Orestis Kontogiannis

Through this study, the synergistic behavior of small-molecular-weight, amphiphilic surfactant molecules and the triblock copolymer Pluronic 188 was extensively evaluated based on their ability to formulate nanocarriers with novel properties for the delivery of class II and IV (biopharmaceutical classification system) chemotherapeutic compounds. The combination of four different surfactants at multiple weight ratios and twelve initially formulated nanosystems resulted in four hybrid delivery platforms, which were further studied in terms of multiple physicochemical characteristics, as well as their stability in protein-rich media (fetal bovine serum/phosphate-buffer saline). Finally, we obtained a single final nanoformulation that exhibited a high loading capacity (%EE ≥ 75%) and a sustained drug release profile under physiological conditions (model drug methotrexate), without altering the original physicochemical characteristics of the carrier. With a mean hydrodynamic radius (Rh) of less than 70 nm, a polydispersity index of 0.219, and no protein complexation, the system is a suitable candidate for in vivo, intravenous, and/or intramuscular administration. The cytotoxicity and genotoxicity of both loaded and unloaded carriers were evaluated through the examination of the upregulation or downregulation of apoptosis-related pathways. Multiple conventional 2D and 3D spheroidal conformations were used for these assessments, including HEK293, HCT-116, and MCF-7 cell lines, the results of which stressed the safety and biocompatibility of the empty nanocarrier. Additionally, experiments on Caenorhabditis elegans were conducted to evaluate the system’s in vivo toxicity, focusing on developmental stages, egg-laying behavior, and locomotion. Nanosystems studied in terms of chemotherapeutic encapsulation have mostly focused on the physiochemical aspect of the development of such novel delivery platforms, with only few exceptions proceeding step-by-step from cellular 2D to 3D to in vivo experimentation. The present study offers a holistic view of the behavior of such a novel system, advancing our understanding of the capabilities of polymeric/surfactant-based nanodelivery platforms.

The medical application of nanotechnology in the field of drug delivery has so far exhibited many efforts in treating simple to extremely complicated and life-threatening human conditions, with multiple products already existing in the market. A plethora of innovative drug delivery carriers, using polymers, surfactants and the combination of the above, have been developed and tested pre-clinically, offering great advantages in terms of targeted drug delivery, low toxicity and immune system activation, cellular biomimicry and enhanced pharmacokinetic properties. Furthermore, such artificial systems can be tailor-made with respect to each therapeutic protocol and disease type falling under the scope of personalized medicine. The simultaneous delivery of multiple therapeutic entities of different nature, such as genes and drugs, can be achieved, while novel technologies can offer systems with multiple modalities often combining therapy with diagnosis. In this review, we present prominent, innovative and state-of-the-art scientific efforts on the applications of surfactant-based, polymer-based, and mixed surfactant-polymer nanoparticle drug formulations intended for use in the medical field and in drug delivery. The materials used, formulation steps, nature, properties, physicochemical characteristics, characterization techniques and pharmacokinetic behavior of those systems, are presented extensively in the length of this work. The material presented is focused on research projects that are currently in the developmental, pre-clinical stage.

The aim of this research was to prepare novel block copolymer-surfactant hybrid nanosystems using the triblock copolymer Pluronic 188, along with surfactants of different hydrophilic to lipophilic balance (HLB ratio—which indicates the degree to which a surfactant is hydrophilic or hydrophobic) and thermotropic behavior. The surfactants used were of non-ionic nature, of which Tween 80^® and Brij 58^® were more hydrophilic, while Span 40^® and Span 60^® were more hydrophobic. Each surfactant has unique innate thermal properties and an affinity towards Pluronic 188. The nanosystems were formulated through mixing the pluronic with the surfactants at three different ratios, namely 90:10, 80:20, and 50:50, using the thin-film hydration technique and keeping the pluronic concentration constant. The physicochemical characteristics of the prepared nanosystems were evaluated using various light scattering techniques, while their thermotropic behavior was characterized via microDSC and high-resolution ultrasound spectroscopy. Microenvironmental parameters were attained through the use of fluorescence spectroscopy, while the cytotoxicity of the nanocarriers was studied in vitro. The results indicate that the combination of Pluronic 188 with the above surfactants was able to produce hybrid homogeneous nanoparticle populations of adequately small diameters. The different surfactants had a clear effect on physicochemical parameters such as the size, hydrodynamic diameter, and polydispersity index of the final formulation. The mixing of surfactants with the pluronic clearly changed its thermotropic behavior and thermal transition temperature (Tm) and highlighted the specific interactions that occurred between the different materials, as well as the effect of increasing the surfactant concentration on inherent polymer characteristics and behavior. The formulated nanosystems were found to be mostly of minimal toxicity. The obtained results demonstrate that the thin-film hydration method can be used for the formulation of pluronic-surfactant hybrid nanoparticles, which in turn exhibit favorable characteristics in terms of their possible use in drug delivery applications. This investigation can be used as a road map for the selection of an appropriate nanosystem as a novel vehicle for drug delivery.

