Development of a respirable, sustained release microcarrier for 5-fluorouracil I: In vitro assessment of liposomes, microspheres, and lipid coated nanoparticles

A remodeled ivermectin polycaprolactone-based nanoparticles for inhalation as a promising treatment of pulmonary inflammatory diseases

In recent years, ivermectin (IVM), an antiparasitic drug of low water solubility and poor oral bioavailability, has shown a profound effect on inflammatory mediators involved in diseases, such as acute lung injury, lung fibrosis, and COVID-19. In order to maximize drug bioavailability, polymeric nanoparticles can be delivered through nebulizers for pulmonary administration. The aim of this study was to prepare IVM-loaded polycaprolactone (PCL) nanoparticles (NPs) by solvent evaporation method. Box-Benkhen design (BBD) was used to optimize entrapment efficiency (Y1), percent drug release after 6 h (Y2), particle size (Y3), and zeta potential (Y4). A study was conducted examining the effects of three independent variables: PCL-IVM ratio (A), polyvinyl alcohol (PVA) concentration (B), and sonication time (C). The optimized formula was also compared to the oral IVM dispersion for lung deposition, in-vivo behavior, and pharmacokinetic parameters. The optimized IVM-PCL-NPs formulation was spherical in shape with entrapment efficiency (% EE) of 93.99 ± 0.96 %, about 62.71 ± 0.53 % released after 6 h, particle size of 100.07 ± 0.73 nm and zeta potential of -3.30 ± 0.23 mV. Comparing the optimized formulation to IVM-dispersion, the optimized formulation demonstrated greater bioavailability with greater area under the curve AUC0-t of 710.91 ± 15.22 μg .ml-1.h for lung and 637.97 ± 15.43 μg .ml-1.h for plasma. Based on the results, the optimized NPs accumulated better in lung tissues, exhibiting a twofold longer residence time (MRT 4.78 ± 0.55 h) than the IVM-dispersion (MRT 2.64 ± 0.64 h). The optimized nanoparticle formulation also achieved higher cmax (194.90 ± 5.01 μg/ml), and lower kel (0.21 ± 0.04 h-1) in lungs. Additionally, the level of inflammatory mediators was markedly reduced. To conclude, inhalable IVM-PCL-NPs formulation was suitable for the pulmonary delivery and may be one of the most promising approaches to increase IVM bioavailability for the successful treatment of a variety of lung diseases.

Inhaled Medicines for Targeting Non-Small Cell Lung Cancer

Throughout the years, considerable progress has been made in methods for delivering drugs directly to the lungs, which offers enhanced precision in targeting specific lung regions. Currently, for treatment of lung cancer, the prevalent routes for drug administration are oral and parenteral. These methods, while effective, often come with side effects including hair loss, nausea, vomiting, susceptibility to infections, and bleeding. Direct drug delivery to the lungs presents a range of advantages. Notably, it can significantly reduce or even eliminate these side effects and provide more accurate targeting of malignancies. This approach is especially beneficial for treating conditions like lung cancer and various respiratory diseases. However, the journey towards perfecting inhaled drug delivery systems has not been without its challenges, primarily due to the complex structure and functions of the respiratory tract. This comprehensive review will investigate delivery strategies that target lung cancer, specifically focusing on non-small-cell lung cancer (NSCLC)-a predominant variant of lung cancer. Within the scope of this review, active and passive targeting techniques are covered which highlight the roles of advanced tools like nanoparticles and lipid carriers. Furthermore, this review will shed light on the potential synergies of combining inhalation therapy with other treatment approaches, such as chemotherapy and immunotherapy. The goal is to determine how these combinations might amplify therapeutic results, optimizing patient outcomes and overall well-being.

LipoParticles: a lipid membrane coating onto polymer particles to enhance the internalization in osteoblast cells

LipoParticles, core-shell assemblies consisting of a polymer core coated by a lipid membrane, are promising carriers for drug delivery applications with intracellular targets. This is of great interest since it is actually challenging to treat infections involving intracellular bacteria such as bone and joint infections where the bacteria are hidden in osteoblast cells. The present work reports for the first time to the best of our knowledge the proof of enhanced internalization of particles in osteoblast cells thanks to a lipid coating of particles (= LipoParticles). The ca. 300 nm-sized assemblies were elaborated by reorganization of liposomes (composed of DPPC/DPTAP 10/90 mol/mol) onto the surface of poly(lactic-co-glycolic acid) (PLGA) particles, and were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and zetametry. Optimization of these assemblies was also performed by adding poly(ethylene glycol) (PEG) chains on their surface (corresponding to a final formulation of DPPC/DPTAP/DPPE-PEG5000 8/90/2 mol/mol/mol). Interestingly, this provided them colloidal stability after their 20-fold dilution in PBS or cell culture medium, and made possible their freeze-drying without forming aggregates after their re-hydration. Their non-cytotoxicity towards a human osteoblast cell line (MG63) was also demonstrated. The enhanced internalization of LipoParticles in this MG63 cell line, in comparison with PLGA particles, was proven by observations with a confocal laser scanning microscope, as well as by flow cytometry assays. Finally, this efficient internalization of LipoParticles in MG63 cells was confirmed by TEM on ultrathin sections, which also revealed localization close to intracellular Staphylococcus aureus.

