Particles and powders: Tools of innovation for non-invasive drug administration

The nasal route for nose-to-brain drug delivery: advanced nasal formulations for CNS disorders

INTRODUCTION

The nasal route offers a feasible alternative to oral and/or parenteral administration, providing a noninvasive route to achieve nose-to-brain drug delivery involving the olfactory and trigeminal nerves, and facilitating local or systemic drug action. Conventional liquid nasal dosage forms have not managed to bridge the gaps of precise dosing and targeted central nervous system (CNS) delivery, while more sophisticated formulation approaches are being explored for brain targeting, aiming to enhance bioavailability and therapeutic efficacy.

AREAS COVERED

This review focuses on preclinical and clinical evaluation of microemulsions, in-situ gels, nasal powders, and nanocarrier-based formulations. Key pharmacokinetic and pharmacodynamic findings are discussed to evaluate their potential and limitations in improving drug bioavailability and CNS targeting. The existing regulatory framework for approval of products for nose-to-brain drug delivery is also addressed and relative hurdles are discussed.

EXPERT OPINION

While nasal drug delivery holds great promise for CNS therapeutics, key challenges remain, including formulation stability, mucosal permeability, patient adherence. Future research should prioritize improving targeting efficiency, overcoming mucociliary clearance, developing user-friendly pharmaceutical products. Personalized medicine and smart delivery systems could further enhance drug targeting and minimize side effects. Continued research and regulatory advancements are essential to fully realize nasal delivery's perspective in CNS therapeutics.

Fabrication of Uniform Melatonin Microparticles Potentially for Nasal Delivery: A Comparison of Spray Drying and Spray Freeze Drying

PURPOSE

Insomnia is a major health concern, and melatonin (MLT) is key for initiating sleep. Delivering MLT nasally can enhance brain bioavailability by targeting the olfactory region. This study aimed to fabricate MLT embedded microparticles for nasal delivery.

METHODS

MLT-cyclodextrin (CD) derivatives complex microparticles (MCCMPs) were fabricated by spray drying and spray freeze drying MLT and CD derivative solutions. Phase solubility and 1H-1H ROSEY NMR analysis assessed MLT-CD assembly. The effects of formulation compositions and process parameters on microparticle structural attributes were investigated. The in vitro nasal release and deposition performances were evaluated by a modified paddle-over-disk apparatus and 3D-printed nasal cavity cast, respectively.

RESULTS

Sodium sulphobutylether-β-cyclodextrin (SBE-β-CD) exhibited the best complexation ability with MLT, with the indole structure of MLT included in its cavity. Spray dried MCCMPs showed dense structure with high density, while the spray freeze dried counterpart showed the brittle and porous structure with low density. Despite the porous structure may promote the release rate of spray freeze dried samples, the high hydrophilicity of the CD derivative overshadows this advantage. Samples prepared by spray drying not only exhibited rapid release rates but also could deposit more effectively in the olfactory region, as they avoid breakage due to their higher mechanical strength. The optimal sample showed ~ 86.70% of the MLT released at 20 min and ~ 10.57% of the deposition fraction in the olfactory region.

CONCLUSIONS

This work compares MCCMPs fabricated by spray drying and spray freeze drying, providing the optimal formulation and process combinations.

Inhaled JAK Inhibitor GDC-0214 Nanoaggregate Powder Exhibits Improved Pharmacokinetic Profile in Rats Compared to the Micronized Form: Benefits of Thin Film Freezing

Asthma is a common chronic disease affecting the airways in the lungs. The receptors of allergic cytokines, including interleukin (IL)-4, IL-5, and IL-13, trigger the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway, which involves the pathogenesis of asthma. GDC-0214 is a JAK inhibitor that was developed as a potent and selective target for the treatment of asthma, specifically targeting the lungs. While inhaled GDC-0214 is a promising novel treatment option against asthma, improvement is still needed to achieve increased potency of the powder formulation and a reduced number of capsules containing powder to be inhaled. In this study, high-potency amorphous powder formulations containing GDC-0214 nanoaggregates for dry powder inhalation were developed using particle engineering technology, thin film freezing (TFF). A high dose per capsule was successfully achieved by enhancing the solubility of GDC-0214 and powder conditioning. Lactose and/or leucine as excipients exhibited optimum stability and aerosolization of GDC-0214 nanoaggregates, and aerosolization of the dose was independent of air flow through the device between 2 and 6 kPa pressure drops. In the rat PK study, formulation F20, which contains 80% GDC-0214 and 20% lactose, resulted in the highest AUC0-24h in the lungs with the lowest AUC0-24h in the plasma that corresponds to a 4.8-fold higher ratio of the lung-to-plasma exposures compared to micronized crystalline GDC-0214 powder administered by dry powder inhalation. Therefore, GDC-0214 nanoaggregates produced by TFF provided an improved dry powder for inhalation that can lead to enhanced therapeutic efficacy with a lower risk of systemic toxicity.

Pharmacological Effects and Clinical Prospects of Cepharanthine

Cepharanthine is an active ingredient separated and extracted from Stephania cepharantha Hayata, a Menispermaceae plant. As a bisbenzylisoquinoline alkaloid, cepharanthine has various pharmacological properties, including antioxidant, anti-inflammatory, immunomodulatory, antitumoral, and antiviral effects. Following the emergence of coronavirus disease 2019 (COVID-19), cepharanthine has been found to have excellent anti-COVID-19 activity. In this review, the important physicochemical properties and pharmacological effects of cepharanthine, particularly the antiviral effect, are systematically described. Additionally, the molecular mechanisms and novel dosage formulations for the efficient, safe, and convenient delivery of cepharanthine are summarized.

