Low Molecular Weight Chitosan Research Articles

Evaluation of Chitosan Based Polymeric Matrices for Sustained Stomach Specific Delivery of Propranolol Hydrochloride

The objective of the present investigation was to explore the potential of Chitosan based polymeric matrices as carrier for sustained stomach specific delivery of model drug Propranolol Hydrochloride. Briefly, single unit hydrodynamically balanced (HBS) capsule formulations were prepared by encapsulating in hard gelatin capsules, intimately mixed physical mixtures of drug, and cationic low molecular weight Chitosan (LMCH) in combination with either anionic medium viscosity sodium alginate (MSA) or sodium carboxymethylcellulose (CMCNa). The effect of incorporation of nonionic polymers, namely, tamarind seed gum (TSG) and microcrystalline cellulose (MCCP), was also investigated. It was observed that HBS formulations remained buoyant for up to 6 h in 0.1 M HCl, when LMCH : anionic/nonionic polymer ratio was at least 4 : 1. It was also observed that LMCH has formed polyelectrolyte complex (PEC) with MSA (4 : 1.5 ratio) and CMCNa (4 : 1 ratio) in situ during the gelation of HBS formulations in 0.1 M HCl. The retardation in drug release was attributed to the PEC formation between LMCH and MSA/CMCNa. Incorporation of MCCP (rapid gel formation) and TSG (Plug formation) was found to be innovative. From the data, it is suggested that Chitosan based polymeric matrices may constitute an excellent carrier for stomach specific drug delivery.

Enzymolysis of chitosan by papain and its kinetics

Low molecular weight chitosan (LMWC) was obtained by the enzymolysis of chitosan by papain. Enzymolysis conditions (initial chitosan concentration, temperature, pH and ratio of papain to chitosan) were optimized by conducting experiments at three different levels using the response surface methodology (RSM) to obtain high soluble reducing sugars (SRSs) concentrations. Meanwhile, the influence of chitosan substrate concentration on the activity of papain was assessed in the experiments. The enzymolysis process was analyzed using pseudo-first-order and pseudo-second-order kinetic models and the experiment data were found to be more consistent with the pseudo-second-order kinetic model. In addition, the kinetic behavior of the enzymolysis was also investigated by using Haldane model, and chitosan exhibited substrate inhibition. It was clear that the Haldane kinetic model adequately described the dynamic behavior of the chitosan enzymolysis by papain. When the initial chitosan concentration was above 8.0g/L, the papain was overloaded and exhibited significant inhibition.

Nanoparticles incorporating pH-responsive surfactants as a viable approach to improve the intracellular drug delivery.

The pH-responsive delivery systems have brought new advances in the field of functional nanodevices and might allow more accurate and controllable delivery of specific cargoes, which is expected to result in promising applications in different clinical therapies. Here we describe a family of chitosan-TPP (tripolyphosphate) nanoparticles (NPs) for intracellular drug delivery, which were designed using two pH-sensitive amino acid-based surfactants from the family N(α),N(ε)-dioctanoyl lysine as bioactive compounds. Low and medium molecular weight chitosan (LMW-CS and MMW-CS, respectively) were used for NP preparation, and it was observed that the size distribution for NPs with LMW-CS were smaller (~168 nm) than that for NPs prepared with MMW-CS (~310 nm). Hemolysis assay demonstrated the pH-dependent biomembrane disruptional capability of the constructed NPs. The nanostructures incorporating the surfactants cause negligible membrane permeabilization at pH7.4. However, at acidic pH, prevailing in endosomes, membrane-destabilizing activity in an erythrocyte lysis assay became evident. When pH decreased to 6.6 and 5.4, hemolytic capability of chitosan NPs increased along with the raise of concentration. Furthermore, studies with cell culture showed that these pH-responsive NPs displayed low cytotoxic effects against 3T3 fibroblasts. The influence of chitosan molecular weight, chitosan to TPP weight ratio, nanoparticle size and nature of the surfactant counterion on the membrane-disruptive properties of nanoparticles was discussed in detail. Altogether, the results achieved here showed that by inserting the lysine-based amphiphiles into chitosan NPs, pH-sensitive membranolytic and potentially endosomolytic nanocarriers were developed, which, therefore, demonstrated ideal feasibility for intracellular drug delivery.

