Cyclodextrins in the production of large porous particles: Development of dry powders for the sustained release of insulin to the lungs

Advancements in cyclodextrin-based controlled drug delivery: Insights into pharmacokinetic and pharmacodynamic profiles

This article discusses and summarizes some fascinating outcomes and applications of cyclodextrins (CDs) and their derivatives in drug delivery. These applications include the administration of protein, peptide medications, and gene delivery. Several innovative drug delivery systems, including NPs, microspheres, microcapsules, and liposomes, are designed with the help of CD, which is highlighted in this article. The use of these compounds as excipients in medicine formulation is reviewed, in addition to their well-known effects on drug solubility and dissolution, as well as their bioavailability, safety, and stability. Furthermore, the article focuses on many factors that influence the development of inclusion complexes, as having this information is necessary to manage these diverse materials effectively. An overview of the commercial availability, regulatory status, and patent status of CDs for pharmaceutical formulation is also presented. Due to the fact that CDs can discover new uses in drug delivery consistently, it is predicted that they will solve a wide range of issues related to the distribution of a variety of unique medications through various delivery channels.

A Review on Micro and Nanoengineering in Powder-Based Pulmonary Drug Delivery

Pulmonary delivery of drugs has emerged as a promising approach for the treatment of both lung and systemic diseases. Compared to other drug delivery routes, inhalation offers numerous advantages including high targeting, fewer side effects, and a huge surface area for drug absorption. However, the deposition of drugs in the lungs can be limited by lung defence mechanisms such as mucociliary and macrophages' clearance. Among the delivery devices, dry powder inhalers represent the optimal choice due to their stability, ease of use, and absence of propellants. In the last decades, several bottom-up techniques have emerged over traditional milling to produce inhalable powders. Among these techniques, the most employed ones are spray drying, supercritical fluid technology, spray freeze-drying, and thin film freezing. Inhalable dry powders can be constituted by micronized drugs attached to a coarse carrier (e.g., lactose) or drugs embedded into a micro- or nanoparticle. Particulate-based formulations are commonly composed of polymeric micro- and nanoparticles, liposomes, solid lipid nanoparticles, dendrimers, nanocrystals, extracellular vesicles, and inorganic nanoparticles. Moreover, engineered formulations including large porous particles, swellable microparticles, nano-in-microparticles, and effervescent nanoparticles have been developed. Particle engineering has also a crucial role in tuning the physical-chemical properties of both carrier-based and carrier-free inhalable powders. This approach can increase powder flowability, deposition, and targeting by customising particle surface features.

Solid Lipid Nanoparticles Containing Dopamine and Grape Seed Extract: Freeze-Drying with Cryoprotection as a Formulation Strategy to Achieve Nasal Powders

(1) Background: DA-Gelucire® 50/13-based solid lipid nanoparticles (SLNs) administering the neurotransmitter dopamine (DA) and the antioxidant grape-seed-derived proanthocyanidins (grape seed extract, GSE) have been prepared by us in view of a possible application for Parkinson's disease (PD) treatment. To develop powders constituted by such SLNs for nasal administration, herein, two different agents, namely sucrose and methyl-β-cyclodextrin (Me-β-CD), were evaluated as cryoprotectants. (2) Methods: SLNs were prepared following the melt homogenization method, and their physicochemical features were investigated by Raman spectroscopy, Scanning Electron Microscopy (SEM), atomic force microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). (3) Results: SLN size and zeta potential values changed according to the type of cryoprotectant and the morphological features investigated by SEM showed that the SLN samples after lyophilization appear as folded sheets with rough surfaces. On the other hand, the AFM visualization of the SLNs showed that their morphology consists of round-shaped particles before and after freeze-drying. XPS showed that when sucrose or Me-β-CD were not detected on the surface (because they were not allocated on the surface or completely absent in the formulation), then a DA surfacing was observed. In vitro release studies in Simulated Nasal Fluid evidenced that DA release, but not the GSE one, occurred from all the cryoprotected formulations. Finally, sucrose increased the physical stability of SLNs better than Me-β-CD, whereas RPMI 2650 cell viability was unaffected by SLN-sucrose and slightly reduced by SLN-Me-β-CD. (4) Conclusions: Sucrose can be considered a promising excipient, eliciting cryoprotection of the investigated SLNs, leading to a powder nasal pharmaceutical dosage form suitable to be handled by PD patients.

The future of dry powder inhaled therapy: Promising or Discouraging for systemic disorders?

