Purpose: A new approach to delivering high doses of dry powder medicaments to the lung is presented. The Orbital dry powder device (DPI) is designed to deliver high-doses of drugs to the respiratory tract in a single dosing unit, via multiple inhalation manoeuvrers, overcoming the need to prime or insert multiple capsules.

Methods: The Orbital was tested in its prototype configuration and compared to a conventional RS01 capsule device. Three formulations were evaluated: 200 mg spray-dried ciprofloxacin formulation for respiratory infection, 200 mg spray-dried mannitol formulation for mucus clearance, and 100, 200 and 400 mg co-spray dried 1:8 formulations containing ciprofloxacin and mannitol as combination therapy. The systems were evaluated in terms of physico-chemical properties and tested using a multistage liquid impinger at 60 L/min. Emptying rates were evaluated and the aerosolisation performance compared to 10 capsules used sequentially in the RS01. 

Results and Discussion: The systems were different in terms of morphology, thermal response, moisture sorption and stability; however, they had similar sizes when measured by laser diffraction making them suitable for comparison in the Orbital and RS01 devices. The aerosolisation performance from the Orbital and RS01 was dependent upon the formulation type; however, the fine particle fraction (FPF) produced by the Orbital device was higher than the RS01.  The FPF for ciprofloxacin, mannitol and co-spray dried formulation were 67.1±1.8, 47.1 ±2.2 and 42.0 ±1.8, respectively. For the Orbital, 90% of the loaded dose was delivered within 10 inhalation maneuvers, with the profile being dependent upon the formulation type. 

Conclusion: The Orbital provides a means of delivering high doses of medicine to the respiratory tract through multiple breath maneuvers after a single actuation. This approach will allow the delivery of a wide range of high-pay load formulations (>100 mg) for the treatment of a variety of lung disorders. To date no such passive device exists that meet these crucial criteria.

Inhalation of antibiotics and mucolytics are the most important combination of inhaled drugs for chronic obstructive lung diseases and have become a standard part of treatment. However, it is yet to be determined whether the administration of a mucolytic has an effect on the transport rate of antibiotics across the airway epithelial cells. Consequently, the aim of this study was to investigate the effects of inhalation dry powder, specifically mannitol, on ciprofloxacin transport using Calu-3 air interface cell model. Transport studies of ciprofloxacin HCl were performed using different configurations including single spray-dried ciprofloxacin alone, co-spray dried ciprofloxacin with mannitol and deposition of mannitol prior to ciprofloxacin deposition. To understand the mechanism of transport and interactions between the drugs, pH measurements of apical surface liquid and further transport studies were performed with ciprofloxacin base, with and without the presence of ion channel/transport inhibitors such as disodium cromoglycate and furosemide. Mannitol was found to delay absorption of ciprofloxacin HCl through the increase in ASL volume and subsequent reduction in pH. Conversely, ciprofloxacin base had a higher transport rate after mannitol deposition. This study clearly demonstrates that the deposition of mannitol prior to ciprofloxacin on the air-interface Calu-3 cell model has an effect on its transport rate. This was also dependent on the salt form of the drug and the timing and sequence of formulations administered.

Liposomal ciprofloxacin formulations have been developed with the aim of enhancing lung residence time, thereby reducing the burden of inhaled antimicrobial therapy which requires multiple daily due to rapid absorptive clearance of antibiotics from the lungs. However, there is a lack of a predictive methodology available to assess controlled release inhalation delivery systems and their effect on drug disposition. In this study three ciprofloxacin formulations were evaluated: a liposomal formulation, a solution formulation and a 1:1 combination of the two (mixture formulation). Different methodologies were utilised to study the release profiles of ciprofloxacin from these formulations: (i) membrane diffusion, (ii) air-interface Calu-3 cells, and (iii) isolated perfused rat lungs. The data from these models were compared to the performance of the formulations in vivo. The solution formulation provided the highest rate of absorptive transport followed by the mixture formulation, with the liposomal formulation providing substantially slower drug release. The rank- order of drug release/transport from the different formulations was consistent across the in vitro and ex-vivo methods, and this was predictive of the profiles in vivo. The use of complimentary in vitro and ex-vivo methodologies provided a robust analysis of formulation behavior, including mechanistic insights, and predicted in vivo pharmacokinetics.

