Formulation and biological activity of antineoplastic proteoglycans derived from Mycobacterium vaccae in chitosan nanoparticles

Impacts of chitosan and its nanoformulations on the metabolic syndromes: a review

A significant public health issue worldwide is metabolic syndrome, a cluster of metabolic illnesses that comprises insulin resistance, obesity, dyslipidemia, hyperglycemia, and hypertension. The creation of natural treatments and preventions for metabolic syndrome is crucial. Chitosan, along with its nanoformulations, is an oligomer of chitin, the second-most prevalent polymer in nature, which is created via deacetylation. Due to its plentiful biological actions in recent years, chitosan and its nanoformulations have drawn much interest. Recently, the chitosan nanoparticle-based delivery of CRISPR-Cas9 has been applied in treating metabolic syndromes. The benefits of chitosan and its nanoformulations on insulin resistance, obesity, diabetes mellitus, dyslipidemia, hyperglycemia, and hypertension will be outlined in the present review, highlighting potential mechanisms for the avoidance and medication of the metabolic syndromes by chitosan and its nanoformulations.

Chitosan-functionalized bioplatforms and hydrogels in breast cancer: immunotherapy, phototherapy and clinical perspectives

Breast cancer is the most common and malignant tumor among women. Chitosan (CS)-based nanoparticles have been introduced into breast cancer therapy as a way to increase the targeted delivery of drugs and genes to the tumor site. CS nanostructures suppress tumorigenesis by enhancing both the targeted delivery of cargo (drug and gene) and its accumulation in tumor cells. The tumor cells internalize CS-based nanoparticles through endocytosis. Moreover, chitosan nanocarriers can also induce phototherapy-mediated tumor ablation. Smart and multifunctional types of CS nanoparticles, including pH-, light- and redox-responsive nanoparticles, can be used to improve the potential for breast cancer removal. In addition, the acceleration of immunotherapy by CS nanoparticles has also been achieved, and there is potential to develop CS-nanoparticle hydrogels that can be used to suppress tumorigenesis.

A Review of Chitosan and Chitosan Nanofiber: Preparation, Characterization, and Its Potential Applications

Chitosan is produced by deacetylating the abundant natural chitin polymer. It has been employed in a variety of applications due to its unique solubility as well as its chemical and biological properties. In addition to being biodegradable and biocompatible, it also possesses a lot of reactive amino side groups that allow for chemical modification and the creation of a wide range of useful derivatives. The physical and chemical characteristics of chitosan, as well as how it is used in the food, environmental, and medical industries, have all been covered in a number of academic publications. Chitosan offers a wide range of possibilities in environmentally friendly textile processes because of its superior absorption and biological characteristics. Chitosan has the ability to give textile fibers and fabrics antibacterial, antiviral, anti-odor, and other biological functions. One of the most well-known and frequently used methods to create nanofibers is electrospinning. This technique is adaptable and effective for creating continuous nanofibers. In the field of biomaterials, new materials include nanofibers made of chitosan. Numerous medications, including antibiotics, chemotherapeutic agents, proteins, and analgesics for inflammatory pain, have been successfully loaded onto electro-spun nanofibers, according to recent investigations. Chitosan nanofibers have several exceptional qualities that make them ideal for use in important pharmaceutical applications, such as tissue engineering, drug delivery systems, wound dressing, and enzyme immobilization. The preparation of chitosan nanofibers, followed by a discussion of the biocompatibility and degradation of chitosan nanofibers, followed by a description of how to load the drug into the nanofibers, are the first issues highlighted by this review of chitosan nanofibers in drug delivery applications. The main uses of chitosan nanofibers in drug delivery systems will be discussed last.