Lipid-Based Inhalable Micro- and Nanocarriers of Active Agents for Treating Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) afflicts about 2 million people worldwide, with both genetic (familial) and environmental factors contributing to its development and spread. The inadequacy of currently available therapeutic techniques, such as surgery, chemotherapy, and radiation therapy, in addressing NSCLC is reflected in the very low survival rate of this disease. Therefore, newer approaches and combination therapy regimens are required to reverse this dismal scenario. Direct administration of inhalable nanotherapeutic agents to the cancer sites can potentially lead to optimal drug use, negligible side effects, and high therapeutic gain. Lipid-based nanoparticles are ideal agents for inhalable delivery owing to their high drug loading, ideal physical traits, sustained drug release, and biocompatibility. Drugs loaded within several lipid-based nanoformulations, such as liposomes, solid-lipid nanoparticles, lipid-based micelles, etc., have been developed as both aqueous dispersed formulations as well as dry-powder formulations for inhalable delivery in NSCLC models in vitro and in vivo. This review chronicles such developments and charts the future prospects of such nanoformulations in the treatment of NSCLC.

An evolving perspective on novel modified release drug delivery systems for inhalational therapy

INTRODUCTION

Drugs delivered via the lungs are predominantly used to treat various respiratory disorders, including asthma, chronic obstructive pulmonary diseases, respiratory tract infections and lung cancers, and pulmonary vascular diseases such as pulmonary hypertension. To treat respiratory diseases, targeted, modified or controlled release inhalation formulations are desirable for improved patient compliance and superior therapeutic outcome.

AREAS COVERED

This review summarizes the important factors that have an impact on the inhalable modified release formulation approaches with a focus toward various formulation strategies, including dissolution rate-controlled systems, drug complexes, site-specific delivery, drug-polymer conjugates, and drug-polymer matrix systems, lipid matrix particles, nanosystems, and formulations that can bypass clearance via mucociliary system and alveolar macrophages.

EXPERT OPINION

Inhaled modified release formulations can potentially reduce dosing frequency by extending drug's residence time in the lungs. However, inhalable modified or controlled release drug delivery systems remain unexplored and underdeveloped from the commercialization perspective. This review paper addresses the current state-of-the-art of inhaled controlled release formulations, elaborates on the avenues for developing newer technologies for formulating various drugs with tailored release profiles after inhalational delivery and explains the challenges associated with translational feasibility of modified release inhalable formulations.

Inhalable Formulations to Treat Non-Small Cell Lung Cancer (NSCLC): Recent Therapies and Developments

Cancer has been the leading cause of mortalities, with lung cancer contributing 18% to overall deaths. Non-small cell lung cancer (NSCLC) accounts for about 85% of all lung cancers. The primary form of therapy used to treat lung cancer still includes oral and systemic administration of drugs, radiotherapy, or chemotherapy. Some patients have to go through a regime of combination therapy. Despite being the only available form of therapy, their use is limited due to the adverse effects, toxicity, and development of resistance over prolonged use. This led to a shift and progressive evolution into using pulmonary drug delivery systems. Being a non-invasive method of drug-administration and allowing localized delivery of drugs to cancer cells, inhalable drug delivery systems can lead to lower dosing and fewer systemic toxicities over other conventional routes. In this way, we can increase the actual local concentration of the drug in lungs, which will ultimately lead to better antitumor therapy. Nano-based systems also provide additional diagnostic advantages during lung cancer treatment, including imaging, screening, and tracking. Regardless of the advantages, pulmonary delivery is still in the early stages of development and various factors such as pharmacology, immunology, and toxicology should be taken into consideration for the development of suitable inhalable nano-based chemotherapeutic drugs. They face numerous physiological barriers such as lung retention and efficacy, and could also lead to toxicity due to prolonged exposure. Nano-carriers with a sustained drug release mechanism could help in overcoming these challenges. This review article will focus on the various inhalable formulations for targeted drug delivery, including nano-based delivery systems such as lipids, liposome, polymeric and inorganic nanocarriers, micelles, microparticles and nanoaggregates for lung cancer treatment. Various devices used in pulmonary drug delivery loaded on various nano-carriers are also discussed in detail.

Nanoparticle-Based Inhalation Therapy for Pulmonary Diseases

The lung is exposed to various pollutants and is the primary site for the onset of various diseases, including infections, allergies, and cancers. One possible treatment approach for such pulmonary diseases involves direct administration of therapeutics to the lung so as to maintain the topical concentration of the drug. Particles with nanoscale diameters tend to reach the pulmonary region. Nanoparticles (NPs) have garnered significant interest for applications in biomedical and pharmaceutical industries because of their unique physicochemical properties and biological activities. In this article, we describe the biological and pharmacological activities of NPs as well as summarize their potential in the formulation of drugs employed to treat pulmonary diseases. Recent advances in the use of NPs in inhalation chemotherapy for the treatment of lung diseases have also been highlighted.

