Spray-dried chitosan microparticles for cellular delivery of an antigenic protein: physico-chemical properties and cellular uptake by dendritic cells and macrophages

Microencapsulation of a Commercial Food-Grade Protease by Spray Drying in Cross-Linked Chitosan Particles

In this study, the use of spray-drying technology for encapsulating Flavourzyme® (protease–peptidase complex) was evaluated to overcome the limitations (low encapsulation efficiency and no large-scale production) of other encapsulation processes. To the best of our knowledge, spray drying has not been applied previously for the immobilization of this enzyme. Firstly, bovine serum albumin (BSA), as a model protein, was encapsulated by spray drying in chitosan and tripolyphoshate (TPP) cross-linked-chitosan shell matrices. The results showed that the chitosan–TPP microcapsules provided a high encapsulation efficiency and better protein stability compared to the non-crosslinked chitosan microcapsules. The effect of enzyme concentration and drying temperature were tested during the spray drying of Flavourzyme®. In this regard, an activity yield of 88.0% and encapsulation efficiency of 78.6% were obtained with a concentration of 0.1% (v/v) and an inlet temperature of 130 °C. Flavourzyme®-loaded chitosan microcapsules were also characterized in terms of their size and morphology using scanning electron microscopy and laser diffractometry.

Pharmaceutical Potential of a Novel Chitosan Derivative Schiff Base with Special Reference to Antibacterial, Anti-Biofilm, Antioxidant, Anti-Inflammatory, Hemocompatibility and Cytotoxic Activities

PURPOSE

Chitosan and its derivatives possess several unique properties relevant in the field of pharmaceutics and medicinal chemistry. This study aimed to evaluate the pharmaceutical performance of an innovative chitosan derivative, methyl acrylate chitosan bearing p-nitrobenzaldehyde (MA*CS*pNBA) Schiff base.

METHODS

The antibacterial activity of MA*CS*pNBA was tested against multi-drug resistant (MDR) Gram-negative and Gram-positive bacteria using agar-well diffusion method. Anti-biofilm formation was analyzed using a microtitre plate. Antioxidant assays were performed to assess the scavenging activity of MA*CS*pNBA using DPPH, hydrogen peroxide, superoxide together with its reducing power activity. Anti-inflammatory activity was evaluated by albumin denaturation, membrane stabilization, and proteinase inhibition methods. MA*CS*pNBA was tested for its hemolytic efficiency on human erythrocytes. Cytotoxicity of MA*CS*pNBA was evaluated by MTT assay.

RESULTS

MA*CS*pNBA showed a significant performance as an antibacterial candidate against MDR bacteria, anti-biofilm, antioxidant and anti-inflammatory biomaterial, evidencing hemocompatibility and no cytotoxicity. It exhibited a significant negative correlation with biofilm formation by the MDR-PA-09 strain. Biological activities were found to be significantly concentration-dependent.

CONCLUSIONS

the newly chitosan derivative MA*CS*pNBA showed to be promising for pharmaceutical applications, expanding the treatment ways toward skin burn infections since it allied excellent antibacterial, anti-biofilm, antioxidant, anti-inflammatory, hemocompatibility and absence of cytotoxic activities.

Enhanced CD40 and ICOSL expression on dendritic cells surface improve anti-tumor immune responses; effectiveness of mRNA/chitosan nanoparticles

Objective: To improve dendritic cells (DCs) function, we targeted DCs to over express CD40 and inducible costimulator ligand (ICOSL) costimulatory molecules along with total messenger RNA (mRNA) of tumor cells to achieve a safe and effective system for treatment of tumor. Materials and methods: We generated CD40 and ICOSL mRNA in vitro and manipulated DCs using chitosan nanoparticles and also lipofectamine transfection system then examined in vitro and in vivo. Results: Mice bone marrow derived DCs pulsed with total tumor mRNA/CD40 mRNA or ICOSL mRNA showed higher expression of DCs maturation markers (CD40, ICOSL, CD86, and MHC-II) and accelerated secretion of pro-inflammatory cytokines. Co-culture of DCs with T cells enhanced proliferation of T cells and shift toward stronger Th1 cytokine responses especially in presence of CD40 over expressed DCs. Intra-tumor administration of manipulated DCs to 4T1 tumor mice model showed delay in growth of tumor volume, trend to increase in mice survival, and stronger anti-tumor cytokines production in splenocytes of mice model (with higher efficacy of mRNA/chitosan nanoparticle system). Conclusions: Hence, we suggest that targeting intra-tumor DCs to elicit expression of CD40 and ICOSL and present broad range of tumor antigens could yield effective anti-tumor responses. In this regard, CD40 molecule manipulation trigger stronger functions, while mRNA/chitosan nanoparticles system could provide a high potent tool for targeting strategies.

Preparation, characterization, and potential application of chitosan, chitosan derivatives, and chitosan metal nanoparticles in pharmaceutical drug delivery

Naturally occurring polymers, particularly of the polysaccharide type, have been used pharmaceutically for the delivery of a wide variety of therapeutic agents. Chitosan, the second abundant naturally occurring polysaccharide next to cellulose, is a biocompatible and biodegradable mucoadhesive polymer that has been extensively used in the preparation of micro-as well as nanoparticles. The prepared particles have been exploited as a potential carrier for different therapeutic agents such as peptides, proteins, vaccines, DNA, and drugs for parenteral and nonparenteral administration. Therapeutic agent-loaded chitosan micro- or nanoparticles were found to be more stable, permeable, and bioactive. In this review, we are highlighting the different methods of preparation and characterization of chitosan micro- and nanoparticles, while reviewing the pharmaceutical applications of these particles in drug delivery. Moreover, the roles of chitosan derivatives and chitosan metal nanoparticles in drug delivery have been illustrated.

Enhanced biostability of nanoparticle-based drug delivery systems by albumin corona

Aims: The long-term efficacy of nanoparticles is limited by their rapid metabolism in tissues. In this work, we aim to enhance nanoparticle biostability by preforming a bovine serum albumin (BSA) corona. Materials & methods: A BSA corona was formed by incubating poly-3-hydroxybutyrate-co-3-hydroxyhexanoate nanoparticles with BSA solution and confirmed by SDS-PAGE and x-ray photoelectron spectroscopy. The impacts of the BSA corona on the drug release, biostability and biodistribution of nanoparticles were investigated. Results: In the presence of the BSA corona, the drug release (coumarin-6 was used as the model drug) of nanoparticles was significantly slower and their stability in liver homogenate and in organs was enhanced. Conclusion: Preformation of a BSA corona may be a promising approach for enhancing drug biostability and for developing long-acting nanoparticle formulations.

Original submitted 25 February 2014; Revised submitted 10 April 2014