Introduction: The Calu-3 lung cell line has been shown to be a promising in vitro model of airway epithelia due to its similarity to in vivo physiology. Hence, over the last decade, it has found increasing applications in the pharmaceutical industry. 

Areas covered: This review focuses on the pharmaceutical applications of the Calu-3 cell line in areas such as drug transport, metabolism, controlled release studies, identification of possible drug-drug interactions, investigations into the mechanisms of action of active compounds and understanding of disease pathophysiology. The main findings of various studies, as well as the predictive potential of this model, are presented and discussed in this review.

Expert opinion: There is still a lack of mechanistic knowledge regarding transport of inhaled therapeutics across the lungs. Cell culture models such as Calu-3 provides a simple and reproducible system to study the underlying mechanisms by which inhaled therapeutics interact with the lungs. However, more complex systems that integrate particle deposition onto different cell culture systems may be useful in addressing some fundamental questions to generate a better understanding of determinants that influences pulmonary drug dissolution, absorption, metabolism and efficacy. Ultimately the use of the Calu-3 cell line provides a basic research tool that enables the development of safer and more effective inhaled therapeutics.

Australian data suggest up to 15% of people with intellectual disability (ID) have asthma. The inhaled route of administration is optimal for the management of obstructive airways diseases; however, correct inhaler use requires dexterity and particular breathing patterns and potentially represents a problem in this population due to physical and cognitive deficits. Understanding the nature and extent of inhaler use in persons with ID is important, as correct inhaler technique is imperative for optimal clinical outcomes; however, currently no evidence base exists to inform health professionals. This study describes respiratory medication use, reported prevalence of asthma, and asthma management practices undertaken in a community sample of Australian adults with ID. Results showed a prevalence of retrospectively reported asthma of 6%, with 86% of asthma patients prescribed inhaled medication. A review of patient records also indicated omission of some recommended asthma management strategies.

Background and objective: We aimed to assess whether co-deposition of a long-acting β2-agonist and a steroid affects their respective transport rates across epithelial cells.

Methods: Drug particles were deposited on the air-interface culture of Calu-3 cells using a twin stage impinger. We compared the transport rate of salmeterol and fluticasone from commercially available formulations (Serevent®, Flixotide® and Seretide®) across the epithelial cells. The transepithelial resistance of Calu-3 cells was measured before and after each deposition to monitor epithelial resistance.

Results: The co-deposition of salmeterol and fluticasone had no significant effect on transport of salmeterol through the cell layer, suggesting that salmeterol particles are deposited evenly across the cell line and each particle could have its own dissolution and uptake profile. In contrast, the rate of FP transport in presence of S was significantly lower (0.53 ± 0.20%) compared to the single FP formulation (2.36 ± 0.97%). Furthermore, the resistance of the epithelial cells was significantly increased after salmeterol deposition from both single and combination product.

Conclusions: Our data demonstrates that salmeterol may decrease the permeability of epithetical cells, resulting in slower fluticasone transport across Calu-3 epithelial monolayer. The subsequent increased residence time of fluticasone in the airways could prolong it’s anti-inflammatory effects.

Purpose: The aim of the present work was to develop solid lipid micro particles (SLMs), as dry powders containing quercetin for direct administration to the lung.

Methods: Quercetin microparticles were prepared by o/w emulsification via a phase inversion technique, using tristearin as the lipid component and phosphatidylcholine as an emulsifier. The quercetin SLMs were characterised for morphology, drug loading (15.5 % ± 0.6, which corresponded to an encapsulation efficiency of 71.4%.), particle size distribution, response to humidity, crystallinity, thermal behaviour and in vitro respirable fraction. Furthermore, the toxicity and the in vitro transport of the SLMs on an air liquid interface model of the Calu-3 cell line were also investigated using a modified twin-stage impinger apparatus.

Results: Results showed that quercetin SLMs could be formulated as dry powder suitable for inhalation drug delivery (20.5 ± 3.3% fine particle fraction ≤ 4.46 mm) that was adsorbed, via a linear kinetic model across the Calu-3 monolayer (22.32 ± 1.51 % over 4 hours). In addition, quercetin SLMs were shown to be non-toxic at the concentrations investigated. Interestingly, no apical to basolateral transport of the micronized quercetin was observed over the period of study.