Evaluation of methotrexate encapsulated polymeric nanocarrier for breast cancer treatment

Herein, Methotrexate-loaded chitosan nanoparticles (Meth-Cs-NPs) was formulated through single-step self-assembly by incorporating the ionic-gelation method. Chitosan was cross-linked with Methotrexate via a sodium tripolyphosphate (STPP) where 49 % Methotrexate was loaded in the nanoparticles (∼143 nm) and zeta potential of 34 ± 3 mV with an entrapment efficiency of 87 %. The efficacy of nanoparticles was assessed for chemically induced breast cancer treatment in the Sprague Dawley rats model. These Meth-Cs-NPs followed the Korsmeyer-Peppas model in-vitro release kinetics. Nanoparticles were further evaluated for in-vitro efficacy on triple-negative breast cancer (MDA-MB-231) cell lines. The MTT assay studies revealed that even slight exposure to Meth-Cs-NPs (IC₅₀ = 15 µg/mL) caused 50 % cell death in 24 h. Further, hemocompatibility studies of Meth-Cs-NPs were performed, deciphered that Meth-Cs-NPs were biocompatible (hemolysis < 2 %). Additional cellular uptake was evaluated by confocal imaging. Moreover, an in-vivo pharmacokinetic study of nanoparticles in rats displayed increased plasma concentration of the drug and retention time, whereas a decrease in cellular clearance compared to free Methotrexate. Further, anti-tumor efficacy studies revealed that nanoparticles could reduce tumor volume from 1414 mm³→385 mm³ compared to free Methotrexate (1414 mm³→855 mm³). The current study presents encouraging prospects of Meth-Cs-NPs to be used as a viable breast cancer treatment modality.

Nanochitosan: Commemorating the Metamorphosis of an ExoSkeletal Waste to a Versatile Nutraceutical

Chitin (poly-N-acetyl-D-glucosamine) is the second (after cellulose) most abundant organic polymer. In its deacetylated form-chitosan-becomes a very interesting material for medical use. The chitosan nano-structures whose preparation is described in this article shows unique biomedical value. The preparation of nanochitosan, as well as the most vital biomedical applications (antitumor, drug delivery and other medical uses), have been discussed in this review. The challenges confronting the progress of nanochitosan from benchtop to bedside clinical settings have been evaluated. The need for inclusion of nano aspects into chitosan research, with improvisation from nanotechnological inputs has been prescribed for breaking down the limitations. Future perspectives of nanochitosan and the challenges facing nanochitosan applications and the areas needing research focus have been highlighted.

Applications of chitosan and chitosan based metallic nanoparticles in agrosciences-A review

The second most abundant biological macromolecule, next to cellulose is Chitosan. It is a versatile naturally occurring hydrophilic polysaccharide, derived as a deacetylated form of chitin. Due to its biocompatibility, biodegradability and antimicrobial activity, it has become a significant area of research towards drug delivery system, plant growth promotion, anti-pathogenic potentiality, seed priming and in plant defense mechanism. Various synthetic strategies have been established in recent years that couples different metals with chitosan nanoparticles. Metals like silver, copper, zinc, iron and nickel are highly compatible to form chitosan metallic nanoparticles and are proved to be non-toxic to the agricultural plant system. This review highlights the mode of action of nanochitosan on Gram-positive and Gram-negative bacteria in a distinguished manner as well as its action on fungi. A prime focus has been given on the skeletal framework of the metallic nanochitosan particles. Our study also projects the antimicrobial mechanism of chitosan based on its physiochemical properties, environmental factors and the type of organism on which it acts. Moreover, the mechanism for stimulation of plant immunity by metallic nanochitosan has also been reviewed. Our study relies on the conclusion that chitosan metallic nanoparticles showed enhanced anti-pathogenic and plant growth promoting activity in comparison to bulk chitosan.

Mycobacteria-Based Vaccines as Immunotherapy for Non-urological Cancers

The arsenal against different types of cancers has increased impressively in the last decade. The detailed knowledge of the tumor microenvironment enables it to be manipulated in order to help the immune system fight against tumor cells by using specific checkpoint inhibitors, cell-based treatments, targeted antibodies, and immune stimulants. In fact, it is widely known that the first immunotherapeutic tools as immune stimulants for cancer treatment were bacteria and still are; specifically, the use of Mycobacterium bovis bacillus Calmette-Guérin (BCG) continues to be the treatment of choice for preventing cancer recurrence and progression in non-invasive bladder cancer. BCG and also other mycobacteria or their components are currently under study for the immunotherapeutic treatment of different malignancies. This review focuses on the preclinical and clinical assays using mycobacteria to treat non-urological cancers, providing a wide knowledge of the beneficial applications of these microorganisms to manipulate the tumor microenvironment aiming at tumor clearance.

