Recent advances in pulmonary drug delivery using large, porous inhaled particles

An aerosol nanocomposite microparticle formulation using rifampicin-cyclodextrin inclusion complexes for the treatment of pulmonary diseases

Rifampicin (RIF) is commonly used in the treatment of tuberculosis (TB), a bacterium that currently infects one fourth of the world's population. Despite the effectiveness of RIF in treating TB, current RIF treatment regimens require frequent and prolonged dosing, leading to decreased patient compliance and, ultimately, increased mortality rates. This project aims to provide an alternative to oral RIF by means of an inhalable spray-dried formulation. TB uses alveolar macrophages to hide and replicate until the cells rupture, further spreading the bacteria. Therefore, delivering RIF directly to the lungs can increase the drug concentration at the site of infection while reducing off-site side effects. Cyclodextrin (CD) was used to create a RIF-CD inclusion complex to increase RIF solubility and biodegradable RIF-loaded NP (RIF NP) were developed to provide sustained release of RIF. RIF NP and RIF-CD inclusion complex were spray dried to form a dry powder nanocomposite microparticles (nCmP) formulation (RIF-CD nCmP). RIF-CD nCmP displayed appropriate aerosol dispersion characteristics for effective deposition in the alveolar region of the lungs (4.0 µm) with a fine particle fraction of 89 %. The nCmP provided both a burst release of RIF due to the RIF-CD complex and pH-sensitive release of RIF due to the RIF NP incorporated into the formulation. RIF-CD nCmP did not adversely affect lung epithelial cell viability and RIF NP were able to effectively redisperse from the nCmP after spray drying. These results suggest that RIF-CD nCmP can successfully deliver RIF to the site of TB infection while providing both immediate and sustained release of RIF. Overall, the RIF-CD nCmP formulation has the potential to improve the efficacy for the treatment of TB.

Modern trends in the formulation of microparticles for lung delivery using porogens: methods, principles and examples

Inhalation drug administration is increasingly used for local pharmacotherapy of lung disorders and as an alternative route for systemic drug delivery. Modern inhalation powder systems aim to target drug deposition in the required site of action. Large porous particles (LPP), characterized by an aerodynamic diameter over 5 μm, density below 0.4 g/cm3, and the ability to avoid protective lung mechanisms, come to the forefront of the research. They are mostly prepared by spray techniques such as spray drying or lyophilization using pore-forming substances (porogens). These substances could be gaseous, solid, or liquid, and their selection depends on their polarity, solubility, and mutual compatibility with the carrier material and the drug. According to the pores-forming mechanism, porogens can be divided into groups, such as osmogens, extractable porogens, and porogens developing gases during decomposition. This review characterizes modern trends in the formulation of solid microparticles for lung delivery; describes the mechanisms of action of the most often used porogens, discusses their applicability in various formulation methods, emphasizes spray techniques; and documents discussed topics by examples from experimental studies.

Airway epithelial-targeted nanoparticle reverses asthma in inhalation therapy

Despite extensive research on corticosteroids for treating asthma, their short residence time in the lungs has limited their therapeutic effects in vivo. Nanoparticles have been widely investigated for inhaled drug delivery due to their potential benefits in prolonging drugs' residence time in the lungs. However, the retention of nanoparticles may be limited by mucus and ciliated epithelium clearance mechanisms in the airway. Herein, we anchored a neonatal-Fc-receptor-targeted peptide (FcBP) onto "mucus-penetrating" polyethylene glycol (PEG) nanoparticles (PEG-NP). Interestingly, the mucus-permeability of PEG-NP was not impaired by FcBP-functionalization. Moreover, FcBP modification enhanced cellular internalization and exocytosis via specific receptor-mediated processes, which subsequently ameliorated transepithelial transport and prolonged pulmonary retention. Importantly, after loading dexamethasone, FcBP-functionalization could effectively help nanoparticles cross the airway epithelial layer and be endocytosed by inflammatory cells, resulting in a marked decrease in inflammatory cytokines. Finally, FcBP modification significantly enhanced the therapeutic effect of dexamethasone-loaded nanoparticles in asthma mice. This study demonstrates that FcBP-functionalized PEG-NP can overcome multiple obstacles in the airway to prolong the pulmonary retention of drugs, providing a promising strategy for inhalation therapy.

Improvement in Inhalation Properties of Theophylline and Levofloxacin by Co-Amorphization and Enhancement in Its Stability by Addition of Amino Acid as a Third Component

Co-amorphous systems are amorphous formulations stabilized by the miscible dispersion of small molecules. This study aimed to design a stable co-amorphous system for the co-delivery of two drugs to the lungs as an inhaled formulation. Theophylline (THE) and levofloxacin (LEV) were used as model drugs for treating lung infection with inflammation. Leucine (LEU) or tryptophan (TRP) was employed as the third component to improve the inhalation properties. The co-amorphous system containing THE and LEV in an equal molar ratio was successfully prepared via spray drying where reduction of the particle size and change to the spherical morphology were observed. The addition of LEU or TRP at a one-tenth molar ratio to THE-LEV did not affect the formation of the co-amorphous system, but only TRP acted as an antiplasticizer. The Fourier transform infrared spectroscopy spectra revealed intermolecular interactions between THE and LEV in the co-amorphous system that were retained after the addition of LEU or TRP. The co-amorphous THE-LEV system exhibited better in vitro aerodynamic performance than a physical mixture of these compounds and permitted the simultaneous delivery of both drugs in various stages. The co-amorphous THE-LEV system crystallized at 40 °C, and this crystallization was not prevented by LEU. However, THE-LEV-TRP maintained its amorphous state for 1 month. Thus, TRP can act as a third component to improve the physical stability of the co-amorphous THE-LEV system, while maintaining the enhanced aerodynamic properties.

Harnessing inhaled nanoparticles to overcome the pulmonary barrier for respiratory disease therapy

The lack of effective treatments for pulmonary diseases presents a significant global health burden, primarily due to the challenges posed by the pulmonary barrier that hinders drug delivery to the lungs. Inhaled nanomedicines, with their capacity for localized and precise drug delivery to specific pulmonary pathologies through the respiratory route, hold tremendous promise as a solution to these challenges. Nevertheless, the realization of efficient and safe pulmonary drug delivery remains fraught with multifaceted challenges. This review summarizes the delivery barriers associated with major pulmonary diseases, the physicochemical properties and drug formulations affecting these barriers, and emphasizes the design advantages and functional integration of nanomedicine in overcoming pulmonary barriers for efficient and safe local drug delivery. The review also deliberates on established nanocarriers and explores drug formulation strategies rooted in these nanocarriers, thereby furnishing essential guidance for the rational design and implementation of pulmonary nanotherapeutics. Finally, this review cast a forward-looking perspective, contemplating the clinical prospects and challenges inherent in the application of inhaled nanomedicines for respiratory diseases.