Nanocarrier Drug Delivery Systems: Characterization, Limitations, Future Perspectives and Implementation of Artificial Intelligence

There has been an increasing demand for the development of nanocarriers targeting multiple diseases with a broad range of properties. Due to their tiny size, giant surface area and feasible targetability, nanocarriers have optimized efficacy, decreased side effects and improved stability over conventional drug dosage forms. There are diverse types of nanocarriers that have been synthesized for drug delivery, including dendrimers, liposomes, solid lipid nanoparticles, polymersomes, polymer-drug conjugates, polymeric nanoparticles, peptide nanoparticles, micelles, nanoemulsions, nanospheres, nanocapsules, nanoshells, carbon nanotubes and gold nanoparticles, etc. Several characterization techniques have been proposed and used over the past few decades to control and predict the behavior of nanocarriers both in vitro and in vivo. In this review, we describe some fundamental in vitro, ex vivo, in situ and in vivo characterization methods for most nanocarriers, emphasizing their advantages and limitations, as well as the safety, regulatory and manufacturing aspects that hinder the transfer of nanocarriers from the laboratory to the clinic. Moreover, integration of artificial intelligence with nanotechnology, as well as the advantages and problems of artificial intelligence in the development and optimization of nanocarriers, are also discussed, along with future perspectives.

Nano-delivery to the lung - by inhalation or other routes and why nano when micro is largely sufficient?

Respiratory diseases gather a wide range of disorders which are generally difficult to treat, partly due to a poor delivery of drugs to the lung with adequate dose and minimum side effects. With the recent developments of nanotechnology, nano-delivery systems have raised interest. In this review, we detail the main types of nanocarriers that have been developed presenting their respective advantages and limitations. We also discuss the route of administration (systemic versus by inhalation), also considering technical aspects (different types of aerosol devices) with concrete examples of applications. Finally, we propose some perspectives of development in the field such as the nano-in-micro approaches, the emergence of drug vaping to generate airborne carriers in the submicron size range, the development of innovative respiratory models to assess regional aerosol deposition of nanoparticles or the application of nano-delivery to the lung in the treatment of other diseases.

Poly(Lactic Acid)-Based Microparticles for Drug Delivery Applications: An Overview of Recent Advances

The sustained release of pharmaceutical substances remains the most convenient way of drug delivery. Hence, a great variety of reports can be traced in the open literature associated with drug delivery systems (DDS). Specifically, the use of microparticle systems has received special attention during the past two decades. Polymeric microparticles (MPs) are acknowledged as very prevalent carriers toward an enhanced bio-distribution and bioavailability of both hydrophilic and lipophilic drug substances. Poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA), and their copolymers are among the most frequently used biodegradable polymers for encapsulated drugs. This review describes the current state-of-the-art research in the study of poly(lactic acid)/poly(lactic-co-glycolic acid) microparticles and PLA-copolymers with other aliphatic acids as drug delivery devices for increasing the efficiency of drug delivery, enhancing the release profile, and drug targeting of active pharmaceutical ingredients (API). Potential advances in generics and the constant discovery of therapeutic peptides will hopefully promote the success of microsphere technology.

Taking leads out of nature, can nano deliver us from COVID-like pandemics?

The COVID-19 crisis has alerted the research community to re-purpose scientific tools that can effectively manage emergency pandemic situations. Researchers were never so desperate to discover a 'magic bullet' that has significant clinical benefits with minimal or no side effects. At the beginning of the pandemic, due to restricted access to traditional laboratory techniques, many research groups delved into computational screening of thousands of lead molecules that could inhibit SARS-CoV-2 at one or more stages of its infectious cycle. Several in silico studies on natural derivatives point out their potency against SARS-CoV-2 proteins. However, theoretical predictions and existing knowledge on related molecules reflect their poor oral bioavailability due to biotransformation in the gut and liver. Nanotechnology has evolved into a key field for precise and controlled delivery of various drugs that lack aqueous solubility, have low oral bioavailability and possess pronounced toxicity in their native form. In this review, we discuss various nanoformulations of natural products with favorable ADME properties, and also briefly explore nano-drug delivery to lungs, the primary site of SARS-CoV-2 infection. Natural products are also envisioned to augment nanotechnology-based 1) personnel protective equipment for ex vivo viral inactivation and 2) wearable sensors that perform rapid and non-invasive analysis of volatile organic compounds in exhaled breath of the infected person after therapeutic food consumption.

The Proposition of the Pulmonary Route as an Attractive Drug Delivery Approach of Nano-Based Immune Therapies and Cancer Vaccines to Treat Lung Tumors

Lung cancer is the leading cause of cancer related deaths globally, making it a major health concern. The lung’s permissive rich microenvironment is ideal for supporting outgrowth of disseminated tumors from pre-existing extra-pulmonary malignancies usually resulting in high mortality. Tumors occurring in the lungs are difficult to treat, necessitating the need for the development of advanced treatment modalities against primary tumors and secondary lung metastasis. In this review, we explore the pulmonary route as an attractive drug delivery approach to treat lung tumors. We also discuss the potential of pulmonary delivery of cancer vaccine vectors to induce mucosal immunity capable of preventing the seeding of tumors in the lung.

