancer

Abstract Purpose: 5-Fluorouracil (5-FU) is one of the standard chemotherapy drugs used to treat pancreatic cancer. However, treatment only extends survival modestly, and disease recurrence is typical due to systemic instability, drug resistance, severe adverse effects, and limited benefits in patients with locally advanced tumors. These shortcomings have necessitated new strategies to develop safer and more effective anticancer agents. The study’s objective was to synthesize, characterize, and evaluate the cytotoxic effects of novel 5-FU analogs in pancreatic cancer cells. Methods: The analogs, XYZ-I-71 and XYZ-I-73, were synthesized by introducing a tetrahydrofuran ring on 5-fluorocytosine (a precursor of 5-FU) and conjugation with octanoyl chloride and lauroyl chloride, respectively. They were characterized by NMR, HPLC, micro-elemental analysis, and mass spectrometry. Cytotoxicity and cell migration studies were performed to determine the effectiveness of the analogs against MiaPaCa-2, PANC-1, and BxPC-3 pancreatic cancer cells. PARP apoptosis study was conducted in MiaPaca-2 cells using the analogs and 5-FU. The metabolic stability of analogs was determined by using human liver microsomes and quantified by HPLC. Results: Analysis of the 1H-NMR spectra displayed amide bonds at 7.80 ppm and 7.73 ppm, confirming the conjugation of octanoyl and lauroyl chloride to 5-fluorocutosine, respectively. The purity of both analogs was 99.6%. We found that the XYZ-I-73 (IC50 3.6 ± 0.4μM) analog was most effective against MiaPaCa-2 cells compared to XYZ-I-71(IC50 12.3±1.7μM), GemHCl (IC50 24.2 ± 1.3 μM), Irinotecan (IC50 10.1 ± 1.5 μM) and 5-FU (IC50 13.2 ± 1.1 μM). For PANC-1 cell growth inhibition, XYZ-I-73 (IC50 3.9 ± 0.5) was again observed as the most effective agent compared to XYZ-I-71(IC50 8.7±0.9 μM), GemHCl (IC50 10.07±0.9), 5-FU (IC50 20.43±1.2) and Irinotecan (IC50 11.6 ±1.1). A similar pattern of XYZ-I-73 (IC50 5.9±0.7) anticancer activity against BxPC-3 cells was found to be higher than XYZ-I-71(IC50 7.7 ± 0.8), GemHCl (IC50 10.95±0.9), 5-FU (IC50 14±1.1) and Irinotecan (IC50 9.5±1.0). For 24-hour MiaPaCa-2 cell migration studies, XYZ-I-73 (5µM) analog significantly reduced migration (# of migrated cells, 168±2.9) followed by XYZ-I-71(315±2.1), Gem-HCl (762±3.1) and 5-FU (710±3.2). PARP studies demonstrated significant inhibition of PARP expression of XYZ-I-73 treated cells compared to 5-FU and XYZ-I-71. Further, BAX and p53 expressions were significantly increased in cells treated with XYZ-I-73 compared to 5-FU and XYZ-I-71. Metabolic stability studies showed that 80 ± 5.9 % of XYZ-I-71 and XYZ-I-73 remained intact after 2-hour exposure in liver microsomal solution compared to 5-FU. Conclusion: XYZ-I-73 demonstrated a remarkable cytotoxic effect and improved in vitro metabolic stability over the selected standard drugs and may have potential anticancer activity against pancreatic cancer. Citation Format: Esther Frimpong, Raviteja Bulusu, Joy Okoro, Andriana Inkoom, Nkafu Ndemazie, Sherise Rogers, Xue Zhu, Bo Han, Edward Agyare. Synthesis and biological evaluation of novel 5-FU analogs against pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1825.

