Excipient Interactions in Glucagon Dry Powder Inhaler Formulation for Pulmonary Delivery

Dry powder inhaler design and particle technology in enhancing Pulmonary drug deposition: challenges and future strategies

OBJECTIVES

The efficient delivery of drugs from dry powder inhaler (DPI) formulations is associated with the complex interaction between the device design, drug formulations, and patient's inspiratory forces. Several challenges such as limited emitted dose of drugs from the formulation, low and variable deposition of drugs into the deep lungs, are to be resolved for obtaining the efficiency in drug delivery from DPI formulations. The objective of this study is to review the current challenges of inhaled drug delivery technology and find a way to enhance the efficiency of drug delivery from DPIs.

METHODS/EVIDENCE ACQUISITION

Using appropriate keywords and phrases as search terms, evidence was collected from the published articles following SciFinder, Web of Science, PubMed and Google Scholar databases.

RESULTS

Successful lung drug delivery from DPIs is very challenging due to the complex anatomy of the lungs and requires an integrated strategy for particle technology, formulation design, device design, and patient inhalation force. New DPIs are still being developed with limited performance and future device design employs computer simulation and engineering technology to overcome the ongoing challenges. Many issues of drug formulation challenges and particle technology are concerning factors associated with drug dispersion from the DPIs into deep lungs.

CONCLUSION

This review article addressed the appropriate design of DPI devices and drug formulations aligned with the patient's inhalation maneuver for efficient delivery of drugs from DPI formulations.

Rapid Correction of the Hypoglycemia State in Nonhuman Primates Using a Glucagon Long-Dissolving Microneedle Patch

The timely administration of glucagon is a standard clinical practice for the treatment of severe hypoglycemia. However, the process involves cumbersome steps, including the reconstitution of labile glucagon and filling of the syringe, which cause considerable delays in emergency situations. Moreover, multiple dosages are often required to prevent the recurrence of the hypoglycemic episode because of the short half-life of glucagon in plasma. Herein, we develop a glucagon-loaded long-dissolving microneedle (GLMN) patch that exhibits the properties of fast onset and sustained activity for the effective treatment of severe hypoglycemia. Three types of MN patches were fabricated with different dimensions (long, medium, and short). The longer MN patch packaged a higher dosage of glucagon and exhibited supreme mechanical strength compared to the shorter one. Additionally, the longer MN patch could insert more deeply into the skin, resulting in higher permeability of glucagon across the skin tissue and more rapid systemic absorption as compared with the shorter MN patch. The GLMN patch was observed to reverse the effects of hypoglycemia within 15 min of application in animal models (specifically, rat and rhesus monkey models) and maintained long-term glycemic control, owing to highly efficient drug permeation and the drug reservoir effect of the MN base. The current study presents a promising strategy for the rapid reversal of severe hypoglycemia that exhibits the desirable properties of easy use, high efficiency, and sustained action.

Impact of Leucine and Magnesium Stearate on the Physicochemical Properties and Aerosolization Behavior of Wet Milled Inhalable Ibuprofen Microparticles for Developing Dry Powder Inhaler Formulation