Development of solid lipid microparticles by melt-emulsification/spray-drying processes as carriers for pulmonary drug delivery

The aim of this study was to optimize the parameters of the complex melt-emulsification process coupled with the spray-drying, in order to maintain the balance between solid lipid microparticles (SLMs) powders aerodynamic performance and salbutamol sulfate release rate. Quality target product profile was identified and risk management and principal component analysis were used to guide formulation development. Obtained dry powders for inhalation (DPIs) were evaluated in terms of SLMs size distribution, morphology, true density, drug content, solid state characterization studies, in vitro aerosol performance and in vitro drug release. SLMs micrographs indicated spherical, porous particles. Selected powders showed satisfactory aerosol performance with a mean mass aerodynamic diameter of around 3 μm and acceptable fine particle fraction (FPF). Addition of trehalose positively affected SLMs aerodynamic properties. The results of in vitro dissolution testing indicated that salbutamol sulfate release from the tested SLMs formulations was modified, in comparison to the raw drug release. In conclusion, SLMs in a form of DPIs were successfully developed and numerous factors that affects SLMs properties were identified in this study. Further research is required for full understanding of each factor's influence on SLMs properties and optimization of DPIs with maximized FPFs.

Nano targeted Therapies Made of Lipids and Polymers have Promising Strategy for the Treatment of Lung Cancer

The introduction of nanoparticles made of polymers, protein, and lipids as drug delivery systems has led to significant progress in modern medicine. Since the application of nanoparticles in medicine involves the use of biodegradable, nanosized materials to deliver a certain amount of chemotherapeutic agents into a tumor site, this leads to the accumulation of these nanoencapsulated agents in the right region. This strategy minimizes the stress and toxicity generated by chemotherapeutic agents on healthy cells. Therefore, encapsulating chemotherapeutic agents have less cytotoxicity than non-encapsulation ones. The purpose of this review is to address how nanoparticles made of polymers and lipids can successfully be delivered into lung cancer tumors. Lung cancer types and their anatomies are first introduced to provide an overview of the general lung cancer structure. Then, the rationale and strategy applied for the use of nanoparticle biotechnology in cancer therapies are discussed, focusing on pulmonary drug delivery systems made from liposomes, lipid nanoparticles, and polymeric nanoparticles. Many nanoparticles fabricated in the shape of liposomes, lipid nanoparticles, and polymeric nanoparticles are summarized in our review, with a focus on the encapsulated chemotherapeutic molecules, ligand-receptor attachments, and their targets. Afterwards, we highlight the nanoparticles that have demonstrated promising results and have been delivered into clinical trials. Recent clinical trials that were done for successful nanoparticles are summarized in our review.

Pharmacokinetics of inhaled nanotherapeutics for pulmonary delivery

Pulmonary delivery of lipid-based nanotherapeutics by inhalation presents an advantageous alternative to oral and intravenous routes of administration that avoids enzymatic degradation in gastrointestinal tract and hepatic first pass metabolism and also limits off-target adverse side effects upon heathy tissues. For lung-related indications, inhalation provides localized delivery in order to enhance therapeutic efficacy at the site of action. Optimization of physicochemical properties, selected drug and inhalation format can greatly influence the pharmacokinetic behavior of inhaled nanoparticle systems and their payloads. The present review analyzes a wide range of nanoparticle systems, their formulations and consequent effect on pharmacokinetic distribution of delivered active components after inhalation.

Inhaled chemotherapy adverse effects: mechanisms and protection methods

Lung cancer is still diagnosed at a late stage due to a lack of symptoms. Although there are novel therapies, many patients are still treated with chemotherapy. In an effort to reduce adverse effects associated with chemotherapy, inhaled administration of platinum analogs has been investigated. Inhaled administration is used as a local route in order to reduce the systemic adverse effects; however, this treatment modality has its own adverse effects. In this mini review, we present drugs that were administered as nebulized droplets or dry powder aerosols for non-small-cell lung cancer. We present the adverse effects and methods to overcome them.

Nanohybrid carriers: the yin–yang equilibrium between natural and synthetic in biomedicine

Nanocarriers are key players in biomedicine applications. The development of hybrid nanoparticles stems from the need to enhance their quality by lowering disadvantages and fusing the positive qualities of both natural and synthetic materials.

Formulation Strategies for Folate-Targeted Liposomes and Their Biomedical Applications

The folate receptor (FR) is a tumor-associated antigen that can bind with folic acid (FA) and its conjugates with high affinity and ingests the bound molecules inside the cell via the endocytic mechanism. A wide variety of payloads can be delivered to FR-overexpressed cells using folate as the ligand, ranging from small drug molecules to large DNA-containing macromolecules. A broad range of folate attached liposomes have been proven to be highly effective as the targeted delivery system. For the rational design of folate-targeted liposomes, an intense conceptual understanding combining chemical and biomedical points of view is necessary because of the interdisciplinary nature of the field. The fabrication of the folate-conjugated liposomes basically involves the attachment of FA with phospholipids, cholesterol or peptides before liposomal formulation. The present review aims to provide detailed information about the design and fabrication of folate-conjugated liposomes using FA attached uncleavable/cleavable phospholipids, cholesterol or peptides. Advances in the area of folate-targeted liposomes and their biomedical applications have also been discussed.

