Scientific and regulatory activities initiated by the U.S. Food and drug administration to foster approvals of generic dry powder inhalers: Bioequivalence perspective.

Regulatory science for generic dry powder inhalers (DPIs) in the United States (U.S.) has evolved over the last decade. In 2013, the U.S. Food and Drug Administration (FDA) published the draft product-specific guidance (PSG) for fluticasone propionate and salmeterol xinafoate inhalation powder. This was the first PSG for a DPI available in the U.S., which provided details on a weight-of-evidence approach for establishing bioequivalence (BE). A variety of research activities including in vivo and in vitro studies were used to support these recommendations, which have led to the first approval of a generic DPI in the U.S. for fluticasone propionate and salmeterol xinafoate inhalation powder in January of 2019. This review describes the scientific and regulatory activities that have been initiated by FDA to support the current BE recommendations for DPIs that led to the first generic DPI approvals, as well as research with novel in vitro and in silico methods that may potentially facilitate generic DPI development and approval.

Scientific and regulatory activities initiated by the U.S. food and drug administration to foster approvals of generic dry powder inhalers: Quality perspective.

Regulatory science for generic dry powder inhalation products worldwide has evolved over the last decade. The revised draft guidance Metered Dose Inhaler (MDI) and Dry Powder Inhaler (DPI) Products - Quality Considerations [1] (Revision 1, April 2018) that FDA issued summarizes product considerations and potential critical quality attributes (CQAs). This guidance emphasizes the need to apply the principles of quality by design (QbD) and elements of pharmaceutical development discussed in the International Conference for Harmonisation of (ICH) guidelines. Research studies related to quality were used to support guidance recommendations, which preceded the first approval of a generic DPI product in the U.S. This review outlines scientific and regulatory hurdles that need to be surmounted to successfully bring a generic DPI to the market. The goal of this review focuses on relevant issues and various challenges pertaining to CMC topics of the generic DPI quality attributes. Furthermore, this review provides recommendations to abbreviated new drug application (ANDA) applicants to expedite generic approvals.

Formulation and Characterization of Nanocluster Ceftazidime for the Treatment of Acute Pulmonary Melioidosis.

Melioidosis is an infectious disease caused by Burkholderia pseudomallei. The disease is responsible for a high proportion of human pneumonia and fatal bacteremia in the endemic areas of the world and is highly resistant to most commonly available antibiotics. Studies have shown that prophylactic antibiotic treatment, when administered 24 h following bacterial challenge, can prevent infection in a murine model. Prophylactic treatment against this disease using a pulmonary antibiotic formulation has not previously been examined, but may reduce the number of treatments required, allow for the delivery of higher doses, eliminate the need for intravenous administration, and help to minimize systemic side effects. Ceftazidime was formulated as a dry powder aerosol suitable for pulmonary delivery using previously developed NanoCluster dry powder technology. Pharmacokinetics of aerosolized ceftazidime was analyzed in a mouse model. This study demonstrates that ceftazidime can be formulated using NanoCluster technology as a dry powder aerosol suitable for pulmonary delivery to humans. We have also demonstrated the retention of nebulized ceftazidime in mouse lungs for up to 6 h after exposure. The results indicate that this treatment may be useful as a prophylactic treatment against melioidosis. Future work will examine the efficacy of this treatment against B. pseudomallei aerosol challenge.

Pulmonary Delivery of Vancomycin Dry Powder Aerosol to Intubated Rabbits.

Antibiotic multiresistant pneumonia is a risk associated with long-term mechanical ventilation. Vancomycin is commonly prescribed for methicillin-resistant Staphylococcus aureus infections; however, current formulations of vancomycin are only given intravenously. High doses of vancomycin have been associated with severe renal toxicity. In this study, we characterized dry powder vancomyin as a potential inhaled therapeutic aerosol and compared pharmacokinetic profiles of iv and pulmonary administered vancomycin in intubated rabbits through an endotracheal tube system. Cascade impaction studies indicated that using an endotracheal tube, which bypasses deposition in the mouth and throat, increased the amount of drug entering the lung. Bypassing the endotracheal tube with a catheter further enhanced drug deposition in the lung. Interestingly, intubated rabbits administered 1 mg/kg vancomycin via inhalation had similar AUC to rabbits that were administered 1 mg/kg vancomycin via a single bolus iv infusion; however, inhalation of vancomycin reduced Cmax and increased Tmax, indicating that inhaled vancomycin resulted in more sustained pulmonary levels of vancomycin. Collectively, these results suggested that dry powder vancomycin can successfully be delivered by pulmonary inhalation in intubated patients. Furthermore, as inhaled vancomycin is delivered locally to the site of pulmonary infection, this delivery route could reduce the total dose required for therapeutic efficacy and simultaneously reduce the risk of renal toxicity by eliminating the high levels of systemic drug exposure required to push the pulmonary dose to therapeutic thresholds during iv administration.