Preparation and Evaluation of Inhalable Amifostine Microparticles Using Wet Ball Milling

The conventional dosage form of Ethyol^® (amifostine), a sterile lyophilized powder, involves reconstituting it with 9.7 mL of sterile 0.9% sodium chloride in accordance with the United States Pharmacopeia specifications for intravenous infusion. The purpose of this study was to develop inhalable microparticles of amifostine (AMF) and compare the physicochemical properties and inhalation efficiency of AMF microparticles prepared by different methods (jet milling and wet ball milling) and different solvents (methanol, ethanol, chloroform, and toluene). Inhalable microparticles of AMF dry powder were prepared using a wet ball-milling process with polar and non-polar solvents to improve their efficacy when delivered through the pulmonary route. The wet ball-milling process was performed as follows: AMF (10 g), zirconia balls (50 g), and solvent (20 mL) were mixed and placed in a cylindrical stainless-steel jar. Wet ball milling was performed at 400 rpm for 15 min. The physicochemical properties and aerodynamic characteristics of the prepared samples were evaluated. The physicochemical properties of wet-ball-milled microparticles (WBM-M and WBM-E) using polar solvents were confirmed. Aerodynamic characterization was not used to measure the % fine particle fraction (% FPF) value in the raw AMF. The % FPF value of JM was 26.9 ± 5.8%. The % FPF values of the wet-ball-milled microparticles WBM-M and WBM-E prepared using polar solvents were 34.5 ± 0.2% and 27.9 ± 0.7%, respectively; while the % FPF values of the wet-ball-milled microparticles WBM-C and WBM-T prepared using non-polar solvents were 45.5 ± 0.6% and 44.7 ± 0.3%, respectively. Using a non-polar solvent in the wet ball-milling process resulted in a more homogeneous and stable crystal form of the fine AMF powder than using a polar solvent.

Inhibition of SARS-CoV-2 Spike Protein Pseudotyped Virus Infection Using ACE2-Tethered Micro/Nanoparticles

Coronavirus disease 2019 (COVID-19) has caused a global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The viral infection is reliant upon the binding between angiotensin-converting enzyme 2 receptor (ACE2) and spike protein (S). Therefore, ACE2 is a key receptor for SARS-CoV-2 to infect the host. Nonetheless, as SARS-CoV-2 is constantly mutating into new variants that cause high infection rates, the development of prophylactic and therapeutic approaches remains a necessity to continue fighting mutated SARS-CoV-2 variants. In this study, ACE2-streptavidin fusion proteins expressed by recombinant DNA technology were anchored on biotinylated fluorescent polystyrene particles of various sizes ranging from 0.15 to 5 µm. The ACE2-tethered micro/nanoparticles were shown to prevent spike protein pseudotyped lentivirus entry into ACE2-expressing HEK293T cells. Compared to ACE2 in soluble form, micro-sized particles (2 and 5 µm) immobilized with ACE2 interfered more efficiently with viral attachment, entry, and the ensuing infection. Our results showed that particles functionalized with ACE2 could be used as efficient decoys to block the infection of SARS-CoV-2 strains.

Nanoparticle Diffusion in Respiratory Mucus Influenced by Mucociliary Clearance: A Review of Mathematical Modeling

Background: Inhalation and deposition of particles in human airways have attracted considerable attention due to importance of particulate pollutants, transmission of infectious diseases, and therapeutic delivery of drugs at targeted areas. We summarize current state-of-the art research in particle deposition on airway surface liquid (ASL) influenced by mucociliary clearance (MCC) by identifying areas that need further investigation. Methodology: We aim to review focus on governing and constitutive equations describing MCC geometry followed by description of mathematical modeling of ciliary forces, mucus rheology properties, and numerical approaches to solve modified time-dependent Navier-Stokes equations. We also review mathematical modeling of particle deposition in ASL influenced by MCC, particle transport in ASL in terms of Eulerian and Lagrangian approaches, and discuss the corresponding mass transport issues in this layer. Whenever required, numerical predictions are contrasted with the pertinent experimental data. Results: Results indicate that mean mucus and periciliary liquid velocities are strongly influenced by mucus rheological characteristics as well as ciliary abnormalities. However, most of the currently available literature on mucus fiber spacing, ciliary beat frequency, and particle surface chemistry is based on particle deposition on ASL by considering a fixed value of ASL velocity. The effects of real ASL flow regimes on particle deposition in this layer are limited. In addition, no other study is available on modeling nonhomogeneous and viscoelastic characteristics of mucus layer on ASL drug delivery. Conclusion: Simplification of assumptions on governing equations of drug delivery in ASL influenced by MCC leads to imposing some limitations on numerical results.

Non-spherical drug particle deposition in human airway using computational fluid dynamics and discrete element method

Currently, the air pollution and the respiratory disease problems that affect human health are increasing rapidly. Hence, there is attention for trend prediction of the located deposition of inhaled particles. In this study, Weibel's based human airway model (G0-G5) was employed. The computational fluid dynamics and discrete element method (CFD-DEM) simulation was successfully validated by comparison to the previous research studies. The CFD-DEM achieves a better balance between numerical accuracy and computational requirement when comparing with the other methods. Then, the model was used to analyze the non-spherical drug transport with different drug particle sizes, shapes, density, and concentrations. The results found that all the studied factors affected the drug deposition and particle out-mass percentage except the drug concentration. The drug deposition was increased with the increasing of particle size and particle density due to the influence of particle inertia. The Tomahawk-shaped drug deposited easier than the cylindrical drug shape because of the different drag behavior. For the effect of airway geometries, G0 was the maximum deposited zone and G3 was the minimum deposited zone. The boundary layer was found around bifurcation due to the shear force at the wall. Finally, the knowledge can give an essential recommendation for curing patients with pharmaceutical aerosol. The design suggestion of a proper drug delivery device can be summarized.