Lipid-polymer hybrid nanoparticles as a next-generation drug delivery platform: state of the art, emerging technologies, and perspectives

Lipid-polymer hybrid nanoparticles (LPHNPs) are next-generation core-shell nanostructures, conceptually derived from both liposome and polymeric nanoparticles (NPs), where a polymer core remains enveloped by a lipid layer. Although they have garnered significant interest, they remain not yet widely exploited or ubiquitous. Recently, a fundamental transformation has occurred in the preparation of LPHNPs, characterized by a transition from a two-step to a one-step strategy, involving synchronous self-assembly of polymers and lipids. Owing to its two-in-one structure, this approach is of particular interest as a combinatorial drug delivery platform in oncology. In particular, the outer surface can be decorated in multifarious ways for active targeting of anticancer therapy, delivery of DNA or RNA materials, and use as a diagnostic imaging agent. This review will provide an update on recent key advancements in design, synthesis, and bioactivity evaluation as well as discussion of future clinical possibilities of LPHNPs.

Enhanced combination cancer therapy using lipid-calcium carbonate/phosphate nanoparticles as a targeted delivery platform

Aim: Melanoma, the most life-threatening skin cancer, requires more effective therapies. Methodology: A new folic acid (FA) receptor-targeted lipid-coated calcium carbonate/phosphate (LCCP) nanoparticle was synthesized, incorporating two often-used therapeutics, cell death siRNA and α-tocopheryl succinate. Results: The nanoparticles were spherical, with an average size of 40 nm. The nanoparticles exhibited a high gene/drug loading efficiency (60%), with folic acid-enhanced cellular uptake. The nanoparticles with both therapeutics enhanced inhibition of B16F0 melanoma cell growth, showing a moderate synergistic effect. The mechanism of the inhibition is associated with induction of cell apoptosis and cell cycle arrest at G1 phase. Conclusion: Our data indicate that lipid-coated calcium carbonate/phosphate nanoparticles are a potential platform for targeted therapy for melanoma.

Lipid-polymer hybrid nanocarrier-mediated cancer therapeutics: current status and future directions

The new generation of nanoparticles (NPs) encompass attributes of lipids and polymers and are referred to as 'lipid-polymer hybrid nanoparticles' (LPHNPs). LPHNPs have helped shed light on the mechanisms involved in targeted and non-specific drug delivery. Research has also highlighted the opportunities and challenges faced by the use of nanomedicine as personalized therapies in oncology. Here, we review the development of LPHNPs as cancer therapeutics, focusing on the methods deployed for enhancing the targeting efficiency and applications of LPHNPs.

Lipid-polymer hybrid nanocarriers for delivering cancer therapeutics

Cancer remained a major cause of death providing diversified challenges in terms of treatment including non-specific toxicity, chemoresistance and relapse. Nanotechnology- based delivery systems grabbed tremendous attention for delivering cancer therapeutics as they provide benefits including controlled drug release, improved biological half-life, reduced toxicity and targeted delivery. Majority of the nanocarriers consists of either a polymer or a lipid component along with other excipients to stabilize the colloidal system. Lipid-based systems provide advantages like better entrapment efficiency, scalability and low- cost raw materials, however, suffer from limitations including instability, a burst release of the drug, and limited surface functionalization. On the other hand, polymeric systems provide an excellent diversity of chemical modifications, stability, controlled release, however limited drug loading capacities and scale up limit their use. Hybrid nanocarriers consisting of lipid and polymer were able to overcome some of these disadvantages while retaining the advantages of both the systems. Designing a stable lipid-polymer hybrid system requires a thorough understanding of the material properties and their behavior in in vitro and in vivo environments. This review highlights the current status and future prospects of lipid-polymer hybrid systems with a particular focus on cancer nanotherapeutics.

Fabrication and Use of Poly(d,l-lactide-co-glycolide)-Based Formulations Designed for Modified Release of 5-Fluorouracil

5-fluorouracil (5-FU) is a chemotherapeutic agent that has been used for the treatment of a variety of malignancies since its initial introduction to the clinic in 1957. Owing to its short biological half-life, multiple dosings are generally required to maintain effective 5-FU plasma concentrations throughout the therapeutic period. Clinical studies have shown that continuous 5-FU administration is generally superior to bolus injection as exhibited by lower toxicities and increased therapeutic efficacy. Optimal therapeutic efficacy, however, is often compromised by the limiting therapeutic index. Whilst oral formulations are also used, these suffer from the drawbacks of variable bioavailability and first-pass metabolism. As a result, sustained release formulations of 5-FU have been investigated in an effort to mimic the kinetics of continuous infusion particularly for situations where local delivery is considered appropriate. The biocompatible, biodegradable, and highly tunable synthetic polymer, poly(d,l-lactide-co-glycolide) (PLGA), is widely used as a vector for sustained drug delivery, however, issues such as insufficient loading and inappropriate burst release kinetics have dogged progress into the clinic for small hydrophilic drugs such as 5-FU. This review provides introductory information about the mechanism of action, pharmacokinetic and physicochemical properties, and clinical use of 5-FU that have contributed to the development of PLGA-based 5-FU release platforms. In addition, this review provides information on fabrication methods used for a range of 5-FU-loaded PLGA formulations and discusses factors affecting the release kinetics of 5-FU as well as the in vitro and in vivo antitumor or antiproliferative efficacy of these platforms.

