Polymeric soft nanocarriers as smart drug delivery systems: State-of-the-art and future perspectives

Current Therapeutic Delivery Approaches Using Nanocarriers for the Treatment of Tuberculosis Disease

Tuberculosis is a major health issue globally and a leading cause of death due to the infective microorganism Mycobacterium tuberculosis. Treatment of drug resistance tuberculosis requires longer treatment with multiple daily doses of drugs. Unfortunately, these drugs are often associated with poor patient compliance. In this situation, a need has been felt for the less toxic, shorter, and more effective treatment of the infected tuberculosis patients. Current research to develop novel anti-tubercular drugs shows hope for better management of the disease. Research on drug targeting and precise delivery of the old anti-tubercular drugs with the help of nanotechnology is promising for effective treatment. This review has discussed the status currently available treatments for tuberculosis patients infected with Mycobacterium alone or in comorbid conditions like diabetes, HIV and cancer. This review also highlighted the challenges in the current treatment and research on the novel anti-tubercular drugs to prevent multi-drug-resistant tuberculosis. It presents the research highlights on the targeted delivery of anti-tubercular drugs using different nanocarriers for preventing multi-drug resistant tuberculosis. Report has shown the importance and development of the research on nanocarriers mediated anti-tubercular delivery of the drugs to overcome the current challenges in tuberculosis treatment.

Using crystallography tools to improve vaccine formulations

This article summarizes developments attained in oral vaccine formulations based on the encapsulation of antigen proteins inside porous silica matrices. These vaccine vehicles show great efficacy in protecting the proteins from the harsh acidic stomach medium, allowing the Peyer's patches in the small intestine to be reached and consequently enhancing immunity. Focusing on the pioneering research conducted at the Butantan Institute in Brazil, the optimization of the antigen encapsulation yield is reported, as well as their distribution inside the meso- and macroporous network of the porous silica. As the development of vaccines requires proper inclusion of antigens in the antibody cells, X-ray crystallography is one of the most commonly used techniques to unveil the structure of antibody-combining sites with protein antigens. Thus structural characterization and modelling of pure antigen structures, showing different dimensions, as well as their complexes, such as silica with encapsulated hepatitis B virus-like particles and diphtheria anatoxin, were performed using small-angle X-ray scattering, X-ray absorption spectroscopy, X-ray phase contrast tomography, and neutron and X-ray imaging. By combining crystallography with dynamic light scattering and transmission electron microscopy, a clearer picture of the proposed vaccine complexes is shown. Additionally, the stability of the immunogenic complex at different pH values and temperatures was checked and the efficacy of the proposed oral immunogenic complex was demonstrated. The latter was obtained by comparing the antibodies in mice with variable high and low antibody responses.

Biodegradable Dendritic Polyglycerol Sulfate for the Delivery and Tumor Accumulation of Cytostatic Anticancer Drugs

Targeted delivery and extended blood circulation of anticancer drugs have been the challenges for decreasing the adverse side effects and improving the therapeutic efficiency in cancer chemotherapy. Herein, we present a drug delivery system (DDS) based on biodegradable dendritic polyglycerol sulfate-bearing poly(caprolactone) (dPGS-PCL) chains, which has been synthesized on 20 g scale using a straightforward two-step protocol. In vivo fluorescence imaging demonstrated a significant accumulation of the DDS in the tumor environment. Sunitinib, an anticancer drug, was loaded into the DDS and the drug-induced toxicity was investigated in vitro and in vivo. The drug encapsulated in dPGS-PCL and the free drug showed similar toxicities in A431 and HT-29 cells, and the cellular uptake was comparable. The straightforward and large-scale synthesis, the organic solvent-free drug-loading approach, together with the tumor targetability of the biodegradable dendritic polyglycerols, render this copolymer a promising candidate for targeted cancer nanomedicine drug delivery systems.

Excipient-Free Pure Drug Nanoparticles Fabricated by Microfluidic Hydrodynamic Focusing

Nanoprecipitation is one of the most versatile methods to produce pure drug nanoparticles (PDNPs) owing to the ability to optimize the properties of the product. Nevertheless, nanoprecipitation may result in broad particle size distribution, low physical stability, and batch-to-batch variability. Microfluidics has emerged as a powerful tool to produce PDNPs in a simple, reproducible, and cost-effective manner with excellent control over the nanoparticle size. In this work, we designed and fabricated T- and Y-shaped Si-made microfluidic devices and used them to produce PDNPs of three kinase inhibitors of different lipophilicity and water-solubility, namely imatinib, dasatinib and tofacitinib, without the use of colloidal stabilizers. PDNPs display hydrodynamic diameter in the 90-350 nm range as measured by dynamic light scattering and a rounded shape as visualized by high-resolution scanning electron microscopy. Powder X-ray diffraction and differential scanning calorimetry confirmed that this method results in highly amorphous nanoparticles. In addition, we show that the flow rate of solvent, the anti-solvent, and the channel geometry of the device play a key role governing the nanoparticle size.