Molecular Layer Deposition (MLD) of a Blocked Mercapto Silane on Precipitated Silica

Chemically modified silica is widely used as a reinforcing filler in elastomers. The modification is generally done in situ while preparing the rubber. However, in order to increase the efficiency and facilitate the mixing process, the silica can be pre-treated by a 2-step molecular layer deposition. The precursors for the modification are 3-mercaptopropyl-triethoxysilane (MPTES) and octanoyl chloride (OC) to react with MPTES and form a blocked silane. The precipitated silica nanofiller was successfully treated with MPTES and showed a self-limiting behavior: saturation occurred at 2.7%. Furthermore, DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) analysis confirmed the successful deposition of MPTES on the silica surface by showing the -SH peak that appeared after the reaction of MPTES and silica. In the second step, OC was introduced to form a thioester on the surface of the MPTES-treated silica, controlling the reactivity of the mercapto group from MPTES by blocking it to prevent a negative influence on the processing behavior of the rubber. Thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS) analytical results confirmed the deposition of the blocked mercapto silane on the silica. TGA results demonstrated the self-limiting behavior of OC, and DRIFTS and XPS proved the thioester formation. A thioester peak after the 2nd reaction step with OC appeared. At the same time, the disappearance of the -SH signal from the MPTES was observed, indicating the formation of the blocked mercapto silane structure. Transmission electron microscopy results showed that the treated silica has a well-distributed carbon and sulfur deposition after MPTES/OC treatment.

Ionic liquid-assisted isolation of lignin from lignocellulose and its esterification with fatty acids

Ionic liquids (ILs) have been widely used for lignocellulose fractionation and lignin isolation. However, the effect of IL treatment on lignin structure has been less explored. This study aimed to explore the chemical structure of lignin isolated by widely used imidazolium based ILs and compare it with the well-known milled wood lignin structure (MWL). Four types of ILs were used, and the effects of the treatment conditions on the isolated lignin (ILL) characteristics were evaluated. As the treatment temperature was increased from 60 to 140 °C, the ILL yield increased, whereas the molecular weight and hydroxyl group content decreased. Among the ILs, [EMIM]Ac produced the highest lignin yield (5.28%), and the ILL obtained had the lowest hydroxyl content (1.27 mM/g) and a molecular weight (Mw) of 29,500 g/mol. Esterification of the ILL isolated with [EMIM]Ac was performed using three fatty acid chlorides, octanoyl chloride (C8), lauroyl chloride (C12), and palmitoyl chloride (C16), to extend its applicability. The effects of esterification on the characteristics of ILL were evaluated, and successful esterification was confirmed using Fourier transform infrared and nuclear magnetic resonance spectroscopies.

Aliphatic chains grafted cellulose nanocrystals with core-corona structures for efficient toughening of PLA composites

To promote the replacement of nondegradable petrochemical-based polymers with green polylactic acid (PLA) materials, aliphatic chains-grafted cellulose nanocrystals (ECNCs) were prepared and used as nanofillers to overcome the disadvantage of poor toughness of PLA. ECNCs with core-corona structures were obtained by modifying cellulose nanocrystals (CNC) with valeryl chloride, octanoyl chloride, dodecanoyl chloride, and stearoyl chloride. ECNCs consists of a cellulose crystalline core and a soft esterified corona layer with aliphatic chains. Among the diverse ECNCs, the obtained EOCNC by esterification of octanoyl chloride exhibited most efficient enhancement of the toughness of PLA. Specifically, PLA/EOCNC-1% film displayed the best elongation at breakage of 108%, which was 6.4 times that of pure PLA. The esterified outer layer of ECNCs, which improves the interfacial compatibility, is one of the key factors contributing to toughening of PLA. These ECNCs with core-corona structure open up new directions for the application of PLA advanced composites.

Chemical characterization of black poplar (Populus nigra L.) sawdust hemicelluloses esterified with acyl chlorides

In the present study, hemicelluloses were isolated from black poplar (Populus nigra L.) sawdust, which is generated by the wood industry in large quantities as lignocellulosic waste. The monosaccharide composition of hemicelluloses was determined by gas chromatography. Xylose was the predominant monosaccharide unit, at 81.13%. Isolated hemicelluloses were then esterified with octanoyl, decanoyl, and lauroyl chloride, and the produced derivatives were characterized in terms of percent yield, degree of substitution (DS), solubility, Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Hemicellulose derivatives had DS values ranging from 0.83 to 0.97, and percent yields ranging from 61.54% to 62.31%. FTIR analysis confirmed esterification. TGA indicated that the hemicellulose derivatives offered lower thermal stabilities than native hemicelluloses. Solubility analysis indicated that esterification increased the hydrophobic capacity of hemicelluloses. Generally, the hemicellulose derivatives obtained could be used to make biodegradable and environmentally friendly plastics, resins, films, and coatings for industrial utilization.