Chitosan-based particulate systems for drug and vaccine delivery in the treatment and prevention of neglected tropical diseases

Neglected tropical diseases (NTDs) are a diverse group of infections which are difficult to prevent or control, affecting impoverished communities that are unique to tropical or subtropical regions. In spite of the low number of drugs that are currently used for the treatment of these diseases, progress on new drug discovery and development for NTDs is still very limited. Therefore, strategies on the development of new delivery systems for current drugs have been the main focus of formulators to provide improved efficacy and safety. In recent years, particulate delivery systems at micro- and nanosize, including polymeric micro- and nanoparticles, liposomes, solid lipid nanoparticles, metallic nanoparticles, and nanoemulsions, have been widely investigated in the treatment and control of NTDs. Among these polymers used for the preparation of such systems is chitosan, which is a marine biopolymer obtained from the shells of crustaceans. Chitosan has been investigated as a delivery system due to the versatility of its physicochemical properties as well as bioadhesive and penetration-enhancing properties. Furthermore, chitosan can be also used to improve treatment due to its bioactive properties such as antimicrobial, tissue regeneration, etc. In this review, after giving a brief introduction to neglected diseases and particulate systems developed for the treatment and control of NTDs, the chitosan-based systems will be described in more detail and the recent studies on these systems will be reviewed. Graphical abstract.

Bio- and Fossil-Based Polymeric Blends and Nanocomposites for Packaging: Structure⁻Property Relationship

In the present review, the possibilities for blending of commodities and bio-based and/or biodegradable polymers for packaging purposes has been considered, limiting the analysis to this class of materials without considering blends where both components have a bio-based composition or origin. The production of blends with synthetic polymeric materials is among the strategies to modulate the main characteristics of biodegradable polymeric materials, altering disintegrability rates and decreasing the final cost of different products. Special emphasis has been given to blends functional behavior in the frame of packaging application (compostability, gas/water/light barrier properties, migration, antioxidant performance). In addition, to better analyze the presence of nanosized ingredients on the overall behavior of a nanocomposite system composed of synthetic polymers, combined with biodegradable and/or bio-based plastics, the nature and effect of the inclusion of bio-based nanofillers has been investigated.

Preparation and application of micro/nanoparticles based on natural polysaccharides

Polysaccharides have attracted more and more attentions and been recognized to be the most promising materials in recent years because of their outstanding merits such as easily available, non-toxic, biocompatible, biodegradable, and easily modified. Considerable research efforts have been directed toward developing polysaccharides-based micro/nanoparticles (PM/NPs). The new major studies of PM/NPs over the past few years are outlined in this review. Methods of preparation, including self-assembly, ionic-gelation, complex coacervation, emulsification, and desolvation method and some others, are summarized. Different applications of PM/NPs in the field of drug-delivery system are highlighted. Besides, another novel application of PM/NPs that are used as emulsifiers to stabilize Pickering emulsion is also introduced. These environmental-friendly particle emulsifiers have received reasonable attention due to their novel applications, especially in food, cosmetics, and pharmaceutics. From literature surveys, we realized that studies on PM/NP systems for different applications have increased rapidly. Hence, the present review is timely.