Dry powder inhalation therapy has been shown to be an effective method for treating respiratory diseases like asthma, Chronic Obstructive Pulmonary Diseases and Cystic Fibrosis. It has also been widely accepted and used in clinical practices. Such success has led to great interest in inhaled therapy on treating systemic diseases in the past two decades. The current coronavirus (COVID-19) pandemic also has increased such interest and is triggering more potential applications of dry powder inhalation therapy in vaccines and antivirus drugs. Would the inhaled dry powder therapy on systemic disorders be as encouraging as expected? This paper reviews the marketed and in-development dry powder inhaler (DPI) products on the treatment of systemic diseases, their status in clinical trials, as well as the potential for COVID-19 treatment. The advancements and unmet problems on DPI systems are also summarized. With countless attempts behind and more challenges ahead, it is believed that the dry powder inhaled therapy for the treatment of systemic disorders still holds great potential and promise.

Complexation of exenatide and cyclodextrin: An approach for the stabilization and sustained release of exenatide in PLGA microsphere

The purpose of this study was to evaluate the effects of cyclodextrins (CyDs) to stabilize exnatide in the microencapsulation medium and influence on the pharmaceutical properties of exenatide loaded PLGA microsphere. Three CyDs interacted differently with exenatide by investigation using ultraviolet, fluorescence and circular dichroism spectroscopy. The binding affinities of CyDs to the hydrophobic tryptophan residues of exenatide increased in following order: α-CyD < β-CyD < γ-CyD. It was consistent with orders of W/O interface stabilizing and anti-adsorption effects. However, the stabilizing effect of β-CyD on liquid-state and freeze-drying of exenatide was greater than that of γ-CyD. The negative values of ΔH₀, ΔS₀, and ΔG₀ indicated that the exenatide-CyDs complex formation was a favorable exothermic and spontaneous processes that increased the order in the complex with structural rigidity. Furthermore, it was also shown that β-CyD improved encapsulation efficiency, in vitro extended release, and in vivo pharmacokinetic and pharmacodynamic properties of prepared PLGA microspheres.

The effect of ethanol on the habit and in vitro aerodynamic results of dry powder inhalation formulations containing ciprofloxacin hydrochloride

In the case of dry powder inhalation systems (DPIs), the development of carrier-free formulations has gained increased attention. Thereby, spray-drying is a promising technology and is widely used to produce carrier-free DPIs. Numerous works have been published about the co-spray-drying of active ingredients with various solid excipients and their effect on the physicochemical characteristics and aerodynamic properties of the formulations. However, only a few studies have been reported about the role of the solvents used in the stock solutions of spray-dried formulations. In the present work, DPI microcomposites containing ciprofloxacin hydrochloride were prepared by spray-drying in the presence of different ethanol concentrations. The work expresses the roughness, depth and width of the dimples for particle size as a novel calculation possibility, and as a correlation between the MMAD/D_0.5 ratio and correlating it with cohesion work, these new terms and correlations have not been published – to the best of our knowledge – which has resulted in gap-filling findings. As a result, different proportions of solvent mixtures could be interpreted and placed in a new perspective, in which the influence of different concentrations of ethanol on the habit of the DPI formulations, and thus on in vitro aerodynamic results. Based on these, it became clear why we obtained the best in vitro aerodynamic results for DPI formulation containing 30% ethanol in the stock solution.

Polylactide/Polyvinylalcohol-Based Porous Bioscaffold Loaded with Gentamicin for Wound Dressing Applications

This study explores the feasibility of modifying the surface liquid spraying method to prepare porous bioscaffolds intended for wound dressing applications. For this purpose, gentamicin sulfate was loaded into polylactide-polyvinyl alcohol bioscaffolds as a highly soluble (hygroscopic) model drug for in vitro release study. Moreover, the influence of inorganic salts including NaCl (10 g/L) and KMnO4 (0.4 mg/L), and post-thermal treatment (T) (80 °C for 2 min) on the properties of the bioscaffolds were studied. The bioscaffolds were characterized by scanning electron microscopy, Fourier Transform infrared spectroscopy, and differential scanning calorimetry. In addition, other properties including porosity, swelling degree, water vapor transmission rate, entrapment efficiency, and the release of gentamicin sulfate were investigated. Results showed that high concentrations of NaCl (10 g/L) in the aqueous phase led to an increase of around 68% in the initial burst release due to the increase in porosity. In fact, porosity increased from 68.1 ± 1.2 to 94.1 ± 1.5. Moreover, the thermal treatment of the Polylactide-polyvinyl alcohol/NaCl (PLA-PVA/NaCl) bioscaffolds above glass transition temperature (Tg) reduced the initial burst release by approximately 11% and prolonged the release of the drug. These results suggest that thermal treatment of polymer above Tg can be an efficient approach for a sustained release.