Esterification of cellulose isolated from black poplar (Populus nigra L.) sawdust with octanoyl chloride

Esterification of cellulose isolated from black poplar (Populus nigra L.) sawdust with octanoyl chloride

Effect of Sustainable Chemical Modifications on Pasting and Gel Properties of Sorghum and Cassava Starch

Starch isolated from two different sorghum hybrids and a commercial cassava starch were modified in order to assess the improvement in rheological and thermal properties that could be produced by sustainable methods. Modifications were acetylation with acetic anhydride, hydrolysis with acetic acid, and esterification with octanoyl chloride. All sorghum starch paste exhibited higher syneresis than cassava ones and acetylation slightly improved water retention. In general, pasting profiles were significantly altered throughout modifications and the paste textural properties and rheological results suggested a physical gel behavior. Cassava and white sorghum unmodified gels showed higher values of textural parameters than those of brown sorghum. The flow data were adequately fitted by the power-law model (R2 > 0.96) with flow behavior index < 1. The acetylation, acid treatment, and octanoyl esterification of cassava and sorghum starch resulted in significant changes in water interaction, indicating a wider range of properties.

Impact of chemical modifications in pilot-scale isolated sorghum starch and commercial cassava starch

The aim of this work was to evaluate the impact of different chemical modification methods on starch from different botanical sources. Brown and white sorghum starch was isolated throughout a time saving process and avoiding the use of dangerous compounds. Brown and white sorghum and commercial cassava starch were treated using acetic acid, acetic anhydride and octanoyl chloride. Its chemical, morphological and thermal characterization was afterwards carried out. The modifications reduced amylose content and increased damaged starch. Both acetylation and acid treatment produced no significant changes in the size and shape of granules; yet, they increased superficial pores. SEM observations supported the results, indicating that octanoyl modification causes a partial destruction of the granule structure. Thus, particle size distribution changes significantly. Crystallinity degree decreased with all the modifications. However, the effect was more pronounced in octanoyl esterification. In general, modifications increase the water absorption of the native starch but no considerable effect was found over oil absorption, and gelatinization parameters were significantly altered as a result of modifications. Starch from these subtilized sources was successfully modified, which could arouse interest in its industrial production.

Mechanical characterization of polymethyl methacrylate composites reinforced with surface‐coated carbon fibers

Using trihydroxy polyether polyol (PPG), diphenylmethane diisocyanate (MDI) as soft segment and hard segment, carbon fiber (CF) as reinforcement, and self‐crosslinking CF/polymethyl methacrylate (PMMA) composite was prepared by prepolymer method. In this study, starch and octanoyl chloride were esterified to obtain esterified starch (SE). The fiber is then melt blended with PMMA matrix to prepare PMMA composite. Fourier‐transform infrared spectroscopy (FTIR) and SEM were used to analyze and characterize the composites produced. The results show that the composite material was prepared by separately modifying the fiber with NaOH and SE, respectively. The mechanical properties of the composite materials prepared by the modified fiber are improved, and the fiber and the PMMA matrix showed better compatibility. The mechanism of comodified fiber enhanced the mechanical properties of its composites.

Low-Level Arsenic Removal from Drinking Water.