Conclusions: These observations suggest quercetin diffusion was enhanced by the presence of the lipid/emulsifying excipients in the SLMs; however further studies are necessary to elucidate the exact mechanisms.

Ciprofloxacin is a well-established broad-spectrum fluroquinolone antibiotic that penetrates well into the lung tissues; still the mechanisms of its transepithelial transport are unknown. Contributions of specific transporters including multidrug efflux transporters, organic cation transporters and organic anion transporting polypeptide transporters on the uptake of ciprofloxacin were investigated in vitro using an air interface bronchial epithelial model. Our results demonstrate that ciprofloxacin is subject to predominantly active influx and a slight efflux component.

Two solution-based pressurised metered dose inhaler (pMDI) formulations were prepared such that they delivered aerosols with identical mass median aerodynamic diameters, but contained either beclomethasone dipropionate (BDP) alone (glycerol-free formulation) or BDP and glycerol in a 1:1 mass ratio (glycerol-containing formulation). The two formulations were deposited onto Calu-3 respiratory epithelial cell layers cultured at an air-interface. Equivalent drug mass (~1000 ng or ~2000 ng of the formulation) or equivalent particle number (1000 ng of BDP in the glycerol-containing vs. 2000 ng of BDP in the glycerol-free formulation) were deposited as aerosolised particles on the air interfaced surface of the cell layers. The transfer rate of BDP across the cell layer after deposition of the glycerol-free particles was proportional to the mass deposited. In comparison the transfer of BDP from the glycerol-containing formulation was independent of the mass deposited, suggesting that the release of BDP is modified in the presence of glycerol. The rate of BDP transfer (and the extent of metabolism) over 2 h was faster when delivered in glycerol-free particles, 465.01 ng ± 95.12 ng of the total drug (20.99 ± 4.29 %; BDP plus active metabolite) transported across the cell layer, compared to 116.17 ng ± 3.07 ng (6.07 ± 0.16 %) when the equivalent mass of BDP was deposited in glycerol-containing particles. These observations suggest that the presence of glycerol in the maturated aerosol particles may influence the disposition of BDP in the lungs.

A series of semi-empirical equations were utilised to design two solution based pressurised metered dose inhaler (pMDI) formulations, with equivalent aerosol performance but different physicochemical properties. Both inhaler formulations contained the drug, beclomethasone dipropionate (BDP), a volatile mixture of ethanol co-solvent and propellant (hydrofluoroalkane-HFA). However, one formulation was designed such that the emitted aerosol particles contained BDP and glycerol, a common inhalation particle modifying excipient, in a 1:1 mass ratio. By modifying the formulation parameters, including actuator orifice, HFA and metering volumes, it was possible to produce two formulations (glycerol-free and glycerol-containing) which had identical mass median aerodynamic diameters (2.4 mm  ± 0.1 and 2.5 mm  ± 0.2), fine particle dose (≤ 5 mm; 66 mg  ± 6 and 68 mg  ± 2) and fine particle fractions (28 % ± 2 and 30 % ± 1), respectively. These observations demonstrate that it is possible to engineer formulations that generate aerosol particles with very different compositions to have similar emitted dose and in vitro deposition profiles, thus making them equivalent in terms of aerosol performance. Analysis of the physicochemical properties of each formulation identified significant differences in terms of morphology, thermal properties and drug dissolution of emitted particles. The particles produced from both formulations were amorphous; however the formulation containing glycerol generated particles with a porous structure, while the glycerol-free formulation generated particles with a primarily spherical morphology. Furthermore, the glycerol-containing particles had a significantly lower dissolution rate (7.8% ± 2.1%, over 180 min) compared to the glycerol-free particles (58.0% ± 2.9%, over 60 min) when measured using a Franz diffusion cell.  It is hypothesised that the presence of glycerol in the emitted aerosol particles altered solubility and drug transport, which may have implications for BDP pharmacokinetics after deposition in the respiratory tract.