Bioactive Betulin and PEG Based Polyanhydrides for Use in Drug Delivery Systems

In the course of this study, a series of novel, biodegradable polyanhydrides based on betulin disuccinate and dicarboxylic derivatives of poly(ethylene glycol) were prepared by two-step polycondensation. These copolymers can be used as carriers in drug delivery systems, in the form of microspheres. Betulin and its derivatives exhibit a broad spectrum of biological activity, including cytotoxic activity, which makes them promising substances for use as therapeutic agents. Microspheres that were prepared from betulin based polyanhydrides show promising properties for use in application in drug delivery systems, including inhalation systems. The obtained copolymers release the active substance-betulin disuccinate-as a result of hydrolysis under physiological conditions. The use of a poly(ethylene glycol) derivative as a co-monomer increases the solubility and bioavailability of the obtained compounds. Microspheres with diameters in the range of 0.5-25 µm were prepared by emulsion solvent evaporation method and their physicochemical and aerodynamic properties were analyzed. The morphological characteristics of the microspheres depended on the presence of poly(ethylene glycol) (PEG) segment within the structure of polyanhydrides. The porosity of the particles depended on the amount and molecular weight of the PEG used and also on the speed of homogenization. The most porous particles were obtained from polyanhydrides containing 20% wt. of PEG 600 by using a homogenization speed of 18,000 rpm.

Structured micro/nano materials synthesized via electrospray: a review

The development of synthetic methods for micro/nano materials with precisely controlled structures, morphologies, and local compositions is of great importance for the advancement of modern nanotechnology. The electrospray method is a "platform" approach for the preparation of a broad range of micro-/nanostructures; electrospray is simple and scalable. This review summarizes recent research on the micro-/nanostructures prepared via the electrospray route. These include spherical structures (e.g. simple, porous, Janus, and core-shell particles), non-spherical structures (e.g. red blood cell-like and spindle-like particles, multi-compartment microrods, 2D holey nanosheets, and nanopyramids), and assembled structures. The experimental details, underlying physical/chemical principles, and key benefits of these structures are comprehensively discussed. The effects and importance of nozzle design, properties of feeding solutions (e.g. concentration of solute, polymer additives, solvent/nonsolvent combinations), working environment (e.g. temperature and humidity), and types of collection media are highlighted.

Preparation and Characterization of a Dry Powder Inhaler Composed of PLGA Large Porous Particles Encapsulating Gentamicin Sulfate

Purpose: Direct delivery of aminoglycosides to the lungs was under extensive evaluations during the last decades. Because of large particle size, low density and porous structure, large porous particles (LPPs) are versatile carriers for this purpose. In this study, poly (lactic-co-glycolic acid) (PLGA) LPPs encapsulating gentamicin sulfate were prepared and in vitro characteristics of their freeze-dried powder as a dry powder inhaler (DPI) were evaluated.

Methods: To prepare PLGA LPPs, a double emulsification-solvent evaporation method was optimized and gentamicin sulfate was post-loaded in the LPPs. in vitro characteristics including morphological features, thermal behavior, aerodynamic profile and cumulative drug release were evaluated by the scanning electron microscope (SEM), differential scanning calorimetry (DSC), next-generation cascade impactor (NGI) and Franz diffusion cell respectively.

Results: The obtained results revealed that the preparation method was capable to produce spherical large homogenous highly porous particles. 94% of gentamicin sulfate released from LPPs up to 30 minutes. Mass median aerodynamic diameter (MMAD) and fine particle fraction (FPF) were 4.9 µm and 39% respectively.

Conclusion: In this study, dry powder formulation composed of PLGA LPPs encapsulating gentamicin sulfate showed a promising in vitro behavior as a pulmonary delivery carrier. Improvements on the aerodynamic behavior and in vivo evaluations recommended for further developments.

Supercritical Fluid-Assisted Decoration of Nanoparticles on Porous Microcontainers for Codelivery of Therapeutics and Inhalation Therapy of Diabetes

The impact of nanotechnology and its advancements have allowed us to explore new therapeutic modalities. To this end, we designed nanoparticles-inlaid porous microparticles (NIPMs) coloaded with small interfering RNA (siRNA) and glucagon-like peptide-1 (GLP-1) using the supercritical carbon dioxide (SC-CO₂) technology as an inhalation delivery system for diabetes therapy. siRNA-encapsulating chitosan (CS) nanoparticles were first synthesized by an ionic gelation method, which resulted in particles with small sizes (100-150 nm), high encapsulation efficiency (∼94.8%), and sustained release performance (∼60% in 32 h). These CS nanoparticles were then loaded with GLP-1-dispersed poly-l-lactide (PLLA) porous microparticles (PMs) by SC-CO₂-assisted precipitation with the compressed antisolvent (PCA) process. The hypoglycemic efficacy of NIPMs administered via pulmonary route in mice persisted longer due to sustained release of siRNA from CS nanoparticles and the synergistic effects of GLP-1 in PMs, which significantly inhibited the expression of dipeptidyl peptidase-4 mRNA (DPP-4-mRNA). This ecofriendly technology provides a convenient way to fabricate nanoparticle-microparticle composites for codelivery of a gene and a therapeutic peptide, which will potentially find widespread applications in the field of pharmaceutics.