The reported ability of cysteine and cystine to bind typical arsenic oxy‐ions in water is used as a basis for a study of the potential for using a surfactant with a cysteine head‐group for selective arsenic binding and removal in an ion flotation process. Several different head‐group attachment methods are studied with cysteine and cystine and with single‐ and double‐chain surfactants. A comparison of the properties of these surfactants with some other surface‐active compounds, with groups like those on cysteine, suggest that few compounds have suitable characteristics for the efficient removal of low levels of arsenic from drinking water. An amino‐acid‐based single‐chain surfactant is synthesized by reacting cysteine with octanoyl chloride to obtain octanoyl cysteine, which is then used in a study of selective ion flotation for the removal of low levels of arsenic from drinking water. This compound has high water solubility and causes extensive foaming in a typical flotation chamber and removed 99.4–99.9% of the 5 mg L−1 arsenic present in the contaminated water in a simple, single‐stage ion flotation process, using either air or nitrogen gas. These laboratory results indicate that these surfactants can be useful in the large‐scale treatment of low‐level arsenic‐contaminated water.

Removal of Triolein Lipid From Aqueous System by Molecularly Imprinted Chitosan and Its Derivative

Chitosan was molecularly imprinted to remove triolein (a model lipid triacylglyceride) from water. Molecularly-imprinted chitosan (chitosan-MIP) was synthesized by crosslinking it with glutaraldehyde in the presence of triolein as the template at 50°C for 2h. MIPs of octanoyl derivative of chitosan(Oct-MIP) were also prepared by similar method. Octanoyl chitosan was synthesized by N-acylation of chitosan using octanoyl chloride at room temperature for 12h. Contact angle measurements of water droplet on chitosan and octanoyl chitosan revealed increased hydrophobicity of octanoyl derivative of chitosan. FTIR spectroscopy was used to characterize the derivative and the MIPs. All the synthesized polymers. Oct-MIP and chitosan-MIP could imprint approximately 77% and 66% of triolein template, respectively. Binding experiments revealed that Oct-MIP exhibit higher triolein binding capacity than corresponding non-acylated polymers. In 6h, 1mg of Oct-MIP and chitosan-MIP could rebind 534.50µg and 380.35µg of triolein respectively. Non Imprinted octanoyl chitosan and chitosan bound 272µg and 198.24µg triolein respectively. Both types of MIPs could also bind a triolein analog (1,3-dioleoyl-2-palmitoyl glycerol).

Removal of heavy metal ions from water using ion flotation

The effects of different single-chain surfactants obtained by reacting cysteine with octanoyl (C8), decanoyl (C10) and dodecanoyl (C12) chloride were investigated for their use in ion flotation removal of low levels of arsenic, mercury, lead, cadmium and chromium ions from aqueous solution. Re-crystallized octanoyl-cysteine (octanoyl-cys) surfactant showed the highest removal efficiency at 99.9%, for Hg ions, using pure nitrogen gas. Successful removal results of most other ions was found to be in the range 99.1–99.7%,using either air or nitrogen gas. Characterization of the octanoyl-cys surfactant was also carried out using elemental analysis, 1H NMR, FT-IR, melting point (MP) and critical micelle concentration (CMC) determination.

New 1-octanoyl-3-aryl thiourea derivatives: Solvent-free synthesis, characterization and multi-target biological activities

&lt;p&gt;An efficient solvent-free synthesis of a 10-member library of octanoyl linked substituted aryl thioureas was accomplished successfully. The octanoyl isothiocyanate was freshly prepared in excellent yield and purity by the reaction of potassium thiocyanate with octanoyl chloride followed by removal of potassium chloride by filtration. The reaction of the latter with a series of ten different substituted anilines by stirring at 60-65°C lead to the formation of the title compounds. The &lt;em&gt;in vitro&lt;/em&gt; antifungal activity of newly synthesized compounds was evaluated against &lt;em&gt;Aspergillus niger, A. flavus&lt;/em&gt; and &lt;em&gt;Fusarium solani&lt;/em&gt; strains of pathogenic fungi. Antibacterial assay was carried out against Gram positive (&lt;em&gt;Staphylococcus aureus, Micrococcus luteus&lt;/em&gt;) and Gram negative bacterial strains (&lt;em&gt;Escherichia coli, Enterobacter aerogens&lt;/em&gt;). Furthermore, anti-oxidant potential and enzyme inhibition studies against α-amylase and butyryl cholinestrase were performed. The results obtained indicated moderate to excellent activities of most of the compounds whilst some derivatives showed potency higher than the standard used.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Video Clips&lt;/strong&gt;:&lt;/p&gt;&lt;p&gt;&lt;a href="https://www.youtube.com/v/GJ8JFPUHdo4"&gt;Antibacterial assay&lt;/a&gt;: 2 min 16 sec&lt;/p&gt;&lt;p&gt;&lt;a href="https://www.youtube.com/v/1j73_wjZaOE"&gt;Enzyme inhibition&lt;/a&gt;: 1 min 27 sec &lt;/p&gt;