Silver nanoparticles (AgNPs) with size ranging from 7 to 70 nm were synthesized using ascorbic acid-citrate seed-mediated growth approach at room temperature. The 8 nm silver particles were prepared using gallic acid in alkaline conditions and used as seed to prepare AgNPs. The presence of ascorbic acid and citrate allows the regulation of size and size distribution of the nanoparticles. The increase in free silver ion-to-seed ratio (Ag+/Ag0) resulted in the changes of particle shape from spherical to pseudo-spherical and minor cylindrical shape. Further repetitive seeding approach resulted in the formation of pseudo-spherical particles with higher polydispersity index and minor distributions of tetrahedral particles. Citrate-capped AgNPs were stable and did not agglomerate upon centrifugation. The effect of AgNPs on biofilm reduction was evaluated using static culture on 96 well microtiter plates. Results showed that AgNPs with the smallest average diameter were the most effective in the reduction of P. aeruginosa biofilm colonies, which accounted for 90% of removal. The biofilm removal activities of the nanoparticles were found to be concentration independent particularly for the concentration within the range of 80 to 200 µg/ml. 

A novel approach to concurrently deliver oral and inhaled drugs as a single formulation is presented. A triple therapy containing theophylline (THEO; orally delivered) with budesonide (BUD) and terbutaline (TERB) (as single and co-spray dried inhaled powders) were prepared as an ordered mix, with THEO acting as a carrier. The aerosolisation performance of THEO formulations containing BUD and TERB alone, physical mix and co-spray dried powder were evaluated using a next generation impactor (NGI). Physico-chemical properties were investigated using electron microscopy, laser diffraction, dynamic vapour sorption and thermal analysis. NGI analysis indicated that >99% of the THEO powder was greater than 4.46 mm, with >90% dissolved within 5 minutes. Particle size analysis showed samples suitable size for inhalation. Thermal and moisture analysis suggested powders to be stable at room temperature up to 70% RH. Aerosol studies indicated different performance of BUD and TERB depending on the mixing procedure. The co-spray dried formulation showed the highest performance, with a fine particle fraction (≤4.46 microns) of BUD and TERB of 34.39 ± 3.56 % and 33.61 ± 5.67 %, respectively. Such observations suggest this multicomponent drug delivery system could be developed to concomitantly deliver oral and inhaled drugs, an approach that, to date does not exist. Ultimately, this technology potentially reduces the requirement for multiple therapies and increases patient compliance.

Purpose: The aim of this study was to characterize the permeability kinetics of salbutamol sulphate, a commonly used 2-agonist in the treatment of asthma exacerbation, across Calu-3 respiratory epithelial cell monolayers in the presence of non-steroidal anti-inflammatory drugs (NSAIDs), as they have been implicated to be able to modulate organic cation transporters (OCT). Methods: Calu-3 cell monolayers were grown in a liquid covered culture (LCC) configuration on 0.33 cm2 Transwell polyester cell culture supports. Monolayers, cultured between 11 and 14 days were evaluated for epithelial resistance, tight junction integrity and expression of OCT using Western blot analysis. The transport of salbutamol across the monolayer was studied as a function of concentration.  Directional transport was investigated by assessing apical-basal (a-b) and basal- apical (b-a) directions. The influence of a non-specific OCT inhibitor (tetraethylammonium, TEA) and three NSAIDs (aspirin, ibuprofen and indomethacin) on the uptake of salbutamol was studied. Results: The flux of salbutamol sulphate increased with increasing concentration, before reaching a plateau suggesting the involvement of a transport mediated uptake mechanism. Western blot analysis detected the presence of OCT1-3 and N1 and N2 sub-types suggesting the presence of functioning transporters. The apparent permeability (Papp) of 0.1 mM salbutamol across the epithelial monolayer displayed directional transport in the a-b direction which was inhibited by  ~70% in the presence of TEA, suggesting OCT mediated uptake. Likewise, the uptake of 0.1 mM salbutamol was decreased in the presence of all three NSAIDs supporting a mechanism whereby NSAIDs inhibit absorption of salbutamol across the bronchial epithelium via effects on the OCT transporters.