Recent Developments and Challenges for Nanoscale Formulation of Botanical Pesticides for Use in Sustainable Agriculture

In recent years, the use of substances of natural origin, such as botanical pesticides, has emerged as a preferred alternative to the use of synthetic pesticides, the excessive use of which has raised a lot of concern over safety to human/animal health and the environment. Recent developments in nanotechnology have opened up a new avenue for the development of more efficient formulations that can overcome many of the obstacles generally faced in their use in the field, such as loss of activity because of degradation, instability, volatilization, and so on. This Review discusses the key developments in this area, as well as the challenges in relation to nanoscale formulation of botanical pesticides. It presents an appraisal of the recent scientific research, along with an account of the products that have already reached the market. While it acknowledges the great potential of nanotechnology-derived formulations of botanical pesticides for increasing agricultural productivity and reducing health and the environmental impacts, it also highlights the technological challenges that must be addressed to enable adoption of the technology for wider use in agri-food production.

Electrohydrodynamic atomization and spray-drying for the production of pure drug nanocrystals and co-crystals

In recent years, nanotechnology has offered attractive opportunities to overcome the (bio)pharmaceutical drawbacks of most drugs such as low aqueous solubility and bioavailability. Among the numerous methodologies that have been applied to improve drug performance, a special emphasis has been made on those that increase the dissolution rate and the saturation solubility by the reduction of the particle size of pure drugs to the nanoscale and the associated increase of the specific surface area. Different top-down and bottom-up methods have been implemented, each one with its own pros and cons. Over the last years, the latter that rely on the dissolution of the drug in a proper solvent and its crystallization or co-crystallization by precipitation in an anti-solvent or, conversely, by solvent evaporation have gained remarkable impulse owing to the ability to adjust features such as size, size distribution, morphology and to control the amorphous/crystalline nature of the product. In this framework, electrohydrodynamic atomization (also called electrospraying) and spray-drying excel due to their simplicity and potential scalability. Moreover, they do not necessarily require suspension stabilizers and dry products are often produced during the formation of the nanoparticles what ensures physicochemical stability for longer times than liquid products. This review overviews the potential of these two technologies for the production of pure drug nanocrystals and co-crystals and discusses the recent technological advances and challenges for their implementation in pharmaceutical research and development.

Cancer-Cell-Specific Mitochondria-Targeted Drug Delivery by Dual-Ligand-Functionalized Nanodiamonds Circumvent Drug Resistance

We demonstrate a nanotechnology approach for the development of cancer-cell-specific subcellular organelle-targeted drug nanocarriers based on photostable nanodiamonds (ND) functionalized with folic acid and mitochondrial localizing sequence (MLS) peptides. We showed that these multifunctional NDs not only distinguish between cancer cells and normal cells, and transport the loaded drugs across the plasma membrane of cancer cells, but also selectively deliver them to mitochondria and induce significant cytotoxicity and cell death compared with free Dox localized in lysosomes. Importantly, the cellular uptake of Dox was dramatically increased in a resistant model of MCF-7 cells, which contributed to the significant circumvention of P-glycoprotein-mediated drug resistance. Our work provides a novel method of designing nanodiamond-based carriers for targeted delivery and for circumventing drug resistance in doxorubicin-resistant human breast adenocarcinoma cancer cells.

Rational design of dendritic thermoresponsive nanogels that undergo phase transition under endolysosomal conditions

In the last few decades, the synthesis of nanodevices has become a very active research field with many applications in biochemistry, biotechnology, and biomedicine. However, there is still a great need for smart nanomaterials that can sense and respond to environmental changes. Temperature- and pH-responsive nanogels (NGs), which are prepared in a one-pot synthesis from N-isopropylacrylamide (NiPAm) and a Newkome-type dendron (ABC) bearing carboxylic acid groups, are being investigated as multi-responsive drug carriers. As a result, NGs have been developed that are able to undergo a reversible volume phase transition triggered by acidic conditions, like the ones found in endolysosomal compartments of cancer cells. The NGs have been thoroughly characterized using dynamic light scattering and spectroscopies, such as infrared, nuclear magnetic resonance, UV-visible, and stimulated Raman. Strong hydrogen bonds have been detected when the ABC moieties are deprotonated, which has led to changes in the transition temperatures of the NGs and a reversible, pH-dependent aggregation. This pH-dependent phase change was exploited for the effective encapsulation and sustained release of the anticancer drug cisplatin and resulted in a faster release of the drug at endolysosomal pH values. The cisplatin-loaded NGs have exhibited high toxicities against A549 cells in vitro, while the unloaded NGs have been found to be not cytotoxic and hemocompatible.