Comparison of the Chitosan Degradation through Hydrothermal and Sonication-Hydrothermal Processes

Chitosan is a natural substance that has many applications in the fields of pharmacy and medicine. Because it hashigh molecular weight and does not dissolved easily in a neutral pH solution, then there is an effort todepolymerize chitosan into low molecular weight chitosan and oligomers. Nowdays, one of the methods used todegrade biomass is hydrothermal. Hydrotermal is one method of biomass degradation and polymers that is quiteeffective and environmentally friendly. Because chitosan has strong hydrogen bonds in addition to highmolecular weight, it is necessary to treat chitosan by sonication before subjected to hydrothermal process. Thisstudy will compare degrading chitosan by only hydrothermal process and also sonication–hydrothermalprocesses. The hydrothermal of chitosan was carried out using a stainless steel tube reactor of 4-mL capacity at200 °C for 4 s under pressures of 25 MPa for both of hydrothermal systems. For sonication– hydrothermalprocesses, chitosan was treated with sonication at 40 oC for 30 and 120 min before subjected to hydrothermalprocess. After hydrothermal, chitosan was characterized by viscosimetry and HPLC to determine molecularwight and also the dissolved product. Based on the product yield of the process, the sonication (40 °C,120 mins,1 %)-hydrothermal process (200 °C, 4 mins) was the best process on this study and gave lactose yield as much as90 %.

Iodine-125 Chitosan-Vitamin C Complex: preparation, characterization and application

Abstract In heterogeneous conditions, water soluble Chitosan-Vitamin C Complex (CSVC) is successfully synthesized via the ionic interaction between γ-degraded CS and VC. Chitosan (CS) of low molecular weight (MW) is prepared using γ-irradiation method. The coupling of CS and vitamin C (VC) is carried out by the chemical treatment of VC with the γ-degraded CS. The formation of CSVC complex instead of physical mixture is confirmed by FT-IR and UV spectrometry. Characterization by transmission electron microscope (TEM) and dynamic light scattering (DLS) shows the formation of a nanostructure in 40 nm range. The preparation of labeled CSVC was performed using chloramines-T oxidation method. The labeling feasibility of CSVC nanostructure by Iodine-125 (125I) is investigated. The optimized conditions of labeling are thought to be 50 μg of oxidizing agent, pH 3, and one minute reaction time. The Biodistribution activity of 125I radiolabeled CSVC nanostructure (125I-CSVC) is examined on a group of different ascites tumor bearing mice. Calculation of the biodistribution percentages shows that the tumor, liver, and kidney are the targeting organs of 125I-CSVC nanostructure.

Dual TNF-α/IL-12p40 Interference as a Strategy to Protect Against Colitis Based on miR-16 Precursors With Macrophage Targeting Vectors.

Cytokines are central components of the mucosal inflammatory responses that take place during the development of Crohn's disease. Cell-specific combination therapies against cytokines may lead to increased efficacy and even reduced side effects. Therefore, a colonic macrophage-specific therapy using miR-16 precursors that can target both TNF-α and IL-12p40 was tested for its efficacy in experimental colitic mice. Galactosylated low molecular weight chitosan (G-LMWC) associated with miR-16 precursors were intracolonically injected into mice. The cellular localization of miR-16 precursors was determined. The therapeutic effects and possible mechanism were further studied in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitic mice. The results show that specific upregulation of miR-16 level in colonic macrophages significantly reduces TNF-α and IL-12p40 expression, which could suppress the associated mucosal inflammation and ultimately result in the relief of colitic symptoms. This strategy, based on the dual silencing of colonic macrophage-specific cytokines, represents a potential therapeutic approach that may be valuable for colitis therapy.

Efficacy of polyglucosamine for weight loss-confirmed in a randomized double-blind, placebo-controlled clinical investigation.

