N-trimethyl Chitosan Research Articles

Intraperitoneal immunization with Urease loaded N-trimethyl Chitosan nanoparticles elicits high protection against Brucella melitensis and Brucella abortus infections

Brucella (B) species are brucellosis causative agents, a worldwide zoonotic illness causing Malta fever in humans and abortion in domestic animals. In this work, we evaluated the vaccine potential of Trimethyl chitosan (TMC) nanoparticles formulation of Urease (TMC/Urease) against brucellosis. TMC/Urease nanoparticles and urease without any adjuvant were separately administered both orally and intraperitoneally. Intraperitoneal (i.p.) administration of urease alone as well as oral administration of both TMC/Urease nanoparticles and urease alone, elicited low titers of specific immunoglobulin G (IgG), while i.p. immunization with TMC/Urease nanoparticles induced high specific IgG production levels. As it was indicated by the cytokine assay and the antibody isotypes, i.p. immunization by urease alone, and TMC/Urease nanoparticles induced a mixed Th1-Th2 immune response, whereas oral administration of both urease alone and TMC/Urease nanoparticles induced a mixed Th1-Th17 immune response. In lymphocyte proliferation assay, spleen cells from i.p.-vaccinated mice with TMC/Urease nanoparticles showed a strong recall proliferative response. Vaccinated animals were challenged with virulent strains of B. melitensis and B. abortus. I.p. vaccination with TMC/Urease nanoparticles resulted in a high degree of protection. Altogether, our results indicated that TMC nanoparticles are a potent delivery system for i.p.-administered Brucella antigens.

Intranasal delivery of Huperzine A to the brain using lactoferrin-conjugated N-trimethylated chitosan surface-modified PLGA nanoparticles for treatment of Alzheimer's disease.

BackgroundSafe and effective delivery of therapeutic drugs to the brain is important for successful therapy of Alzheimer’s disease (AD).PurposeTo develop Huperzine A (HupA)-loaded, mucoadhesive and targeted polylactide-co-glycoside (PLGA) nanoparticles (NPs) with surface modification by lactoferrin (Lf)-conjugated N-trimethylated chitosan (TMC) (HupA Lf-TMC NPs) for efficient intranasal delivery of HupA to the brain for AD treatment.MethodsHupA Lf-TMC NPs were prepared using the emulsion–solvent evaporation method and optimized using the Box–Behnken design. The particle size, zeta potential, drug entrapment efficiency, adhesion and in vitro release behavior were investigated. The cellular uptake was investigated by fluorescence microscopy and flow cytometry. MTT assay was used to evaluate the cytotoxicity of the NPs. In vivo imaging system was used to investigate brain targeting effect of NPs after intranasal administration. The biodistribution of Hup-A NPs after intranasal administration was determined by liquid chromatography–tandem mass spectrometry.ResultsOptimized HupA Lf-TMC NPs had a particle size of 153.2±13.7 nm, polydispersity index of 0.229±0.078, zeta potential of +35.6±5.2 mV, drug entrapment efficiency of 73.8%±5.7%, and sustained release in vitro over a 48 h period. Adsorption of mucin onto Lf-TMC NPs was 86.9%±1.8%, which was significantly higher than that onto PLGA NPs (32.1%±2.5%). HupA Lf-TMC NPs showed lower toxicity in the 16HBE cell line compared with HupA solution. Qualitative and quantitative cellular uptake experiments indicated that accumulation of Lf-TMC NPs was higher than nontargeted analogs in 16HBE and SH-SY5Y cells. In vivo imaging results showed that Lf-TMC NPs exhibited a higher fluorescence intensity in the brain and a longer residence time than nontargeted NPs. After intranasal administration, Lf-TMC NPs facilitated the distribution of HupA in the brain, and the values of the drug targeting index in the mouse olfactory bulb, cerebrum (with hippocampus removal), cerebellum, and hippocampus were about 2.0, 1.6, 1.9, and 1.9, respectively.ConclusionLf-TMC NPs have good sustained-release effect, adhesion and targeting ability, and have a broad application prospect as a nasal drug delivery carrier.

Oral immunization of mice with Omp31-loaded N-trimethyl chitosan nanoparticles induces high protection against Brucella melitensis infection.