Both FA- and mPEG-conjugated chitosan nanoparticles for targeted cellular uptake and enhanced tumor tissue distribution

Both folic acid (FA)- and methoxypoly(ethylene glycol) (mPEG)-conjugated chitosan nanoparticles (NPs) had been designed for targeted and prolong anticancer drug delivery system. The chitosan NPs were prepared with combination of ionic gelation and chemical cross-linking method, followed by conjugation with both FA and mPEG, respectively. FA-mPEG-NPs were compared with either NPs or mPEG-/FA-NPs in terms of their size, targeting cellular efficiency and tumor tissue distribution. The specificity of the mPEG-FA-NPs targeting cancerous cells was demonstrated by comparative intracellular uptake of NPs and mPEG-/FA-NPs by human adenocarcinoma HeLa cells. Mitomycin C (MMC), as a model drug, was loaded to the mPEG-FA-NPs. Results show that the chitosan NPs presented a narrow-size distribution with an average diameter about 200 nm regardless of the type of functional group. In addition, MMC was easily loaded to the mPEG-FA-NPs with drug-loading content of 9.1%, and the drug releases were biphasic with an initial burst release, followed by a subsequent slower release. Laser confocal scanning imaging proved that both mPEG-FA-NPs and FA-NPs could greatly enhance uptake by HeLa cells. In vivo animal experiments, using a nude mice xenograft model, demonstrated that an increased amount of mPEG-FA-NPs or FA-NPs were accumulated in the tumor tissue relative to the mPEG-NPs or NPs alone. These results suggest that both FA- and mPEG-conjugated chitosan NPs are potentially prolonged drug delivery system for tumor cell-selective targeting treatments.

Recent advances of chitosan nanoparticles as drug carriers

Chitosan nanoparticles are good drug carriers because of their good biocompatibility and biodegradability, and can be readily modified. As a new drug delivery system, they have attracted increasing attention for their wide applications in, for example, loading protein drugs, gene drugs, and anticancer chemical drugs, and via various routes of administration including oral, nasal, intravenous, and ocular. This paper reviews published research on chitosan nanoparticles, including its preparation methods, characteristics, modification, in vivo metabolic processes, and applications.

Hydrogel nanoparticles in drug delivery

Hydrogel nanoparticles have gained considerable attention in recent years as one of the most promising nanoparticulate drug delivery systems owing to their unique potentials via combining the characteristics of a hydrogel system (e.g., hydrophilicity and extremely high water content) with a nanoparticle (e.g., very small size). Several polymeric hydrogel nanoparticulate systems have been prepared and characterized in recent years, based on both natural and synthetic polymers, each with its own advantages and drawbacks. Among the natural polymers, chitosan and alginate have been studied extensively for preparation of hydrogel nanoparticles and from synthetic group, hydrogel nanoparticles based on poly (vinyl alcohol), poly (ethylene oxide), poly (ethyleneimine), poly (vinyl pyrrolidone), and poly-N-isopropylacrylamide have been reported with different characteristics and features with respect to drug delivery. Regardless of the type of polymer used, the release mechanism of the loaded agent from hydrogel nanoparticles is complex, while resulting from three main vectors, i.e., drug diffusion, hydrogel matrix swelling, and chemical reactivity of the drug/matrix. Several crosslinking methods have been used in the way to form the hydrogel matix structures, which can be classified in two major groups of chemically- and physically-induced crosslinking.

Characterization of immobilized nuclease P1

To improve the efficiency of the use of nuclease P1, enzyme immobilization technology was applied using nuclease P1. Characterization of immobilized nuclease P1 on different supports was studied. The results showed that the optimum pH and temperature of nuclease P1 immobilized via different supports were enhanced. The immobilized enzyme was obviously stable when stored for long periods and was reusable. The best results were obtained when nuclease P1 was immobilized on chitosan nanoparticles. The nanoparticles were applied to protect the activity of nuclease P1 and improved enzyme activity by 13.17% over that of free nuclease P1 at the same conditions. The Michaelis constant Km and Vmax were determined for free and immobilized enzyme as well.

Preparation of chitosan nanoparticles as carrier for immobilized enzyme

This work investigated the preparation of chitosan nanoparticles used as carriers for immobilized enzyme. The morphologic characterization of chitosan nanoparticles was evaluated by scanning electron microscope. The various preparation methods of chitosan nanoparticles were discussed and chosen. The effect of factors such as molecular weight of chitosan, chitosan concentration, TPP concentration, and solution pH on the size of chitosan nanoparticles was studied. Based on these results, response surface methodology was employed. The results showed that solution pH, TPP concentration, and chitosan concentration significantly affected the size of chitosan nanoparticles. The adequacy of the predictive model equation for predicting the magnitude orders of the size of chitosan nanoparticles was verified effectively by the validation data. Immobilization conditions were investigated as well. The minimum particles size was about 42 +/- 5 nm under the optimized conditions. The optimal conditions of immobilization were as follows: one milligram of neutral proteinase was immobilized on chitosan nanoparticles for about 15 min at 40 degrees C. Under the optimized conditions, the enzyme activity yield was 84.3%.