HPLC-UV/VIS for Determination of Ipratropium Bromide Mixed with Salbuterol, Beclomethasone Propionate and Budesonide using Dual Wavelength-Detection Method

BACKGROUND

Inhalation preparation involves liquid or solid raw materials for delivering to lungs as aerosol or vapor. The liquid preparation for nebulizer is effective for convenient use and patient compliance and it has been extensively used in the treatment of clinical lung diseases. Clinical staff often mixes the compound ipratropium bromide with beclomethasone propionate and budesonide inhaler but reference values of inhalants for clinical use need to be established for simplifying the operation procedure. The high-performance liquid chromatography (HPLC) method of compound ipratropium bromide solution, beclomethasone propionate suspension and budesonide suspension after mixed atomization was studied.

METHODS

The specificity, linearity, recovery (accuracy), precision and stability of compound ipratropium bromide, beclomethasone propionate and budesonide were tested to verify the developed liquid phase method.

RESULTS

The developed liquid phase method had high specificity, linear R2≥0,999, recovery (accuracy) RSD (relative standard deviation) less than 2%, precision RSD less than 2,0%, and stability RSD less than 2,0%.

CONCLUSION

The liquid phase methodology developed in this study can be used for the determination of compound ipratropium bromide mixed with beclomethasone propionate and budesonide. The current methodology can also be used to provide a reference for the determination of its content after mixing, and further data support for its clinical medication.

Nanotechnology as a tool to overcome macromolecules delivery issues

Nanocarriers can deliver drugs to specific organs or cells, potentially bridging the gap between a drug's function and its interaction with biological systems such as human physiology. The untapped potential of nanotechnology stems from its ability to manipulate materials, allowing control over physical and chemical properties and overcoming drug-related problems, e.g., poor solubility or poor bioavailability. For example, most protein drugs are administered parenterally, each with challenges and peculiarities. Some problems faced by bioengineered macromolecule drugs leading to poor bioavailability are short biological half-life, large size and high molecular weight, low permeability through biological membranes, and structural instability. Nanotechnology emerges as a promising strategy to overcome these problems. Nevertheless, the delivery system should be carefully chosen considering loading efficiency, physicochemical properties, production conditions, toxicity, and regulations. Moving from the bench to the bedside is still one of the major bottlenecks in nanomedicine, and toxicological issues are the greatest challenges to overcome. This review provides an overview of biotech drug delivery approaches, associated nanotechnology novelty, toxicological issues, and regulations.

Advances in nanomaterial-based targeted drug delivery systems

Nanomaterial-based drug delivery systems (NBDDS) are widely used to improve the safety and therapeutic efficacy of encapsulated drugs due to their unique physicochemical and biological properties. By combining therapeutic drugs with nanoparticles using rational targeting pathways, nano-targeted delivery systems were created to overcome the main drawbacks of conventional drug treatment, including insufficient stability and solubility, lack of transmembrane transport, short circulation time, and undesirable toxic effects. Herein, we reviewed the recent developments in different targeting design strategies and therapeutic approaches employing various nanomaterial-based systems. We also discussed the challenges and perspectives of smart systems in precisely targeting different intravascular and extravascular diseases.

The emergence of nanoporous materials in lung cancer therapy

Lung cancer is one of the most common cancers, affecting more than 2.1 million people across the globe every year. A very high occurrence and mortality rate of lung cancer have prompted active research in this area with both conventional and novel forms of therapies including the use of nanomaterials based drug delivery agents. Specifically, the unique physico-chemical and biological properties of porous nanomaterials have gained significant momentum as drug delivery agents for delivering a combination of drugs or merging diagnosis with targeted therapy for cancer treatment. This review focuses on the emergence of nano-porous materials for drug delivery in lung cancer. The review analyses the currently used nanoporous materials, including inorganic, organic and hybrid porous materials for delivering drugs for various types of therapies, including chemo, radio and phototherapy. It also analyses the selected research on stimuli-responsive nanoporous materials for drug delivery in lung cancer before summarizing the various findings and projecting the future of emerging trends. This review provides a strong foundation for the current status of the research on nanoporous materials, their limitations and the potential for improving their design to overcome the unique challenges of delivering drugs for the treatment of lung cancer.

Spray Freeze-Drying for inhalation application: Process and Formulation Variables

High porous particles with specific aerodynamic properties were processed by the spray freeze-drying (SFD) method. Comprehensive knowledge about all aspects of the SFD method is required for particle engineering of various pharmaceutical products with good flow properties. In this review, different types of the SFD method, the most frequently employed excipients, properties of particles prepared by this method, and most recent approaches concerning SFD are summarized. Generally, this technique can prepare spherical-shaped particles with a highly porous interior structure, responsible for the very low density of powders. Increasing the solubility of spray freeze-dried formulations achieves the desired efficacy. Also, due to the high efficiency of SFD, by determining the different features of this method and optimizing the process by model-based studies, desirable results for various inhaled products can be achieved and significant progress can be made in the field of pulmonary drug delivery.

Engineered-inhaled particles: Influence of carbohydrates excipients nature on powder properties and behavior

Pulmonary drug administration has long been used for local or systemic treatment due to several advantages. Dry powder inhalers emerge as the most promising due to efficiency, ecologic, and drug stability concerns. Coarse lactose-carrier is still the gold standard when inhalation powders are developed. Despite some efforts to produce new types of powders, the lung drug deposition is still poorly controlled, which will ultimately impact therapeutic effectiveness. In this study, we developed "engineered-inhalation powders" using the spray-drying technique. Multiple carbohydrates excipients were binary mixed and combined with two active pharmaceutical ingredients for asthma therapy (budesonide and formoterol). Particle morphology, from spherical to deflated shapes, was characterized by the number and the depth of dimples measured from SEM images. We define a new characteristic deflation ratio ξ as the product between the number of dimples and their depth. Six different powders having opposite morphologies have been selected and we have demonstrated a linear correlation between the fine particle fraction and the deflation ratio of produced powders. Overall, we showed first that the morphology of inhalable powder can be finely tuned by spray-drying technique when excipients varied. Secondly, we developed stable inhalation powders that simultaneously induced high fine particle fractions (>40%) for two drugs due to their deflated surface. The stability has been evaluated for up to 2 months at room temperature.