Brucellosis is a group of closely associated zoonotic bacterial illnesses caused by members of the genus Brucella. B. melitensis Omp31 is a promising candidate for a subunit vaccine against brucellosis. This study surveyed the immunogenicity of Omp31 alone and with incomplete Freund’s adjuvant (Omp31-IFA) and N-trimethyl chitosan (TMC/Omp31) nanoparticles (NPs), as well as the effect of Omp31 immunization route on immunological responses and protection. After expression and purification, the recombinant Omp31 (rOmp31) was loaded onto TMC NPs by ionic gelation. The particle size, loading efficiency and in vitro release of the NPs were examined. Omp31-IFA was administered intraperitoneally, while TMC/Omp31 NPs were administered orally and intraperitoneally. According to the antibody subclasses and cytokine profile, intraperitoneal immunization by Omp31-IFA and TMC/Omp31 NPs induced T helper 1 (Th1) and Th1–Th2 immune responses, respectively. On the other hand, oral immunization with TMC/Omp31 NPs elicited a mixed Th1–Th17 immune response. Data obtained from the cell proliferation assay showed that vaccination with Omp31 stimulated a vigorous antigen-specific cell proliferative response, which could be further increased after oral immunization with TMC/Omp31 NPs. Vaccinated groups of mice when challenged with B. melitensis 16M were found to be significantly protected in the orally administered group in comparison with the intraperitoneally immunized mice. Results of this study indicated that the reason for high protection after oral vaccination can be via elicited Th17 response.

Enhanced antitumor efficacy of arginine modified amphiphilic nanoparticles co-delivering doxorubicin and iSur-pDNA via the multiple synergistic effect

Arginine and α-tocopherol succinate (α-TOS) double grafted N-trimethyl chitosan chloride (TMC) nanoparticles (TAS NPs) were designed and developed for effective co-delivery of doxorubicin (DOX) and Survivin shRNA-expressing pDNA (iSur-pDNA). With DOX loading into the hydrophobic core and iSur-pDNA combining to the hydrophilic shell, TAS/DOX/pDNA NPs demonstrated favorable structural stability and sustained release properties in vitro. With the special non-clathrin-dependent endocytosis, TAS/DOX/pDNA NPs presented higher cellular uptake and mainly distributed in ER and Golgi rather than lysosomes following internalization. The in vitro nuclear localization, gene silencing efficiency, cell apoptosis, and growth inhibition of tumor cells were significantly promoted by arginine modification. In the tumor-bearing mice model, TAS/DOX/pDNA NPs possessed the maximum antitumor efficiency as compared with single delivery of DOX or iSur-pDNA. Particularly, blank TAS NPs were selectively be toxic to tumor cells as evidenced by their capabilities to inhibit proliferation and induce apoptosis of tumor cells. The promising tumor treatment of TAS/DOX/pDNA NPs via a multiple synergistic manner arising from DOX and pDNA as well as the vectors would provide a potential strategy for a dual-delivery system to improve their therapeutic efficacies.

EDIII-DENV3 nanospheres drive immature dendritic cells into a mature phenotype in an in vitro model.

Domain III of E protein of dengue virus (DENV) is a target for vaccine development. Unfortunately, this protein based platform has low general immunogenicity. To circumvent this problem, the use of an adjuvant-nanoparticle delivery system to facilitate immunogenicity of soluble DENV-EDIII protein was investigated. One of the key features of this delivery system is its ability to simultaneously deliver antigens and exert adjuvanticity on specialized immune cells. In this study, N-trimethyl chitosan (TMC) nanoparticles (NPs) were generated to be used as adjuvant and carrier for soluble E-domain III of dengue virus serotype 3 (sEDIII-D3). Using ionotropic gelation, purified sEDIII-D3 was encapsulated into TMC NPs to form EDIII-D3 TMC NPs. After optimization, EDIII-D3 TMC particles exhibited a loading efficiency of 81% and a loading capacity of 41%. The immunogenicity of EDIII-D3 TMC NPs was tested using monocyte-derived dendritic cells (MoDCs). It was found that EDIII-D3 TMC NPs were well taken up by MoDCs. In addition, EDIII-D3 TMC NP treated MoDCs significantly upregulated maturation markers (CD80, CD83, CD86 and HLA-DR) and induced secretion of various cytokines and chemokines (IFN-α, IL-1β, IL-6, IL-2, IL-12p70, IFN-γ, IL-4, IL-10, IL-8, MCP-1, macrophage inflammatory protein-1β, granulocyte-colony stimulating factor, granulocyte-macrophage colony-stimulating factor and IL-7). These results indicate that EDIII-D3 TMC NPs are potent immunogens, at least in vitro, with the ability to induce maturation of DCs and highlight the potential use of TMC NPs for enhancing immunogenicity of a non-replicating dengue vaccine.