Engineering the right formulation for enhanced drug delivery

Dry powder inhalers (DPIs) can be used with a wide range of drugs such as small molecules and biologics and offer several advantages for inhaled therapy. Early DPI products were intended to treat asthma and lung chronic inflammatory disease by administering low-dose, high-potency drugs blended with lactose carrier particles. The use of lactose blends is still the most common approach to aid powder flowability and dose metering in DPI products. However, this conventional approach may not meet the high demand for formulation physical stability, aerosolisation performance, and bioavailability. To overcome these issues, innovative techniques coupled with modification of the traditional methods have been explored to engineer particles for enhanced drug delivery. Different particle engineering techniques have been utilised depending on the types of the active pharmaceutical ingredient (e.g., small molecules, peptides, proteins, cells) and the inhaled dose. This review discusses the challenges of formulating DPI formulations of low-dose and high-dose small molecule drugs, and biologics, followed by recent and emerging particle engineering strategies utilised in developing the right inhalable powder formulations for enhanced drug delivery.

Development of In Vitro Evaluation System for Assessing Drug Dissolution Considering Physiological Environment in Nasal Cavity

Estimating the dissolution behavior of a solid in the nasal mucus is challenging for solid dosage forms designed for the nasal application as the solid dissolves into nasal mucus and permeates through the mucosa. In the current study, the dissolution behavior of powders in the artificial nasal fluid was investigated using a 3D-printed chamber system to establish in vitro evaluation system for the dissolution of solid formulations that can simulate the intranasal environment in vivo. The dissolution rates of the five model drugs correlated with their solubility (r2 = 0.956, p < 0.01). The permeation rate of drugs across the Calu-3 cell layers after powder application depends on the membrane permeability of the drug. An analysis of membrane permeability considering the dissolution of powders showed the possibility of characterizing whether the drug in the powder was dissolution-limited or permeation-limited. This suggests that critical information can be obtained to understand which mechanism is more effective for the improvement of drug absorption from powders. This study indicates that the elucidation of drug dissolution behavior into nasal mucus is an important factor for the formulation of nasal powders and that the in vitro system developed could be a useful tool.

Polymeric Microparticles: Synthesis, Characterization and In Vitro Evaluation for Pulmonary Delivery of Rifampicin

Rifampicin, a potent broad-spectrum antibiotic, remains the backbone of anti-tubercular therapy. However, it can cause severe hepatotoxicity when given orally. To overcome the limitations of the current oral therapy, this study designed inhalable spray-dried, rifampicin-loaded microparticles using aloe vera powder as an immune modulator, with varying concentrations of alginate and L-leucine. The microparticles were assessed for their physicochemical properties, in vitro drug release and aerodynamic behavior. The spray-dried powders were 2 to 4 µm in size with a percentage yield of 45 to 65%. The particles were nearly spherical with the tendency of agglomeration as depicted from Carr’s index (37 to 65) and Hausner’s ratios (>1.50). The drug content ranged from 0.24 to 0.39 mg/mg, with an association efficiency of 39.28 to 96.15%. The dissolution data depicts that the in vitro release of rifampicin from microparticles was significantly retarded with a higher L-leucine concentration in comparison to those formulations containing a higher sodium alginate concentration due to its hydrophobic nature. The aerodynamic data depicts that 60 to 70% of the aerosol mass was emitted from an inhaler with MMAD values of 1.44 to 1.60 µm and FPF of 43.22 to 55.70%. The higher FPF values with retarded in vitro release could allow sufficient time for the phagocytosis of synthesized microparticles by alveolar macrophages, thereby leading to the eradication of M. tuberculosis from these cells.

Spray dried powders for nasal delivery: Process and formulation considerations

Powders for nasal delivery have been recognized as advantageous dosage forms over liquids due to increased stability and residence time on nasal mucosa, with improved bioavailability. They can be manufactured by spray-drying, allowing the optimization of the particle properties that are critical to guarantee nasal deposition, as size and shape. It is also a scalable and flexible method already explored extensively in the pharmaceutical industry. However, it is important to understand how process parameters, particle physical properties and formulation considerations affect the product performance. Hence, this review aims to provide an overview of nasal powder formulation and processing through spray drying, with an emphasis on the variables that impact on performance. To this purpose, we describe the physical, biological and pharmacological phenomena prior to drug absorption as well as the most relevant powder properties. Formulation considerations including qualitative and quantitative composition are then reviewed, as well as manufacturing considerations including spray drying relevant parameters.

Fluorescence-enabled evaluation of nasal tract deposition and coverage of pharmaceutical formulations in a silicone nasal cast using an innovative spray device

INTRODUCTION

The characterisation of nasal formulations is a critical point. However, there are still no recommendations or guidelines in terms of standard approaches for evaluating the formulation's nasal deposition and/or coverage profile. This study optimises a method for quantifying silicone nasal cast deposition and coverage of liquid formulations using different nasal devices.

OBJECTIVES

The present work investigates the nasal deposition and coverage patterns of innovative nasal spray nozzles producing slow velocity soft mists, using a nasal cavity replica and a fluorescent dye.

METHODS

The study of the deposition pattern of a fluorescent liquid formulation in a transparent nasal cast was carried out in both the presence and absence of a simulated inhalation flow. The extent of the deposition pattern was investigated using ImageJ and fluorescence in the nasal cast, quantified by fluorometric analysis. The particle size distribution and initial droplet velocity were determined using a laser diffractometer and a high-speed camera with a frame rate of 1000 fps.

RESULTS

A uniform intranasal coverage was obtained with droplets of a volume median particle size (Dv50) between 15 and 25 µm in airflow between 10 and 30 L/min. In these conditions, aerosol formulations can be uniformly deposited in the vestibule and turbinate cavity nasal regions, with less than 10 % passing beyond the nasopharyngeal region.

CONCLUSION

The method applied allowed for the determination of the coverage of the nasal cast in different regions using images analysis and fluorometric analysis. Droplet velocity is a critical parameter in the deposition in the nasal cavity. With standard swirl nozzles, many droplets are found on the surface of the nasal vestibule. Soft mist nozzles produce smaller droplets at a much lower initial velocity (<1 m/s), resulting in a more uniform coverage.