Sustained therapeutic efficacy of budesonide-loaded chitosan swellable microparticles after lung delivery: Influence of in vitro release, treatment interval and dose

Sustained drug delivery to the respiratory tract is highly desirable for local treatment of chronic lung diseases. In this context, a correlation of in vitro drug release with in vivo efficacy data is essential to accelerate the application of sustained drug delivery system for inhalation into the clinical setting. In this study, budesonide was incorporated into distinct chitosan-based swellable microparticles, which were characterized, and the in vitro drug release behavior determined. The particles were then given to an allergic asthma animal model as single and successive administrations, and the therapeutic response was determined by measuring cell counts, IL-4 and IL-5 levels in bronchoalveolar lavage fluid, IL-4 and IL-5 mRNA in the lung and by histopathologic examination of lung tissues. After a single administration, the time-dependent therapeutic effect of the swellable microparticles was correlated with the in vitro release behavior, which lasted for 12 or 18 h depending on the molecular weight of the chitosan. After seven days of successive treatment, the number of eosinophils decreased further and IL-4 and IL-5 mRNA expression in the lung tissue was more greatly inhibited. Moreover, the chitosan-based swellable microparticles allowed longer administration intervals (every two days), which decreased the required dose for effectiveness by 50%. These results demonstrate that chitosan-based swellable microparticles can sustain the therapeutic effect of budesonide in the respiratory tract which in principal can be applied to other drugs for the treatment of local lung diseases.

Novel technique of insulin loading into porous carriers for oral delivery

The increasing demand for oral macromolecule delivery encouraged the development of microencapsulation technologies to protect such drugs against gastric and enzymatic degradation. However, microencapsulation often requires harsh conditions that may jeopardize their biological activity. Accordingly, many trials attempted to load macromolecules into porous drug carriers to bypass any formulation induced instability. In this study, we prepared chitosan coated porous poly (d, l-lactide-co-glycolide) (PLGA) microparticles (MPs) loaded with insulin using a novel loading technique; double freeze-drying. The results showed a significant increase in drug loading using only 5 mg/ml initial insulin concentration and conveyed a sustained drug release over uncoated MPs. Furthermore, SEM and confocal microscopy confirmed pore blocking and insulin accumulation within the MPs respectively. The oral pharmacodynamic data on rats also proved the preservation of insulin bioactivity after formulation. Finally, the new coating technique proved to be efficient in producing robust layer of chitosan with higher insulin loading while maintaining insulin activity.

Process optimization of spray-dried fanhuncaoin powder for pulmonary drug delivery and its pharmacokinetic evaluation in rats

The optimization of process parameters of spray-dried powder containing fanhuncaoin, a newly discovered anti-inflammatorily active phenolic acid isolated from Chinese herb, was conducted using response surface methodology (RSM). The experimental results were fitted into partial cubic polynomial model to describe and predict the response quality in terms of the final angle of repose, aerodynamic diameter, respirable fraction (RF), and yield. The recommended optimum spray-drying parameters for the development of fanhuncaoin powder with optimum quality were 110 °C inlet temperature, 0.50 m³/min aspiration speed, and 7.95 ml/min feed flow rate. The obtained optimum process parameters were employed for the production of spray-dried fanhuncaoin powder and to check the validity of the partial cubic model. Small and insignificant deviations were found between the predicted values and the experimental ones, showing the efficiency of the model in predicting the quality attributes of fanhuncaoin powder. The optimized powder was further examined for its pharmacokinetic properties in rats. A UPLC/MS assay was used to determine plasma fanhuncaoin concentration. Statistical analysis demonstrated that there was no significant difference in the t_1/2 and dose-normalized C_max and AUC as well as other pharmacokinetic parameters between the groups dosed differently following intratracheal administration (p > .05), indicating that fanhuncaoin followed linear kinetics. The pharmacokinetic parameters of fanhuncaoin after intratracheal administration differed significantly from the ones observed after intravenous administration (p < .05). The lower values of C_max and AUC_(0-∞) obtained following intratracheal administration may lead to effective drug concentrations at the target site with minimal systemic bioavailability and side effects.