Inhalation delivery of repurposed drugs for lung cancer: Approaches, benefits and challenges

Lung cancer (LC) is one of the leading causes of mortality accounting for almost 25% of cancer deaths throughout the world. The shortfall of affordable and effective first-line chemotherapeutics, the existence of resistant tumors, and the non-optimal route of administration contribute to poor prognosis and high mortality in LC. Administration of repurposed non-oncology drugs (RNODs) loaded in nanocarriers (NCs) via inhalation may prove as an effective alternative strategy to treat LC. Furthermore, their site-specific release through inhalation route using an appropriate inhalation device would offer improved therapeutic efficacy, thereby reducing mortality and improving patients' quality of life. The current manuscript offers a comprehensive overview on use of RNODs in LC treatment with an emphasis on their inhalation delivery and the associated challenges. The role of NCs to improve lung deposition and targeting of RNODs via inhalation are also elaborated. In addition, information about various RNODs in clinical trials for the treatment of LC, possibility for repurposing phytoceuticals against LC via inhalation and the bottlenecks associated with repurposing RNODs against cancer are also highlighted. Based on the reported studies covered in this manuscript, it was understood that delivery of RNODs via inhalation has emerged as a propitious approach. Hence, it is anticipated to provide effective first-line treatment at an affordable cost in debilitating LC from low and middle-income countries (LMIC).

Protein and peptide delivery to lungs by using advanced targeted drug delivery

The challenges and difficulties associated with conventional drug delivery systems have led to the emergence of novel, advanced targeted drug delivery systems. Therapeutic drug delivery of proteins and peptides to the lungs is complicated owing to the large size and polar characteristics of the latter. Nevertheless, the pulmonary route has attracted great interest today among formulation scientists, as it has evolved into one of the important targeted drug delivery platforms for the delivery of peptides, and related compounds effectively to the lungs, primarily for the management and treatment of chronic lung diseases. In this review, we have discussed and summarized the current scenario and recent developments in targeted delivery of proteins and peptide-based drugs to the lungs. Moreover, we have also highlighted the advantages of pulmonary drug delivery over conventional drug delivery approaches for peptide-based drugs, in terms of efficacy, retention time and other important pharmacokinetic parameters. The review also highlights the future perspectives and the impact of targeted drug delivery on peptide-based drugs in the coming decade.

Pulmonary Delivery of Docetaxel and Celecoxib by PLGA Porous Microparticles for Their Synergistic Effects Against Lung Cancer

BACKGROUND

using a combination of chemotherapeutic agents with novel drug delivery platforms to enhance the anticancer efficacy of the drug and minimizing the side effects, is very imperative for lung cancer treatments.

OBJECTIVE

The aim of the present study was to develop, characterize, and optimize porous poly (D, L-lactic-co-glycolic acid) (PLGA) microparticles for simultaneous delivery of docetaxel (DTX) and celecoxib (CXB) through the pulmonary route for lung cancer.

METHODS

Drug-loaded porous microparticles were prepared by an emulsion solvent evaporation method. The impact of various processing and formulation variables including PLGA amount, dichloromethane volume, homogenization speed, polyvinyl alcohol volume and concentration were assessed on entrapment efficiency, mean release time, particle size, mass median aerodynamic diameter, fine particle fraction and geometric standard deviation using a two-level factorial design. An optimized formulation was prepared and evaluated in terms of size and morphology using a scanning electron microscope.

RESULTS

FTIR, DSC, and XRD analysis confirmed drug entrapment and revealed no drug-polymer chemical interaction. Cytotoxicity of DTX along with CXB against A549 cells was significantly enhanced compared to DTX and CXB alone and the combination of DTX and CXB showed the greatest synergistic effect at a 1/500 ratio.

CONCLUSION

In conclusion, the results of the present study suggest that encapsulation of DTX and CXB in porous PLGA microspheres with desirable features are feasible and their pulmonary co-administration would be a promising strategy for the effective and less toxic treatment of various lung cancers.

A new purification technique to obtain specific size distribution of giant lipid vesicles using dual filtration

A new purification technique is developed for obtaining distribution of giant unilamellar vesicles (GUVs) within a specific range of sizes using dual filtration. The GUVs were prepared using well known natural swelling method. For filtration, different combinations of polycarbonate membranes were implemented in filter holders. In our experiment, the combinations of membranes were selected with corresponding pore sizes-(i) 12 and 10 μm, (ii) 12 and 8 μm, and (iii) 10 and 8 μm. By these filtration arrangements, obtained GUVs size distribution were in the ranges of 6-26 μm, 5-38 μm and 5-30 μm, respectively. In comparison, the size distribution range was much higher for single filtration technique, for example, 6-59 μm GUVs found for a membrane with 12 μm pores. Using this technique, the water-soluble fluorescent probe, calcein, can be removed from the suspension of GUVs successfully. The size distributions were analyzed with lognormal distribution. The skewness became smaller (narrow size distribution) when a dual filtration was used instead of single filtration. The mode of the size distribution obtained in dual filtration was also smaller to that of single filtration. By continuing this process of purification for a second time, the GUVs size distribution became even narrower. After using an extra filtration with dual filtration, two different size distributions of GUVs were obtained at a time. This experimental observation suggests that different size specific distributions of GUVs can be obtained easily, even if GUVs are prepared by different other methods.

Optimization of Very Low-Dose Formulation of Vitamin D3 with Lyophilizate for Dry Powder Inhalation System by Simple Method Based on Time-of-Flight Theory

It has been previously reported that active vitamin D3 (VD3) is a candidate drug that can repair alveolar damage in chronic obstructive pulmonary disease at a very low dose. We herein report the optimization of a very low-dose formulation of VD3 for dry powder inhalation by a simple method based on time-of-flight (TOF) theory. As the preparation content of VD3 is very low, aerodynamic particle size distribution cannot be measured by pharmacopeial methods that require quantification of the main drug. Thus, a simple method based on TOF theory, which can measure aerodynamic particle size distribution without quantification, was used. The optimized formulation for an inhalation system using a lyophilized cake contained phenylalanine as the excipient (VD3 1 μg/vial + phenylalanine 0.3 mg/vial) and showed high performance with fine particle fraction ≤ 3 μm = 47.2 ± 4.4%. The difference between the results of pharmacopeial methods and simple method was examined using the formulation containing 10 µg/vial of VD3 and was within 5.0%. The preparation is expected to efficiently deliver VD3 to the lungs. Our simple method can optimize dry powder inhalation formulations more easily and rapidly even when the content of the main drug in a preparation is very low.