Antibiotic activity of iron-sequestering polymers.

Increasing antibiotic resistance has compelled the development of novel antibiotics and adjuvant therapies that enhance the efficacy of existing antibiotics. Iron plays a critical role in bacterial infections, yet the use of iron chelators as adjuvant therapy with antibiotics has yielded highly variable outcomes. Multivalent polymeric materials offer an alternative approach to bind and sequester iron via high avidity interactions. Here, a biomimetic iron-sequestering polymer (PAI-DHBA) was synthesized by modifying side chains of cross-linked polyallylamine (cPAI) with 2,3-dihydroxybenzoic acid (DHBA). PAI-DHBA polymer gels with various DHBA contents showed high iron affinity indices and high selectivity for iron. The polymers showed mild antibiotic properties when used to treat established bacterial cultures. Pretreating culture media with PAI-DHBA polymer, however, removed all detectable iron from media and effectively inhibited the growth of Pseudomonas aeruginosa. In addition, bacterial growth was more susceptible to antibiotics combined with PAI-DHBA. Multivalent polymers that bind and sequester iron, such as PAI-DHBA, offer a promising early intervention or adjuvant to antibiotics.

NanoCluster Itraconazole Formulations Provide a Potential Engineered Drug Particle Approach to Generate Effective Dry Powder Aerosols.

BACKGROUND: Itraconazole (ITZ), a triazole antifungal agent, is a poorly water-soluble drug that is orally administered for treatment of fungal infections such as allergic bronchopulmonary aspergillosis (ABPA) and invasive aspergillosis (IA). ABPA is relatively well controlled but IA can be fatal, especially in immunosuppressed patients. Aerosolized ITZ delivered to the lung may provide a local treatment and prophylaxis against IA at the primary site of infection in the lungs. Variations of the percent fine particle fraction (FPF), the percent emitted dose, and the physical properties of the aerosol (e.g., crystallinity) can confound consistent delivery. METHODS: ITZ NanoClusters were formulated via milling (top-down process) or precipitation (bottom-up process) without using any excipients. Itraconazole formulations (ITZ) were prepared by milling 1 gram of micronized itraconazole in 300 mL of fluid. The suspension was collected at 0.5, 1, and 2 hours milling time. Milled ITZ was compared to ITZ prepared by anti-solvent precipitation and to the stock micronized itraconazole. The aerosolization performance of ITZ formulations was determined using an Andersen Cascade Impactor (ACI). RESULTS: The physicochemical properties and aerosol performance of different ITZ NanoClusters suggested an optimized wet milling was the preferred process compared to precipitation. ITZ NanoClusters prepared by wet milling showed better aerosol performance compared to micronized ITZ as received and ITZ NanoClusters prepared by precipitation. ITZ NanoClusters prepared by precipitation methods also showed an amorphous state, while ITZ milled in 10% EtOH maintained the crystalline character of ITZ throughout a 2 hour milling time. CONCLUSIONS: The aerosol performance of milled ITZ NanoClusters was dramatically improved compared to micronized ITZ as received due to the difference of drug particle structures. ITZ NanoCluster formulations represent a potential engineered drug particle approach for inhalation therapy, providing effective aerosol properties and stability due to the crystalline state of the drug powders.

NanoClusters surface area allows nanoparticle dissolution with microparticle properties.

Poorly water-soluble drugs comprise the majority of new drug molecules. Nanoparticle agglomerates, called NanoClusters, can increase the dissolution rate of poorly soluble compounds by increasing particle surface area. Budesonide and danazol, two poorly soluble steroids, were studied as model compounds. NanoCluster suspensions were made using a Netzsch MiniCer media mill with samples collected between 5 and 15 h and lyophilized. Differential scanning calorimetry (DSC) and powder X-ray Diffraction were used to evaluate the physicochemical properties of the powders, and Brunauer, Emmett and Teller (BET) analysis was used to determine surface area. Scanning electron microscopy confirmed NanoClusters were between 1 and 5 µm. NanoCluster samples showed an increase in dissolution rate compared with the micronized stock and similar to a dried nanoparticle suspension. BET analysis determined an increase in surface area of eight times for budesonide NanoClusters and 10-15 times for danazol NanoClusters compared with the micronized stock. Melting temperatures decreased with increased mill time of NanoClusters by DSC. The increased surface area of NanoClusters provides a potential micron-sized alternative to nanoparticles to increase dissolution rate of poorly water-soluble drugs.