Carrier particle emission and dispersion in transient CFD-DEM simulations of a capsule-based DPI

The dispersion of carrier-based formulations in capsule-based dry powder inhalers depends on several factors, including the patient's inhalation profile and the motion of capsule within the device. In the present study, coupled computational fluid dynamics and discrete element method simulations of a polydisperse cohesive lactose carrier in an Aerolizer® inhaler were conducted at a constant flow rate of 100 L/min and considering an inhalation profile of asthmatic children between 5 and 17 years approximated from literature data. In relevant high-speed photography experiments, it was observed that the powder was distributed to both capsule ends before being ejected from the capsule. Several methods of ensuring similar behavior in the simulations were presented. Both the constant flow rate simulation and the profile simulations showed a high powder retention in the capsule (7.37-19.00%). Although the inhaler retention was negligible in the constant flow rate simulation due to consistently high air velocities in the device, it reached values of around 7% in most of the profile simulations. In all simulations, some of the carrier powder was ejected from the capsule as particle clusters. These clusters were larger in the profile simulation than in the constant flow rate simulation. Of the powder discharged from the capsule, a high percentage was bound in clusters in the profile simulation in the beginning and at the end of the inhalation profile while no more than 10% of the powder ejected from the capsule in the 100 L/min constant flow rate simulation were in clusters at any time. The powder emission from the capsule was studied, indicating a strong dependency of the powder mass flow from the capsule on the angular capsule position. When the capsule holes face the inhaler's air inlets, the air flow into the capsule restricts the powder discharge. The presented results provide a detailed view of some aspects of the powder flow and dispersion of a cohesive carrier in a capsule-based inhaler device. Furthermore, the importance of considering inhalation profiles in addition to conventional constant flow rate simulations was confirmed.

Flurbiprofen sodium microparticles and soft pellets for nose-to-brain delivery: Serum and brain levels in rats after nasal insufflation

Neuroinflammation in Alzheimer's disease (AD) revamped the role of a preventive therapeutic action of non steroidal anti-inflammatory drugs; flurbiprofen could delay AD onset, provided its access to brain is enhanced and systemic exposure limited. Nasal administration could enable direct drug access to central nervous system (CNS) via nose-to-brain transport. Here, we investigated the insufflation, deposition, dissolution, transmucosal permeation, and in vivo transport to rat brain of flurbiprofen from nasal powders combined in an active device. Flurbiprofen sodium spray-dried microparticles as such, or soft pellets obtained by agglomeration of drug microparticles with excipients, were intranasally administered to rats by the pre-metered insufflator device. Blood and brain were collected to measure flurbiprofen levels. Excipient presence in soft pellets lowered the metered drug dose to insufflate. Nevertheless, efficiency of powder delivery by the device, measured as emitted fraction, was superior with soft pellets than microparticles, due to their coarse size. Both nasal powders resulted into rapid flurbiprofen absorption. Absolute bioavailability was 33% and 58% for microparticles and pellets, respectively. Compared to intravenous flurbiprofen, the microparticles were more efficient than soft pellets at enhancing direct drug transport to CNS. Direct Transport Percentage index evidenced that more than 60% of the intranasal dose reached the brain via direct nose-to-brain transport for both powders. Moreover, remarkable drug concentrations were measured in the olfactory bulb after microparticle delivery. Bulb connection with the entorhinal cortex, from where AD initiates, makes flurbiprofen sodium administration as nasal powder worth of further investigation in an animal model of neuroinflammation.

Estimating inter-patient variability of dispersion in dry powder inhalers using CFD-DEM simulations

Drug delivery from a capsule-based dry powder inhaler depends on the inhaler's design, the drug's formulation, and the inhalation maneuver. The latter affects both the air flow and the capsule motion in the inhaler. It is well known that patient-to-patient variability is a major challenge in the design of new inhaler types. Modeling and simulation are important tools for understanding such systems, yet quite complex. Simulation studies of capsule-based dry powder inhalers have disregarded the transient nature of the inhalation process, adopting a constant flow rate through the inhaler instead. In addition, either no capsules, a capsule in a fixed position, or a capsule rotating at a constant rate have been considered. In this work, literature data for three inhalation flow profiles were incorporated into coupled simulations of the air flow and carrier particle motion through an Aerolizer® dry powder inhaler with a rotating capsule and compared to simulations at constant air flow rates. The results for the profile simulations indicated that the carrier powder experienced larger velocity fluctuations. Acceleration events were tracked as a measure of collision- and flow-induced dispersion. The majority of fast particle accelerations occurred when the particles collided with the swirl chamber walls. Of the two common particle dispersion metrics, only the peak particle force distribution appeared to be sensitive to the inhalation profiles, while the effect of the profiles on the cumulative impulse was small.

Intranasal delivery of interferon-β-loaded nanoparticles induces control of neuroinflammation in a preclinical model of multiple sclerosis: A promising simple, effective, non-invasive, and low-cost therapy

Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system (CNS). Interferon (IFN)-β constitutes one of the first-line therapies to treat MS, but has limited efficacy due to the injectable systemic administration, short half-life, and limited CNS access. To address these limitations, we developed IFN-β-loaded chitosan/sulfobutylether-β-cyclodextrin nanoparticles (IFN-β-NPs) for delivery of IFN-β into the CNS via the intranasal (i.n.) route. The nanoparticles (NPs) (≈200 nm, polydispersity ≈0.1, and zeta potential ≈20 mV) were prepared by mixing two aqueous solutions and associated human or murine IFN-β with high efficiency (90%). Functional in vitro assays showed that IFN-β-NPs were safe and that IFN-β was steadily released while retaining biological activity. Biodistribution analysis showed an early and high fluorescence in the brain after nasal administration of fluorescent probe-loaded NPs. Remarkably, mice developing experimental autoimmune encephalomyelitis (EAE), an experimental model of MS, exhibited a significant improvement of clinical symptoms in response to intranasal IFN-β-NPs (inIFN-β-NPs), whereas a similar dose of intranasal or systemic free IFN-β had no effect. Importantly, inIFN-β-NPs treatment was equally effective despite a reduction of 78% in the total amount of weekly administered IFN-β. Spinal cords obtained from inIFN-β-NPs-treated EAE mice showed fewer inflammatory foci and demyelination, lower expression of antigen-presenting and costimulatory proteins on CD11b⁺ cells, and lower astrocyte and microglia activation than control mice. Therefore, IFN-β treatment at tested doses was effective in promoting clinical recovery and control of neuroinflammation in EAE only when associated with NPs. Overall, inIFN-β-NPs represent a potential, effective, non-invasive, and low-cost therapy for MS.

