Surface-Modified Mesoporous Ceramics as Delivery Vehicle for Haemoglobin

Aquasomes nanoformulation for controlled release of drug and improved effectiveness against bacterial infections

Aim: The study aimed to develop and evaluate an aquasome drug-delivery system for controlled drug delivery of cefprozil monohydrate. Materials & methods: Aquasomes were prepared by the spinal method with a calcium phosphate core, sugar-coated using cellobiose and drug-loaded by adsorption. The formulations were characterized for size, morphology and drug release. An antibacterial study was conducted for Gram-positive and -negative bacteria. Results: It showed particle size of 2791.9 nm, zeta potential of -0.3 mV with good stability, and 99.08% of drug loading and drug release were controlled and prolonged, achieving 56% within 8 h and possessing potential for 100% release beyond 12 h. Conclusion: An aquasome drug-delivery system was developed for novel controlled drug delivery for pharmaceutical antibiotic therapeutics.

Biodistribution PET/CT Study of Hemoglobin-DFO-89Zr Complex in Healthy and Lung Tumor-Bearing Mice

Proteins, as a major component of organisms, are considered the preferred biomaterials for drug delivery vehicles. Hemoglobin (Hb) has been recently rediscovered as a potential drug carrier, but its use for biomedical applications still lacks extensive investigation. To further explore the possibility of utilizing Hb as a potential tumor targeting drug carrier, we examined and compared the biodistribution of Hb in healthy and lung tumor-bearing mice, using for the first time ⁸⁹Zr labelled Hb in a positron emission tomography (PET) measurement. Hb displays a very high conjugation yield in its fast and selective reaction with the maleimide-deferoxamine (DFO) bifunctional chelator. The high-resolution X-ray structure of the Hb-DFO complex demonstrated that cysteine β93 is the sole attachment moiety to the αβ-protomer of Hb. The Hb-DFO complex shows quantitative uptake of ⁸⁹Zr in solution as determined by radiochromatography. Injection of 0.03 mg of Hb-DFO-⁸⁹Zr complex in healthy mice indicates very high radioactivity in liver, followed by spleen and lungs, whereas a threefold increased dosage results in intensification of PET signal in kidneys and decreased signal in liver and spleen. No difference in biodistribution pattern is observed between naïve and tumor-bearing mice. Interestingly, the liver Hb uptake did not decrease upon clodronate-mediated macrophage depletion, indicating that other immune cells contribute to Hb clearance. This finding is of particular interest for rapidly developing clinical immunology and projects aiming to target, label or specifically deliver agents to immune cells.

Advanced trends in protein and peptide drug delivery: a special emphasis on aquasomes and microneedles techniques

Proteins and peptides have a great potential as therapeutic agents; they have higher efficiency and lower toxicity, compared to chemical drugs. However, their oral bioavailability is very low; also, the transdermal peptide delivery faces absorption limitations. Accordingly, most of proteins and peptides are administered by parenteral route, but there are many problems associated with this route such as patient discomfort, especially for pediatric use. Thus, it is a great challenge to develop drug delivery systems for administration of proteins and peptides by routes other than parenteral one. This review provides an overview on recent advances adopted for protein and peptide drug delivery, focusing on oral and transdermal routes. This is followed by an emphasis on two recent approaches adopted as delivery systems for protein and peptide drugs, namely aquasomes and microneedles. Aquasomes are nanoparticles fabricated from ceramics developed to enhance proteins and peptides stability, providing an adequate residence time in circulation. It consists of ceramic core coated with poly hydroxyl oligomer, on which protein and peptide drug can be adsorbed. Aquasomes preparation, characterization, and application in protein and peptide drug delivery are discussed. Microneedles are promising transdermal approach; it involves creation of micron-sized pores in the skin for enhancing the drug delivery across the skin, as their length ranged between 150 and 1500 μm. Types of microneedles with different drug delivery mechanisms, characterization, and application in protein and peptide drug delivery are discussed. Graphical abstract.

Calcium phosphate nanoparticles: second-generation nonviral vectors in gene therapy

Adverse effects of viral vectors, instability of naked DNA, cytotoxicity and low transfection of cationic lipids, cationic polymers and other synthetic vectors are currently severe limitations in gene therapy. In addition to targeting a specific cell type, an ideal nonviral vector must manifest an efficient endosomal escape, render sufficient protection of DNA in the cytosol and help provide an easy passage of cytosolic DNA to the nucleus. Virus-like size calcium phosphate nanoparticles have been found to overcome many of these limitations in delivering genes to the nucleus of specific cells. This review has focused on some applications of DNA-loaded calcium phosphate nanoparticles as nonviral vectors in gene delivery, and their potential use in gene therapy, as well as highlighting the mechanistic studies to probe the reason for high transfection efficiency of the vector. It has been demonstrated that calcium ions play an important role in endosomal escape, cytosolic stability and enhanced nuclear uptake of DNA through nuclear pore complexes. The special role of exogenous calcium ions to overcome obstacles in practical realization of this field suggests that calcium phosphate nanoparticles are not 'me too' synthetic vectors and can be designated as second-generation nonviral vectors for gene therapy.

