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N-trimethyl chitosan of two quaternization degrees, DQ = 20 and 80 mol% and labeled as TMC20 and TMC80, were synthesized and characterized by 1H NMR. Polyelectrolyte complexes (PECs) of TMC/alginate (TMC/ALG) were prepared at pHs 2, 7 and 10 by mixing the aqueous solutions of unlike polymers. The PECs were characterized through infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTG) and wide-angle X-ray scattering (WAXS). Using the TMC of DQ = 20 mol% and following the same methodology for preparing the PECs, beads of TMC20/ALG were obtained at pH 2 and loaded with curcumin (CUR) at pH 6.0–6.5. The morphology of the beads was evaluated by scanning electron microscopy (SEM). Studies in vitro of the controlled release of CUR from beads were investigated in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF) and treated using conventional and partition-diffusion models. Results indicated that the beads based on TMC20 and ALG presented potential as drug-carrier to improve the solubility and biological activity of CUR at pH close to physiological one.

The effect of N-trimethylchitosan chloride on the intestinal permeability of capreomycin sulfate, a polypeptide antibiotic, using an in vitro model, was evaluated. To improve the mucoadhesivity and permeation enhancer properties of N-trimethylchitosan chloride, it was used a synthetic pathway that selectively alkylated the amino groups and not the hydroxyl groups in carbons 3 and 6, which decreases the potency of the polymer, leading to use higher quantities and limit its potential as a functional excipient. This non-methoxylated derivative of the studied polymer reduced in a reversible way the transepithelial electrical resistance of CaCo-2 monolayers at concentrations not higher than 0.003 % w/v, indicating that the absence of steric hindrance from methoxyl groups improves the effect of N-trimethylchitosan chloride, but at expense of a narrow range of action and higher cytotoxicity. The results of in vitro permeation studies conducted in bicameral Transwell® systems suggested that the permeability of capreomycin sulfate is low, although it was not established if the transport is exclusively paracellular or membrane transporters are involved. By using increasing concentrations of the polymer in the range of 0.001 - 0.003% w/v, it was observed a slight increase in the transport of capreomycin. Therefore, it was concluded that further studies should use N-trimethylchitosan chloride with a lower degree of quaternization or controlled methoxylation, in order to increase the mass to use and obtain a product that is able to remain retained in the intestinal lumen and which in turn interacts with the epithelium., Colegio de Farmacéuticos de la Provincia de Buenos Aires

Microneedle-based transcutaneous immunisation is an appealing alternative to the classical manner of injecting vaccines by intramuscular or subcutaneous route. Importantly, as a consequence of the fact that the skin is in direct contact with the environment and should protect the body against pathogens, it contains more antigen presenting cells, such as dendritic cells than the muscles or subcutaneous tissue and thereby offers the possibility to induce a more effective immune response. The combination of microneedles and adjuvanted subunit vaccines may offer effective vaccination whereas ensuring patient safety and vaccine application in a painless manner. The principal aim of this thesis was to design subunit vaccine formulations that can be combined with microneedles for transcutaneous immunisation. The approaches described in this thesis have generated new insights into the main requirements for transcutaneous immunisation. Microneedles definitively have the potential to be an excellent utensil for the delivery of vaccines into the skin. However, the skin is a very elastic organ and the actual conduits formed by microneedle pre-treatment will be considerably smaller than the diameter of the microneedles. Therefore, a small antigen-adjuvant entity is the preferred formulation, as it will be transported efficiently through the microneedle conduits while it retains the co-delivery of antigen and adjuvant.

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Lymphatic metastasis plays a critical role in ovarian cancer, indicates poor prognoses and correlates to the majority of cancer deaths. Camptothecin derivatives exhibit promising activity for the treatment of solid tumors because of its specific inhibition of eukaryotic DNA topoisomerase I. Yet, its application is hindered due to extreme water insolubility and severe side effects. It is essential to establish an efficient and safe protocol for the administration of camptothecin versus tumor metastasis and growth. In the current research, we encapsulated camptothecin with N-trimethyl chitosan (CPT-TMC) to increase its water-solubility and lower its side effects, and tested it on a high potential lymphogenous metastatic model of human ovarian cancer. In the prophase study, we successfully transfected SKOV3 cells with VEGF-D recombinant plasmid DNA (pcDNA3.1(+)/VEGF-D) to construct a cell line named SKOV3/VEGF-D and establish a feasible lymphogenous metastatic model. The antitumor and antimetastatic activities of CPT-TMC were evaluated in nude mice subcutaneously inoculated with SKOV3/VEGF-D cells at the left hindlimb claw pad. The tumor-bearing mice were divided randomly into four groups and treated twice per week for three weeks. Evan's Blue Dye was used to delineate functional lymphatic vessels. Lymphatic metastasis rates were detected by hematoxylin and eosin (HE) staining. Expression of VEGF-D and MMP-9 were investigated by immunohistochemistry. In contrast to controls, administration of CPT-TMC achieved effective inhibition in primary tumor volume and lymphogenous metastasis, yet without apparent systemic toxic effects. These effects were associated with simultaneously down-regulated VEGF-D and MMP-9 expression, significantly decreased tumor-associated lymphatic and blood sprouts, tremendously reduced systemic toxic effects, dramatically increased tumor apoptotic index. Our data indicate that CPT-TMC is superior to CPT by maximizing its anticancer and antimetastatic activities with minimal toxicity on hosts. CPT-TMC may become a potentially therapeutic strategy against human advanced ovarian cancer.