Nanosystems for the Encapsulation of Natural Products: The Case of Chitosan Biopolymer as a Matrix

Chitosan is a cationic natural polysaccharide, which has emerged as an increasingly interesting biomaterialover the past few years. It constitutes a novel perspective in drug delivery systems and nanocarriers' formulations due to its beneficial properties, including biocompatibility, biodegradability and low toxicity. The potentiality of chemical or enzymatic modifications of the biopolymer, as well as its complementary use with other polymers, further attract the scientific community, offering improved and combined properties in the final materials. As a result, chitosan has been extensively used as a matrix for the encapsulation of several valuable compounds. In this review article, the advantageous character of chitosan as a matrix for nanosystemsis presented, focusing on the encapsulation of natural products. A five-year literature review is attempted covering the use of chitosan and modified chitosan as matrices and coatings for the encapsulation of natural extracts, essential oils or pure naturally occurring bioactive compounds are discussed.

An orally delivered microbial cocktail for the removal of nitrogenous metabolic waste in animal models of kidney failure

Patients with kidney failure commonly require dialysis to remove nitrogenous wastes and to reduce burden to the kidney. Here, we show that a bacterial cocktail orally delivered in animals with kidney injury can metabolize blood nitrogenous waste products before they diffuse through the intestinal mucosal barrier. The microbial cocktail consists of three strains of bacteria isolated from faecal microbiota that metabolize urea and creatinine into amino acids, and is encapsulated in calcium alginate microspheres coated with a polydopamine layer that is selectively permeable to small-molecule nitrogenous wastes. In murine models of acute kidney injury and chronic kidney failure, and in porcine kidney failure models, the encapsulated microbial cocktail significantly reduced urea and creatinine concentrations in blood, and did not lead to any adverse effects.

Effects of the antibiotic component on in-vitro bacterial killing, physico-chemical properties, aerosolization and dissolution of a ternary-combinational inhalation powder formulation of antibiotics for pan-drug resistant Gram-negative lung infections

Combinational antibiotic formulations have emerged as an important strategy to combat antibiotic resistance. The main objective of this study was to examine effects of individual components on the antimicrobial activity, physico-chemical properties, aerosolization and dissolution of powder aerosol formulations when three synergistic drugs were co-spray dried. A ternary dry powder formulation consisting of meropenem (75.5 %w/w), colistin (15.1 %w/w) and rifampicin (9.4 %w/w) at the selected ratio was produced by spray drying. The ternary formulation was characterized for in-vitro antibacterial activity, physico-chemical properties, surface composition, aerosol performance and dissolution. All of the formulations demonstrated excellent aerosolization behavior achieving a fine particle fraction of >70%, which was substantially higher than those for the Meropenem-SD and Colistin-Meropenem formulations. The results indicated that rifampicin controlled the surface morphology of the ternary and binary combination formulations resulting in the formation of highly corrugated particles. Advanced characterization of surface composition by XPS supported the hypothesis that rifampicin was enriched on the surface of the combination powder formulations. All spray-dried formulations were amorphous and absorbed substantial amount of water at the elevated humidity. Storage at the elevated humidity caused a substantial decline in aerosolization performance for the Meropenem-SD and Colistin-Meropenem, which was attributed to increased inter-particulate capillary forces or particle fusion. In contrast, the ternary combination and binary Meropenem-Rifampicin formulations showed no change in aerosol performance at the elevated storage humidity conditions; attributable to the enriched hydrophobicity of rifampicin on the particle surface that acted as a barrier against moisture condensation and particle fusion. Interestingly, in the ternary formulation rifampicin enrichment on the surface did not interfere with the dissolution of other two components (i.e. meropenem and colistin). Our study provides an insight on the impact of each component on the performance of co-spray dried combinational formulations.

Anti-inflammatory flurbiprofen nasal powders for nose-to-brain delivery in Alzheimer's disease

Neuroinflammation occurs in the early stages of Alzheimer's disease (AD). Thus, anti-inflammatory drugs in this asymptomatic initial phase could slow down AD progression, provided they enter the brain. Direct nose-to-brain drug transport occurs along olfactory or trigeminal nerves, bypassing the blood-brain barrier. Nasal administration may enable the drug to access the brain. Here, flurbiprofen powders for nose-to-brain drug transport in early AD-related neuroinflammation were studied. Their target product profile contemplates drug powder deposition in the nasal cavity, prompt dissolution in the mucosal fluid and attainment of saturation concentration to maximise diffusion in the tissue. Aiming to increase drug disposition into brain, poorly soluble flurbiprofen requires the construction of nasal powder microparticles actively deposited in nose for prompt drug release. Two groups of powders were formulated, composed of flurbiprofen acid or flurbiprofen sodium salt. Two spray dryer apparatuses, differing for spray and drying mechanisms, and particle collection, were applied to impact on the characteristics of the microparticulate powders. Flurbiprofen sodium nasal powders disclosed prompt dissolution and fast ex vivo transport across rabbit nasal mucosa, superior to the acid form, in particular when the powder was prepared using the Nano B-90 spray dryer at the lowest drying air temperature.