BackgroundThe purpose of this clinical study was to ascertain whether low molecular weight chitosan polyglucosamine is able to produce significantly better weight loss than placebo.Method115 participants were included in the study. We used a two-center randomized, double blind, placebo-controlled design. The participants followed a standard treatment (ST), which included the combination of a low-calorie diet achieved through creating a daily calorie deficit (500 cal) and an increased daily physical activity (7 MET-h/week). They were randomized to receive standard treatment plus placebo (ST + PL) or standard treatment plus polyglucosamine (ST + PG), respectively. Participants were instructed to take 2 × 2 tablets before the two meals containing the highest fat content for at least 24 weeks. Body weight, BMI, waist circumference and the time needed for a 5 % body weight reduction (5R) were taken as main variables.ResultsThe average weight loss over a period of 25 weeks in the ITT population was 5.8 ± 4.09 kg in the ST + PG group versus 4.0 ± 2.94 kg in the ST + PL (pU = 0.023; pt = 0.010). After 25 weeks, 34 participants achieved 5R in the ST + PG group (64.1 %) compared to only 23 participants in the ST + PL group (42.6 %) (ITT) (p Fisher = 0.033). Weight loss through hypo-caloric diets have been found to be effective. The additional effect of PG in combination with standard treatment is able to produce significantly better weight loss than placebo.ConclusionsParticipants treated with ST + PG showed a significant amount of weight loss, an additional 1.8 kg, compared to controls treated with ST + PL.Trial registrationTrial Registration at ClinicalTrials.gov: NCT02410785 Registered 07 April 2015

Production of antimicrobial chitosan nanoparticles against food pathogens

Chitosan nanoparticles (NPs) may be a promissory delivery system of polyphenols. The main objective of this study was to produce chitosan NPs encapsulated with polyphenols with antimicrobial and antioxidant activity against food pathogens. The NPs produced with low and high molecular weight chitosan (LMWC and HMWC) were successfully obtained showing slight variations in the particle size, in the range 300–600nm, and zeta potential values in the range 20–30mV, exhibiting a moderate stability. The best encapsulation performance was obtained for NPs produced with LMWC and the polyphenol rosmarinic acid. The antimicrobial studies proved that all free and encapsulated compounds have inhibitory activity upon the tested bacteria (Bacillus cereus, Escherichia coli O157, Listeria innocua, Staphylococcus aureus, Salmonella typhimurium and Yersinia enterocolitica). The images obtained by electronic microscopy showed that it was possible to obtain NPs capable of affecting the cellular structure of bacteria reinforcing their antimicrobial activity.

Influence of glutathione on the bioactivity of subcutaneously or orally administered insulin to rats.

The effect of reduced (GSH) and oxidized (GSSG) glutathione on the bioactivity of insulin was studied. A polyelectrolyte complex (PEC) of insulin with low molecular weight chitosan (13 kDa) was prepared and characterized. The PEC was then solubilized, in the presence and absence of GSH and GSSG, in a reverse micelle consisting of oleic acid and two surfactants (PEG-8 caprylic/capric glycerides and polyglycerol-6-dioleate). The in vitro and in vivo performances of the reverse micelle formulations (RMFs) were evaluated in rats. At pH 6.5 the association efficiency of the PEC was 76.2%. In vitro insulin release from the RMs was negligible at pH 1.2 and was markedly increased at pH 6.8. The hypoglycemic activity of insulin in the PEC was reduced when administered via the subcutaneous route, regardless of the GSH content. On the other hand, the presence of GSSG significantly enhanced hypoglycemia. When the RMF was administered via the oral route, the presence of GSH had no effect on the hypoglycemic activity of insulin compared with the GSH free system. However, the presence of GSSG in the oral preparation increased the hypoglycemic activity of insulin; probably by inhibiting insulin degradation, thereby prolonging its effect. Thus, incorporation of GSSG in the RMF reduces blood glucose levels in rats and protects insulin from degradation.

Degradation of four organophosphorous pesticides catalyzed by chitosan-metal coordination complexes.

Three types of chitosan with high (3.40 × 10(6)), medium (2.11 × 10(5)), and low (5.89 × 10(4)) molecular weights were chosen as ligands to synthesize chitosan magnesium, calcium, iron(III), and zinc coordination complexes. Degradation of four organophosphorous pesticides (dichlorvos, omethoate, dimethoate, and chlorpyrifos) by the above complexes in a heterogeneous system was studied using solid-phase extraction (SPE) and gas chromatography (GC). The degradation effect is related to the different types of chitosan, metal, and organophosphorus pesticides (OPs). Complexes of transition metals and the low molecular weight chitosan showed high hydrolytic activity. The chitosan-iron(III) complex was further used to study its catalytic kinetics on the hydrolysis of OPs. At pH 7.0 and 20 °C, the half-life of dichlorvos hydrolyzed by chitosan iron(III) was 52 h, whereas that of spontaneous dichlorvos hydrolysis was 105 h. The degradation ratio of omethoate and dimethoate increased to 38 and 52 %, respectively, which were 34 and 48 % higher than the control after 6 days at pH 7.0 and 20 °C. For all tested conditions, an increase of pH and temperature resulted in a higher degradation rate.