Development and physicochemical characterization of acetalated dextran aerosol particle systems for deep lung delivery

Biocompatible, biodegradable polymers are commonly used as excipients to improve the drug delivery properties of aerosol formulations, in which acetalated dextran (Ac-Dex) exhibits promising potential as a polymer in various therapeutic applications. Despite this promise, there is no comprehensive study on the use of Ac-Dex as an excipient for dry powder aerosol formulations. In this study, we developed and characterized pulmonary drug delivery aerosol microparticle systems based on spray-dried Ac-Dex with capabilities of (1) delivering therapeutics to the deep lung, (2) targeting the particles to a desired location within the lungs, and (3) releasing the therapeutics in a controlled fashion. Two types of Ac-Dex, with either rapid or slow degradation rates, were synthesized. Nanocomposite microparticle (nCmP) and microparticle (MP) systems were successfully formulated using both kinds of Ac-Dex as excipients and curcumin as a model drug. The resulting MP were collapsed spheres approximately 1μm in diameter, while the nCmP were similar in size with wrinkled surfaces, and these systems dissociated into 200nm nanoparticles upon reconstitution in water. The drug release rates of the Ac-Dex particles were tuned by modifying the particle size and ratio of fast to slow degrading Ac-Dex. The pH of the environment was also a significant factor that influenced the drug release rate. All nCmP and MP systems exhibited desirable aerodynamic diameters that are suitable for deep lung delivery (e.g. below 5μm). Overall, the engineered Ac-Dex aerosol particle systems have the potential to provide targeted and effective delivery of therapeutics into the deep lung.

Low-Molecular-Weight Heparin-Coated and Montelukast-Filled Inhalable Particles: A Dual-Drug Delivery System for Combination Therapy in Asthma

Montelukast, a cysteinyl leukotriene type 1 receptor antagonist, exhibits secondary anti-inflammatory properties when used at higher concentrations. Low-molecular-weight heparin (LMWH) evokes pronounced anti-inflammatory effects by interrupting leukocyte adhesion and migration. We hypothesized that inhalable particles containing montelukast plus LMWH release both drugs in a sustained fashion and protect the lungs against allergen-induced inflammation. Large porous particles of montelukast and LMWH were prepared using a double-emulsion-solvent-evaporation method. Montelukast was first encapsulated in copolymer-based particles using polyethylenimine as a porosigen; the resulting particles were then coated with LMWH. The particles were evaluated for physicochemical properties, respirability, and release profiles. The anti-inflammatory effect of the optimized formulation was studied in ovalbumin-sensitized asthmatic Sprague Dawley rats. The optimized large porous particles had a diameter of 10.3 ± 0.7 μm, exhibited numerous surface indentations and pores, showed acceptable drug entrapment efficiency (66.8% ± 0.4% for montelukast; 91.7% ± 0.8% adsorption efficiency for LMWH), demonstrated biphasic release patterns, and escaped the uptake by the rat alveolar macrophages. The number of infiltrating inflammatory cells in asthmatic rat lungs, treated with dual-drug particles, was >74% fewer than in untreated asthmatic rat lungs. Similarly, the airway walls of asthmatic animals treated with dual-drug particles were 3-fold thinner than those of untreated asthmatic animals (p < 0.001). The optimized formulation protects lungs against methacholine-induced airway hyper-reactivity. Overall, this study demonstrates the feasibility of loading 2 drugs, montelukast and LMWH, into an inhalable particulate system and establishes that this novel combination therapy produces sustained drug release and elicits a robust anti-inflammatory response in the lungs.

Aerosolizable modified-release particles of montelukast improve retention and availability of the drug in the lungs

Montelukast, a cysteinyl leukotriene receptor antagonist available as oral tablets, is used as a second-line therapy in asthma. In this study, we sought to enhance the availability of montelukast in the lungs by encapsulating the drug in poly (lactide-co-glycolic acid)-based (PLGA) respirable large porous particles. We determined the oral and lung specific availability of montelukast by assessing metabolic stability of the drug in the lung and liver homogenates, respectively. We similarly measured the oral and inhalational bioavailability by monitoring the pharmacokinetics and disposition of the drug in live animals. After preparing montelukast-loaded particles with various polymers, in the absence or presence of polyethylenimine (PEI-1), we characterized the particles for physical-chemical properties, entrapment efficiency, in vitro release, uptake by alveolar macrophages, deposition in the lungs, and safety after pulmonary administration. When incubated in lung or liver homogenates, the amount of intact drug in the lung homogenates was greater than that in the liver homogenates. Likewise, the extent of montelukast absorption via the lungs was greater than that via the oral route. Compared with smaller non-porous particles, large porous particles (PEI-1) were taken up by the alveolar macrophages at a lesser extent but deposited in the lungs at a greater extent. The levels of injury markers in the bronchoalveolar lavage fluid (BALF), collected from rat lungs treated with PEI-1, were no different from that in BALF collected from saline treated rats. Overall, the retention time and concentration of montelukast in the lungs can be increased by formulating the drug in large porous particles of PLGA.