Background: Chronic obstructive pulmonary disease (COPD) is characterised by mucus hyper-production. This pathology, together with other inflammatory contributions, leads to airway obstruction and breathing complications. Newer therapeutic approaches are of increased interest, including the use of HMG-CoA reductase inhibitors. Retrospective studies have shown that statins are effective in reducing patient mortality, and blood cytokines levels. These findings suggest statins may also provide a new therapeutic approach in COPD treatment. Purpose: The aim of the present work was to study the transport of SV across Calu-3 epithelial cells and to investigate its pharmacological action with respect to reduction in mucus production. Methods: Calu-3 cells were grown under liquid covered culture (LCC) conditions for transport studies in order to demonstrate the ability of SV to transport across the monolayer. For mucus detection, cells were grown under air interface culture (AIC) conditions. Samples collected for microscope analysis, were stained with alcian blue; images of the stained cell surface were acquired and the mucus was quantified as the RGBB ratio. Results: SV was transported through the cell monolayer and ‘retained’ inside the Calu-3 cells. Colour analysis of stained Calu-3 monolayers microscope-images, showed that chronic administration of SV for 14 days caused a significant inhibition in mucus production. Conclusion: These findings suggest that local delivery of SV directly to the lungs may provide a promising treatment and potential disease management approach of COPD, with significant effects on mucus reduction.

Context: Salbutamol sulphate is widely used as bronchodilator for the treatment of asthma. Its use is limited by the relatively short duration of action and hence sustained delivery of salbutamol sulphate offers potential benefits to patients.

Objective: This study explores the preparation of lipid microparticles (LMs) as biocompatible carrier for the prolonged release of salbutamol sulphate.

Materials and methods: The LMs were produced using different lipidic materials and surfactants, by classical melt emulsification-based methods (oil-in-water and water-in-oil-in-water emulsions) and the spray congealing technique.

Results: For the LMs obtained by melt emulsification a lack of release modulation was observed. On the other hand, the sustained release of salbutamol sulphate was achieved with glyceryl behenate microparticles prepared by spray congealing. These LMs were characterized by scanning electron microscopy, X-ray diffractometry and differential scanning calorimetry. The drug loading was 4.72% (w/w). The particle size distribution measured by laser diffraction and electrical zone sensing was represented by a volume median diameter (Dv50) of 51.7–71.4 µm. Increasing the atomization air pressure from 4 to 8 bar produced a decrease of the Dv50 to 12.7–17.5 µm.

Conclusions: Incorporation of the hydrophilic salbutamol sulphate into LMs with sustained release characteristics was achieved by spray congealing.

Treatment for tuberculosis (TB) using the standard oral antibiotic regimen is effective but inefficient, requiring high drug dosing and lengthy treatment times. Three concurrent first-line antibiotics recommended by the World Health Organization (WHO) guidelines are pyrazinamide, rifampicin and isoniazid. Combining these antibiotics in a novel formulation for dry powder inhalation (DPI) may facilitate rapid and efficient resolution of local and systemic infection. However, spray-dried individually, these antibiotics were found to be physically unstable. A solution of the three antibiotics, at the WHO-recommended ratio, was spray-dried. The collected powder was assessed by a series of in vitro methods to investigate aerosol performance, particle physico-chemical characteristics and dissolution profile. Particles obtained were spherical with a surface composed primarily of rifampicin, as identified by TOF-SIMS. A mass median aerodynamic diameter of 3.5±0.1μm and fine particle fraction (<5μm) of 45±3% indicated excellent aerosol performance. The combination powder was differentiated by the presence of rifampicin dihydrate and the delta polymorph of pyrazinamide. Quantitative analysis indicated individual particles contained the three antibiotics at the expected proportions (400:150:75 w/w). This excipient-free triple antibiotic DPI formulation could be used as a significant enhanced treatment for TB.

Background: In silico simulation and percolation theory are important tools in the study of physical and mechanical behavior of pharmaceutical compacts. The aim was to generate a new in silico simulation program that describes the mechanical structure of binary compacts formed from an excipient with excellent compactibility and a drug with null compactibility.

