Papers by Keyword: Drug Delivery

Abstract: The oral administration of pharmaceuticals is typically preferred over other methods due to its non-intrusiveness and convenience of administration. However, the varying chemical environments of the gastro-intestinal tract pose a challenge in ensuring the stability and inertness of a drug compound until it reaches its target. Polymers that are responsive to pH changes have potential as smart materials for the controlled oral administration of pharmaceuticals. In this study, linear and hyperbranched copolymers of methacrylic acid (MAA) and poly (ethylene glycol) methyl ether methacrylate (PEGMEMA) were synthesized by RAFT polymerization. High molecular weight polymers were produced with PDI values close to 1.0. These smart materials underwent phase changes at pH 5.15-5.6. This property enabled the amphiphilicity of the copolymers to be switched on or off. By doing so in in vitro drug release studies with ibuprofen as the model hydrophobic drug, the copolymers were able to inhibit drug release in simulated stomach conditions to up to 13% while enhancing drug release in simulated intestinal conditions to up to 75% within 6 hours. These indicate that copolymers based on MAA and PEGMEMA have potential as smart materials for drug delivery applications.

Abstract: Nanotechnology as a multidisciplinary and scientific innovation plays an important role in numerous biomedical applications, such as molecular imaging, biomarkers and biosensors and also drug delivery. A wide range of studies have been conducted on using of nanoparticles for early diagnosis and targeted drug therapy of various diseases. In fact, the small size, customized surface, upgraded solubility, or multi-functionality of nanoparticles enabled them to interact with complex cellular functions in new ways which opened many doors and created new biomedical applications. These studies demonstrated that nanotechnology vehicles can formulate biological products effectively, and this nano-formulated products with a potent ability against different diseases, were represented to have better biocompatibility, bioaccessibility and efficacy, under in vitro and in vivo conditions.

Abstract: Chemotherapy is a major therapeutic approach for the treatment of localized and metastasized cancers. Although Doxorubicin (DOX) possesses abroad spectrum of anticancer activity, its clinical use is limited because of it cause heart failure. Chitosan nanoparticles was prepared by using ionic gelation method. These nanoaparticles were used as polyload of anticancer DOX to form safer and non-toxic anticancer drug. infrared spectroscopy (FTIR) and transmission electron microscope (TEM) were used to characterize the prepared nanoparticles. The cancer animals’ experiments using Ehrlich static cancer, (EAC) cells using six groups of experimental animals were performed to evaluate the efficiency of Doxorubicin and Doxorubicin loaded chitosan nanoparticles as anticancer drug especially from its toxicity towards heart. Tumor volume was calculated as to monitor the response to treatment. Cytotoxicity of Doxorubicin and Doxorubicin loaded chitosan nanoparticles were evaluated. Biochemical parameters were be estimated to illustrate the cytotoxicity of these drugs on heart.

Abstract: The theory of dissolution kinetics of gentamicin from polylactic acid-hydroxyapatite thin film composites is spotlighted with the combination of diffusion and polymer degradation modeling. The use of various mathematical models, characterizing diffusion, dissolution or/and erosion prevalence as well as a mix of dissolution-diffusion rate processes were employed in order to compare theory with experimental data. A number of factors influence the release kinetics of gentamicin from medical drug release systems and devices. It is difficult to have a single mathematical model that takes all these factors into account. It is shown that the degradation of the polymer matrix plays the biggest role in the release kinetics of polymer-ceramics thin film composites. It was also observed that multistage drug release form these devices depends also on the degradation kinetics of the polymer matrix. The effect of pH and device sizes were not studied but could also be of interest in future studies.

Abstract: pH responsive polymeric nanoparticles have emerged as a promising technology platform for targeted and controlled drug delivery in recent years. In this paper, endosomal pH-activatable doxorubicin (DOX) and core-crosslinked polymeric nanoparticles (DCNPs) were prepared and investigated for potent growth inhibition of human cancer cells in vitro. In vitro drug release studies, DOX conjugated nanoparticles with hydrazone bond showed a pH sensitive release phenomenon, that is, the releasing is significantly faster at mildly acidic condition with pH of 5.5 than that at physiological condition. Confocal laser scanning microscope (CLSM) observations revealed that DOX conjugated nanoparticles delivered and released DOX into the cytosols as well as cell nuclei of Hela cells following 6 h incubation. MTT assays demonstrated that these pH-sensitive DOX nanoparticles exhibited high antitumor effect to HeLa cells. The conjugated DOX polymeric nanoparticles may be a promising candidate as a nanoscale and pH-sensitive drug delivery vehicle for cancer therapy.

Abstract: We have designed a polymer micelles based on Pluronic P₁₂₃ and Polyethyleneimine 600 (termed as P₁₂₃P₆₀₀). Upon critical micelle concentration the P₁₂₃P₆₀₀ unimer formed micelles in water. These micelles not only could simultaneously delivery hydrophobic anticancer drug paclitaxel (PTX) to cancer cells but also could deplete ATP and inhibit P-gp expression in MDR cells. In vitro researches demonstrated that these micelles showed the excellent biocompatibility, high drug loading efficiency, stably controlled releasing behavior, enhanced cellular up-take and improved serum stability. In vivo studies demonstrated that the PTX loaded micelles induced tumor cell apoptosis and inhibited the growth of tumor to overcome drug resistance through a synergistic effect. All these findings suggested that P₁₂₃P₆₀₀ for delivery of anticarcinogen provided a promising strategy for reversal of MDR in cancer treatment.