This study investigated the development and characterization of leucine and magnesium stearate (MgSt) embedded wet milled inhalable ibuprofen (IBF) dry powder inhaler (DPI) formulations. IBF microparticles were prepared by a wet milling homogenization process and were characterized by SEM, FTIR, DSC, XRD and TGA. Using a Twin-Stage Impinger (TSI), the in vitro aerosolization of the formulations with and without carrier lactose was studied at a flow rate of 60± 5 L/min and the IBF was determined using a validated HPLC method. The flow properties were determined by the Carr's Index (CI), Hausner Ratio (HR) and Angle of Repose (AR) of the milled IBF with 4-6.25% leucine and leucine containing formulations showed higher flow property than those of formulations without leucine. The fine particle fraction (FPF) of IBF from the prepared formulations was significantly (p = 0.000278) higher (37.1 ± 3.8%) compared to the original drug (FPF 3.7 ± 0.9%) owing to the presence of leucine, which enhanced the aerosolization of the milled IBF particles. Using quantitative phase analysis, the XPRD data revealed the crystallinity and accurate weight percentages of the milled IBF in the formulations. FTIR revealed no changes of the structural integrity of the milled IBF in presence of leucine or MgSt. The presence of 2.5% MgSt in the selected formulations produced the highest solubility (252.8 ± 0.6 µg/mL) of IBF compared to that of unmilled IBF (147.4 ± 1.6 µg/mL). The drug dissolution from all formulations containing 4-6.25% leucine showed 12.2-18.6% drug release in 2.5 min; however, 100% IBF dissolution occurred in 2 h whereas around 50% original and dry milled IBF dissolved in 2 h. The results indicated the successful preparation of inhalable IBF microparticles by the wet milling method and the developed DPI formulations with enhanced aerosolization and solubility due to the presence of leucine may be considered as future IBF formulations for inhalation.

Recent developments in lactose blend formulations for carrier-based dry powder inhalation

Lactose is the most commonly used excipient in carrier-based dry powder inhalation (DPI) formulations. Numerous inhalation therapies have been developed using lactose as a carrier material. Several theories have described the role of carriers in DPI formulations. Although these theories are valuable, each DPI formulation is unique and are not described by any single theory. For each new formulation, a specific development trajectory is required, and the versatility of lactose can be exploited to optimize each formulation. In this review, recent developments in lactose-based DPI formulations are discussed. The effects of varying the material properties of lactose carrier particles, such as particle size, shape, and morphology are reviewed. Owing to the complex interactions between the particles in a formulation, processing adhesive mixtures of lactose with the active ingredient is crucial. Therefore, blending and filling processes for DPI formulations are also reviewed. While the role of ternary agents, such as magnesium stearate, has increased, lactose remains the excipient of choice in carrier-based DPI formulations. Therefore, new developments in lactose-based DPI formulations are crucial in the optimization of inhalable medicine performance.

"Smart" Composite Microneedle Patch Stabilizes Glucagon and Prevents Nocturnal Hypoglycemia: Experimental Studies and Molecular Dynamics Simulation

Hypoglycemia is a major complication associated with insulin therapy in people with diabetes that could cause life-threatening conditions if untreated. Glucagon, a counter-acting hormone, is thus administered for rescue of severe hypoglycemia. However, due to the instability of glucagon, only limited medications are available for emergency use, which are unsuitable for patients with hypoglycemia unawareness or with the inability to self-administer, especially during sleep (namely, nocturnal hypoglycemia). To prevent unattended and extended hypoglycemia, we designed a "smart" composite microneedle (cMN) patch capable of stabilizing glucagon, sensing hypoglycemia, and delivering glucagon automatically on demand. In this design, native glucagon was encapsulated in glucose-responsive microgels containing a glucagon-stabilizing component rationally selected by molecular dynamics (MD) simulation. A cMN patch was then prepared by incorporating the glucagon microgels with poly(methyl vinyl ether-alt-maleic anhydride) (PMVE-MAH) and poly(ethylene glycol) (PEG) followed by thermal cross-linking. The rationally designed zwitterionic polymer-based microgels preserved the native structure of glucagon and prevented heat-induced fibrillation evidenced by RP-HPLC, circular dichroism, and transmission electron microscopy. MD simulations suggested that the polymeric microgels stabilized glucagon by inhibition of oligomer formation via peptide-polymer noncovalent interactions. The polymer formed multiple hydrogen bonds with the polar and charged amino acid residues of the glucagon molecule, shielding the peptide surface from aggregation. In vivo efficacy studies using streptozotocin-induced type 1 diabetic (T1D) rats demonstrated that the glucagon-loaded cMN patch could prevent hypoglycemia induced by insulin overdose during a 12 h period. The results suggest that this new glucagon "smart" patch may be a promising system for improving the quality of life of those suffering from nocturnal hypoglycemia and hypoglycemia unawareness.