Multifunctional nanoparticles for gene delivery and spinal cord injury.

Methylprednisolone (MP) is a glucocorticoid that is used as an anti-inflammatory agent to the treat spinal cord injury (SCI). A low molecular weight chitosan was used to synthesize chitosan-MP conjugate, which was used to evaluate the gene therapy, anti-inflammatory and anti-apoptotic effects of MP. The cytotoxicity of chitosan-MP nanoparticles and the transfection efficiency of plasmid DNA were evaluated by MTT and luciferase assays. A chitosan-MP/pDNA complexes was injected into injured spinal cord to evaluate the anti-inflammatory and anti-apoptotic effects of these complexes using terminal deoxynucleotide transferase dUTP nick end labeling (TUNEL) and ED1 staining, respectively. In addition, to evaluate the distribution of chitosan-MP/pDNA complexes, pβ-gal encapsulated chitosan-MP was injected into the injected site. Cell survival was similar in cells treated with chitosan-MP conjugate and untreated cells. Luciferase expression was higher in cells treated with the chitosan-MP/pDNA than cells treated with the chitosan/pDNA. The chitosan-MP/pDNA complexes also reduced apoptosis and inflammation at the injury site. These results suggest that chitosan-MP conjugation is an effective gene delivery system to treat SCI.

Controlled delivery of valsartan by cross-linked polymeric matrices: Synthesis, in vitro and in vivo evaluation

The purpose of study was to develop chemically cross-linked chitosan-co-poly(AMPS) hydrogel based on low molecular weight chitosan for pH-responsive and controlled drug delivery of a model drug. Cross-linking was achieved chemically, by using free radical polymerization technique. Polymer (low molecular weight chitosan) was chemically cross-linked with monomer (2-acrylamido-2-methylpropane sulfonic acid) in aqueous medium. N, N′-Methylenebisacrylamide (MBA) was used as cross-linking agent. Sodium hydrogen sulfite (SHS) and ammonium peroxodisulphate (APS) were used as initiators in a chemical reaction. Hydrogels were characterized by FT-IR, SEM and DSC. Swelling studies and pH-sensitivity of hydrogels were studies at pH 1.2 and 7.4. Chitosan-co-poly(AMPS) hydrogels were administered to rabbits orally to evaluate its pharmacokinetic behavior. As a result of successful cross-linking of polymer and monomer, novel co-polymer has been developed, having suitable characteristics as desired for controlled release drug delivery system. Maximum swelling, drug loading and release have been observed at pH 7.4. In vivo results exhibited significant drug release and absorption at pH 7.4 in rabbits. It is concluded that highly swelling chitosan-AMPS based hydrogels were developed having pH independent swelling and pH dependent drug release properties. These hydrogels have great potential to be used for loading and controlled release of various therapeutic agents.

Influence of Molecular Weight and Degree of Deacetylation of Low Molecular Weight Chitosan on the Bioactivity of Oral Insulin Preparations

The objective of the present study was to prepare and characterize low molecular weight chitosan (LMWC) with different molecular weight and degrees of deacetylation (DDA) and to optimize their use in oral insulin nano delivery systems. Water in oil nanosized systems containing LMWC-insulin polyelectrolyte complexes were constructed and their ability to reduce blood glucose was assessed in vivo on diabetic rats. Upon acid depolymerization and testing by viscosity method, three molecular weights of LMWC namely, 1.3, 13 and 18 kDa were obtained. As for the DDA, three LMWCs of 55%, 80% and 100% DDA were prepared and characterized by spectroscopic methods for each molecular weight. The obtained LMWCs showed different morphological and in silico patterns. Following complexation of LMWCs with insulin, different aggregation sizes were obtained. Moreover, the in vivo tested formulations showed different activities of blood glucose reduction. The highest glucose reduction was achieved with 1.3 kDa LMWC of 55% DDA. The current study emphasizes the importance of optimizing the molecular weight along with the DDA of the incorporated LMWC in oral insulin delivery preparations in order to ensure the highest performance of such delivery systems.