Abstract: One of the most used calcium phosphate implant materials in bone tissue regeneration is synthetic hydroxyapatite, which is similar to mineral phase of bone. By adding antibacterial effect to hydroxyapatite properties and creating controlled drug delivery systems based on this material, it is possible to obtain multifunctional material. Thus, in this study hydroxyapatite was doped with silver up to 1 wt% to provide antibacterial effect and from the obtained material dense and porous scaffolds were prepared. Prepared scaffolds were coated with chitosan and cross-linked with dexamethasone sodium phosphate (DEXA). Scaffolds were characterized and it is shown that linkage between chitosan coating and DEXA on the surface of hydroxyapatite and silver doped hydroxyapatite can ensure the controlled drug release up to 70 h.

Abstract: In order to mimic natural tissues, a successful strategy is to design bio-inspired materials including controlled morphological and biochemical cues as nature guidelines suggested. In this context, old and new process technologies, case by case, have to be adapted to develop innovative templates with the finest control of structural/functional properties able to correctly interact with biological tissues. Since organic and inorganic materials from synthetic or natural source do not singularly satisfy all the requirements, the discovery of new process solutions able to combine two or more materials into multicomponent systems (i.e., blends, composites, hybrids) may represent an interesting alternative for scaffold design. In order to simplify process conditions, without limiting the complexity of final device, current trends mainly address to bottom up approaches based on fibres used as micro-tassels, variously combined as a function of the desired properties – biochemical, mechanical or biological ones, to form the final device.Here, two different approaches based on the use of polymeric fibres have been proposed. Continuous microfibres processed by capillary extrusion can be integrated as reinforcement agent of porous biodegradable matrices to develop composite scaffolds with multiscale degradation properties suitable for hard tissue regeneration. Alternatively, micro-or submicro-fibres made of synthetic and/or natural polymers can be randomly assembled or patterned to form uniaxially oriented or textured platforms, thanks to the high customization of electrofluidodynamic techniques (i.e., electrospinning). Both approaches offer a large variety of micro and nanostructured platforms - with micro/nanoscale architecture and peculiar chemical composition - suitable as scaffolds or biotextiles for tissue regeneration or other biomedical uses.

Abstract: A ‘biomaterial’, recognizes some materials for biomedical applications like replacement of living system and wound stressing. ‘Biomaterials’ includes different compounds from diverse origins, like polymers, metals, ceramics and composites. Along with conventional natural polymers (polysaccharides, proteins), synthetic and biodegradable polymers like Polyvinyl alcohol, Polyvinylpyrrolidone, Polyetheleneglycol, Polylactic acid, Polyhydroxy acid are promisingly used in drug delivery, tissue engineering, biomedical sensing, skin grafting and medical adhesives. ‘Hydrogel’ a new generation biodegradable polymer typically used for pharmaceutical and medical purposes. Hydrogels are coined as super absorbent with significant function in health care, especially in wound treatment and protection. Unique characteristics features like enhanced hydrophilicity, biocompatibility, zero-toxicity and biodegradability along with soft and rubbery consistency, low interfacial tension and ‘self-healing’ properties make them compatible with living tissues. Hydrogels have been widely investigated as the carrier for drug delivery systems owing to their unusual characteristics like swelling in aqueous medium, pH and temperature sensitivity, or sensitivity towards other stimuli. Hydrogels being biocompatible materials have been recognized to function as drug protectors, especially for peptides and proteins, from in-vivo environment. In present context, development of ‘in situ’ forming systems for various biomedical applications, including drug delivery, cell encapsulation, and tissue repair are emerging. Among several typical hydrogel synthesis approaches like, solvent exchange, UV-irradiation, ionic cross-linkage, pH change, and temperature modulation, the ‘thermosensitive’ approach is advantageous since it does not require use of any organic solvents, co-polymerization agents and externally applied trigger for gelation. This review presents an overview to the advances in hydrogel based drug delivery system with some reconstructive features in the biomedical applications.

Abstract: In order to explore a smart carrier which can control drug delivery in special pH environment, a type of nanometer material, namely, poly acrylic acid acrylamide (P(AA-AM)) was synthesized with acrylic acid and acrylamide as monomers. Its structure was determined using Fourier transform infrared spectroscopy (FTIR) and its swelling properties were tested by measuring its weight evolution. The drug delivery control potential was estimated by monitoring its swelling performances in the solutions of different pH values. The cycle characteristics were also investigated to determine its degradation properties in the environment. The results indicate that the synthesized material is sensitive to pH and is suitable for controlling drug delivery at the pH range from 10 to11 and below 7. Furthermore, this material can be automatic decomposition in the environment so that it is a degradable green material without causing burden to the environment.