NanoCluster budesonide formulations enable efficient drug delivery driven by mechanical ventilation.

Agglomerates of budesonide nanoparticles (also known as 'NanoClusters') are fine dry powder aerosols that were hypothesized to enable drug delivery through ventilator circuits. These engineered powders were delivered via a Monodose inhaler or a novel device, entrained through commercial endotracheal tubes, and analyzed by cascade impaction. Inspiration flow rates and other parameters such as inspiration patterns and inspiration volumes were controlled by a ventilator. NanoCluster budesonide (NC-Bud) formulations had a higher efficiency of aerosol delivery compared to micronized budesonide with NC-Bud showing a much higher percent emitted fraction (%EF). Different inspiration patterns (sine, square, and ramp) did not affect the powder performance of NC-Bud when applied through a 5.0 mm endotracheal tube. The aerosolization of NC-Bud also did not change with the inspiration volume (1.5-2.5 L) nor with the inspiration flow rate (20-40 L/min) suggesting fast emptying times for budesonide capsules. The %EF of NC-Bud was higher at 51% relative humidity compared to 82% RH. The novel device and the Monodose showed the same efficiency of drug delivery but the novel device fit directly to a ventilator and endotracheal tubing connections. The new device combined with NanoCluster formulation technology allowed convenient and efficient drug delivery through endotracheal tubes.

Delivery and performance of surfactant replacement therapies to treat pulmonary disorders.

Lung surfactant is crucial for optimal pulmonary function throughout life. An absence or deficiency of surfactant can affect the surfactant pool leading to respiratory distress. Even if the coupling between surfactant dysfunction and the underlying disease is not always well understood, using exogenous surfactants as replacement is usually a standard therapeutic option in respiratory distress. Exogenous surfactants have been extensively studied in animal models and clinical trials. The present article provides an update on the evolution of surfactant therapy, types of surfactant treatment, and development of newer-generation surfactants. The differences in the performance between various surfactants are highlighted and advanced research that has been conducted so far in developing the optimal delivery of surfactant is discussed.

Development of budesonide nanocluster dry powder aerosols: preformulation.

Wet milling was previously demonstrated as a simple process for producing agglomerates of budesonide nanoparticles (also known as NanoClusters) for use in dry powder aerosol formulation. The resulting budesonide NanoCluster powders exhibited a large emitted fraction and a high fine particle fraction (FPF) from a Monodose® dry powder inhaler. In this work, excipients were added premilling or postmilling and the performance of budesonide NanoCluster dry powders was investigated. Sodium chloride, Pluronic®, or ethanol was added prior to milling due to their ability to modify surface tension or ionic strength and thereby affect the attrition/agglomeration process. Lactose or l-leucine was added after milling because these are known to modify powder flow and dispersion. The chemical stability of budesonide was maintained in all cases, but the physical aerosol properties changed substantially with the addition of excipients. In all cases, the addition of excipients led to an increase in the size of the budesonide NanoClusters and tended to reduce the emitted fraction and FPF. Titrating excipients may provide a means to discretely modify the aerosol properties of budesonide NanoClusters but did not match the performance of excipient-free NanoCluster powder.

Development of budesonide nanocluster dry powder aerosols: formulation and stability.

The physical and chemical stability of dry powder aerosol formulations is an essential component in the development of an inhaled therapeutic. The pharmaceutical processing methods and storage conditions are primary determinants of the stability of a dry powder inhaler (DPI) formulation. Wet milling was used to produce budesonide NanoClusters (NCs), which are agglomerates of drug nanoparticles (≈ 300 nm) with a mean aerodynamic diameter between 1 and 3 µm, capable of deep lung penetration. In this study, the reproducibility of NC processing and performance was established. The physical stability of a selected budesonide NC formulation was investigated using industry standard dose content uniformity and cascade impaction techniques. The chemical stability of the lead formulation was also determined as a function of processing parameters and storage conditions. This study confirms the reproducibility and robust stability of NC powders as a novel means to turn drug particles into high-performance aerosols.