Diphtheria toxoid and N-trimethyl chitosan layer-by-layer coated pH-sensitive microneedles induce potent immune responses upon dermal vaccination in mice

Dermal immunization using antigen-coated microneedle arrays is a promising vaccination strategy. However, reduction of microneedle sharpness and the available surface area for antigen coating is a limiting factor. To overcome these obstacles, a layer-by-layer coating approach can be applied onto pH-sensitive microneedles. Following this approach, pH-sensitive microneedle arrays (positively charged at coating pH5.8 and nearly uncharged at pH7.4) were alternatingly coated with negatively charged diphtheria toxoid (DT) and N-trimethyl chitosan (TMC), a cationic adjuvant. First, the optimal DT dose for intradermal immunization was determined in a dose-response study, which revealed that low-dose intradermal immunization was more efficient than subcutaneous immunization and that the EC50 dose of DT upon intradermal immunization is 3-fold lower, as compared to subcutaneous immunization. In a subsequent immunization study, microneedle arrays coated with an increasing number (2, 5, and 10) of DT/TMC bilayers resulted in step-wise increasing DT-specific immune responses. Dermal immunization with microneedle arrays coated with 10 bilayers of DT/TMC (corresponding with ±0.6μg DT delivered intradermally) resulted in similar DT-specific immune responses as subcutaneous immunization with 5μg of DT adjuvanted with aluminum phosphate (8-fold dose reduction). Summarizing, the layer-by-layer coating approach onto pH-sensitive microneedles is a versatile method to precisely control the amount of coated and dermally-delivered antigen that is highly suitable for dermal immunization.

Development of MPC-DPA polymeric nanoparticle systems for inhalation drug delivery applications

Inhalation of nanoparticles for pulmonary drug delivery offers the potential to harness nanomedicine formulations of emerging therapeutics, such as curcumin, for treatment of lung cancer. Biocompatible nanoparticles composed of poly(2-methacryloyloxyethyl phosphorylcholine)-b-poly(2-(diisopropylamino)ethyl methacrylate) (MPC-DPA) have been shown to be suitable nanocarriers for drugs, whilst N-trimethyl chitosan chloride (TMC) coating of nanoparticles has been reported to further enhance their cellular delivery efficacy; the combination of the two has not been previously investigated. Development of effective systems requires the predictable, controllable, and reproducible ability to prepare nanosystems possessing particle sizes, and drug loading capacities, appropriate for successful airway travel, lung tissue penetration, and tumor suppression. Although a number of MPC-DPA based nanosystems have been described, a complete understanding of parameters controlling nanoparticle formation, size, and morphology has not been reported; in particular the effects of differing solvents phases remains unclear. In this current study a matrix of 31 solvent combinations were examined to provide novel data pertaining to the formation of MPC-DPA nanoparticles, and in doing so afforded the selection of systems with particle sizes appropriate for pulmonary delivery applications to be loaded with curcumin, and coated with TMC. This paper presents the first report of novel data detailing the successful preparation, characterisation, and optimisation of MPC-DPA nanoparticles of circa 150–180nm diameter, with low polydispersity, and a curcumin loading range of circa 2.5–115μM, tunable by preparation parameters, with and without TMC coating, and thus considered suitable candidates for inhalation drug delivery applications.

Effect of silibinin-loaded nano-niosomal coated with trimethyl chitosan on miRNAs expression in 2D and 3D models of T47D breast cancer cell line