Effects of Polyvinyl Alcohol on Drug Release from Nanocomposite Particles Using Poly (L-lactide-co-glycolide)

The effects of polyvinyl alcohol (PVA) on the release behavior of polymer nanoparticles from nanocomposite particles using amino acids were investigated. Rifaximin (RFX) was used as a hydrophobic drug model. RFX-loaded poly(L-lactide-co-glycolide) (PLLGA) nanoparticles were prepared using an antisolvent diffusion method. They were then spray-dried with equal amounts of amino acids to prepare the nanocomposite particles. The mean diameters of nanocomposite particles were 2.86-5.42 μm. The particle size increased as the concentration of PVA aqueous solution increased. The mean diameters of RFX-loaded PLLGA nanoparticles were 150-160 nm; however, the particle size distributions of those prepared using 0.25% (w/v) PVA aqueous solution differed significantly immediately after preparation and after redispersion from nanocomposite particles. The release test results of nanocomposite particles revealed that those prepared using 0.25% and 0.50% (w/v) aqueous PVA solutions rapidly released RFX. In contrast, particles prepared using 2.00 and 4.00% (w/v) PVA aqueous solution showed sustained drug release. The results of drug release tests of nanoparticles redispersed from nanocomposite particles showed that the nanoparticles prepared using 0.50% and 2.00% (w/v) PVA aqueous solution suppressed the initial burst. Therefore, we considered that the results of the drug release behavior of the nanoparticles in these particles reflectsreflect the release behavior of the nanoparticles from the nanocomposite particles. These results indicate that the rate of redispersion from nanocomposite particles to nanoparticles can be controlled by changing the concentration of PVA aqueous solution.

High-Efficiency Dry Powder Aerosol Delivery to Children: Review and Application of New Technologies

While dry powder aerosol formulations offer a number of advantages, their use in children is often limited due to poor lung delivery efficiency and difficulties with consistent dry powder inhaler (DPI) usage. Both of these challenges can be attributed to the typical use of adult devices in pediatric subjects and a lack of pediatric-specific DPI development. In contrast, a number of technologies have recently been developed or progressed that can substantially improve the efficiency and reproducibility of DPI use in children including: (i) nose-to-lung administration with small particles, (ii) active positive-pressure devices, (iii) structures to reduce turbulence and jet momentum, and (iv) highly dispersible excipient enhanced growth particle formulations. In this study, these technologies and their recent development are first reviewed in depth. A case study is then considered in which these technologies are simultaneously applied in order to enable the nose-to-lung administration of dry powder aerosol to children with cystic fibrosis (CF). Using a combination of computational fluid dynamics (CFD) analysis and realistic in vitro experiments, device performance, aerosol size increases and lung delivery efficiency are considered for pediatric-CF subjects in the age ranges of 2-3, 5-6 and 9-10 years old. Results indicate that a new 3D rod array structure significantly improves performance of a nasal cannula reducing interface loss by a factor of 1.5-fold and produces a device emitted mass median aerodynamic diameter (MMAD) of 1.67 μm. For all ages considered, approximately 70% of the loaded dose reaches the lower lung beyond the lobar bronchi. Moreover, significant and rapid size increase of the aerosol is observed beyond the larynx and illustrates the potential for targeting lower airway deposition. In conclusion, concurrent CFD and realistic in vitro analysis indicates that a combination of multiple new technologies can be implemented to overcome obstacles that currently limit the use of DPIs in children as young as two years of age.

Enhancing nanoparticle penetration through airway mucus to improve drug delivery efficacy in the lung

Introduction: Airway mucus gel layer serves as a key delivery barrier that limits the performance of inhaled drug delivery nanoparticles. Conventional nanoparticles are readily trapped by the airway mucus and rapidly cleared from the lung via mucus clearance mechanisms. These nanoparticles cannot distribute throughout the lung airways, long-reside in the lung and/or reach the airway epithelium. To address this challenge, strategies to enhance particle penetration through the airway mucus have been developed and proof-of-concept has been established using mucus model systems..Areas covered: In this review, we first overview the biochemical and biophysical characteristics that render the airway mucus a challenging delivery barrier. We then introduce strategies to improve particle penetration through the airway mucus. Specifically, we walk through two classes of approaches, including modification of physicochemical properties of nanoparticles and modulation of barrier properties of airway mucus.Expert opinion: State-of-the-art strategies to overcome the airway mucus barrier have been introduced and experimentally validated. However, data should be interpreted in the comprehensive context of therapeutic delivery from the site of administration to the final destination to determine clinically-relevant approaches. Further, safety should be carefully monitored, particularly when it comes to mucus-altering strategies that may perturb physiological functions of airway mucus.

Inhalation of sustained release microparticles for the targeted treatment of respiratory diseases

Delivering drugs through inhalation for systemic and local applications has been in practice since several decades to treat various diseases. In recent times, inhalation drug delivery is becoming one of the highly focused areas of research in the pharmaceutical industry. It is being considered as one of the major portals for delivering drugs because of its wide range of advantages like requirement of low concentrations of drug to reach therapeutic efficacy, surpassing first pass metabolism and a very low incidence of side effects as compared to conventional delivery of drugs. Owing to these favorable characteristics of pulmonary drug delivery, diverse pharmaceutical formulations like liposomes, nanoparticles, and microparticles are developed through consistent efforts for delivery drugs to lungs in suitable form. However, drug-loaded microparticles have displayed various advantages over the other pharmaceutical dosage forms which give a cutting edge over other inhalational drug delivery systems. Assuring results with respect to sustained release through inhalational delivery of drug-loaded microparticles from pre-clinical studies are anticipative of similar benefits in the clinical settings. This review centralizes partly on the advantages of inhalational microparticles over other inhalational dosage forms and largely on the therapeutic applications and future perspectives of inhalable microparticle drug delivery systems.

Simple Method to Measure the Aerodynamic Size Distribution of Porous Particles Generated on Lyophilizate for Dry Powder Inhalation

Recently, statistical techniques such as design of experiments are being applied for efficient optimization of oral formulations. To use these statistical techniques for inhalation formulations, efficient methods for rapid determination of the aerodynamic particle size distribution of many samples are needed. Therefore, we aimed to develop a simple method to measure aerodynamic particle size distribution that closely agrees with the results of inhalation characteristic tests. We added attachments for dispersion to the aerodynamic particle sizer (APS) so that formulations could be dispersed under the same condition as for multi-stage liquid impinger (MSLI) measurement. Then, we examined the correlation between MSLI and APS using lyophilizate for dry powder inhalation formulations that generate porous particles just on inhalation. It is difficult to obtain the accurate aerodynamic particle size distribution of porous particles by APS because the particle density is difficult to estimate accurately. However, there was a significant correlation between MSLI and APS when the particle density settings for APS measurement was calculated by a conversion factor based on the result of MSLI. The APS with dispersion attachments and this conversion factor can measure a number of samples in a short time, thereby enabling more efficient optimization of dry powder inhalers.

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.