Chitosan nanoparticles encapsulated vesicular systems for oral immunization: preparation, in-vitro and in-vivo characterization

BSA-loaded chitosan nanoparticles were prepared and encapsulated in vesicles (liposomes and niosomes) to make them acid resistant upon oral administration. Prepared systems were characterized in-vitro for shape, size, entrapment efficiency and stability in simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.5). The immune stimulating activity was studied by measuring serum IgG titre and secretory IgA (sIgA) levels in mucosal secretions following oral administration of various formulations in albino rats. Significantly higher (P < 0.05) serum IgG titres were achieved following oral administration of novel nanoparticulate vesicular formulations as compared with unmodified chitosan nanoparticles. Further, high sIgA levels in mucosal secretions advocated a possible application of chitosan nanoparticle encapsulated in vesicles as an oral vaccine delivery carrier-adjuvant system.

SRL172 (killed Mycobacterium vaccae) may augment the efficacy of trastuzumab in metastatic breast cancer patients

SRL172, non-specific immunological adjuvant downregulates interleukin-4, upregulates interleukin-2 production, switching towards a T-helper-1 response, induces an increase in natural killer cells and activates antigen presenting cells. The human epidermal growth factor receptor 2 gene amplification is frequently observed in a number of primary tumors, suggesting that the overexpression of this growth factor receptor may contribute to transformation and tumorigenesis. Gene amplification occurs in approximately 15-20% of human breast cancers Amplification is associated with aggressive tumor behavior and shortened survival. Trastuzumab, humanized anti-HER-2 antibody targets the HER-2 protein with high affinity. Trastuzumab when used alone or in combination with cytotoxic chemotherapy can induce reasonably durable remissions in a significant percentage of women with metastatic breast cancer whose tumors demonstrate Her-2/neu gene amplification. One of the proposed mechanisms of trastuzumab antitumor action is through antibody dependent cellular cytotoxocity. Pivotal study showed that Trastuzumab+IL-2 resulted in NK cell expansion with enhanced in vitro targeted killing of HER-2-expressing cells. SRL172 by increasing IL-2 production and number of natural killer cells may augment the efficacy of trastuzumab in metastatic breast cancer patients. SRL 172 increases IL-2 production and the number of NK cells in vivo. Based on these data, a clinical trial can be performed to test whether SRL 172 added to trastuzumab is safe and more efficacious.

Physicochemical characterization of chitosan nanoparticles: electrokinetic and stability behavior

Some physical properties of nanogel particles formed by chitosan ionically cross-linked by tripolyphosphate (TPP) have been studied. Electrokinetic properties and colloidal stability were analyzed as a function of pH and ionic strength of the medium. Chitosan particles showed volume phase transitions (swelling/shrinking processes) when the physicochemical conditions of the medium were changed. Experimental data were mainly obtained by electrophoretic mobility measurements and by photon correlation spectroscopy and static light scattering techniques. Chitosan chains possess glucosamine groups that can be deprotonated if the pH increases. Therefore, modification of pH from acid to basic values caused a deswelling process based on a reduction of the intramolecular electric repulsions inside the particle mesh. Electrophoretic mobility data helped to corroborate the above electrical mechanism as responsible for the size changes. Additionally, at those pH values around the isoelectric point of the chitosan-TPP particles, the system became colloidally unstable. Ionic strength variations also induced important structural changes. In this case, the presence of KCl at low and moderate concentrations provoked swelling, which rapidly turned on particle disintegration due to the weakness of chitosan-TPP ionic interactions. These last results were in good agreement with the predictions of gel swelling theory by salt in partially ionized networks.