Synthesis, Characterization, and Performance of a Novel Polymeric Cationic Surfactant Based on Low Molecular Weight Chitosan and 3‐Chloro‐2‐Hydroxypropyl Dimethyl Dehydroabietyl Ammonium Chloride (CHPDMDHA)

AbstractA series of novel polymeric cationic surfactants based on low molecular weight chitosan (LWCS) and 3‐chloro‐2‐hydroxypropyl dimethyl dehydroabietyl ammonium chloride (CHPDMDHA), LWCS‐g‐CHPDMDHA, were obtained by the grafting modification of LWCS with CHPDMDHA as grafting agent. The structure of LWCS‐g‐CHPDMDHA was confirmed by FT‐IR and 1H NMR, and the degree of quaternizing substitution (DS) of LWCS‐g‐CHPDMDHA was determined according to the results of elemental analysis. The aggregation behavior and surface activities of LWCS‐g‐CHPDMDHA in aqueous solution were investigated by transmission electron microscopy (TEM) and determination of surface tension, respectively. The experimental results showed that the DS and molecular weight (Mw) of LWCS have significant influence on the critical micelle concentrations (CMC) and the surface tensions at the CMC (γcmc). The shape of aggregates changed with the variation of concentration of LWCS‐g‐CHPDMDHA in aqueous solution. When the LWCS‐g‐CHPDMDHA was utilized as an emulsifier, the increase of DS of LWCS‐g‐CHPDMDHA and Mw of LWCS were favorable for improving the stability of emulsions composed of water and benzene.

Effect of different chitosan derivatives on in vitro scratch wound assay: A comparative study

Different strategies have been developed to make the wound-healing process faster and less painful. Recently, numerous studies demonstrated the ability of chitosan to accelerate wound healing. Aim of the present study has been to evaluate the effect of different chitosan derivatives to improve wound healing process. Quaternary ammonium–chitosan conjugates with low or high molecular weight (MW) and their thiolated derivatives effect were studied on human skin fibroblasts in terms of viability and migration (scratch wound assay). Results were compared both with basal medium (untreated cells) and with a positive control (chitosan chlorhydrate). After 24h both high and low MW chitosan derivatives were non-toxic up to 10μg/ml. The concentration of 10μg/ml was used for wound healing experiments. High-MW quaternary ammonium–chitosan conjugates bearing thiol groups on their chains were more effective in promoting cell migration than the non-thiolated conjugates and the chitosan chlorhydrate. Moreover, they significantly improve wound healing process compared to untreated cells.According to the present in vitro preliminary results, high MW thiolated quaternary ammonium–chitosan conjugates can be considered good candidates for the management of wounds.

Synthesis and Characterization of Low Molecular Weight Chitosan

Chitosan can be widely used in many areas owing to its unique properties, although its poor solubility in water is still a limiting factor. In the present study, low molecular weight chitosan (LMWC) was prepared by degradation with NaClO so that chitosan was able to dissolve in water. Chitosan to liquor ratio, NaClO content, temperature, and time were considered variables of NaClO degradation, and the Box-Behnken design was used to determine optimal conditions. There was good agreement between the experimental data and their predicted counterparts. The optimum conditions for chitosan degradation were estimated to be 1:67.91 of chitosan to liquor ratio, 22.03% of NaClO content, a temperature of 90.3 °C, and a time of 3.07 h. It was found that synthesis under these optimized conditions achieved the lowest molecular weight (10,937.4 Daltons). In addition, Fourier transform infrared spectroscopy, X-ray diffractograms, and thermogravimetric analysis showed that the structure of LMWC was similar to the original chitosan, while the crystallinity and thermal stability decreased after degradation.