Total emitted dose of salbutamol sulphate at different inhalation flows and inhalation volumes through different types of dry powder inhalers

The aim of the present study was to compare the performance of two different dry powder inhalers (DPIs) at different inhalations volumes and inhalation flows. Ventolin Diskus contain blisters of 200µg salbutamol. To test the TED from Aerolizer, salbutamol in Diskus blister was emptied and placed in size 3 capsules suitable for use with Aerolizer. Total emitted dose (TED) delivered by Diskus and Aerolizer was determined using DPI sampling apparatus after one and two inhalations from the same dose. 10-60L/min inhalation flows at 2 and 4L inhalation volume were used in the determination. At inhalation flow ≤30L/min, two inhalations resulted in higher TED than one inhalation (p < 0.05) and Diskus resulted in higher TED than Aerolizer (p < 0.05). The highest TED was at inhalation flow 40L/min above which the effect of the second inhalation and formula device relation were negligible. Device formula relation is present at low inhalation flow but at flow >30L/min Diskus drug formula can be delivered by Aerolizer with no significant difference in TED produced. For the best TED patients are required to inhale as fast as possible (a minimum of 40L/min). At lower inhalation flow two inhalations results in better emitted dose than one inhalation for both DPIs. So, we recommend patients with poor inspiratory efforts to inhale twice and as hard and deep as possible from each dose as they may not receive much benefit from one inhalation even when using DPI with low resistance (Aerolizer) or medium resistance (Diskus). However, further in-vivo study are required to validate this recommendtation.

In vivo nose-to-brain delivery of the hydrophilic antiviral ribavirin by microparticle agglomerates

Nasal administration has been proposed as a potential approach for the delivery of drugs to the central nervous system. Ribavirin (RBV), an antiviral drug potentially useful to treat viral infections both in humans and animals, has been previously demonstrated to attain several brain compartments after nasal administration. Here, a powder formulation in the form of agglomerates comprising micronized RBV and spray-dried microparticles containing excipients with potential absorption enhancing properties, i.e. mannitol, chitosan, and α-cyclodextrin, was developed for nasal insufflation. The agglomerates were characterized for particle size, agglomeration yield, and ex vivo RBV permeation across rabbit nasal mucosa as well as delivery from an animal dry powder insufflator device. Interestingly, permeation enhancers such as chitosan and mannitol showed a lower amount of RBV permeating across the excised nasal tissue, whereas α-cyclodextrin proved to outperform the other formulations and to match the highly soluble micronized RBV powder taken as a reference. In vivo nasal administration to rats of the agglomerates containing α-cyclodextrin showed an overall higher accumulation of RBV in all the brain compartments analyzed as compared with the micronized RBV administered as such without excipient microparticles. Hence, powder agglomerates are a valuable approach to obtain a nasal formulation potentially attaining nose-to-brain delivery of drugs with minimal processing of the APIs and improvement of the technological and biopharmaceutical properties of micronized API and excipients, as they combine optimal flow properties for handling and dosing, suitable particle size for nasal deposition, high surface area for drug dissolution, and penetration enhancing properties from excipients such as cyclodextrins.

Brain targeting of resveratrol by nasal administration of chitosan-coated lipid microparticles

Lipid microparticles (LMs) uncoated or coated with chitosan and containing the neuroprotective polyphenol resveratrol were developed for its targeting to the brain via nasal administration. The lipid microparticles loaded with resveratrol (LMs-Res) were produced by melt emulsification, using stearic acid as lipid material and phosphatidylcholine as the surfactant. The chitosan coated particles LMs-Res-Ch (1.75% w/v chitosan solution) and LMs-Res-Ch-plus (8.75% w/v chitosan solution) were prepared by adding a chitosan solution to the formed particles. The mean diameter of the particles were 68.5 ± 3.1 μm, 76.3 ± 5.2 μm and 84.5 ± 8.1 μm for LMs-Res, LMs-Res-Ch and LMs-Res-Ch-plus respectively, suitable for nasal delivery. Chitosan coating changed the particle surface charge from a negative zeta potential value (-12.7 ± 2.1 mV) for the uncoated particles to a higher positive values respectively, 24.0 ± 4.7 and 44.6 ± 3.1 mV for the chitosan coated LM-Res-Ch and LM-Res-Ch-plus. Permeation studies across human NCM460 cell monolayers demonstrated that their transepithelial electrical resistance (TEER) values were not modified in the presence of free resveratrol, unloaded LMs, loaded LMs-Res or LMs-Res-Ch. On the other hand, the TEER values decreased from 150 ± 7 to 41 ± 3 Ω cm² in the presence of LMs-Res-Ch-plus, which corresponded to a significant increase in the apparent permeability (P_app) of resveratrol from 518 ± 8 × 10^-4 cm/min to 750 ± 98 × 10^-4 cm/min. In vivo studies demonstrated that no resveratrol was detected in the rat cerebrospinal fluid (CSF) after an intravenous infusion of the polyphenol. Conversely, the nasal delivery of resveratrol in a chitosan suspension or encapsulated in uncoated LMs-Res dispersed in water achieved the uptake of resveratrol in the CSF with C_max after 60 min of 1.30 ± 0.30 μg/ml and 0.79 ± 0.15 μg/ml, respectively. However, a dramatic increase in the levels of resveratrol reaching the CSF was attained by the administration of an aqueous suspension of LMs-Res-Ch-plus with a C_max after 60 min of 9.7 ± 1.9 μg/ml. This marked increase in the CSF bioavailability was achieved without any distribution in the systemic circulation, demonstrating a direct and specific nose to brain delivery.

Imagine the Superiority of Dry Powder Inhalers from Carrier Engineering

Inhalation therapy has strong history of more than 4000 years and it is well recognized around the globe within every culture. In early days, inhalation therapy was designed for treatment of local disorders such as asthma and other pulmonary diseases. Almost all inhalation products composed a simple formulation of a carrier, usually α-lactose monohydrate orderly mixed with micronized therapeutic agent. Most of these formulations lacked satisfactory pulmonary deposition and dispersion. Thus, various alternative carrier's molecules and powder processing techniques are increasingly investigated to achieve suitable aerodynamic performance. In view of this fact, more suitable and economic alternative carrier's molecules with advanced formulation strategies are discussed in the present review. Furthermore, major advances, challenges, and the future perspective are discussed.