Development of Optimized, Inhalable, Gemcitabine-Loaded Gelatin Nanocarriers for Lung Cancer

BACKGROUND

Aerosol delivery of chemotherapeutic nanocarriers represents a promising alternative for lung cancer therapy. This study optimized gemcitabine (Gem)-loaded gelatin nanocarriers (GNCs) cross-linked with genipin (Gem-GNCs) to evaluate their potential for nebulized lung cancer treatment.

METHODS

Gem-GNCs were prepared by two-step desolvation and optimized through Taguchi design and characterized for physicochemical properties. Particle size and morphology were confirmed by scanning and transmission electron microscopy. In vitro release of Gem from Gem-GNCs performed in Dulbecco's phosphate-buffered saline and simulated lung fluid was evaluated to determine release mechanisms. Particle size stability was assessed under varying pH. Differential scanning calorimetry and powder X-ray diffraction were used to determine the presence and stability of Gem-GNC components and amorphization of Gem, respectively. Gem-GNC efficacy within A549 and H460 cells was evaluated using MTT assays. Mucus rheology upon treatment with Gem-GNCs, lactose, and normal saline control was measured. Andersen cascade impaction identified the aerodynamic particle size distribution of the nebulized formulation.

RESULTS

Gem-GNCs had particle size, zeta potential, entrapment efficiency, and loading efficiency of 178 ± 7.1 nm, -18.9 mV, 92.5%, and 9.1%, respectively. The Gem and formulation excipients where molecularly dispersed and configured amorphously. Gem-GNCs were stable at pH 5.4-7.4 for 72 hours. Gem release from Gem-GNCs was governed by non-Fickian controlled release due to diffusion/erosion from a matrix-based nanocarrier. Gem-GNCs elicited a 40% reduction of the complex viscosity η*(1 Hz) of human bronchial epithelial cell mucus containing 3 wt% solids to mimic mild airway disease. The nebulized Gem-GNCs had a mass median aerodynamic diameter (MMAD) of 2.0 ± 0.16 μm, geometric standard deviation (GSD) of 2.7 ± 0.16, and fine particle fraction (FPF) of 75.2% ± 2.4%. The Gem-GNC formulation did not outperform the Gem solution in A549 cells. However, in H460, Gem-GNCs outperformed the Gem IC50 reduction by ∼5-fold at 48 and 10-fold 72 hours.

CONCLUSION

Stable, effective, and sustained-release Gem-GNCs were developed. The nebulized Gem-GNCs had satisfactory MMAD, GSD, and FPF and the formulation reduced the dynamic complex viscosity of mucus consistent with increased mobility of nanoparticles.

Preparation of particulate polymeric therapeutics for medical applications

Particulate therapeutics fabricated from polymeric materials have become increasingly popular over the past several decades. Generally, polymeric systems are easy to synthesize and have tunable parameters, giving them significant potential for wide use in the clinic. They come in many different forms, including as nanoparticles, microparticles, and colloidal gels. In this review, we discuss the current preparation methods for each type of platform, as well as some representative applications. To achieve enhanced performance, lipid coatings and other surface modification techniques for introducing additional functionality are also mentioned. We hope that, by outlining the various methods and techniques for their preparation, it will be possible to provide insights into the utility of these polymeric platforms and further encourage their development for biomedical applications.

Lipid-Based Drug Delivery Systems in Cancer Therapy: What Is Available and What Is Yet to Come

Cancer is a leading cause of death in many countries around the world. However, the efficacy of current standard treatments for a variety of cancers is suboptimal. First, most cancer treatments lack specificity, meaning that these treatments affect both cancer cells and their normal counterparts. Second, many anticancer agents are highly toxic, and thus, limit their use in treatment. Third, a number of cytotoxic chemotherapeutics are highly hydrophobic, which limits their utility in cancer therapy. Finally, many chemotherapeutic agents exhibit short half-lives that curtail their efficacy. As a result of these deficiencies, many current treatments lead to side effects, noncompliance, and patient inconvenience due to difficulties in administration. However, the application of nanotechnology has led to the development of effective nanosized drug delivery systems known commonly as nanoparticles. Among these delivery systems, lipid-based nanoparticles, particularly liposomes, have shown to be quite effective at exhibiting the ability to: 1) improve the selectivity of cancer chemotherapeutic agents; 2) lower the cytotoxicity of anticancer drugs to normal tissues, and thus, reduce their toxic side effects; 3) increase the solubility of hydrophobic drugs; and 4) offer a prolonged and controlled release of agents. This review will discuss the current state of lipid-based nanoparticle research, including the development of liposomes for cancer therapy, different strategies for tumor targeting, liposomal formulation of various anticancer drugs that are commercially available, recent progress in liposome technology for the treatment of cancer, and the next generation of lipid-based nanoparticles.