Development of budesonide nanocluster dry powder aerosols: processing.

Aerosolized medicine is one of the fastest growing areas in the pharmaceutical industry. Dry powder aerosols of pharmaceutical compounds are particularly attractive for the prevention and treatment of respiratory diseases but are also emerging as a treatment option for systemic diseases. Engineering particles in dry powder formulations can overcome many of the limitations of traditional inhaled pharmaceuticals. Here, a wet milling process for producing agglomerated budesonide nanoparticles (i.e., "NanoClusters") was explored. Parameters such as milling time and drug concentration were investigated, and the aerosol performance of dried budesonide NanoClusters was characterized. The wet milling process was able to produce aerosol particles composed entirely of budesonide. High emitted fraction and a large fine particle fraction suggested that the NanoCluster budesonide formulation would offer highly efficient delivery of drug throughout the lung.

Pharmaceutical plasticizers for drug delivery systems.

In the field of pharmaceutical science and drug development, there are important and particular challenges related to the selection of suitable and compatible ingredients as well as the design of successful formulations. As plasticization is a phenomenon widely exploited in all formulation fields, plasticizers should be recognized as a critical aspect for drug delivery. The choice of an appropriate plasticizer requires a wide background of information. This is because they are incorporated into drug delivery systems containing an assortment of ingredients which may have different reactions to the presence of plasticizers. Concurrently, there are numerous pharmaceutical plasticizers and various environmental issues dictating favored solutions. To address these encumbrances, an extensive information concerning plasticizers; their types, properties, pharmaceutical roles, etc. is discussed. Additionally, the specific objective of this review is to substantiate the safety and performance of newly discovered plasticizers.

Nanocluster budesonide formulations enhance drug delivery through endotracheal tubes.

The pulmonary system is an attractive route for drug delivery because the lungs have a large accessible surface area for treatment. For ventilated patients, an endotracheal tube is required for delivering drugs into the lungs. Such tubes are generally poor conduits for delivering traditional aerosol formulations. Both the formulation and the properties of the endotracheal tube are important effectors of delivery efficiency. In this study, agglomerates of budesonide nanoparticles (NanoClusters) were formulated with or without l-leucine or lactose. Teflon tubing was compared with commercial endotracheal tubes as a conduit for delivering budesonide powders into a cascade impactor. The effects of volumetric flow rate, tube size, and humidity were also investigated. NanoCluster budesonide (NC-Bud) formulations had a considerably higher emitted dose and fine particle fraction compared with stock budesonide and the commercial Flexhaler powder when applied through endotracheal tubes. Tubing material did not significantly affect powder performance, but decreasing tubing diameter or increasing volumetric flow rates yielded a smaller mass median aerodynamic diameter for NC-Bud. Engineered NC-Bud powders may dramatically improve drug delivery through endotracheal tubes when using proper ventilator settings.

Nanoparticle agglomerates of fluticasone propionate in combination with albuterol sulfate as dry powder aerosols.

Particle engineering strategies remain at the forefront of aerosol research for localized treatment of lung diseases and represent an alternative for systemic drug therapy. With the hastily growing popularity and complexity of inhalation therapy, there is a rising demand for tailor-made inhalable drug particles capable of affording the most proficient delivery to the lungs and the most advantageous therapeutic outcomes. To address this formulation demand, nanoparticle agglomeration was used to develop aerosols of the asthma therapeutics, fluticasone or albuterol. In addition, a combination aerosol was formed by drying agglomerates of fluticasone nanoparticles in the presence of albuterol in solution. Powders of the single drug nanoparticle agglomerates or of the combined therapeutics possessed desirable aerodynamic properties for inhalation. Powders were efficiently aerosolized (∼75% deposition determined by cascade impaction) with high fine particle fraction and rapid dissolution. Nanoparticle agglomeration offers a unique approach to obtain high performance aerosols from combinations of asthma therapeutics.

Iodinated NanoClusters as an inhaled computed tomography contrast agent for lung visualization.

Improvements to contrast media formulations may be an effective way to increase the accuracy and effectiveness of thoracic computed tomography (CT) imaging in disease evaluation. To achieve contrast enhancement in the lungs, a relatively large localized concentration of contrast media must be delivered. Inhalation offers a noninvasive alternative to intrapleural injections for local lung delivery, but effective aerosolization may deter successful imaging strategies. Here, NanoCluster technology was applied to N1177, a diatrizoic acid derivative, to formulate low density nanoparticle agglomerates with aerodynamic diameters

Floating tablet of trimetazidine dihydrochloride: an approach for extended release with zero-order kinetics.