Physico-Chemical Properties, Aerosolization and Dissolution of Co-Spray Dried Azithromycin Particles with L-Leucine for Inhalation

PURPOSE

Inhalation therapy is popular to treat lower respiratory tract infections. Azithromycin is effective against some bacteria that cause respiratory tract infections; but it has poor water solubility that may limit its efficacy when administrated as inhalation therapy. In this study, dry powder inhaler formulations were developed by co-spray drying azithromycin with L-leucine with a purpose to improve dissolution.

METHODS

The produced powder formulations were characterized regarding particle size, morphology, surface composition and in-vitro aerosolization performance. Effects of L-leucine on the solubility and in-vitro dissolution of azithromycin were also evaluated.

RESULTS

The spray dried azithromycin alone formulation exhibited a satisfactory aerosol performance with a fine particle fraction (FPF) of 62.5 ± 4.1%. Addition of L-leucine in the formulation resulted in no significant change in particle morphology and FPF, which can be attributed to enrichment of azithromycin on the surfaces of composite particles. Importantly, compared with the spray-dried amorphous azithromycin alone powder, the co-spray dried powder formulations of azithromycin and L-leucine demonstrated a substantially enhanced in-vitro dissolution rate. Such enhanced dissolution of azithromycin could be attributed to the formation of composite system and the acidic microenvironment around azithromycin molecules created by the dissolution of acidic L-leucine in the co-spray dried powder. Fourier transform infrared spectroscopic data showed intermolecular interactions between azithromycin and L-leucine in the co-spray dried formulations.

CONCLUSIONS

We developed the dry powder formulations with satisfactory aerosol performance and enhanced dissolution for a poorly water soluble weak base, azithromycin, by co-spray drying with an amino acid, L-leucine.

Opportunity and challenges of nasal powders: Drug formulation and delivery

In the field of nasal drug delivery, among the preparations defined by the European Pharmacopoeia, nasal powders facilitate the formulation of poorly water-soluble active compounds. They often display a simple composition in excipients (if any), allow for the administration of larger drug doses and enhance drug diffusion and absorption across the mucosa, improving bioavailability compared to nasal liquids. Despite the positive features, however, nasal products in this form still struggle to enter the market: the few available on the market are Onzetra Xsail® (sumatriptan) for migraine relief and, for the treatment of rhinitis, Rhinocort® Turbuhaler® (budesonide), Teijin Rhinocort® (beclomethasone dipropionate) and Erizas® (dexamethasone cipecilate). Hence, this review tries to understand why nasal powder formulations are still less common than liquid ones by analyzing whether this depends on the lack of (i) real evidence of superior therapeutic benefit of powders, (ii) therapeutic and/or commercial interest, (iii) efficient manufacturing methods or (iv) availability of suitable and affordable delivery devices. To this purpose, the reader's attention will be guided through nasal powder formulation strategies and manufacturing techniques, eventually giving up-to-date evidences of therapeutic efficacy in vivo. Advancements in the technology of insufflation devices will also be provided as nasal drug products are typical drug-device combinations.

Nasal powders of thalidomide for local treatment of nose bleeding in persons affected by hereditary hemorrhagic telangiectasia

In this work nasal powder formulations of thalidomide were designed and studied to be used by persons affected by hereditary hemorrhagic telangiectasia as a complementary anti-epistaxis therapy, with the goal of sustaining the effect obtained with thalidomide oral treatment after its discontinuation for adverse effects. Three nasal powders were prepared using as carriers β-CD or its more hydrophilic derivatives such as hydropropyl-β-CD and sulphobutylether-β-CD and tested with respect to technological and biopharmaceutical features after emission with active and passive nasal powder devices. For all formulated powders, improved dissolution rate was found compared to that of the raw material, making thalidomide promptly available in the nasal environment at a concentration favouring an accumulation in the mucosa. The very limited transmucosal transport measured in vitro suggests a low likelihood of significant systemic absorption. The topical action on bleeding could benefit from the poor absorption and from the fact that about 2-3% of the thalidomide applied on the nasal mucosa was accumulated within the tissue, particularly with the β-CD nasal powder.

Supercritical CO₂-Assisted Spray Drying of Strawberry-Like Gold-Coated Magnetite Nanocomposites in Chitosan Powders for Inhalation

Lung cancer is one of the leading causes of death worldwide. Therefore, it is of extreme importance to develop new systems that can deliver anticancer drugs into the site of action when initiating a treatment. Recently, the use of nanotechnology and particle engineering has enabled the development of new drug delivery platforms for pulmonary delivery. In this work, POXylated strawberry-like gold-coated magnetite nanocomposites and ibuprofen (IBP) were encapsulated into a chitosan matrix using Supercritical Assisted Spray Drying (SASD). The dry powder formulations showed adequate morphology and aerodynamic performances (fine particle fraction 48%-55% and aerodynamic diameter of 2.6-2.8 µm) for deep lung deposition through the pulmonary route. Moreover, the release kinetics of IBP was also investigated showing a faster release of the drug at pH 6.8, the pH of lung cancer. POXylated strawberry-like gold-coated magnetite nanocomposites proved to have suitable sizes for cellular internalization and their fluorescent capabilities enable their future use in in vitro cell based assays. As a proof-of-concept, the reported results show that these nano-in-micro formulations could be potential drug vehicles for pulmonary administration.