Modulation of monocyte-tumour cell interactions by Mycobacterium vaccae

Immunotherapy with Mycobacterium vaccae as an adjuvant to chemotherapy has recently been applied to treatment of patients with cancer. One of the mechanisms of antitumour activity of Mycobacterium bovis bacillus Calmette-Guérin (BCG), the prototype immunomodulator, is associated with activation of monocytes/macrophages. These studies were undertaken to determine how M. vaccae affects monocyte tumour cell interactions and, in particular, whether it can prevent or reverse deactivation of monocytes that occurrs following their contact with tumour cells during coculture in vitro. Deactivation is characterised by the impaired ability of monocytes to produce tumour necrosis factor alpha (TNF-alpha), interleukin 12 (IL-12), and enhanced IL-10 secretion following their restimulation with tumour cells. To see whether deactivation of monocytes can be either prevented or reversed, three different strains of M. vaccae--B 3805, MB 3683, and SN 920--and BCG were used to stimulate monocytes before or after exposure to tumour cells. Pretreatment of monocytes with M. vaccae MB 3683, SN 920 and BCG before coculture resulted in increased TNF-alpha and decreased IL-10 production. All strains of M. vaccae and BCG used for treatment of deactivated monocytes enhanced depressed TNF-alpha secretion. Strain SN 920 and BCG increased IL-12 release but only BCG treatment inhibited an enhanced IL-10 production by deactivated monocytes. Thus, although some strains of M. vaccae may either prevent or reverse tumour-induced monocyte deactivation, none of them appears to be more effective than BCG.

Mucosal immunization against respiratory bacterial pathogens

Bacterial respiratory diseases remain a major cause of morbidity and mortality throughout the world. The young and the elderly are particularly susceptible to the pathogens that cause these diseases. Therapeutic approaches remain dependent upon antibiotics contributing to the persistent increases in antibiotic resistance. The main causes of respiratory disease discussed in this review are Mycobacterium tuberculosis, Corynebacterium diphtheriae, Bordatella pertussis, Streptococcus pneumoniae, non-typeable Haemophilus influenzae, Moraxella catarrhalis and Pseudomonas aeruginosa. All these organisms initiate disease at the mucosal surface of the respiratory tract and thus the efficacy of the host's response to infection needs to be optimal at this site. Vaccines available for diseases caused by many of these pathogens have limitations in accessibility or efficacy, highlighting the need for improvements in approaches and products. The most significant challenges in both therapy and prevention of disease induced by bacteria in the respiratory tract remain the development of non-injectable vaccines and delivery systems/immunization regimens that improve mucosal immunity.

A randomized phase II trial of SRL172 (Mycobacterium vaccae) +/- low-dose interleukin-2 in the treatment of metastatic malignant melanoma

We conducted a randomized phase II trial of SRL172 (Mycobacterium vaccae) +/- low-dose interleukin-2 (IL-2) as treatment for stage IV malignant melanoma. The objectives were to establish the safety and efficacy of SRL172 with and without IL-2. All patients had measurable metastatic disease and none received concurrent chemotherapy, radiotherapy, corticosteroids or any other investigational agent. Sixteen patients were randomized into each arm of the trial prior to closure. The trial was halted prematurely when no responses were seen in the first 16 patients receiving SRL172 alone, predicting a response rate of less than 20%. Three partial remissions were seen in the 16 patients receiving SRL172 + IL-2. These patients remained on monthly SRL172 + IL-2, with disease progression at 12, 15 and 23 months. They continued on the trial regimen following surgical management of their disease progression. This trial provides preliminary evidence of a new, non-toxic, immunotherapeutic regimen in the management of malignant melanoma. Further trials are required to establish a definitive response rate and to compare the combination regimen with the regimen of low-dose IL-2 used in this trial. A biological basis for the responses seen in the SRL172 + IL-2 arm also needs to be established.