Silibinin is a natural flavonoid with a strong antioxidant property and weak cytotoxic activity. It has demonstrated anti-tumoural activity against many types of malignancies; however, due to its hydrophobic structure, it has poor water solubility, bioavailability and permeability across intestinal epithelial cells. To improve the effect of silibinin, we have vehiculated silibinin by a highly stable niosomal nanostructure based on a Span 60/cholesterol (CH)/N-trimethyl chitosan (TMC) system in order to study its potential application for the delivery of silibinin in T47D cultured under three-dimensional (3D) and two-dimensional (2D) conditions. To study the effect of nanodrug on miRNAs expression, we evaluated quantitative expression of miRNA-21 and miRNA-15a as well as miR-141 and miR-200c which act as oncogene and tumour suppressors by real-time PCR. Results demonstrated that the mechanism of nanodrug action as well as the response of tumour cells differed in 3D culture as compared to 2D. Delivery of silibinin-loaded niosomes coated with TMC was found to be more effective in inhibiting the growth of tumour cells and inducing apoptosis than free silibinin administration. In silibinin‐treated cells, death occurred in a dose- and time- dependent manner by induction of apoptosis and alteration of the cell cycle. Real-time PCR analysis revealed a decrease in miR-21, miR-15a and miR-141while increase in miR-200c expression levels was observed in silibinin-treated cells relative to the levels in the untreated cells. The results show that nanodrug delivery was more effective than free silibinin administration in changing the level of miRNAs expression in cancer cells. Therefore, niosomal nanostructure with TMC could be a suitable vehicle for hydrophobic compounds, such as silibinin, by improving their action in cancer therapy.

Preparation of N, N, N-trimethyl chitosan via a novel approach using dimethyl carbonate

N,N,N-trimehtyl chitosan (TMC) is a water-soluble derivate of chitosan, which has been widely used as a biomedical material due to its excellent biocompatibility, biodegradability and bacterial properties. To date, TMC can only be prepared by the quaternization of chitosan using alkyl halide or dimethyl sulfate. However, alkyl halide and dimethyl sulfate are highly toxic, cancerigenic for humans, and harmful to the environment. This paper puts forward a novel approach to preparing TMC using dimethyl carbonate as a methylation reagent in an ionic liquid. The as-synthesized O-methyl-free TMC was characterized using NMR, FTIR, XRD and TG analyses. The results showed that TMC with a degree of quaternization of 9.11% was successfully obtained and the crystallinity of chitosan decreased with the increasing degree of N-methylation, the thermal stability of TMC was lower than that of chitosan. Furthermore, the effects of the dose of ionic liquid and dimethyl carbonate were disscussed.

Efficient induction of antimicrobial activity with vancomycin nanoparticle-loaded poly(trimethylene carbonate) localized drug delivery system.

Surgery and the local placement of an antibiotic are the predominant therapies to treat chronic osteomyelitis. Vancomycin-loaded N-trimethyl chitosan nanoparticles (VCM/TMC NPs) as a potential drug delivery system have high intracellular penetration and effective intracellular antibacterial activity. This study investigated the effects of a biocompatible material, poly(trimethylene carbonate) (PTMC), to increase the sustained effectiveness of an intracellular antibiotic and its potential application in antibiotic delivery. VCM/TMC NP-PTMC was characterized using scanning electron microscopy and Fourier transform infrared spectroscopy to determine the morphology, stability and chemical interaction of the drug with the polymer. Further, the biodegradation, antibacterial activity, protein adsorption, cell proliferation and drug release characteristics were evaluated. In addition, a Staphylococcus aureus-induced osteomyelitis rabbit model was used to investigate the antibiotic activity and bone repair capability of VCM/TMC NP-PTMC. The results showed that the composite beads of VCM/TMC NPs followed a sustained and slow release pattern and had excellent antibacterial activity and a higher protein adsorption and cell proliferation rate than the VCM-PTMC in vitro. Furthermore, VCM/TMC NP-PTMC inhibits bacteria and promotes bone repair in vivo. Thus, VCM/TMC NP-PTMC might be beneficial in periodontal management to reduce the bacterial load at the infection site and promote bone repair.

Gamma sterilization of diclofenac sodium loaded- N-trimethyl chitosan nanoparticles for ophthalmic use

This study was conducted to investigate the effect of gamma irradiation on physicochemical properties of N-trimethyl chitosan (TMC), diclofenac sodium (DC) and diclofenac sodium loaded N-trimethylchitosan nanoparticles (DC-TMCNs), and to determine suitable doses of gamma rays for sterilization of DC-TMCNs. Physicochemical properties of TMC, DC and DC-TMCNs before and after exposure to gamma rays at various doses were investigated. It was found that gamma irradiation at doses of 5–25kGy did not cause any significant changes in physical and chemical properties of TMC, DC and DC-TMCNs. The bioburden of DC-TMCNs was 1.5×106 CFU/vial. The initial contaminating bacteria were radiosensitive bacteria. A number of microorganisms was reduced to 10−6 after exposure to 9.9kGy of gamma rays. Therefore, DC-TMCNs could be sterilized by gamma irradiation at a dose of 10kGy, which did not alter their physicochemical properties and did not produce any substances toxic to the eye.