Gene therapy is the most promising strategy for treating a number of diseases at their most fundamental, genetic level, and it has a wide range of promising clinical and emerging preclinical uses in both the clinic and the laboratory. Gene therapy systems are composed of three fundamental components, with the delivery platform being responsible for the protection and successful delivery of the incorporated therapeutic nucleic acid sequences. A successful delivery platform is critical in the achievement of a therapeutic outcome, and an effective delivery platform is essential in achieving this. A variety of different gene delivery platforms - vectors - are evaluated in this dissertation in terms of their nature, mechanism of action, potential applications, and safety. Of particular importance is the evaluation of their post-delivery pharmacokinetic and adverse drug-metabolite profiles. The different types of vectors, including viral, non-viral, and alternative vectors, are discussed separately in each chapter, while important issues related to the incorporation of these vectors into clinical practice are discussed as well, including the topics of vector development and manufacturing, as well as the current regulatory landscape and efforts to improve it, and finally their prospects for the immediate future. Context Gene delivery vectors consist of a broad spectrum of natural or synthetically produced vehicles that represent one out of the three essential aspects of each gene delivery system, without which the successful and effective (in terms of the clinical translation) delivery of therapeutic nucleic acids to a diseased mal- or sub-functioning cell would be impossible. Objective The presentation and evaluation of the in vivo pharmacokinetic behavior of different viral and non viral gene delivery vectors including a wide review of their mechanism of action, possible safety concerns as well as the promise each holds for future applications. Data Sources A systematic literature search was conducted using the electronic databases PubMed, Google Scholar and Science Direct while also utilizing the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The keywords included in the research effort were the following: viral vectors, adeno-associated viral vectors, non viral vectors, oncolytic vectors, novel gene delivery vectors, pharmacokinetics of viral vectors, retroviral vectors, recombinant adeno-associated viral vectors, toxicity of gene delivery vectors, Vitravene, Oncorene, Approved gene delivery vectors. Study Selection Case studies and review articles published in scientifically accepted, high impact factor journals focused on gene delivery vectors and published in English between the years 1999 to 2021 in order to include the most significant findings in terms of both well established data through the years as well as the most recent breakthroughs in terms of preclinical and clinical application. Data Extraction Essential information were retrieved regarding the various types, behavior, mechanisms of action, safety and in vivo pharmacokinetic behavior of the most prominent viral and non viral gene delivery vectors. Results Of a total of 186 records a total of 36 full text articles were reviewed covering a total of 92 case studies and review articles on the topic of the pharmacokinetic behavior of gene delivery vectors including promising future considerations for their clinical use. Limitations The outcome of this review article was limited by findings that were shared between different articles published in a variety of literary platforms as well as from papers that lacked sufficient details in order to be included. Conclusion This scoping review has examined what is currently known and recently discovered regarding the wholesome of the aspects of utilizing specific gene delivery vehicles for a variety of different therapeutic purposes. Their nature, characteristics, as well as their individual action once inserted into the organism and/or in a variety of different in vivo experiments was examined and the implication of their use regarding their shortcomings and possible dangers, as well as their therapeutic advantages and probable future applications were weighted.