Improving the Intracellular Drug Concentration in Lung Cancer Treatment through the Codelivery of Doxorubicin and miR-519c Mediated by Porous PLGA Microparticle

Porous PLGA microparticle for the coencapsulation of doxorubicin and miR-519c was successfully constructed through the water-oil-water emulsion solvent evaporation method, using ammonium bicarbonate as a porogen. It has been characterized with high porous surface, adaptive aerodynamic diameter (<10 μm), favorable drug loading, and sustained release profile. The release supernatant exhibited a higher inhibition of cell proliferation than those from porous PLGA microparticles harboring a single component (doxorubicin or miR-519c), attributing to the enhanced induction of cell apoptosis and cell cycle arrest at S phase. Finally, the improved intracellular concentration of doxorubicin was elucidated by flow cytometry and liquid chromatography with tandem mass spectrometry, owing to the knockdown of drug transporter ABCG2 by miR-519c. Overall, the porous PLGA microparticle combining chemotherapy and gene therapy could facilitate the antitumor efficacy and reduce the side effects, and thus, it is potential to be used as a sustained release system for lung cancer treatment via pulmonary administration.

Nanocomposite microparticles (nCmP) for the delivery of tacrolimus in the treatment of pulmonary arterial hypertension

Tacrolimus (TAC) has exhibited promising therapeutic potential in the treatment of pulmonary arterial hypertension (PAH); however, its application is prevented by its poor solubility, instability, poor bioavailability, and negative systemic side effects. To overcome the obstacles of using TAC for the treatment of PAH, we developed nanocomposite microparticles (nCmP) for the pulmonary delivery of tacrolimus in the form of dry powder aerosols. These particles can provide targeted pulmonary delivery, improved solubility of tacrolimus, the potential of penetration through mucus barrier, and controlled drug release. In this system, tacrolimus-loaded polymeric nanoparticles (NP) were prepared via emulsion solvent evaporation and nCmP were prepared by spray drying these NP with mannitol. The NP were approximately 200nm in diameter with narrow size distribution both before loading into and after redispersion from nCmP. The NP exhibited smooth, spherical morphology and the nCmP were raisin-like spheres. High encapsulation efficacy was achieved both in the encapsulation of tacrolimus in NP and that of NP in nCmP. nCmP exhibited desirable aerosol dispersion properties, allowing them to deposit into the deep lung regions for effective drug delivery. A549 cells were used as in vitro models to demonstrate the non-cytotoxicity of TAC nCmP. Overall, the designed nCmP have the potential to aid in the delivery of tacrolimus for the treatment of PAH.

Synthesis and Characterization of Nanocomposite Microparticles (nCmP) for the Treatment of Cystic Fibrosis-Related Infections

PURPOSE

Pulmonary antibiotic delivery is recommended as maintenance therapy for cystic fibrosis (CF) patients who experience chronic infections. However, abnormally thick and sticky mucus present in the respiratory tract of CF patients impairs mucus penetration and limits the efficacy of inhaled antibiotics. To overcome the obstacles of pulmonary antibiotic delivery, we have developed nanocomposite microparticles (nCmP) for the inhalation application of antibiotics in the form of dry powder aerosols.

METHODS

Azithromycin-loaded and rapamycin-loaded polymeric nanoparticles (NP) were prepared via nanoprecipitation and nCmP were prepared by spray drying and the physicochemical characteristics were evaluated.

RESULTS

The nanoparticles were 200 nm in diameter both before loading into and after redispersion from nCmP. The NP exhibited smooth, spherical morphology and the nCmP were corrugated spheres about 1 μm in diameter. Both drugs were successfully encapsulated into the NP and were released in a sustained manner. The NP were successfully loaded into nCmP with favorable encapsulation efficacy. All materials were stable at manufacturing and storage conditions and nCmP were in an amorphous state after spray drying. nCmP demonstrated desirable aerosol dispersion characteristics, allowing them to deposit into the deep lung regions for effective drug delivery.

CONCLUSIONS

The described nCmP have the potential to overcome mucus-limited pulmonary delivery of antibiotics.

Synergistic co-delivery of doxorubicin and paclitaxel by porous PLGA microspheres for pulmonary inhalation treatment

PLGA porous microspheres loaded with doxorubicin (DOX) and paclitaxel (PTX) were developed for in situ treatment of metastatic lung cancer. The synergistic effect of the combined drugs was investigated against B16F10 cells to obtain the optimal prescription for in vivo studies. The combination therapy showed great synergism when DOX was the majority in the combination therapy, while they showed moderate antagonism when PTX is in major. The combination of DOX and PTX at a molar ratio of 5/1 showed the best synergistic therapeutic effect in the free form. However, the drugs exhibited more synergism in the PLGA microspheres at a molar ratio of 2/1, due to the difference in drug release rate. The in vivo study verified the synergism of DOX and PTX at the optimal molar ratio. These results suggested that dual encapsulation of DOX and PTX in porous PLGA microspheres would be a promising technology for long effective lung cancer treatment.

