In vivo biocompatibility, clearance, and biodistribution of albumin vehicles for pulmonary drug delivery

Albumin nanostructures as advanced drug delivery systems

INTRODUCTION

One of the biggest impacts that the nanotechnology has made on medicine and biology, has been in the area of drug delivery systems (DDSs). Many drugs suffer from serious problems concerning insolubility, instability in biological environments, poor uptake into cells and tissues, sub-optimal selectivity for targets and unwanted side effects. Nanocarriers can be designed as DDSs to overcome many of these drawbacks. One of the most versatile building blocks to prepare these nanocarriers is the ubiquitous, readily available and inexpensive protein, serum albumin. Areas covered: This review covers the use of different types of albumin (human, bovine, rat, and chicken egg) to prepare nanoparticle and microparticle-based structures to bind drugs. Various methods have been used to modify the albumin structure. A range of targeting ligands can be attached to the albumin that can be recognized by specific cell receptors that are expressed on target cells or tissues. Expert opinion: The particular advantages of albumin used in DDSs include ready availability, ease of chemical modification, good biocompatibility, and low immunogenicity. The regulatory approvals that have been received for several albumin-based therapeutic agents suggest that this approach will continue to be successfully explored.

Combined computational and experimental studies of molecular interactions of albuterol sulfate with bovine serum albumin for pulmonary drug nanoparticles

Albumin-based nanoparticles (NPs) are a promising technology for developing drug-carrier systems, with improved deposition and retention profiles in lungs. Improved understanding of these drug–carrier interactions could lead to better drug-delivery systems. The present study combines computational and experimental methods to gain insights into the mechanism of binding of albuterol sulfate (AS) to bovine serum albumin (BSA) on the molecular level. Molecular dynamics simulation and surface plasmon resonance spectroscopy were used to determine that there are two binding sites on BSA for AS: the first of which is a high-affinity site corresponding to AS1 and the second of which appears to represent the integrated functions of several low-affinity sites corresponding to AS2, AS3, and AS8. AS1 was the strongest binding site, established via electrostatic interaction with Glu243 and Asp255 residues in a hydrophobic pocket. Hydrogen bonds and salt bridges played a main role in the critical binding of AS1 to BSA, and water bridges served a supporting role. Based upon the interaction mechanism, BSA NPs loaded with AS were prepared, and their drug-loading efficiency, morphology, and -release profiles were evaluated. Successful clinical development of AS-BSA-NPs may improve therapy and prevention of bronchospasm in patients with reversible obstructive airway disease, and thus provide a solid basis for expanding the role of NPs in the design of new drug-delivery systems.

Radio-nanomaterials for biomedical applications: state of the art

The incorporation of radioactive isotope(s) into conventional nanomaterials can bring extra properties which are not possessed by original materials. The resulting radioactive nanomaterials (radio-nanomaterials), with added physical/chemical properties, can be used as important tools for different biomedical applications. In this review, our goal is to provide an up-to-date overview on these applications using radio-nanomaterials. The first section illustrates the utilization of radionanomaterials for understanding of in vivo kinetics of their parent nano-materials. In the second section, we focus on two primary applications of radio-nanomaterials: imaging and therapeutic delivery. With various methods being used to form radio-nanomaterials, they can be used for positron emission tomography (PET), single-photon emission computed tomography (SPECT), and multimodal imaging. Therapeutic isotopes-loading radio-nanomaterials can possess selective killing efficacy of diseased cells (e.g. tumor cells) and can provide promises for certain isotopes which are not able to be used in a conventional manner. The successful and versatile biomedical applications of radio-nanomaterials warrants further investigations of those materials and their optimizations can pave the way to future imaging guidable, personalized treatments in patients.

Disposition and safety of inhaled biodegradable nanomedicines: Opportunities and challenges

The inhaled delivery of nanomedicines can provide a novel, non-invasive therapeutic strategy for the more localised treatment of lung-resident diseases and potentially also enable the systemic delivery of therapeutics that are otherwise administered via injection alone. However, the clinical translation of inhalable nanomedicine is being hampered by our lack of understanding about their disposition and clearance from the lungs. This review provides a comprehensive overview of the biodegradable nanomaterials that are currently being explored as inhalable drug delivery systems and our current understanding of their disposition within, and clearance from the lungs. The safety of biodegradable nanomaterials in the lungs is discussed and latest updates are provided on the impact of inflammation on the pulmonary pharmacokinetics of inhaled nanomaterials. Overall, the review provides an in-depth and critical assessment of the lung clearance mechanisms for inhaled biodegradable nanomedicines and highlights the opportunities and challenges for their translation into the clinic.

Evaluation of New Fluorescent Lipophosphoramidates for Gene Transfer and Biodistribution Studies after Systemic Administration

The objective of lung gene therapy is to reach the respiratory epithelial cells in order to deliver a functional nucleic acid sequence. To improve the synthetic carrier's efficacy, knowledge of their biodistribution and elimination pathways, as well as cellular barriers faced, depending on the administration route, is necessary. Indeed, the in vivo fate guides the adaptation of their chemical structure and formulation to increase their transfection capacity while maintaining their tolerance. With this goal, lipidic fluorescent probes were synthesized and formulated with cationic lipophosphoramidate KLN47 (KLN: Karine Le Ny). We found that such formulations present constant compaction properties and similar transfection results without inducing additional cytotoxicity. Next, biodistribution profiles of pegylated and unpegylated lipoplexes were compared after systemic injection in mice. Pegylation of complexes led to a prolonged circulation in the bloodstream, whereas their in vivo bioluminescent expression profiles were similar. Moreover, systemic administration of pegylated lipoplexes resulted in a transient liver toxicity. These results indicate that these new fluorescent compounds could be added into lipoplexes in small amounts without perturbing the transfection capacities of the formulations. Such additional properties allow exploration of the in vivo biodistribution profiles of synthetic carriers as well as the expression intensity of the reporter gene.