Development of drug alone and carrier-based GLP-1 dry powder inhaler formulations

The study aimed to develop two types of dry powder inhaler (DPI) formulations containing glucagon-like peptide-1(7-36) amide (GLP-1): carrier-free (drug alone, no excipients) and carrier-based DPI formulations for pulmonary delivery of GLP-1. This is the first study focusing on the development of excipient free GLP-1 DPI formulations for inhaled therapy in Type 2 diabetes. The aerosolisation performance of both DPI formulations was studied using a next generation impactor and a DPI device (Handihaler®) at flow rate of 30 L min^-1. Carriers employed were either a 10% w/w glycine-mannitol prepared by spray freeze drying or commercial mannitol. Spray freeze dried (SFD) carrier was spherical and porous whereas commercial mannitol carrier exhibited elongated particles (non-porous). GLP-1 powder without excipients for inhalation was prepared using spray drying and characterised for morphology including size, thermal behaviour, and moisture content. Spray dried (SD) GLP-1 powders showed indented/dimpled particles in the particle size range of 1 to 5 µm (also mass median aerodynamic diameter, MMAD: <5 µm) suitable for pulmonary delivery. Across formulations investigated, carrier-free DPI formulation showed the highest fine particle fraction (FPF: 90.73% ± 1.76%, mean ± standard deviation) and the smallest MMAD (1.96 µm ± 0.07 µm), however, low GLP-1 delivered dose (32.88% ± 7.00%, total GLP-1 deposition on throat and all impactor stages). GLP-1 delivered dose was improved by the addition of SFD 10% glycine-mannitol carrier to the DPI formulation (32.88% ± 7.00% -> 45.92% ± 5.84%). The results suggest that engineered carrier-based DPI formulations could be a feasible approach to enhance the delivery efficiency of GLP-1. The feasibility of systemic pulmonary delivery of SD GLP-1 for Type 2 diabetes therapy can be further investigated in animal models.

Inhaled Edoxaban dry powder inhaler formulations: Development, characterization and their effects on the coagulopathy associated with COVID-19 infection

Herein, we demonstrated the development and characterization of a dry powder inhaler (DPI) formulation of edoxaban (EDX); and investigated the in-vitro anticoagulation effect for the management of pulmonary or cerebral coagulopathy associated with COVID-19 infection. The formulations were prepared by mixing the inhalable micronized drug with a large carrier lactose and dispersibility enhancers, leucine, and magnesium stearate. The drug-excipient interaction was studied using X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) methods. The drug and excipients showed no physical inter particulate interaction. The in-vitro drug aerosolization from the developed formulation was determined by a Twin Stage Impinger (TSI) at a flow rate of 60 ± 5 L /min. The amount of drug deposition was quantified by an established HPLC-UV method. The fine particle fraction (FPF) of EDX API from drug alone formulation was 7%, whereas the formulations with excipients increased dramatically to almost 7-folds up to 47%. The developed DPI formulation of EDX showed a promising in-vitro anticoagulation effect at a very low concentration. This novel DPI formulation of EDX could be a potential and effective inhalation therapy for managing pulmonary venous thromboembolism (VTE) associated with COVID-19 infection. Further studies are warranted to investigate the toxicity and clinical application of the inhaled EDX DPI formulation.