Dry powders for oral inhalation free of lactose carrier particles

Dry powder inhaler (DPI) products have traditionally comprised a simple formulation of micronised drug mixed with a carrier excipient, typically lactose monohydrate. The presence of the carrier is aimed at overcoming issues of poor flowability and dispersibility, associated with the cohesive nature of small, micronised active pharmaceutical ingredient (API) particles. Both the powder blend and the DPI device must be carefully designed so as to ensure detachment of the micronised drug from the carrier excipient on inhalation. Over the last two decades there has been a significant body of research undertaken on the design of carrier-free formulations for DPI products. Many of these formulations are based on sophisticated particle engineering techniques; a common aim in formulation design of carrier-free products being to reduce the intrinsic cohesion of the particles, while maximising dispersion and delivery from the inhaler. In tandem with the development of alternative formulations has been the development of devices designed to ensure the efficient delivery and dispersion of carrier-free powder on inhalation. In this review we examine approaches to both the powder formulation and inhaler design for carrier-free DPI products.

Improving the efficacy of inhaled drugs in cystic fibrosis: challenges and emerging drug delivery strategies

Cystic fibrosis (CF) is the most common autosomal recessive disease in Caucasians associated with early death. Although the faulty gene is expressed in epithelia throughout the body, lung disease is still responsible for most of the morbidity and mortality of CF patients. As a local delivery route, pulmonary administration represents an ideal way to treat respiratory infections, excessive inflammation and other manifestations typical of CF lung disease. Nonetheless, important determinants of the clinical outcomes of inhaled drugs are the concentration/permanence at the lungs as well as the ability of the drug to overcome local extracellular and cellular barriers. This review focuses on emerging delivery strategies used for local treatment of CF pulmonary disease. After a brief description of the disease and formulation rules dictated by CF lung barriers, it describes current and future trends in inhaled drugs for CF. The most promising advanced formulations are discussed, highlighting the advantages along with the major challenges for researchers working in this field.

Aerosolized montelukast polymeric particles-an alternative to oral montelukast-alleviate symptoms of asthma in a rodent model

PURPOSE

Cysteinyl leukotrienes (CysLTs) propagate inflammatory reactions that result from allergen exposure in asthma. Montelukast, a CysLT type-1 receptor antagonist, disrupts mediator-receptor interactions and minimizes inflammatory response. In this study, we have evaluated anti-asthmatic efficacy of inhalable montelukast-loaded large porous particulate formulations in ovalbumin-induced rat airway inflammation model that mimics asthma.

METHODS

The anti-inflammatory effects of a montelukast-loaded formulation were investigated in rats by measuring the total protein content, levels of injury markers and number of inflammatory cells in the bronchoalveolar lavage fluid (BALF). The histopathological studies assessed the morphological and structural changes that occur in asthmatic lungs. Animals were also challenged with methacholine to examine the airway hyper-reactivity.

RESULTS

Compared with healthy animals, asthmatic animals showed a 3.8- and 4.77-fold increase in the protein content and number of inflammatory cells in BALF, respectively. Intratracheal montelukast particles reduced the protein content by 3.3-fold and the number of inflammatory cells by 2.62-fold. Also, montelukast particles reduced the lactate dehydrogenase (LDH) and myeloperoxidase (MPO) levels by a 4.87- and 6.8-fold in BALF, respectively. Montelukast particles reduced the airway wall thickness by 2.5-fold compared with untreated asthmatic lungs. Further, particulate formulation protected the lungs against methacholine-induced bronchial provocation (p < 0.05).

CONCLUSIONS

Respirable large porous particles containing montelukast alleviated allergen-induced inflammatory response in an animal model and prevented histological changes associated with asthma. Thus montelukast-loaded large porous polylactic acid (PLA) particles could be an aerosolized delivery approach for administration of currently available oral montelukast.

Development of high efficiency ventilation bag actuated dry powder inhalers

New active dry powder inhaler systems were developed and tested to efficiently aerosolize a carrier-free formulation. To assess inhaler performance, a challenging case study of aerosol lung delivery during high-flow nasal cannula (HFNC) therapy was selected. The active delivery system consisted of a ventilation bag for actuating the device, the DPI containing a flow control orifice and 3D rod array, and streamlined nasal cannula with separate inlets for the aerosol and HFNC therapy gas. In vitro experiments were conducted to assess deposition in the device, emitted dose (ED) from the nasal cannula, and powder deaggregation. The best performing systems achieved EDs of 70-80% with fine particle fractions <5 μm of 65-85% and mass median aerodynamic diameters of 1.5 μm, which were target conditions for controlled condensational growth aerosol delivery. Decreasing the size of the flow control orifice from 3.6 to 2.3mm reduced the flow rate through the system with manual bag actuations from an average of 35 to 15LPM, while improving ED and aerosolization performance. The new devices can be applied to improve aerosol delivery during mechanical ventilation, nose-to-lung aerosol administration, and to assist patients that cannot reproducibly use passive DPIs.