Resveratrol solid lipid microparticles as dry powder formulation for nasal delivery, characterization and in vitro deposition study

This study focuses on development and in vitro characterisation of a nasal delivery system based on uncoated or chitosan-coated solid lipid microparticles (SLMs) containing resveratrol, a natural anti-inflammatory molecule, as an effective alternative to the conventional steroidal drugs. The physico-chemical characteristics of the SLMs loaded with resveratrol were evaluated in terms of morphology, size, thermal behaviour and moisture sorption. The SLMs appeared as aggregates larger than 20 μm. In vitro nasal deposition was evaluated using a USP specification Apparatus E 7-stage cascade impactor equipped with a standard or a modified nasal deposition apparatus. More than 95% of resveratrol was recovered onto the nasal deposition chamber and stage 1 of impactor, suggesting that the SLMs mostly deposited in the nasal cavity. Additionally, the SLMs were not toxic on RPMI 2650 nasal cell line up to a concentration of approximately 40 μM of resveratrol.

Multivariate Analysis of Effects of Asthmatic Patient Respiratory Profiles on the In Vitro Performance of a Reservoir Multidose and a Capsule-Based Dry Powder Inhaler

PURPOSE

The aim of this work was to evaluate the effect of two different dry powder inhalers, of the NGI induction port and Alberta throat and of the actual inspiratory profiles of asthmatic patients on in-vitro drug inhalation performances.

METHODS

The two devices considered were a reservoir multidose and a capsule-based inhaler. The formulation used to test the inhalers was a combination of formoterol fumarate and beclomethasone dipropionate. A breath simulator was used to mimic inhalatory patterns previously determined in vivo. A multivariate approach was adopted to estimate the significance of the effect of the investigated variables in the explored domain.

RESULTS

Breath simulator was a useful tool to mimic in vitro the in vivo inspiratory profiles of asthmatic patients. The type of throat coupled with the impactor did not affect the aerodynamic distribution of the investigated formulation. However, the type of inhaler and inspiratory profiles affected the respirable dose of drugs.

CONCLUSIONS

The multivariate statistical approach demonstrated that the multidose inhaler, released efficiently a high fine particle mass independently from the inspiratory profiles adopted. Differently, the single dose capsule inhaler, showed a significant decrease of fine particle mass of both drugs when the device was activated using the minimum inspiratory volume (592 mL).

Choice of excipients for gelly-like pulp prepared ex tempore "on a spoon"- "placebo" and with sartans

CONTEXT

To ensure safe oral administration, pediatric patients require an appropriate dosage form to be swallowed without relevant difficulties. Ex tempore hydrated powders, forming viscous pulp "on a spoon", have recently gained much interest as pediatric formulations. The aim of this study was to evaluate the viscosity-increasing substances and disintegrants, alone or in mixtures, as excipients suitable for preparing such formulations, with candesartan and valsartan chosen as model active substances.

METHODS

The mixtures of excipients were prepared in the form of powders, granules or lyophilizates, which were evaluated in terms of their ability to form a homogenous mass after hydration with a small amount of water. The best compositions were tested with candesartan cilexetil and valsartan (2% and 10% w/w, respectively). Performed studies include macroscopic, organoleptic and microscopic observations, as well as a textural analysis, determination of gelation time and rheological measurements.

RESULTS

Mixtures of guar gum, lactose and one of the disintegrants (F-Melt M, Prosolv 50, Prosolv Easy, Lycatab, Pharmaburst, Pearlitol) demonstrated the best properties. With regard to drug-incorporating formulations, granules were evaluated as the most satisfying form, while the functional properties of lyophilized formulations were poor.

CONCLUSION

Granules with candesartan cilexetil (2%) were found to be the most promising for further development.

Interest of cyclodextrins in spray-dried microparticles formulation for sustained pulmonary delivery of budesonide

To achieve an efficient lung delivery and efficacy, both active ingredient aerosolisation properties and permeability through the lung need to be optimized. To overcome these challenges, the present studies aim to develop cyclodextrin-based spray-dried microparticles containing a therapeutic corticosteroid (budesonide) that could be used to control airway inflammation associated with asthma. The complexation between budesonide and hydroxypropyl-β-cyclodextrin (HPBCD) has been investigated. Production of inhalation powders was carried out using a bi-fluid nozzle spray dryer and was optimized based on a design of experiments. Spray-dried microparticles display a specific "deflated-ball like shape" associated with an appropriate size for inhalation. Aerodynamic assessment show that the fine particle fraction was increased compared to a classical lactose-based budesonide formulation (44.05 vs 26.24%). Moreover, the budesonide permeability out of the lung was shown to be reduced in the presence of cyclodextrin complexes. The interest of this sustained budesonide release was evaluated in a mouse model of asthma. The anti-inflammatory effect was compared to a non-complexed budesonide formulation at the same concentration and attests the higher anti-inflammatory activity reach with the cyclodextrin-based formulation. This strategy could therefore be of particular interest for improving lung targeting while decreasing systemic side effects associated with high doses of corticosteroids. In conclusion, this works reports that cyclodextrins could be used in powder for inhalation, both for their abilities to improve active ingredient aerosolisation properties and further to their dissolution in lung fluid, to decrease permeability out of the lungs leading to an optimized activity profile.

Effect of Flow Rate on In Vitro Aerodynamic Performance of NEXThaler(®) in Comparison with Diskus(®) and Turbohaler(®) Dry Powder Inhalers

Background: European and United States Pharmacopoeia compendial procedures for assessing the in vitro emitted dose and aerodynamic size distribution of a dry powder inhaler require that 4.0 L of air at a pressure drop of 4 kPa be drawn through the inhaler. However, the product performance should be investigated using conditions more representative of what is achievable by the patient population. This work compares the delivered dose and the drug deposition profile at different flow rates (30, 40, 60, and 90 L/min) of Foster NEXThaler^® (beclomethasone dipropionate/formoterol fumarate), Seretide^® Diskus^® (fluticasone propionate/salmeterol xinafoate), and Symbicort^® Turbohaler^® (budesonide/formoterol fumarate).

Methods: The delivered dose uniformity was tested using a dose unit sampling apparatus (DUSA) at inhalation volumes either 2.0 or 4.0 L and flow rates 30, 40, 60, or 90 L/min. The aerodynamic assessment was carried out using a Next Generation Impactor by discharging each inhaler at 30, 40, 60, or 90 L/min for a time sufficient to obtain an air volume of 4 L.