Puerarin dry powder inhaler formulations for pulmonary delivery: Development and characterization

This study aims at developing and characterizing the puerarin dry powder inhaler (DPI) formulations for pulmonary delivery. The inhalable particles size (<2 μm) was accomplished by micronization and its morphology was examined by scanning electron microscopy (SEM). The puerarin-excipient interaction in powder mixtures was analyzed by using Fourier transform infrared spectroscopy (FTIR), Raman confocal microscopy, X-Ray powder Diffraction (XRD), and differential scanning calorimetry (DSC) methods. Using a Twin stage impinger (TSI), the in-vitro aerosolization of the powder formulations was carried out at a flow rate of 60 L/min and the drug was quantified by employing a validated HPLC method. No significant interactions between the drug and the excipients were observed in the powder formulations. The fine particle fraction (FPF) of the drug alone was 4.2% which has increased five to six-fold for the formulations with aerosolization enhancers. Formulation containing lactose as large carriers produced 32.7% FPF, which further increased with the addition of dispersibility enhancers, leucine and magnesium stearate (40.8% and 41.2%, respectively). The Raman and FTIR techniques are very useful tool for understanding structural integrity and stability of the puerarin in the powder formulations. The puerarin was found to be compatible with the excipients used and the developed DPI formulation may be considered as an efficient formulation for pulmonary delivery for the management of various diseases at a very low dose.

A quantitative approach to predicting lung deposition profiles of pharmaceutical powder aerosols

Dry powder inhalers (DPI) are widely used systems for pulmonary delivery of therapeutics. The inhalation performance of DPIs is influenced by formulation features, inhaler device and inhalation pattern. The current review presents the affecting factors with great focus on powder characteristics which include particle size, shape, surface, density, hygroscopicity and crystallinity. The properties of a formulation are greatly influenced by a number of physicochemical factors of drug and added excipients. Since available particle engineering techniques result in particles with a set of modifications, it is difficult to distinguish the effect of an individual feature on powder deposition behavior. This necessitates developing a predictive model capable of describing all influential factors on dry powder inhaler delivery. Therefore, in the current study, a model was constructed to correlate the inhaler device properties, inhalation flow rate, particle characteristics and drug/excipient physicochemical properties with the resultant fine particle fraction. The r² value of established correlation was 0.74 indicating 86% variability in FPF values is explained by the model with the mean absolute errors of 0.22 for the predicted values. The authors believe that this model is capable of predicting the lung deposition pattern of a formulation with an acceptable precision when the type of inhaler device, inhalation flow rate, physicochemical behavior of active and inactive ingredients and the particle characteristics of DPI formulations are considered.

Advances in Pulmonary Drug Delivery

Pulmonary drug delivery represents an attractive, non-invasive administration option. In addition to locally acting drugs, molecules that are intended to produce systemic effects can be delivered via the pulmonary route. Several factors need to be considered in the context of delivering drugs to or via the lungs—in addition to the drug itself, its formulation into an appropriate inhalable dosage form of sufficient stability is critical. It is also essential that this formulation is paired with a suitable inhaler device, which generates an aerosol of a particle/droplet size that ensures deposition in the desired region of the respiratory tract. Lastly, the patient’s (patho-) physiology and inhalation manoeuvre are of importance. This Special Issue brings together recent advances in the areas of inhalation device testing, aerosol formulation development, use of in vitro and in silico models in pulmonary drug deposition and drug disposition studies, and pulmonary delivery of complex drugs, such as vaccines, antibiotics and peptides, to or via the lungs.

Development of an Innovative, Carrier-Based Dry Powder Inhalation Formulation Containing Spray-Dried Meloxicam Potassium to Improve the In Vitro and In Silico Aerodynamic Properties

Most of the marketed dry powder inhalation (DPI) products are traditional, carrier-based formulations with low drug concentrations deposited in the lung. However, due to their advantageous properties, their development has become justified. In our present work, we developed an innovative, carrier-based DPI system, which is an interactive physical blend of a surface-modified carrier and a spray-dried drug with suitable shape and size for pulmonary application. Meloxicam potassium, a nonsteroidal anti-inflammatory drug (NSAID), was used as an active ingredient due to its local anti-inflammatory effect and ability to decrease the progression of cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). The results of the in vitro and in silico investigations showed high lung deposition in the case of this new formulation, confirming that the interparticle interactions were changed favorably.