Purpose The purpose of this study was to gain insight into the delivery and immunogenicity of N-trimethyl chitosan (TMC) adjuvanted diphtheria toxoid (DT) formulations applied transcutaneously with microneedles. Methods Mice were vaccinated with DT-loaded TMC nanoparticles, a solution of TMC and DT (TMC/DT) or DT alone. The formulations were applied onto the skin before or after microneedle treatment with two different 300-µm-long microneedle arrays and also injected intradermally (ID). As a positive control, alum-adjuvanted DT (DT-alum) was injected subcutaneously (SC). Ex vivo confocal microscopy studies were performed with rhodamine-labelled TMC. Results Independent of the microneedle array used and the sequence of microneedle treatment and vaccine application, transcutaneous immunisation with the TMC/DT mixture elicited 8-fold higher IgG titres compared to the TMC nanoparticles or DT solution. The toxin-neutralising antibody titres from this group were similar to those elicited by SC DT-alum. After ID immunisation, both TMC-containing formulations induced enhanced titres compared to a DT solution. Confocal microscopy studies revealed that transport of the TMC nanoparticles across the microneedle conduits was limited compared to a TMC solution. Conclusions In conclusion, TMC has an adjuvant function in transcutaneous immunisation with microneedles, but only if applied in a solution. Electronic Supplementary Material The online version of this article (doi:10.1007/s11095-010-0182-y) contains supplementary material, which is available to authorized users.

The purpose of this study was the development and physicochemical and immunological characterization of intranasal (i.n.) vaccine formulations of whole inactivated influenza virus (WIV) coated with N,N,N-trimethyl chitosan (TMC).Synthesized TMCs with a degree of quarternization of 15% (TMC15) or 37% (TMC37) were tested in vitro for their ability to decrease the transepithelial resistance (TEER) of an epithelial cell monolayer. TMC15- and TMC37-coated WIV (TMC15-WIV and TMC37-WIV) were characterized by zeta potential measurements, dynamic light scattering, electron microscopy and gel permeation chromatography. Mice were vaccinated i.n. with selected vaccine formulations and immunogenicity was determined by measuring serum hemagglutination inhibition (HI) and serum IgG, IgG1 and IgG2a/c titers. Also a pulse-chase study with TMCs in solution administered i.n. 2 h prior to WIV was performed. Protective efficacy of vaccination was determined by an aerosol virus challenge.TMC37 induced a reversible decrease in TEER, suggesting the opening of tight junctions, whereas TMC15 did not affect TEER. Simple mixing of (negatively charged) WIV with TMC15 or TMC37 resulted in positively charged particles with TMCs being partially bound. Intranasal immunization with TMC37-WIV or TMC15-WIV induced stronger HI, IgG, IgG1 and IgG2a/c titers than WIV alone. TMC37-WIV induced the highest immune responses. Both TMC15-WIV and TMC37-WIV provided protection against challenge, whereas WIV alone was not protective. Intranasal administration of TMC prior to WIV did not result in significant immune responses, indicating that the immunostimulatory effect of TMC is primarily based on improved i.n. delivery of WIV.Coating of WIV with TMC is a simple procedure to improve the delivery and immunogenicity of i.n. administered WIV and may enable effective i.n. vaccination against influenza.