Results: Foster^® NEXThaler^® and Seretide^® Diskus^® showed a consistent dose delivery for both the drugs included in the formulation, independently of the applied flow rate. Contrary, Symbicort^® Turbohaler^® showed a high decrease of the emitted dose for both budesonide and formoterol fumarate when the device was operated at airflow rate lower that 60 L/min. The aerosolizing performance of NEXThaler^® and Diskus^® was unaffected by the flow rate applied. Turbohaler^® proved to be the inhaler most sensitive to changes in flow rate in terms of fine particle fraction (FPF) for both components. Among the combinations tested, Foster NEXThaler^® was the only one capable to deliver around 50% of extra-fine particles relative to delivered dose.

Conclusions: NEXThaler^® and Diskus^® were substantially unaffected by flow rate through the inhaler in terms of both delivered dose and fine particle mass.

Spray-dried powders enhance vaginal siRNA delivery by potentially modulating the mucus molecular sieve structure

Vaginal small interfering RNA (siRNA) delivery provides a promising strategy for the prevention and treatment of vaginal diseases. However, the densely cross-linked mucus layer on the vaginal wall severely restricts nanoparticle-mediated siRNA delivery to the vaginal epithelium. In order to overcome this barrier and enhance vaginal mucus penetration, we prepared spray-dried powders containing siRNA-loaded nanoparticles. Powders with Pluronic F127 (F127), hydroxypropyl methyl cellulose (HPMC), and mannitol as carriers were obtained using an ultrasound-assisted spray-drying technique. Highly dispersed dry powders with diameters of 5-15 μm were produced. These powders showed effective siRNA protection and sustained release. The mucus-penetrating properties of the powders differed depending on their compositions. They exhibited different potential of opening mesh size of molecular sieve in simulated vaginal mucus system. A powder formulation with 0.6% F127 and 0.1% HPMC produced the maximum increase in the pore size of the model gel used to simulate vaginal mucus by rapidly extracting water from the gel and interacting with the gel; the resulting modulation of the molecular sieve effect achieved a 17.8-fold improvement of siRNA delivery in vaginal tract and effective siRNA delivery to the epithelium. This study suggests that powder formulations with optimized compositions have the potential to alter the steric barrier posed by mucus and hold promise for effective vaginal siRNA delivery.

Nanospray drying as a novel technique for the manufacturing of inhalable NSAID powders

The aim of this research was to evaluate the potential of the nanospray drier as a novel apparatus for the manufacturing of a dry powder for inhalation containing ketoprofen lysinate, a nonsteroidal anti-inflammatory drug able to control the inflammation in cystic fibrosis patients. We produced several ketoprofen lysinate and leucine powder batches by means of nanospray dryer, studying the influence of process parameters on yield, particle properties (size distribution and morphology), and, mainly, aerodynamic properties of powders. Micronized particles were prepared from different hydroalcoholic solutions (alcohol content from 0 to 30% v/v) using ketoprofen in its lysine salt form and leucine as dispersibility enhancer in different ratios (from 5 to 15% w/w) with a total solid concentration ranging from 1 to 7% w/v. Results indicated that the spray head equipped with a 7 µm nozzle produced powders too big to be inhaled. The reduction of nozzle size from 7 to 4 µm led to smaller particles suitable for inhalation but, at the same time, caused a dramatic increase in process time. The selection of process variables, together with the nozzle pretreatment with a surfactant solution, allowed us to obtain a free flowing powder with satisfying aerosol performance, confirming the usefulness of the nanospray drier in the production of powder for inhalation.

Nasal polysaccharides-glucose regulator microparticles: optimization, tolerability and antidiabetic activity in rats

The aim of the present study was to load the post-prandial glucose regulator, repaglinide (REP), on spray dried mucoadhesive microparticles (MPs) comprising anionic polysaccharides. The formulation parameters of the polysaccharides-REP spray dried powders (SDP) namely, polysaccharide type and drug to polymer (D/P) ratio, were optimized for % release after 5 min (R%5 min) and time required for 80% release (T80%). The suitability of the selected formulae for nasal application was evaluated by ex vivo mucoadhesion, in vitro cytocompatability and tolerability studies. A pharmacodynamic study in diabetic rats was conducted. Results showed that both polysaccharide type and amount greatly influenced the chosen responses. REP was highly incorporated in mucoadhesive MPs with proven safety on the rat nasal mucosa. The selected REP loaded powders exhibited a significant two to threefold increase in total decrease in blood glucose compared to the nasal and intravenous solutions.

Differences in physical chemistry and dissolution rate of solid particle aerosols from solution pressurised inhalers

Solution composition alters the dynamics of beclomethasone diproprionate (BDP) particle formation from droplets emitted by pressurised metered dose inhalers (pMDIs). The hypothesis that differences in inhaler solutions result in different solid particle physical chemistry was tested using a suite of complementary calorimetric techniques. The atomisation of BDP-ethanol solutions from commercial HFA-pMDI produced aerodynamically-equivalent solid particle aerosols. However, differences in particle physico-chemistry (morphology and solvate/clathrate formation) were detected by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and supported by hot stage microscopy (HSM). Increasing the ethanol content of the formulation from 8 to 12% (w/w), which retards the evaporation of propellant and slows the increase in droplet surface viscosity, enhanced the likelihood of particles drying with a smooth surface. The dissolution rate of BDP from the 12% (w/w) ethanol formulation-derived particles (63% dissolved over 120 min) was reduced compared to the 8% (w/w) ethanol formulation-derived particles (86% dissolved over 120 min). The addition of 0.01% (w/w) formoterol fumarate or 1.3% (w/w) glycerol to the inhaler solution modified the particles and reduced the BDP dissolution rate further to 34% and 16% dissolved in 120 min, respectively. These data provide evidence that therapeutic aerosols from apparently similar inhaler products, including those with similar aerodynamic performance, may behave non-equivalently after deposition in the lungs.