Tamara Perchyonok

Towards Development of Novel Chitosan Based Drug Delivery Prototypes: Devices for Targeted Delivery Drug Therapy at the Molecular Level in Aqueous Media

We recently showed that chitosan containing hydrogel isare capable of displaying antioxidant activity and prevents formation of oxidative DNA damage in vitro [9]. In this short communication we report our investigations towards developing two alternative novel simple flexible and effective drug delivery systems that provide optimal dosage of drugs precisely where and when needed and therefore achieve and sustain a complex delivery profile. Two topics of a. free radical generation in biocompatible media and b. supramolecular host-guest recognition through miniaturizing and multi-functionalizing molecular carriers for improved drug delivery in disease-specific manner are combined with the aim of harnessing free radical reactivity within the laboratory and developing alternative and effective treatments for disease states mediated by free radicals.

Bioactive-Functionalized Interpenetrating Network Hydrogel (BIOF-IPN): A Novel Biomaterial Transforming the Mechanism of Bio-Repair, Bio-Adhesion and Therapeutic Capability – An In Vitro Study

The purpose of this investigation was to evaluate and report the in vitro performance of a few selected Bioactive- Functionalized Interpenetrating Network Hydrogels (BIOF-IPN); a novel biomaterial with a build-in mechanism of biorepair capacity, bio-adhesion and therapeutic capability. The study also evaluates the cytotoxicity of the newly developed material, and its ability to be used in the dental field. In this study, four bioactive-functionalized interpenetrating network hydrogels (BIOF-IPN) were prepared by dispersion of different therapeutic agents. The dentin bond strength is tested, the bio-adhesivity, modulus of elasticity and cytotoxicity of the materials were investigated, and the performance of the therapeutic-agents release profile, evaluated. The gels used in this study demonstrated excellent capacity in leading to high internal surface areas with low diffusional resistance. An increase in bond strength of the dentin treated with the BIOF-IPNs compared to the bond strength of the conventionally bonded teeth was indicated, and a significant increase in the modulus of elasticity observed. BIOF-INPs showed high adhesive force promotes binding to the negative surface of skin or dentin structure. It was found that chitosan alone increased the cell survival rate remarkably (113%) and its presence with naproxen and ibuprofen increased the cell survival rate [naproxen (93%), chitosan/naproxen (96.6%), ibuprofen (76.6%), and chitosan/ibuprofen (89.1%). The use of BIOF-IPNs has increased the time of the release of therapeutic agents, and protected the active ingredient from any type of free radical damage produced in and around the active site. Present results demonstrate the capability of the BIOF-IPNs to play an important role in the defense mechanism, and in the functional multidimensional restorative repair materials. The findings suggest that the new material would definitely find applications in functional dental composites and regenerative dentistry.

Novel Melatonin-chitosan Hydrogels as Suitable Oral Bio-drug Delivery Systems to Fight Oral Mucositis: Synergy of Antioxidants and Bioactives in Action

Oral mucositis is a consequence of the toxic effects of chemotherapeutic agents and irradiation on oral mucosa cells. It is estimated that oral mucositis is a complication in 40% of patients receiving chemotherapy, more than 90% of those irradiated for head and neck cancer. This condition is frequently associated with severe pain and inflammation and can cause malnutrition, systemic infections, and low quality of life, as well as limiting chemotherapy doses. The pineal hormone melatonin inhibits the production of free radicals that mediate the toxicity of chemotherapy. The main objectives of this study is to develop and evaluate a novel occlusive bioadhesive system for prophylaxis and/or treatment of oral mucositis based on chitosan and melatonin in order to exploit natural biomaterials as functional biocompatible gels and evaluate the performance of the alternative drug delivery system towards in-vitro generated free-radical mediated inflammation response as a model system for oral mucosatis.

Cyclodextrins as Oral Drug Carrier Molecular Devices: Origins, Reasons and In-vitro Model Applications

Cyclodextrins are cyclic oligomers of glucose that can form water-soluble inclusion complexes with small molecules and por- tions of large compounds. These biocompatible, cyclic oligosaccharides do not elicit immune responses and have low toxicities in ani- mals and humans. Cyclodextrins are used in pharmaceutical applications for numerous purposes, including improving the bioavailability of drugs. Current cyclodextrin-based therapeutics are described and possible future applications discussed with particular focus on oral drug administration. This article focuses on development of in vitro reliable and simple prototypes for oral drug delivery by combing chemical, structural and pharmacological knowledge available to date in order to create an optimal oral drug delivery system based on modified cyclodextrins. Practical in vitro model is also demonstrated.