Smart designing of new hybrid materials based on brushite-alginate and monetite-alginate microspheres: bio-inspired for sequential nucleation and growth

In this report new hybrid materials based on brushite-alginate and monetite-alginate were prepared by self-assembling alginate chains and phosphate source ions via a gelation process with calcium ions. The alginate served as nanoreactor for nucleation and growth of brushite or/and monetite due to its gelling and swelling properties. The alginate gel framework, the crystalline phase and morphology of formed hybrid biomaterials were shown to be strongly dependent upon the concentration of the phosphate precursors. These materials were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX).

The changing face of vascular interventional radiology: the future role of pharmacotherapies and molecular imaging

Interventional radiology has had to evolve constantly because there is the ever-present competition and threat from other specialties within medicine, surgery, and research. The development of new technologies, techniques, and therapies is vital to broaden the horizon of interventional radiology and to ensure its continued success in the future. In part, this change will be due to improved chronic disease prevention altering what we treat and in whom. The most important of these strategies are the therapeutic use of statins, Beta-blockers, angiotensin-converting enzyme inhibitors, and substances that interfere with mast cell degeneration. Molecular imaging and therapeutic strategies will move away from conventional techniques and nano and microparticle molecular technology, tissue factor imaging, gene therapy, endothelial progenitor cells, and photodynamic therapy will become an important part of interventional radiology of the future. This review looks at these new and exciting technologies.

WITHDRAWN: Inorganic nanoparticles for cancer imaging and therapy

The Publisher regrets that this article is an accidental duplication of an article that has already been published, doi:10.1016/j.jconrel.2011.07.005. The duplicate article has therefore been withdrawn.

Inorganic nanoparticles for cancer imaging and therapy

Inorganic nanoparticles have received increased attention in the recent past as potential diagnostic and therapeutic systems in the field of oncology. Inorganic nanoparticles have demonstrated successes in imaging and treatment of tumors both ex vivo and in vivo, with some promise towards clinical trials. This review primarily discusses progress in applications of inorganic nanoparticles for cancer imaging and treatment, with an emphasis on in vivo studies. Advances in the use of semiconductor fluorescent quantum dots, carbon nanotubes, gold nanoparticles (spheres, shells, rods, cages), iron oxide magnetic nanoparticles and ceramic nanoparticles in tumor targeting, imaging, photothermal therapy and drug delivery applications are discussed. Limitations and toxicity issues associated with inorganic nanoparticles in living organisms are also discussed.

Porous bioactive diopside (CaMgSi(2)O(6)) ceramic microspheres for drug delivery

Ideal bioceramic microspheres for bone regeneration need to be bioactive and degradable, but at the same time possess a controlled drug-release ability. The main disadvantage of the currently available microspheres is their failure to combine these properties. The aim of this study is to develop bioactive ceramic microspheres with optimal properties for use in bone-tissue regeneration. In this study, we utilize diopside (CaMgSi(2)O(6), DP) with proven excellent bioactivity and degradation ability to develop microspheres by controlling their porosity and size, and further modify their surface with polymer to enhance and control their drug-loading/release ability. The phase composition, surface and inner microstructure, and porosity of DP microspheres were tested. Results indicate that carbon powders as porogens with various contents determined the porosity of the porous DP microspheres. The drug-loading and release ability of dexamethazone (DEX) from porous DP microspheres was regulated by their porosity and size. Poly(lactide-co-glycolide) modification forms a film on the surface of DP microspheres and resulted in an enhanced DEX-loading and release ability of the microspheres. Results presented here indicate that the developed DP microspheres have the potential to be used as bioactive filling materials for bone-tissue regeneration.

Porous carriers for controlled/modulated drug delivery

Considerable research efforts have been directed in recent years towards the development of porous carriers as controlled drug delivery matrices because of possessing several features such as stable uniform porous structure, high surface area, tunable pore size and well-defined surface properties. Owing to wide range of useful properties porous carriers have been used in pharmaceuticals for many purposes including development of floating drug delivery systems, sustained drug delivery systems. Various types of pores like open, closed, transport and blind pores in the porous solid allow them to adsorb drugs and release them in a more reproducible and predictable manner. Pharmaceutically exploited porous adsorbents includes, silica (mesoporous), ethylene vinyl acetate (macroporous), polypropylene foam powder (microporous), titanium dioxide (nanoporous). When porous polymeric drug delivery system is placed in contact with appropriate dissolution medium, release of drug to medium must be preceded by the drug dissolution in the water filled pores or from surface and by diffusion through the water filled channels. The porous carriers are used to improve the oral bioavailability of poorly water soluble drugs, to increase the dissolution of relatively insoluble powders and conversion of crystalline state to amorphous state.

Nano- and microparticle-based imaging of cardiovascular interventions: overview

The rapid progress of nanoscience and the application of nanotechnology are changing the foundations of diagnosis, treatment, and prevention of cardiovascular diseases. As the core of nanotechnology, nano- and microparticles offer "three-in-one" functions as imaging agents, target probes, and therapeutic carriers. While nano- and microparticle-based imaging of cardiovascular interventions is still in its developing phase, it has already presented the exciting potential to monitor primary interventional procedures for precise therapeutic delivery, enhance the effectiveness of delivered therapeutics, and monitor therapeutic efficiency after interventions performed to treat cardiovascular diseases. This article provides an overview of the current status of the application of nano- and microparticles in the imaging of cardiovascular interventions.