Chitosan nanoparticles for targeting and sustaining minoxidil sulphate delivery to hair follicles

This work developed minoxidil sulphate-loaded chitosan nanoparticles (MXS-NP) for targeted delivery to hair follicles, which could sustain drug release and improve the topical treatment of alopecia. Chitosan nanoparticles were obtained using low-molecular weight chitosan and tripolyphosphate as crosslink agent. MXS-NP presented a monomodal distribution with hydrodynamic diameter of 235.5±99.9nm (PDI of 0.31±0.01) and positive zeta potential (+38.6±6.0mV). SEM analysis confirmed nanoparticles average size and spherical shape. A drug loading efficiency of 73.0±0.3% was obtained with polymer:drug ratio of 1:1 (w/w). Drug release through cellulose acetate membranes from MXS-NP was sustained in about 5 times in comparison to the diffusion rate of MXS from the solution (188.9±6.0μg/cm2/h and 35.4±1.8μg/cm2/h). Drug permeation studies through the skin in vitro, followed by selective recovery of MXS from the hair follicles, showed that MXS-NP application resulted in a two-fold MXS increase into hair follicles after 6h in comparison to the control solution (5.9±0.6μg/cm2 and 2.9±0.8μg/cm2). MXS-loading in nanoparticles appears as a promising and easy strategy to target and sustain drug delivery to hair follicles, which may improve the topical treatment of alopecia.

Effects of low-molecular-weight-chitosan on the adenine-induced chronic renal failure rats in vitro and in vivo

The effects of low-molecular-weight-chitosan (LMWC) on chronic renal failure (CRF) rats induced by adenine were investigated in vivo and in vitro. Chitosan were hydrolyzed using chitosanase at pH 6–7 and 37° for 24 h to obtain LMWC. In vitro, the effect of LMWC on the proliferation of renal tubular epithelial cells (RTEC) showed that it had no cytotoxic effect and could promote cell growth. For the in vivo experiment, chronic renal failure rats induced by adenine were randomly divided into control group, Niaoduqing group, and high-, medium- and low-dose LMWC groups. For each group, we detected serum creatinine (SCR), blood urea nitrogen (BUN), and total superoxide dismutase (T-SOD), glutathione oxidase (GSH-Px) activities of renal tissue, and obtained the ratio of kidney weight/body weight, pathological changes of kidney. The levels of serum SCR, BUN were higher in the adenine-induced rats than those in the control group, indicating that the rat chronic renal failure model worked successfully. The results after treatment showed that LMWC could reduce the SCR and BUN levels and enhance the activities/levels of T-SOD and GSH-PX in kidney compared to control group. Histopathological examination revealed that adenine-induced renal alterations were restored by LMWC at three tested dosages, especially at the low dosage of 100 mg kg−1 d−1.

Determination of the parameters of binding between lipopolysaccharide and chitosan and its N-acetylated derivative using a gravimetric piezoquartz biosensor

The interaction of endotoxin (lipopolysaccharide — LPS) with low molecular weight chitosan (5.5kDa), its N-acylated derivative and chitoliposomes was studied using a gravimetric piezoelectric quartz crystal microbalance biosensor. The optimal conditions for the formation of a biolayer based on immobilized LPS on the resonator surface and its regeneration were elaborated. The association and dissociation rate constants for LPS binding to chitosans were determined and the affinity constants (Kaf) were calculated based on the data on changes in the oscillation frequency of the quartz crystal resonator. The Kaf values correlated with the ones obtained using other methods. The affinity of N-acylated chitosan binding to LPS was higher than that of the parent chitosan binding to LPS. Based on the results obtained, we suggest that water-soluble N-acylated derivatives of chitosan with low degree of substitution of amino groups could be useful compounds for endotoxin binding and neutralization.

Removal of cadmium from aqueous solution using low molecular weight chitosan derivative

A 23 factorial design was used to examine the sorption of Cd2+ onto cross-linked low molecular weight chitosan pyruvic acid derivative. Three factors and two levels of solution pH (A) (6.0 or 10.0), temperature (B) (45 or 70°C) and Cd(II) concentration (C) (1 or 3mg/L) were considered. Batch mode system was employed with 0.05g of the sorbent and 25mL of Cd(II) solution. The efficiency of cadmium removal during an exposition time of 4h was then evaluated. The factors and their interaction effect on the cadmium removal efficiency followed the order: Cd(II) concentration>solution pH>interaction between solution pH and Cd(II) concentration>interaction between solution pH, temperature and Cd(II) concentration. Langmuir isotherm model was the best isotherm model. The Pseudo second order fitted well the kinetic data. The thermodynamic studies revealed the nature of the cadmium sorption.