Many water-soluble N -substituted chitosan derivatives have been prepared having the typical -NH-CH 2 - linkage. Both the Michael reaction and alkylation with monochloroacetic acid at pH 8 - 8.5 offer relatively simple ways for their synthesis. Keywords: N-carboxymethyl chitosan; N-dicarboxymethyl chitosan; N-carboxyethyl chitosan; N-carboxybutyl chitosan; N-trimethyl chitosan; 5-methylpyrolidinone chitosan AJSTD Vol.22(3) pp.261-270 (2005)

The research described in this thesis was aimed at evaluating the potential of particulate TMC carrier systems for delivering therapeutic proteins and antigens across respiratory (nasal and pulmonary) epithelia. To this end, TMC nanoparticles and microparticles loaded with different model proteins as well as a therapeutic protein (insulin) and antigens (influenza subunit antigen and diphtheria toxoid) were prepared and characterized, and their efficacy for nasal and pulmonary delivery of these proteins was investigated in animal models. The results presented in this thesis show that TMC formulations are promising for nasal and pulmonary delivery of therapeutic proteins and vaccines.

The research described in this thesis was aimed at evaluating the potential of particulate TMC carrier systems for delivering therapeutic proteins and antigens across respiratory (nasal and pulmonary) epithelia. To this end, TMC nanoparticles and microparticles loaded with different model proteins as well as a therapeutic protein (insulin) and antigens (influenza subunit antigen and diphtheria toxoid) were prepared and characterized, and their efficacy for nasal and pulmonary delivery of these proteins was investigated in animal models. The results presented in this thesis show that TMC formulations are promising for nasal and pulmonary delivery of therapeutic proteins and vaccines.

Xiao-juan Hu,1,* Yang Liu,1,* Xiao-feng Zhou,2,3 Qiao-ling Zhu,1 Yong-yan Bei,1 Ben-gang You,1 Chun-ge Zhang,1 Wei-liang Chen,1 Zhou-li Wang,1 Ai-jun Zhu,1 Xue-nong Zhang,1 Yu-jiang Fan4 1Department of Pharmaceutics, College of Pharmaceutical Sciences, Soochow University, Suzhou, People's Republic of China; 2College of Radiological Medicine and Protection, Soochow University, People's Republic of China; 3Changshu Hospital of Traditional Chinese Medicine, Changshu, People's Republic of China; 4Department of Clinical Laboratory, Second People's Hospital of Akesu, Akesu, People's Republic of China *These authors contributed equally to this work Abstract: Novel amphiphilic chitosan derivatives (N-caprinoyl-N-trimethyl chitosan [CA-TMC]) were synthesized by grafting the hydrophobic moiety caprinoyl (CA) and hydrophilic moiety trimethyl chitosan to prepare carriers with good compatibility for poorly soluble drugs. Based on self-assembly, CA-TMC can form micelles with sizes ranging from 136 nm to 212 nm. The critical aggregation concentration increased from 0.6 mg · L-1 to 88 mg · L-1 with decrease in the degree of CA substitution. Osthole (OST) could be easily encapsulated into the CA-TMC micelles. The highest entrapment efficiency and drug loading of OST-loaded CA-TMC micelles(OST/CA-TMC) were 79.1% and 19.1%, respectively. The antitumor efficacy results show that OST/CA-TMC micelles have significant antitumor activity on Hela and MCF-7 cells, with a 50% of cell growth inhibition (IC50) of 35.8 and 46.7 µg · mL-1, respectively. Cell apoptosis was the main effect on cell death of Hela and MCF-7 cells after OST administration. The blank micelles did not affect apoptosis or cell death of Hela and MCF-7 cells. The fluorescence imaging results indicated that OST/CA-TMC micelles could be easily uptaken by Hela and MCF-7 cells and could localize in the cell nuclei. These findings suggest that CA-TMC micelles are promising carriers for OST delivery in cancer therapy. Keywords: N-trimethyl chitosan, micelle solubilization, antitumor activity

Chitosan was N-permethylated by reaction with formaldehyde and sodium borohydride under controlled conditions (pH 4·0, 15°C, reaction times 12 and 8 h, respectively). The N-permethylated chitosan was reacted with methyl iodide at 35°C and N-trimethyl chitosan iodide with a quaternary nitrogen degree of 60% was obtained. This material may have uses as an antibiotic and an ion exchange material.

We present here the synthesis of a highly O-carboxymethylated chitosan derivative. First, an improved protocol for the two-step synthesis of N-trimethyl chitosan (TMC) from chitosan was developed, yielding a maximum degree of quaternization (DQ) of up to 46.6%. Successively, the chitosan derivative O-carboxymethyl-N-trimethyl chitosan (CMTMC) was synthesized from the TMC obtained by applying an optimized synthesis pathway. In contrast to previous reports, the optimized protocol was shown to yield very high rates (>85%) of O-carboxymethylation of CMTMC, as shown by (1)H NMR and heteronuclear single quantum correlation ((1)H-(13)C HSQC). Finally, in vitro cytocompatibility (viability >80%) of the polymer was demonstrated using human fibroblasts.