Recent advances in the development of microparticles for pulmonary administration

Pulmonary drug delivery offers several benefits for the management of various conditions over other conventional routes. Inhalation of drugs can also be useful for targeting alveolar macrophages and for maintaining a higher drug concentration in the lung tissues to improve the efficacy of drugs and shorten the duration of treatment, thereby reducing drug toxicities. Thus, such an approach is useful in the treatment of various pulmonary and nonpulmonary diseases. Newer techniques and delivery devices have been used for the formulation of inhalable microparticles. Here. we not only focus on advances in inhalation therapy and in the preparation of microparticles, but also address the clinical development and regulatory aspects of such therapies.

Inhaled nanoparticles-An updated review

We are providing an update to our previously published review paper on inhaled nanoparticles, thus updating with the most recent reports in the literature. The field of nanotechnology may hold the promise of significant improvements in the health and well-being of patients, as well as in manufacturing technologies. The knowledge of the impact of nanomaterials on public health is limited so far. This paper reviews the unique size-controlled properties of nanomaterials, their disposition in the body after inhalation, and the factors influencing the fate of inhaled nanomaterials. The physiology of the lungs makes it an ideal target organ for non-invasive local and systemic drug delivery, especially for protein and poorly water-soluble drugs that have low oral bioavailability via oral administration. More recently, inhaled nanoparticles have been reported to improve therapeutic efficacies and decrease undesirable side effects via pulmonary delivery. The potential application of pulmonary drug delivery of nanoparticles to the lungs, specifically in context of published results reported on nanomaterials in environmental epidemiology and toxicology is reviewed in this paper. This article presents updated delivery systems, process technologies, and potential of inhaled nanoparticles for local and systemic therapies administered to the lungs. The authors acknowledge the contributions of Wei Yang in our 2008 paper published in this journal.

Development, In Vitro Characterization, and In Vivo Toxicity Evaluation of Chitosan-Alginate Nanoporous Carriers Loaded with Cisplatin for Lung Cancer Treatment

Polysaccharide-based aerogels are promising drug carriers. Being nanoporous with a high specific surface area allows their use as a drug vehicle for various delivery routes. Intratracheal and intravenous administration of free cisplatin causes toxicity in the rat liver, lungs, and kidneys. In this work, microspherical particles based on alginate-chitosan without a traditional crosslinker were evaluated for targeted delivery of cisplatin by intratracheal administration. The aerogel particles were prepared using the emulsion gelation method, followed by supercritical carbon dioxide extraction. Loading of cisplatin on the prepared porous particles was performed by impregnation using supercritical fluid technology. The prepared carrier and the loaded drug were evaluated for drug content, release, and in vivo acute and subacute toxicity. Cisplatin was successfully loaded (percent drug loading > 76%) on the prepared carrier (particle size = 0.433 ± 0.091 μm) without chemically interacting with the carrier and without losing its crystal form. Sixty percent of cisplatin was released within 2 h, and the rest was loaded inside the polymer pores and had a sustained first-order release over 6 h. Loading cisplatin on the carrier developed herein reduced the cisplatin lung toxicity but increased the liver toxicity after intratracheal administration with nephrotoxicity being proportional to cisplatin dose in case of carrier-loaded cisplatin. Moreover, loading cisplatin on the carrier significantly reduced mortality rate and prevented weight loss in rats as compared to free cisplatin in subacute studies after intratracheal administration. Thus, the developed carrier showed high potential for targeted delivery of cisplatin for lung cancer treatment by inhalation. Graphical abstract.

Scope and limitations on aerosol drug delivery for the treatment of infectious respiratory diseases

The rise of antimicrobial resistance has created an urgent need for the development of new methods for antibiotics delivery to patients with pulmonary infections in order to mainly increase the effectiveness of the drugs administration, to minimize the risk of emergence of resistant strains, and to prevent patients reinfection. Since bacterial resistance is often related to antibiotic concentration, their pulmonary administration could eradicate strains resistant to the same drug at the concentration achieved through the systemic circulation. Pulmonary administration offers several advantages; it directly targets the site of the infection which allows the inhaled dose of the drug to be reduced compared to that administered orally or parenterally while keeping the same local effect. The review article is made with an objective to compile information about various existing modern technologies developed to provide greater patient compliance and reduce the undesirable side effect of the drugs. In conclusion, aerosol antibiotic delivery appears as one of the best technologies for the treatment of pulmonary infectious diseases and able to limit the systemic adverse effects related to the high drug dose and to make life easier for the patients.

Targeted Pulmonary Delivery of the Green Tea Polyphenol Epigallocatechin Gallate Controls the Growth of Mycobacterium tuberculosis by Enhancing the Autophagy and Suppressing Bacterial Burden

Growing rates of tuberculosis (TB) superbugs are alarming, which has hampered the progress made to-date to control this infectious disease, and new drug candidates are few. Epigallocatechin gallate (EGCG), a major polyphenolic compound from green tea extract, shows powerful efficacy against TB bacteria in in vitro studies. However, the therapeutic efficacy of the molecule is limited due to poor pharmacokinetics and low bioavailability following oral administration. Aiming to improve the treatment outcomes of EGCG therapy, we investigated whether encapsulation and pulmonary delivery of the molecule would allow the direct targeting of the site of infection without compromising the activity. Microencapsulation of EGCG was realized by scalable spray-freeze-drying (SFD) technology, forming free-flowing micrometer-sized microspheres (epigallocatechin-3-gallate-loaded trehalose microspheres, EGCG-t-MS) of trehalose sugar. These porous microspheres exhibited appropriate aerodynamic parameters and high encapsulation efficiencies. In vitro studies demonstrated that EGCG-t-MS exhibited dose- and time-dependent killing of TB bacteria inside mouse macrophages by cellular mechanisms of lysosome acidification and autophagy induction. In a preclinical study on TB-infected Balb/c mice model (4 weeks of infection), we demonstrate that the microencapsulated EGCG, administered 5 days/week for 6 weeks by pulmonary delivery, showed exceptional efficacy compared to oral treatment of free drug. This treatment approach exhibited therapeutic outcomes by resolution of inflammation in the infected lungs and significant reduction (P < 0.05) in bacterial burden (up to ∼2.54 Log₁₀ CFU) compared to untreated control and orally treated mice groups. No pathological granulomas, lesions, and inflammation were observed in the histopathological investigation, compared to untreated controls. The encouraging results of the study may pave the avenues for future use of EGCG in TB therapeutics by targeted pulmonary delivery and lead to its translational success.