Promotion of the transdermal delivery of protein drugs by N-trimethyl chitosan nanoparticles combined with polypropylene electret.

We recently reported that electret, which was prepared by a corona charging system with polypropylene film, could enhance the transdermal delivery of several drugs of low molecular weight. The aim of this study was to investigate whether electret could enhance the transdermal delivery of protein drugs by N-trimethyl chitosan nanoparticles (TMC NPs) prepared by an ionic gelation method. A series of experiments were performed, including in vitro skin permeation assays and anti-inflammatory effects, to evaluate the transdermal delivery of protein drugs by TMC NPs in the presence of electret. The results showed that in the presence of electret, the transdermal delivery of protein drugs in TMC NPs was significantly enhanced, as demonstrated by in vitro permeation studies and confocal laser scanning microscopy. Notably, superoxide dismutase-loaded TMC NPs combined with electret exhibited the best inhibitory effect on the edema of the mouse ear. TMC NPs combined with electret represent a novel platform for the transdermal delivery of protein drugs.

Characterization of pDNA-TMC Nanoparticle Interaction and Stability

Formulation of nanoparticulate DNA vaccines requires the assessment of stability and integrity of the components implicated. Stability of cationic nanoparticles made of N-trimethyl chitosan and chondroitin sulfate (TMC nanoparticles) was investigated in aqueous solution and after freeze-drying by characterization of their size, polydispersity index (PDI), and zeta potential. Furthermore, the structural integrity of plasmid DNA (pDNA) on adsorption to the nanoparticle surface was investigated. Agarose gel electrophoresis showed DNA retention when applied with the nanocarrier, suggesting that pDNA adsorption on nanoparticles took place. In circular dichroism (CD) spectra, ellipticity of pDNA decreased at 280 nm and increased at 245 nm, and the maximum wavelength shifted from 275 nm to 285 nm when nanoparticles were present. Once released from the particles, the secondary structure of the plasmid was retained in its native form. pDNA release from pDNA-TMC nanoparticles was indicated by a rise in zeta potential from initially -32 mV (pDNA adsorbed to particles) to 14 mV during one hour, and to 36 mV after 24 hours. Unloaded TMC nanoparticles remained stable in suspension for 24 hours, maintaining diameters of around 200 nm, and zeta potential values of approximately 38 mV. Freeze-drying with sucrose could ensure storage for 30 days, with minimal increase in size (291 nm) and charge (62 mV). In conclusion, TMC nanoparticles may potentially be freeze-dried in the presence of sucrose to be stored for prolonged periods of time. Furthermore, pDNA was successfully adsorbed to the cationic nanoparticles and remained intact after being released.

Enhancing insulin oral absorption by using mucoadhesive nanoparticles loaded with LMWP-linked insulin conjugates

Although significant progress has been achieved, effective oral delivery of protein drugs such as insulin by nanoparticle-based carrier systems still faces certain formidable challenges. Considerable amount of protein drug is released from the nanoparticles (NPs) in the gastrointestinal (GI) tract. Because of their low permeability through the intestinal mucosa, the released protein would be soon degraded by the large amount of proteases in the GI tract. Herein, we report an oral insulin delivery system that can overcome the above-mentioned problems by mucoadhesive NPs (MNPs) loaded with cell penetrating peptide-linked insulin conjugates. On one hand, after conjugation with low molecular weight protamine (LMWP), a cell penetrating peptide (CPP), insulin showed greatly improved permeability through intestinal mucus layer and epithelia. On the other hand, the mucoadhesive N-trimethyl chitosan chloride-coated PLGA nanoparticles (MNPs) that were loaded with conjugates enhanced the retention in the intestinal mucus layer. By adopting this delivery strategy, the LMWP-insulin conjugates released from the MNPs could be deprived from enzymatic degradation, due to the short distance in reaching the epithelia and the high permeation of the conjugates through epithelia. The oral delivery system of insulin designed by us showed a long-lasting hypoglycemia effect with a faster onset in diabetic rats. The pharmacological availability of orally delivered conjugates-loaded MNPs was 17.98±5.61% relative to subcutaneously injected insulin solution, with a 2-fold higher improvement over that by MNPs loaded with native insulin. Our results suggested that conjugation with CPP followed by encapsulation in MNPs provides an effective strategy for oral delivery of macromolecular therapeutics.