Cellulose Esterification with Octanoyl Chloride and its Application to Films and Aerogels

Homogeneous esterification of cellulose with octanoyl chloride (a long-chain fatty acid) was investigated in lithium chloride/N,N-dimethyl acetamide (LiCl/DMAc) medium. Cellulose was readily esterified by the octanoyl chloride, as shown by 1H NMR analysis. The effects of the ratio of octanoyl chloride to cellulose hydroxyl groups, the reaction temperature, and the reaction time on the yield and degrees of substitution (DS) of cellulose esters (CEs) were investigated. CEs with high DS (2.2) were achieved after 8 h at 100 °C with a 1.6 to 1.8 of molar ratio of octanoyl chloride to cellulose hydroxyl groups. Furthermore, hydrophobic, fully transparent CE films and aerogels were prepared using CE tetrahydrofuran (THF) solutions. The CE aerogels exhibited high porosity and were formed with evenly distributed porosity, as revealed by scanning electron microscopy (SEM).

Tetraamido‐oxacalix[4]arene Derivatives: Synthesis, Structures and Supramolecular Assemblies

AbstractTetraamido‐oxacalix[4]arene derivatives have been synthesized via the reactions of tetraamino‐oxacalix[4]arene with excess butyryl chloride, octanoyl chloride, benzoyl chloride and p‐toluenesulfonyl chloride, respectively. 1H NMR results suggest that these oxacalix[4]arene derivatives preferentially adopt the 1,3‐alternate (saddle‐like) conformation in solution, which were also the case in the solid state as demonstrated by single crystal X‐ray analysis. A dimerized slipped capsule could be formed by tetra‐butyramido‐oxacalix[4]arene in the solid state via intermolecular hydrogen bond interactions under the assistance of two encapsulated methanol molecules. On the other hand, a molecular cavity was formed by tetra‐p‐toluenesulfonamido‐oxacalix[4]arene which can encapsulate a solvent molecule of ethyl acetate.

Structural modification of ginsenoside Rh2 by fatty acid esterification and its detoxification property in antitumor

Ginsenoside Rh(2), one of the most important ginsenosides with anticancer properties in red ginseng, has been developed as principal antitumor ingredient for clinical use. However, the cytotoxicity test in human hepatocyte cell line QSG-7701 (IC(50) 37.3μM) indicated that Rh(2) might show strong cytotoxic side-effect on the normal liver cells. For blunting the toxicity, Rh(2) was structurally modified by reacting with octanoyl chloride to give a dioctanoyl ester of Rh(2) (D-Rh(2)) in the present study. MTT assay in QSG-7701 cell line in vitro showed that the cytotoxicity of D-Rh(2) on human hepatocyte cells (IC(50) 80.5μM) was significantly lower than that of Rh(2). While antitumor xenograft assay in mice bearing H22 liver cancer cells in vivo showed that the antitumor activity of D-Rh(2) retained to be strong as that of Rh(2). According to previous pharmacokinetic studies, the fatty acid esterification of Rh(2) might be of detoxification reaction to cells. Additionally, D-Rh(2) showed significant enhancement on increasing thymus index at the dose of 10mg/kg compared with vehicle treated control group. Thus, D-Rh(2) might indirectly affect tumor growth by stimulating lymphocytes to become cytotoxic to tumor cells. Finally, our findings suggested that D-Rh(2), the fatty acid ester of Rh(2), might attenuate the side-effect by detoxification to human normal cell and could be a more potential candidate for developing as an antitumor drug.