Pulmonary targeting potential of rosuvastatin loaded nanostructured lipid carrier: Optimization by factorial design

Rosuvastatin (RSVS), an anti-lipidemic agent suggested for the treatment of airway remodeling in chronic obstructive pulmonary disease (COPD). It shows a pleiotropic effect on airway smooth muscles and inhibits proliferative activities of physiological mitogens. The aim of the present study was to develop and investigate the targeting potential of rosuvastatin (RSVS) to lung as loaded in nanostructured lipid carrier dry powder for inhalation (RNLC-DPI). RNLC dispersion was converted into respirable particle by lyophilization using 5% mannitol as cryoprotectant-carrier. Targeting efficiency of RNLC-DPI was evaluated in vitro for aerosol performance using 8-stage cascade impactor as well in vivo in Wistar rats for pulmokinetics. In vitro aerosol performance demonstrated mass median aerodynamic diameter of <3 μm with fine particle fraction of >90% at 60 L/min. Improved aerosol performance was observed for RNLC-DPI prepared using l-leucin as anti-static agent. Modified in vivo performance with higher Cmax (1.14-fold), improvement in t1/2 (5-fold) and 35-fold improvement in AUC0-∞ indicated significant improvement in bioavailability of RNLC-DPI. Lipidic nature and smaller size of particles helped in bypassing macrophage clearance leading to higher targeting factor. Thus, study demonstrated potential of RNLC-DPI for lung targeting and further for COPD treatment.

Application of 5-Fluorouracil-Polycaprolactone Sustained-Release Film in Ahmed Glaucoma Valve Implantation Inhibits Postoperative Bleb Scarring in Rabbit Eyes

This study was designed to investigate whether 5-fluorouracil (5-Fu)-polycaprolactone sustained-release film in Ahmed glaucoma valve implantation inhibits postoperative bleb scarring in rabbit eyes. Eighteen New Zealand white rabbits were randomly divided into three groups (A, B and C; n = 6 per group). Group A received combined 5-Fu-polycaprolactone sustained-release film application and Ahmed glaucoma valve implantation, group B received local infiltration of 5-Fu and Ahmed glaucoma valve implantation, and group C received Ahmed glaucoma valve implantation. Postoperative observations were made of the anterior segment, intraocular pressure, central anterior chamber depth, blebs, drainage tube, and accompanying ciliary body detachment. The pathology of the blebs and surrounding tissues were observed at month 3 postoperatively. We revealed that the 5-Fu-polycaprolactone sustained-release film maintained a release concentration range of 13.7 ± 0.12 to 37.41 ± 0.47 μg/ml over three months in vitro. Postoperatively, diffuse blebs with ridges were found in all eyes in group A, two blebs were observed in group B, and no bleb formation was present in group C. The postoperative central anterior chamber depth in group A was significantly less than that of the other two groups. The postoperative intraocular pressure of group A stabilized at 6.33-8.67 mmHg, whereas that of group C gradually remained at 7.55-10.02 mmHg. The histopathology showed that the fibrous tissue thickness of the blebs in group A was significantly thinner than that of the other groups. We conclude that the 5-Fu-polycaprolactone sustained-release film had a sustained drug release effect, which promoted the inhibition of bleb scarring after Ahmed glaucoma valve implantation.

Bone regeneration using a freeze-dried 3D gradient-structured scaffold incorporating OIC-A006-loaded PLGA microspheres based on β-TCP/PLGA

To reveal the latent capacity of the growth factor-like low-molecular-weight material OIC-A006 in tissue regeneration, it is essential to design a porous scaffold in order to concurrently accommodate cells and drug release in a controlled manner. Consequently, we fabricated poly (L-lactide-co-glycolide) (PLGA)-based microspheres with an OIC-A006-loaded gradient-structured β-TCP/PLGA scaffold by freeze-drying which could then be used for drug delivery and bone regeneration. The OIC-A006-loaded β-TCP/PLGA scaffold consisted of two parts which loaded different doses of OIC-A006 (6.25 μM, outside; 12.5 μM, inside). The porosity, compressive strength, SEM, degradation, and cumulative amount of drug release in vitro were characterized. Furthermore, we confirmed the incorporation of OIC-A006 into the PLGA-based microspheres within the scaffolds using UV-spectrophotometry, and the amount of drug remaining in the scaffold was maintained by 10 % for up to 28 days. The drug release was slower in the normal-structured drug-loaded scaffold. The OIC-A006 released action from the OIC-A006-loaded β-TCP/PLGA scaffold with ideal therapeutic prospects in tissue regeneration. In vitro cell culture results showed that this gradient-structured composite scaffold can induce the adhesion and proliferation of rat bone marrow stromal cells towards osteoblasts. These results showed that the newly developed OIC-A006-loaded scaffolds with gradient structure can be potentially applied to bone regeneration in clinical applications.