A STELLA simulation model for in vitro dissolution testing of respirable size particles

In vitro dissolution testing is a useful quality control tool to discriminate the formulations and to approximate the in vivo drug release profiles. A dissolution apparatus has been custom-made for dissolution testing of dry powder formulations in a small volume of stationary medium (25 μL spread over 4.91 cm² area i.e. ~50 μm thick). To understand the system and predict the key parameters which influence the dissolution of respirable size particles, a simulation model was constructed using STELLA modeling software. Using this model, the permeation (dissolution followed by diffusion through the membrane) of two anti-tubercular drugs of differing solubilities, moxifloxacin (17.68 ± 0.85 mg mL^-1) and ethionamide (0.46 ± 0.02 mg mL^-1), from the respirable size particles and their diffusion from a solution were simulated. The simulated permeation profiles of moxifloxacin from solution and respirable size particles were similar, indicating fast dissolution of the particles. However, the simulated permeation profile of ethionamide from respirable size particles showed slower permeation compared to the solution indicating the slow dissolution of the respirable size particles of ethionamide. The sensitivity analysis suggested that increased mucus volume and membrane thickness decreased the permeation of drug. While this model was useful in predicting and distinguishing the dissolution behaviours of respirable size moxifloxacin and ethionamide, further improvement could be made using appropriate initial parameter values obtained by experiments.

PLGA Porous Microspheres Dry Powders for Codelivery of Afatinib-Loaded Solid Lipid Nanoparticles and Paclitaxel: Novel Therapy for EGFR Tyrosine Kinase Inhibitors Resistant Nonsmall Cell Lung Cancer

Combination therapy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR TKIs) with other chemotherapeutic agents is a feasible strategy to overcome resistance that often occurs after 9-13 months of EGFR TKIs administration in nonsmall cell lung cancer (NSCLC). In this study, a pulmonary microspheres system that codelivers afatinib and paclitaxel (PTX) is developed for treatment of EGFR TKIs resistant NSCLC. In this system, afatinib is loaded in stearic acid-based solid lipid nanoparticles, then these nanoparticles and PTX are loaded in poly-lactide-co-glycolide-based porous microspheres. These inhaled microspheres systems are characterized including geometric particle size, drug encapsulation efficiency, morphology by scanning electron microscopy, specific surface area, in vitro drug release, and aerodynamic particle size. Cell experiments indicate that afatinib and PTX have a synergistic effect and the codelivery system shows a superior treatment effect in drug-resistant NSCLC cells. The biocompatibility, pharmacokinetic, and tissue distribution experiments in Sprague-Dawley rats show that afatinib and PTX in the system can maintain 96 h of high lung concentration but low concentration in other tissues, with acceptable safety. These results demonstrate that this system may be a prospective delivery strategy for drug combination treatment in cancers developing resistance, especially drug-resistant lung cancer.

Airborne Particulate Matter: Human Exposure and Health Effects

OBJECTIVE

Exposure to airborne particulate matter (PM) is estimated to cause millions of premature deaths annually. This work conveys known routes of exposure to PM and resultant health effects.

METHODS

A review of available literature.

RESULTS

Estimates for daily PM exposure are provided. Known mechanisms by which insoluble particles are transported and removed from the body are discussed. Biological effects of PM, including immune response, cytotoxicity, and mutagenicity, are reported. Epidemiological studies that outline the systemic health effects of PM are presented.

CONCLUSION

While the integrated, per capita, exposure of PM for a large fraction of the first-world may be less than 1 mg per day, links between several syndromes, including attention deficit hyperactivity disorder (ADHD), autism, loss of cognitive function, anxiety, asthma, chronic obstructive pulmonary disease (COPD), hypertension, stroke, and PM exposure have been suggested. This article reviews and summarizes such links reported in the literature.

Pulmonary delivery of Nanocomposite Microparticles (NCMPs) incorporating miR-146a for treatment of COPD

The treatment and management of COPD by inhalation to the lungs has emerged as an attractive alternative route to oral dosing due to higher concentrations of the drug being administered to site of action. In this study, Nanocomposite Microparticles (NCMPs) of microRNA (miR-146a) containing PGA-co-PDL nanoparticles (NPs) for dry powder inhalation were formulated using l-leucine and mannitol. The spray-drying (Buchi B290) process was optimised and used to incorporate NPs into NCMPs using mix of l-leucine and mannitol excipients in different ratios (F1; 100:0% w/w, F2; 75:25% w/w, F3; 50:50% w/w, F4; 25:75% w/w, F5; 0:100% w/w) to investigate yield %, moisture content, aerosolisation performance and miR-146a biological activity. The optimum condition was performed at feed rate 0.5 ml/min, aspirator rate 28 m³/h, atomizing air flow rate 480 L/h, and inlet drying temperature 70 °C which produced highest yield percentage and closest recovered NPs size to original prior spray-drying. The optimum formulation (F4) had a high yield (86.0 ± 15.01%), recovered NPs size after spray-drying 409.7 ± 10.05 nm (initial NPs size 244.8 ± 4.40 nm) and low moisture content (2.02 ± 0.03%). The aerosolisation performance showed high Fine Particle Fraction (FPF) 51.33 ± 2.9%, Emitted Dose (ED) of 81.81 ± 3.0%, and the mass median aerodynamic diameter (MMAD) was ≤5 µm suggesting a deposition in the respirable region of the lungs. The biological activity of miR-146a was preserved after spray-drying process and miR-146a loaded NCMPs produced target genes IRAK1 and TRAF6 silencing. These results indicate the optimal process parameters for the preparation of NCMPs of miR-146a-containing PGA-co-PDL NPs suitable for inhalation in the treatment and management of COPD.

Therapeutic potential of andrographolide-loaded nanoparticles on a murine asthma model

Corticosteroids commonly prescribed in asthma show several side-effects. Relatively non-toxic andrographolide (AG) has an anti-asthmatic potential. But its poor bioavailability and short plasma half-life constrain its efficacy. To overcome them, we encapsulated AG in nanoparticle (AGNP) and evaluated AGNP for anti-asthmatic efficacy on murine asthma model by oral/pulmonary delivery. AGNP had 5.47% drug loading with a sustained drug release in vitro. Plasma and lung pharmacokinetic data showed predominantly improved AG-bioavailability upon AGNP administered orally/by pulmonary route. Cell numbers, IL-4, IL-5, and IL-13 levels in broncho-alveolar lavage fluid and serum IgE content were reduced significantly after administration of AGNP compared to free-AG treatment. AGNP-mediated suppression of NF-κβ was predominantly more compared to free-AG. Further, pulmonary route showed better therapeutic performance. In conclusion, AGNP effectively controlled mild and severe asthma and the pulmonary administration of AGNP was more efficacious than the oral route.