Hydrogels for controlled pulmonary delivery

A significant number of research articles have focused on pulmonary delivery as an alternative administration route owing to no first-pass metabolism, low protease activity, thin epithelium barrier and large surface area in the lung system. Controlled release in the pulmonary delivery system further reduces loading dose, frequency of dosing and systemic side effects, and also increases duration of action and patient compliance. Compared with other microparticles used in controlled-release pulmonary administration, hydrogels (3D polymeric matrix networks) have recently been investigated due to their swelling and mucoadhesive properties that could help bypass pulmonary delivery barriers. This review introduces controlled-release drug delivery to the lung, followed by a summary of currently available approaches for controlled-release pulmonary drug delivery. Lastly, the origin, advantages, detailed applications and concerns of hydrogels in pulmonary delivery are discussed.

Porous microsphere and its applications

Porous microspheres have drawn great attention in the last two decades for their potential applications in many fields, such as carriers for drugs, absorption and desorption of substances, pulmonary drug delivery, and tissue regeneration. The application of porous microspheres has become a feasible way to address existing problems. In this essay, we give a brief introduction of the porous microsphere, its characteristics, preparation methods, applications, and a brief summary of existing problems and research tendencies.

Design, physicochemical characterization, and optimization of organic solution advanced spray-dried inhalable dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine poly(ethylene glycol) (DPPE-PEG) microparticles and nanoparticles for targeted respiratory nanomedicine delivery as dry powder inhalation aerosols

Novel advanced spray-dried and co-spray-dried inhalable lung surfactant-mimic phospholipid and poly(ethylene glycol) (PEG)ylated lipopolymers as microparticulate/nanoparticulate dry powders of biodegradable biocompatible lipopolymers were rationally formulated via an organic solution advanced spray-drying process in closed mode using various phospholipid formulations and rationally chosen spray-drying pump rates. Ratios of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine PEG (DPPE-PEG) with varying PEG lengths were mixed in a dilute methanol solution. Scanning electron microscopy images showed the smooth, spherical particle morphology of the inhalable particles. The size of the particles was statistically analyzed using the scanning electron micrographs and SigmaScan^® software and were determined to be 600 nm to 1.2 μm in diameter, which is optimal for deep-lung alveolar penetration. Differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) were performed to analyze solid-state transitions and long-range molecular order, respectively, and allowed for the confirmation of the presence of phospholipid bilayers in the solid state of the particles. The residual water content of the particles was very low, as quantified analytically via Karl Fischer titration. The composition of the particles was confirmed using attenuated total-reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy and confocal Raman microscopy (CRM), and chemical imaging confirmed the chemical homogeneity of the particles. The dry powder aerosol dispersion properties were evaluated using the Next Generation Impactor™ (NGI™) coupled with the HandiHaler^® dry powder inhaler device, where the mass median aerodynamic diameter from 2.6 to 4.3 μm with excellent aerosol dispersion performance, as exemplified by high values of emitted dose, fine particle fraction, and respirable fraction. Overall, it was determined that the pump rates defined in the spray-drying process had a significant effect on the solid-state particle properties and that a higher pump rate produced the most optimal system. Advanced dry powder inhalers of inhalable lipopolymers for targeted dry powder inhalation delivery were successfully achieved.

Spray freeze-dried porous microparticles of a poorly water-soluble drug for respiratory delivery

Particles of poorly water-soluble drugs were prepared to develop a dry powder inhaler (DPI). Spray freeze-drying (SFD) technique using a four-fluid nozzle (4N), which has been developed by authors, was applied in this research. Ciclosporin and mannitol were used as a poorly water-soluble model drug and a dissolution-enhanced carrier, respectively. The organic solution of ciclosporin and aqueous solution of mannitol were separately and simultaneously atomized through the 4N, and the two solutions were collided with each other at the tip of the nozzle edge. The spray mists were immediately frozen in liquid nitrogen to form a suspension. Then, the iced droplets were freeze-dried to prepare the composite particles of the drug and carrier. tert-Butyl alcohol (t-BuOH) was used as the organic spray solvent due to its relatively high freezing point. The resultant composite particles with varying drug content were characterized depending on their morphological and physicochemical properties. The particles contained amorphous ciclosporin and δ-crystalline mannitol. The characteristic porous structure of SFD particles potentially contributed to their good aerodynamic performance. A series of particles with a similar size distribution and different drug content revealed that the incorporation of mannitol successfully improved the cohesive behavior of ciclosporin, leading to enhanced aerosol dispersion. The dissolution test method using low-volume medium was newly established to simulate the release process from particles deposited on the surface of the bronchus and pulmonary mucosa. The composite with hydrophilic mannitol dramatically improved the in vitro dissolution behavior of ciclosporin in combination with the porous structure of SFD particles.