Anticancer activity of mycobacterial DNA: effect of formulation as chitosan nanoparticles

Mycobacterium phlei (M. phlei) DNA inhibits cancer cell division but is susceptible to degradation by DNase. Chitosan forms nanoparticulate polyelectrolyte complexes with DNA, and may thus reduce nuclease degradation. We have characterized chitosan-DNA nanoparticle formation, determined DNase susceptibility, and evaluated their antiproliferative activity. Nanoparticle diameter initially decreased with increasing phosphate charge density. However nanoparticle diameter increased above 6 micromol of phosphate. Particle aggregation occurred at 16.2 micromol phosphate and was related to reduced surface charge. Incorporation of DNA within chitosan nanoparticles significantly decreased degradation by DNase. The ability of M. phlei DNA-chitosan nanoparticles to inhibit melanoma cell division was determined relative to M. phlei DNA and a cationic liposomal M. phlei DNA formulation. M. phlei DNA had antiproliferative activity (MTT reduction, IC50 = 0.9 mg/ml) without intrinsic cytotoxicity (LDH release, ED50 > 50 microg/ml). Cationic polyphosphate chitosan nanoparticles were inert (antiproliferative IC50 > 1 mg/ml, ED50 > 1 mg/ml). M. phlei DNA-chitosan nanoparticles were 20-fold more potent than M. phlei DNA. Cationic DOTAP/DOPE liposomes were cytostatic (IC50 = 49 microg/ml) and cytotoxic (ED50 = 87 microg/ml), and complexation of M. phlei DNA resulted in a significant reduction of antiproliferative activity. Chitosan nanoparticles may therefore be appropriate delivery vehicles for M. phlei DNA.

Acute cardio-respiratory effects in rats of PS4alpha, an antineoplastic peptidoglycan from Mycobacterium vaccae

PS4alpha is a high molecular weight peptidoglycan extracted from Mycobacterium vaccae, which has demonstrated considerable antineoplastic activity in-vivo without apparent toxicity. Available fortesting in only small quantities, a sensitive in-vivo method for measuring pulse and breathing rates in cannulated rats was applied to this compound at doses of 5, 50 and 500 microg kg(-1). Various parameters (mean arterial pressure, maximum transpulmonary pressure, compliance, heart rate, minute volume, respiratory rate and tidal volume) were followed for up to 1 h and demonstrated no significant deviation in the baseline values obtained before injection. This compound at doses up to 500 microg kg(-1) had no apparent acute toxicity in rats, but chronic effects at this and higher doses have to be determined by more conventional toxicological methods before proceeding to evaluate PS4alpha as an antineoplastic agent.

Polysaccharide colloidal particles as delivery systems for macromolecules

Mucosal delivery of complex molecules such as peptides, proteins, oligonucleotides, and plasmids is one of the most intensively studied subjects. The use of colloidal carriers made of hydrophilic polysaccharides, i.e. chitosan, has arisen as a promising alternative for improving the transport of such macromolecules across biological surfaces. This article reviews the approaches which have aimed to associate macromolecules to chitosan in the form of colloidal structures and analyzes the evidence of their efficacy in improving the transport of the associated molecule through mucosae and epithelia. Chitosan has been shown to form colloidal particles and entrap macromolecules through a number of mechanisms, including ionic crosslinking, desolvation, or ionic complexation, though some of these systems have been realized only in conjunction with DNA molecules. An alternative involving the chemical modification of chitosan has also been useful for the association of macromolecules to self-assemblies and vesicles. To date, the in vivo efficacy of these chitosan-based colloidal carriers has been reported for two different applications: while DNA-chitosan hybrid nanospheres were found to be acceptable transfection carriers, ionically crosslinked chitosan nanoparticles appeared to be efficient vehicles for the transport of peptides across the nasal mucosa. The potential applications and future prospects of these new systems for mucosal delivery of macromolecules are highlighted at the end of the chapter.

Biodegradable polymeric nanoparticles as drug delivery devices

This review presents the most outstanding contributions in the field of biodegradable polymeric nanoparticles used as drug delivery systems. Methods of preparation, drug loading and drug release are covered. The most important findings on surface modification methods as well as surface characterization are covered from 1990 through mid-2000.