Formation Mechanisms of Porous Particles from Self-Assembly of Amphiphilic Diblock Copolymers inside an Oil-in-Water Emulsion Droplet upon Solvent Evaporation

The formation mechanisms of porous particles from self-assembly of amphiphilic diblock copolymers inside an oil-in-water emulsion droplet upon evaporation of the organic solvent are investigated based on Monte Carlo simulations for the first time. A morphological diagram of particles is constructed as a function of the surfactant concentration (φ) and the copolymer composition characterized by the volume fraction of the hydrophilic B block ( f_B). Particles with various morphologies are predicted. Morphological sequences from non-porosity to closed-porosity to capsules and finally to open-porosity particles are usually observed with increasing φ when f_B ≤ 1/2, with the only exception that capsules do not occur when f_B = 1/6. Furthermore, the critical φ value for a given morphological transition usually decreases with increasing f_B. Micelles are always observed at higher φ regions when f_B > 1/2. It is found that the specific surface area falls on almost the same regime for particles with the same kind of morphology, indicating that the morphology of a particle largely determines its specific surface area. The chain stretching varies with the particle morphology. It is the presence of the surfactant that makes the formation of porous particles possible, while when φ > 0, multiple morphological transitions can be induced by changing f_B. In the process of organic solvent removal, the value of f_B may affect the shape of pores inside the droplet and hence leads to the f_B dependence of the morphological sequences. When the solvent evaporation is not too fast, the resulting morphological sequence does not depend on the evaporation rate. Our results are compared with related experiments.

Targeted Drug Delivery to Upper Airways Using a Pulsed Aerosol Bolus and Inhaled Volume Tracking Method

The pulmonary route presents an attractive delivery pathway for topical treatment of lung diseases. While significant progress has been achieved in understanding the physical underpinnings of aerosol deposition in the lungs, our ability to target or confine the deposition of inhalation aerosols to specific lung regions remains meagre. Here, we present a novel inhalation proof-of-concept in silico for regional targeting in the upper airways, quantitatively supported by computational fluid dynamics (CFD) simulations of inhaled micron-sized particles (i.e. 1-10 μm) using an intubated, anatomically-realistic, multi-generation airway tree model. Our targeting strategy relies on selecting the particle release time, whereby a short-pulsed bolus of aerosols is injected into the airways and the inhaled volume of clean air behind the bolus is tracked to reach a desired inhalation depth (i.e. airway generations). A breath hold maneuver then follows to facilitate deposition, via sedimentation, before exhalation resumes and remaining airborne particles are expelled. Our numerical findings showcase how particles in the range 5-10 μm combined with such inhalation methodology are best suited to deposit in the upper airways, with deposition fractions between 0.68 and unity. In contrast, smaller (< 2 μm) particles are less than optimal due to their slow sedimentation rates. We illustrate further how modulating the volume inhaled behind the pulsed bolus, prior to breath hold, may be leveraged to vary the targeted airway sites. We discuss the feasibility of the proposed inhalation framework and how it may help pave the way for specialized topical lung treatments.

Non-invasive delivery strategies for biologics

Biologics now constitute a significant element of available medical treatments. Owing to their clinical and commercial success, biologics are a rapidly growing class and have become a dominant therapeutic modality. Although most of the successful biologics to date are drugs that bear a peptidic backbone, ranging from small peptides to monoclonal antibodies (~500 residues; 150 kDa), new biologic modalities, such as nucleotide-based therapeutics and viral gene therapies, are rapidly maturing towards widespread clinical use. Given the rise of peptides and proteins in the pharmaceutical landscape, tremendous research and development interest exists in developing less-invasive or non-invasive routes for the systemic delivery of biologics, including subcutaneous, transdermal, oral, inhalation, nasal and buccal routes. This Review summarizes the current status, latest updates and future prospects for such delivery of peptides, proteins and other biologics.

High dose dry powder inhalers to overcome the challenges of tuberculosis treatment

Tuberculosis (TB) is a major global health burden. The emergence of the human immunodeficiency virus (HIV) epidemic and drug resistance has complicated global TB control. Pulmonary delivery of drugs using dry powder inhalers (DPI) is an emerging approach to treat TB. In comparison with the conventional pulmonary delivery for asthma and chronic obstructive pulmonary disease (COPD), TB requires high dose delivery to the lung. However, high dose delivery depends on the successful design of the inhaler device and the formulation of highly aerosolizable powders. Particle engineering techniques play an important role in the development of high dose dry powder formulations. This review focuses on the development of high dose dry powder formulations for TB treatment with background information on the challenges of the current treatment of TB and the potential for pulmonary delivery. Particle engineering techniques with a particular focus on the spray drying and a summary of the developed dry powder formulations using different techniques are also discussed.

Materials and methods for delivery of biological drugs

Biological drugs generated via recombinant techniques are uniquely positioned due to their high potency and high selectivity of action. The major drawback of this class of therapeutics, however, is their poor stability upon oral administration and during subsequent circulation. As a result, biological drugs have very low bioavailability and short therapeutic half-lives. Fortunately, tools of chemistry and biotechnology have been developed into an elaborate arsenal, which can be applied to improve the pharmacokinetics of biological drugs. Depot-type release systems are available to achieve sustained release of drugs over time. Conjugation to synthetic or biological polymers affords long circulating formulations. Administration of biological drugs through non-parenteral routes shows excellent performance and the first products have reached the market. This Review presents the main accomplishments in this field and illustrates the materials and methods behind existing and upcoming successful formulations and delivery strategies for biological drugs.

Delivery system for budesonide based on lipid-DNA

Budesonide is a hydrophobic glucocorticoid with high anti-inflammatory activity for the treatment of asthma, inflammatory bowel disease and rheumatoid arthritis. A micellar drug-delivery system based on lipid-DNA may provide a strategy to maximize its drug efficacy and reduce adverse effects. In this work, we report the use of lipid-DNAA (UU11mer), featuring two hydrophobic alkyl chains and forming micelles at a comparatively low critical micelle concentration, to render budesonide water-soluble with a high loading capacity (LC). The inhibition of interleukin-8 (IL-8) release shows that the new delivery system retains the inhibitory activity in cell-based assays. In conclusion, this research provides a novel approach to formulate and administer budesonide in a non-invasive manner, which dramatically improves its water-solubility while retaining its bioavailability.