Characterization of Chemically Modified Potato Starch Films Through Enzymatic Degradation

The present investigation was undertaken to characterize the biodegradation pattern of chemically modified starch films. Chemically modified starch films obtained by esterification of the hydroxyl groups of the polysaccharide have shown lower water sorption than native starch films, being therefore more attractive for a number of processing applications. However, no systematic study characterizing their biodegradation behavior and comparing it with the degradation pattern of native starch films has still been published. In the current contribution we characterized the enzymatic degradation pattern of three derivatized starch films by use of a commercial α-amylase from Bacillus licheniformis. Optimum degradation conditions were chosen upon assaying the effect of enzyme load and temperature on the reaction course of native starch films. Under the conditions selected, comparison of different derivatization procedures revealed that the starch film modified with octanoyl chloride was enzymatically hydrolyzed at a much higher rate than native starch film. Maleated starch films also showed higher susceptibility to α-amylolytic hydrolysis than native starch, whereas acetylated starch showed a hydrolysis pattern similar to that of native starch. Differences in degradation rates of chemically modified films were explained in terms of their amylose content which promotes dense networks that hinder the access of starch-degrading enzymes.

Homogeneous Esterification of Poplar Wood in an Ionic Liquid under Mild Conditions: Characterization and Properties

Wood meal was completely dissolved under constant conditions (130 °C, 6 h) in the ionic liquid 1-butyl-3-methylimidazolium chloride ([C4mim]Cl), and the various factors and potential mechanism of the homogeneous esterification of wood in this reaction medium were mainly studied. The physicochemical properties of the esterified wood were also investigated. It has been shown that highly substituted wood esters could be obtained by reacting wood dissolved in [C(4)mim]Cl with octanoyl chloride in the presence of triethylamine as a neutralizer. The weight percent gain was arranged from 121.5% to 297.4%. All reactions were performed under mild conditions, low excess of reagent, and a short reaction time compared to the heterogeneous chemical modification. Meanwhile, characterization of the derivatives confirmed that the homogeneous esterification was successfully processed. It was also found that thermal stability and morphological properties of the esterified wood were significantly different from those in previous reports. Octanoylation of wood meal in the [C(4)mim]Cl homogeneous system reduced the initial temperature of their thermal degradation and decreased the thermal stability compared to those in unmodified wood meal. Furthermore, the fibrillar appearance of wood meal changed into a relatively more homogeneous macrostructure of the esterfied wood. All these results suggested that homogeneous esterification of poplar wood in [C(4)mim]Cl would enhance the compatibility and improve the processability of wood with synthetic polymers.

Bioadhesive hydrophobic chitosan microparticles for oral delivery of insulin: In vitro characterization and in vivo uptake studies

AbstractHydrophobically modified polymeric matrices for drug delivery were developed by N‐acylation of chitosan with long(C18) and medium chain(C8) fatty acid chlorides like octanoyl and oleoyl chloride. Chemical modifications of chitosan were confirmed by IR spectra and trinitrobenzenesulphonic acid assay. Modified chitosan particles were prepared by ionotropic gelation with sodium tripolyphosphate. Hydrophobic modification was confirmed by contact angle measurements. Scanning electron micrographs showed the presence of compact microparticles. Swelling studies showed that oleoyl chitosan exhibited low swelling profile than octanoyl chitosan at acidic pH. In vitro release profile at pH 7.4 showed that about 90% of insulin was released by 5th hour. ELISA studies proved that the microparticles were capable of maintaining biological activity of insulin. Mucoadhesion studies proved that oleoyl derivative was more mucoadhesive than octanoyl derivative. In vivo uptake studies of fluorescent‐labeled microparticles on rat intestinal sections showed that oleoyl chitosan microparticles exhibited significant uptake than octanoyl chitosan. These results suggests that oleoyl moiety would resist degradation by the gastric enzymes and will enhance mucoadhesivity through hydrophobic interactions and also the permeability by loosening the tight junctions, thus making it a useful carrier for oral peptide delivery applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010