Trimetazidine dihydrochloride is an effective anti-anginal agent; however, it is freely soluble in water and suffers from a relatively short half-life. To solve this encumbrance, it is a prospective candidate for fabricating trimetazidine extended-release formulations. Trimetazidine extended-release floating tablets were prepared using different hydrophilic matrix forming polymers including HPMC 4000 cps, carbopol 971P, polycarbophil, and guar gum. The tablets were fabricated by dry coating technique. In vitro evaluation of the prepared tablets was performed by the determination of the hardness, friability, content uniformity, and weight variation. The floating lag time and floating duration were also evaluated. Release profile of the prepared tablets was performed and analyzed. Furthermore, a stability study of the floating tablets was carried out at three different temperatures over 12 weeks. Finally, in vivo bioavailability study was done on human volunteers. All tablet formulas achieved < 0.5 min of floating lag time, more than 12 h of floating duration, and extended t (1/2). The drug release in all formulas followed zero-order kinetics. T4 and T8 tablets contained the least polymer concentration and complied with the dissolution requirements for controlled-release dosage forms. These two formulas were selected for further stability studies. T8 exhibited longer expiration date and was chosen for in vivo studies. T8 floating tablets showed an improvement in the drug bioavailability compared to immediate-release tablets (Vastrel® 20 mg).

Dry powdered aerosols of diatrizoic acid nanoparticle agglomerates as a lung contrast agent.

Aerosolized contrast agents may improve the resolution of biomedical imaging modalities and enable more accurate diagnosis of lung diseases. Many iodinated compounds, such as diatrizoic acid, have been shown to be safe and useful for radiographic examination of the airways. Formulations of such compounds must be improved in order to allow imaging of the smallest airways. Here, diatrizoic acid nanoparticle agglomerates were created by assembling nanoparticles into inhalable microparticles that may augment deposition in the lung periphery. Nanoparticle agglomerates were fully characterized and safety was determined in vivo. After dry powder insufflation to rats, no acute alveolar tissue damage was observed 2h post-dose. Diatrizoic acid nanoparticle agglomerates possess the characteristics of an efficient and safe inhalable lung contrast agent.

Transdermal delivery of salbutamol sulphate: formulation and evaluation.

Salbutamol patches were prepared and evaluated. The effect of different Eudragits and various plasticizers on the properties of the patches were studied. Patches were prepared by casting method employing different plasticizers. These patches were evaluated for weight, thickness uniformity, swelling index, tensile strength, elongation percent and moisture absorption capacity. Release was studied. Tensile strength of the patches using Eudragit RS 100 as well as RS100 + L100 and triacetin was the lowest. Formulae containing 10% oleic acid and 5% dimethyl formamide, respectively, showed the highest permeability. These two formulae were studied clinically, the first formula only showed a significant improvement.

Combination chemotherapeutic dry powder aerosols via controlled nanoparticle agglomeration.

PURPOSE: To develop an aerosol system for efficient local lung delivery of chemotherapeutics where nanotechnology holds tremendous potential for developing more valuable cancer therapies. Concurrently, aerosolized chemotherapy is generating interest as a means to treat certain types of lung cancer more effectively with less systemic exposure to the compound. METHODS: Nanoparticles of the potent anticancer drug, paclitaxel, were controllably assembled to form low density microparticles directly after preparation of the nanoparticle suspension. The amino acid, L-leucine, was used as a colloid destabilizer to drive the assembly of paclitaxel nanoparticles. A combination chemotherapy aerosol was formed by assembling the paclitaxel nanoparticles in the presence of cisplatin in solution. RESULTS: Freeze-dried powders of the combination chemotherapy possessed desirable aerodynamic properties for inhalation. In addition, the dissolution rates of dried nanoparticle agglomerate formulations (approximately 60% to 66% after 8 h) were significantly faster than that of micronized paclitaxel powder as received (approximately 18% after 8 h). Interestingly, the presence of the water soluble cisplatin accelerated the dissolution of paclitaxel. CONCLUSIONS: Nanoparticle agglomerates of paclitaxel alone or in combination with cisplatin may serve as effective chemotherapeutic dry powder aerosols to enable regional treatment of certain lung cancers.