Acyclovir Entrapped N-Trimethyl Chitosan Nanoparticles for Oral Bioavailability Enhancement

Objective: The aim of the study was to evaluate a nanoparticulate system composed of Ntrimethyl chitosan (TMC) for improving the oral bioavailability of Acyclovir (ACV). Methods: TMC was prepared by methylation of chitosan and characterized by H-NMR spectroscopy. The ionic gelation method was used to prepare ACV loaded TMC nanoparticles. Non-everted sac technique was used to assess ex vivo permeation in rats. A pharmacokinetic study of the optimized formulation was carried out in male Wistar rats in comparison with ACV alone. Results: Ex vivo studies exhibited a significant rise in the permeation of ACV from the rat intestinal membrane when formulated as nanoparticles. The results showed an increase in plasma concentration of ACV from the nanoformulation and significant difference (p < 0.05) in pharmacokinetic parameters as compared to pure drug, ACV. Conclusion: The results suggest that higher oral delivery of ACV can be achieved by combining the benefits of both TMC and nanoparticles.

Formulation of insulin-loaded N-trimethyl chitosan microparticles with improved efficacy for inhalation by supercritical fluid assisted atomization

Supercritical fluid assisted atomization introduced by a hydrodynamic cavitation mixer (SAA-HCM) was proposed as a green technique to fabricate insulin-loaded dry powders for inhalation administration. N-trimethyl chitosan (TMC), a polymeric mucoadhesive absorption enhancer, was synthesized and successfully micronized from aqueous solution using SAA-HCM. The prepared well-defined spherical TMC microparticles with preserved structure and thermal stability were potential carriers for delivery of proteins. Then, insulin-loaded TMC microparticles with high loading efficiency were coprecipitated from aqueous solutions using SAA-HCM without use of any organic solvents. The polymer/protein ratio revealed to be a factor influencing the particle morphology, and non-coalescing composite microparticles in amorphous state mainly ranging from 1μm to 5μm could be obtained in this work. Aerodynamic properties were assessed by next generation impactor (NGI) and the mass median aerodynamic diameter (MMAD) lied inside the inhalable range of 1–5μm, while fine particle fraction (FPF) reached above 60%. The structural integrity of encapsulated insulin was confirmed by HPLC, circular dichroism and fluorescence spectroscopy. In vivo study demonstrated that TMC could enhance the absorption and bioavailability of the pulmonarily administered insulin formulation for SD rats. These results suggest that TMC microparticles could be efficiently prepared as a promising vehicle for drug delivery, and SAA-HCM is a promising technique to prepare inhalable polymer/protein composite dry powders.

Signal amplification strategy using gold/N-trimethyl chitosan/iron oxide magnetic composite nanoparticles as a tracer tag for high-sensitive electrochemical detection.

This study presents a novel signal amplification method for high-sensitive electrochemical immunosensing. Gold (Au)/N-trimethyl chitosan (TMC)/iron oxide (Fe3O4) (shell/shell/core) nanocomposite was used as a tracing tag to label antibody. The tag was shown to be capable of amplifying the recognition signal by high-density assembly of Au nanoparticles (NPs) on TMC/Fe3O4 particles. The remarkable conductivity of AuNPs provides a feasible pathway for electron transfer. The method was found to be simple, reliable and capable of high-sensitive detection of human serum albumin as a model, down to 0.2 pg/ml in the range of 0.25-1000 pg/ml. Findings of the present study would create new opportunities for sensitive and rapid detection of various analytes.

Liposomes coated with N-trimethyl chitosan to improve the absorption of harmine in vivo and in vitro.