High-performing dry powder inhalers of paclitaxel DPPC/DPPG lung surfactant-mimic multifunctional particles in lung cancer: physicochemical characterization, in vitro aerosol dispersion, and cellular studies

Inhalable lung surfactant-based carriers composed of synthetic phospholipids, dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG), along with paclitaxel (PTX), were designed and optimized as respirable dry powders using organic solution co-spray-drying particle engineering design. These materials can be used to deliver and treat a wide variety of pulmonary diseases with this current work focusing on lung cancer. In particular, this is the first time dry powder lung surfactant-based particles have been developed and characterized for this purpose. Comprehensive physicochemical characterization was carried out to analyze the particle morphology, surface structure, solid-state transitions, amorphous character, residual water content, and phospholipid bilayer structure. The particle chemical composition was confirmed using attenuated total reflectance-Fourier-transform infrared (ATR-FTIR) spectroscopy. PTX loading was high, as quantified using UV-VIS spectroscopy, and sustained PTX release was measured over weeks. In vitro cellular characterization on lung cancer cells demonstrated the enhanced chemotherapeutic cytotoxic activity of paclitaxel from co-spray-dried DPPC/DPPG (co-SD DPPC/DPPG) lung surfactant-based carrier particles and the cytotoxicity of the particles via pulmonary cell viability analysis, fluorescent microscopy imaging, and transepithelial electrical resistance (TEER) testing at air-interface conditions. In vitro aerosol performance using a Next Generation Impactor™ (NGI™) showed measurable powder deposition on all stages of the NGI and was relatively high on the lower stages (nanometer aerodynamic size). Aerosol dispersion analysis of these high-performing DPIs showed mass median diameters (MMADs) that ranged from 1.9 to 2.3 μm with excellent aerosol dispersion performance as exemplified by high values of emitted dose, fine particle fractions, and respirable fractions.

Delivery strategies for sustained drug release in the lungs

Drug delivery to the lungs by inhalation offers a targeted drug therapy for respiratory diseases. However, the therapeutic efficacy of inhaled drugs is limited by their rapid clearance in the lungs. Carriers providing sustained drug release in the lungs can improve therapeutic outcomes of inhaled medicines because they can retain the drug load within the lungs and progressively release the drug locally at therapeutic levels. This review presents the different formulation strategies developed to control drug release in the lungs including microparticles and the wide array of nanomedicines. Large and porous microparticles offer excellent aerodynamic properties. Their large geometric size reduces their uptake by alveolar macrophages, making them a suitable carrier for sustained drug release in the lungs. Similarly, nanocarriers present significant potential for prolonged drug release in the lungs because they largely escape uptake by lung-surface macrophages and can remain in the pulmonary tissue for weeks. They can be embedded in large and porous microparticles in order to facilitate their delivery to the lungs. Conjugation of drugs to polymers as polyethylene glycol can be particularly beneficial to sustain the release of proteins in the lungs as it allows high protein loading. Drug conjugates can be readily delivered to respiratory airways by any current nebulizer device. Nonetheless, liposomes represent the formulation most advanced in clinical development. Liposomes can be prepared with lipids endogenous to the lungs and are particularly safe. Their composition can be adjusted to modulate drug release and they can encapsulate both hydrophilic and lipophilic compounds with high drug loading.

Surfactant-based drug delivery systems for treating drug-resistant lung cancer

Among all cancers, lung cancer is the major cause of deaths. Lung cancer can be categorized into two classes for prognostic and treatment purposes: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Both categories of cancer are resistant to certain drugs. Various mechanisms behind drug resistance are over-expression of superficial membrane proteins [glycoprotein (P-gp)], lung resistance-associated proteins, aberration of the intracellular enzyme system, enhancement of the cell repair system and deregulation of cell apoptosis. Structure-performance relationships and chemical compatibility are consequently major fundamentals in surfactant-based formulations, with the intention that a great deal investigation is committed to this region. With the purpose to understand the potential of P-gp in transportation of anti-tumor drugs to cancer cells with much effectiveness and specificity, several surfactant-based delivery systems have been developed which may include microspheres, nanosized drug carriers (nanoparticles, nanoemulsions, stealth liposomes, nanogels, polymer-drug conjugates), novel powders, hydrogels and mixed micellar systems intended for systemic and/or localized delivery.

Efficacy versus safety concerns for aerosol chemotherapy in non-small-cell lung cancer: a future dilemma for micro-oncology

Inhaled chemotherapy was first used more than 30 years ago. Since then, numerous chemotherapeutic agents have been used in either in vitro or in vivo studies. Several aspects of the methodology of the drug administration have been thoroughly demonstrated and explained. However, the safety concerns of these studies were not thoroughly investigated and different results regarding the same drug formulations have been reported. There are cases where the studies failed to demonstrate the long-term effects of the chemotherapeutic drug formulations to the lung parenchyma. Acute and latent effects observed in a small number of human trial studies are still under investigation of inhaled chemotherapy administration. This review provides data regarding all up-to-date inhaled chemotherapy studies and presents the methodological parameters of the safety measures incorporated. In addition, a commentary regarding the safety concerns for the medical staff participating in these studies will be presented.