Insights into functional tea infused-chitosan hydrogels as potential bio-active restorative materials

Introduction: We described novel chitosan hydrogels (chitosan-H) containing tea infusions (green, red and black) as functional additive prototypes with special focus on the design and functionality of dual action composite restorative materials. Their intended uses include remineralizing bases/liners, therapeutically active restorative materials and/or functional additives as well as functional prototype of the drug delivery system. Materials and Methods: The above mentioned hydrogels were prepared by dispersion of the corresponding component in glycerol and acetic acid with the addition of chitosan gelling agent. The surface morphology scanning electron microscope (SEM), release behavior (physiological pH as well as acidic conditions), stability of the hydrogels as well as antioxidant capacity of the tea infused hydrogels was evaluated. Results: It was found that all the anti-oxidant chitosan-H hydrogels treated dentine gave significantly (P < 0.05; Non-parametric ANOVA test) higher shear bond strength values than dentine treated or not treated with phosphoric acid. Overall, there was a small relapse in the shear bond strength after 6 months. The SEM is employed to observe the surface of the newly made functional restorative materials. The anti-oxidant capacity of various black, red and green tea infusions was investigated and demonstrated increased antioxidant stability of the newly prepared material stability. Conclusion: We have developed and evaluated several functional chitosan hydrogels with several targets as therapeutic restorative materials, the added benefits of their unique functionality involve increased dentin adhesive bond strengths (after 24 h and after 6 month), concept of using functional materials as carriers for pro-drugs as well as display certain degree of defense mechanism for a free radical damage.

Synergistic Effect of Copolymer Particle and Surfactant on the Morphology of Macroporous Materials Based on High Internal Phase Emulsion

The open porous materials (PolyHIPEs) based on high internal phase emulsions (HIPEs) stabilized by copolymer particles had been prepared through adding small quantity (about 0.5 wt% relative to the external phase) of cationic surfactant, cetyltrimethylammonium bromide (CTAB), into the oil (external) phase. The effect of copolymer particle concentration, surfactant concentration and CTAB position in HIPEs on the morphologies of PolyHIPEs was investigated. All these factors could tune the internal structures of the Poly- HIPEs and some of them generated pore throats on the pore wall. Obvious synergistic interaction between the negative-charged particles and cationic surfactant CTAB in HIPE was displayed: CTAB could not only adsorb on the oil-water interface competitively with the copolymer particles but also cross the interface to absorb on the particle surface, which changed the particle hydrophilicity. The further investigation on the stability of HIPE proved that the HIPEs with CTAB in the oil phase were more prone to form open porous materials after polymerizing the monomer in the external phase.

Bioactive-functionalized interpenetrating network hydrogel (BIOF-IPN)

The implication of oxidative stress in the etiology of many chronic and degenerative diseases, the body’s protective antioxidant mechanisms and the role dietary antioxidants play, suggests that an antioxidant therapy represents a promising avenue for treatment. In this chapter, we focus on the advantages of a novel functional biomaterial, the Bioactive-Functionalized Interpenetrating Network Hydrogel (BIOF-IPN). BIOF-IPN is a chitosan based and chitosan-containing biomaterial, designed for several uses in the dental field through amalgamation of structural features and build in therapeutic free radical defence capacity and desired dental properties. In addition, the use of antioxidants together with conventional therapeutic agents as a platform for development of novel prototypes of functional chitosan based hydrogels as drug-delivery systems, and the in vitro evaluation of their performance using conventional chemistry.

Towards bioactive dental restorative materials with chitosan and nanodiamonds: evaluation and application

Traditional dentistry has now evolved to a stage where, under optimal conditions, success rates of up to over 90% have been reported for some procedures (for example, for dental implants) after a period of 10 years [1]. The development of new materials with enhanced properties, careful attention to factors that influence the technique sensitivity of some procedures, and a generally greater awareness of oral health issues among the population have all helped to contribute to these improvements in treatment outcomes [2]. Bioactive materials have evolved over the past three decades from relatively specialized, highly biocompatible, but low-strength dental materials into product compositions for expanded clinical use in restorative dentistry [3].