In this study, harmine liposomes (HM-lip) were prepared through the thin-film hydration–pH-gradient method and then coated with N-trimethyl chitosan (TMC). Particle size, zeta potential, entrapment efficiency, and in vitro release of HM-lip and TMC-coated harmine liposomes (TMC-HM-lip) were also determined. Sprague Dawley rats were further used to investigate the pharmacokinetics in vivo. Retention behavior in mouse gastrointestinal tract (GIT) was studied through high-performance liquid chromatography and near-infrared imaging. Degradation was further evaluated through incubation with Caco-2 cell homogenates, and a Caco-2 monolayer cell model was used to investigate the uptake and transport of drugs. HM-lip and TMC-HM-lip with particle size of 150–170 nm, an entrapment efficiency of about 81%, and a zeta potential of negative and positive, respectively, were prepared. The release of HM from HM-lip and TMC-HM-lip was slower than that from HM solution and was sensitive to pH. TMC-HM-lip exhibited higher oral bioavailability and had prolonged retention time in GIT. HM-lip and TMC-HM-lip could also protect HM against degradation in Caco-2 cell homogenates. The uptake amount of TMC-HM-lip was higher than that of HM and HM-lip. TMC-HM-lip further demonstrated higher apparent permeability coefficient (Papp) from the apical to the basolateral side than HM and HM-lip because of its higher uptake and capability to open tight junctions in the cell monolayers. TMC-HM-lip can prolong the retention time in the GIT, protect HM against enzyme degradation, and improve transport across Caco-2 cell monolayers, thus enhancing the oral bioavailability of HM.

Improved oral delivery of resveratrol from N-trimethyl chitosan-g-palmitic acid surface-modified solid lipid nanoparticles

Despite the therapeutic effects of resveratrol, its clinical application is restricted by its poor oral bioavailability, low water solubility, and instability. Solid lipid nanoparticles (SLNs)-based drug delivery systems have been shown to provide excellent support for the delivery of hydrophobic drugs. The poor stability and burst release behavior in stomach acidic pH conditions of SLNs result in increased aggregation of the particles in the gastrointestinal environment, limiting the success of these particles as an oral delivery system for hydrophobic drugs. N-trimethyl chitosan (TMC) graft palmitic acid (PA) (TMC-g-PA) mucoadhesive copolymer was hypothesized to be a promising candidate for the surface modification of PA-decorated resveratrol-loaded SLNs to stabilize SLNs and circumvent all the above mentioned obstacles. TMC and TMC-g-PA copolymers were therefore synthesized and characterized by 1H-nuclear magnetic resonance (1H NMR) and Fourier-transformed infra-red (FT-IR) spectroscopy. Resveratrol-loaded SLNs (SLRNs) that comprised Precirol ATO 5, PA, Gelucire 50/13, Tween 80, and resveratrol as well as TMC-g-PA SLRNs were formulated and characterized in terms of physicochemical properties, stability, cytotoxicity, and in vitro and in vivo effects. The in vitro release studies of TMC-g-PA SLRNs demonstrated negligible release of resveratrol in simulated gastric and sustained release in simulated intestinal conditions and the relative bioavailability of resveratrol was furthermore found to be 3.8-fold higher from TMC-g-PA SLRNs than that from resveratrol suspension. Overall, the findings reported here indicate that TMC-g-PA SLRNs represent a potential oral drug delivery system for resveratrol.

Ocular delivery of cyanidin-3-glycoside in liposomes and its prevention of selenite-induced oxidative stress

Context: Cataracts have become the leading cause of blindness around the world, which is mainly mediated by oxidative stress.Objective: N-trimethyl chitosan (TMC)-coated liposomes of cyanidin-3-glycoside (C3G) (C3G-TCL) were prepared to attenuate oxidative stress induced by selenite sodium in rats.Materials and methods: C3G-TCL were prepared by reverse-phase evaporation method and then coated with self-synthesized TMC. The physicochemical properties were determined. A gamma-scintigraphy study was employed to evaluate the precorneal elimination of the radioactive preparations. The transcorneal visualization for fluorescence-labeled samples was determined by confocal laser scanning microscopy (CLSM). The in vivo anti-oxidative study using C3G-TCL was carried out in rats with selenite-induced cataracts by topical administration.Results: The sphere-like morphological characterization of the vesicles was confirmed by TEM, with a size of 158.3 ± 2.8 nm and a zeta potential of 31.7 mV. The encapsulation efficiency was (53.7 ± 0.2) % as measured by ultrafiltration. C3G-TCL showed a 3.3-fold increment in precorneal residence time when compared with that of the 99mTc-solution. A TMC coating enhanced the transepithelial transport of liposomes to a depth of 40-μm in the cornea. Moreover, C3G-TCL could significantly elevate the activity of superoxide dismutase and catalase in lens and also show a considerable reversal of reduced glutathione activity. The lipid peroxidation in lens was strongly prevented when compared with that of groups treated with uncoated C3G-loaded liposomes.Discussion and conclusion: The coating material TMC for liposomes helps improve the anti-oxidative effect of C3G in vivo through prolonged residence time on the cornea and improved permeability in the corneal epithelium.