Materials and methods: Paracetamol and microcrystalline cellulose powders were compressed under different pressures. Values for the indentation hardness and tensile strength were measured and fitted to the Leuenberger’s model. On the other hand, compacts with different composition were in silico simulated. In each system, the biggest excipient cluster was identified and quantified using the Hoshen−Kopelman algorithm. Then, the size of the biggest in silico cluster was correlated with experimental compactibility values.

Results and discussion: The Leuenberger’s model resulted in good fit to the experimental data for all formulations over 40% of excipient load. Formulations with high drug load (≥0.8) had reduced range for forming compacts and gave low compactibility values. The excipient percolation threshold for the simulated system was 0.3395, indicating that over this excipient fraction, a compact with defined mechanical properties will be formed. The compactibility values presented a change in the range of 0.3–0.4 of excipient fraction load, just where the in silico excipient percolation threshold was found.

Conclusion: Physical measurements of the binary compacts showed good agreement with computational measurements. Subsequently, this in silico approach may be used for the optimization of pharmaceutical powder formulations used in tablet compression.

Read More: http://informahealthcare.com/doi/abs/10.3109/03639045.2012.683439

The aerosol performance of budesonide solution-based pMDIs (HFA 134a), with various amounts of ethanol (5-30%, w/w) as co-solvents, was evaluated using the impaction and the laser diffraction. With the increase of ethanol concentration in a formulation, the mass median aerodynamic diameter (MMAD) was increased and the fine particle fraction (FPF) showed a significant decline. Although data obtain from the laser diffraction oversized that of the impaction measurements, good correlations were established between the two sets of data. Particles emitted from all the five formulations in this study were amorphous, with two different types of morphology – the majority had a smooth surface with a solid core and the others were internally porous with coral-like surface morphology. The addition of ethanol in the formulation decreased the percentage of such irregular-shape particles from approximate 52% to 2.5% when the ethanol concentration was increased from 5% to 30%. A hypothesis regarding the possible particle formation mechanisms was also established. Due to the difference of droplet composition from the designed formulation during the atomization process, the two types of particle may have gone through distinct drying processes: both droplets will have a very short period of co-evaporation, droplets with less ethanol may be dried during such period; while the droplets containing more ethanol will undergo an extra condensation stage before the final particle formation.

The potential of excipient coating to enhance aerosol performance of micronized drugs in carrier excipient-drug blends, used in dry powder inhalers, was investigated. Both EC (ethyl cellulose) and PVP (polyvinylpyrrolidone) were used as coating agents. Carriers were prepared via sieve fractioning followed by spray drying, with and without polymer additive. Each uncoated and coated carrier salbutamol sulphate (SS) blended systems were evaluated for particle size, morphology, drug carrier adhesion and aerosolisation performance, after blending and storage for 24h. All carrier-based systems prepared had similar particle sizes and morphologies. The surface chemistries of the carriers were significantly different, as was drug-carrier adhesion and aerosolisation performance. Particle adhesion between SS and aerosol performance (fine particle fraction; FPF) followed the rank: PVP coated>un-coated>EC coated lactose. This rank order could be attributed to the surface energy measured by contact goniometry and related to the chemistry of lactose and each polymer. Storage did not significantly affect aerosol performance, however a rank increase in mean FPF value was observed for uncoated and EC coated lactose. Finally, the net electrostatic charge across the aerosol cloud indicated that the EC coated lactose transferred less charge to SS particles. The performance of each carrier system could be attributed to the carrier surface chemistry and, in general, by careful selection of the coating polymer, drug-carrier adhesion, electrostatic charge and aerosol performance could be controlled.

Purpose

Liposomal ciprofloxacin nanoparticles were developed to overcome the rapid clearance of antibiotics from the lungs. The formulation was evaluated for its release profile using an air interface Calu-3 cell model and further characterised for aerosol performance and antimicrobial activity.

Methods

Liposomal and free ciprofloxacin formulations were nebulised directly onto Calu-3 bronchial epithelial cells placed in an in vitro twin-stage impinger (TSI) to assess the kinetics of release. The aerosol performance of both the liposomal and free ciprofloxacin formulation was characterised using the next generation impactor. Minimum inhibitory and bactericidal concentrations (MICs and MBCs) were determined and compared between formulations to evaluate the antibacterial activity.

Results

The liposomal formulation successfully controlled the release of ciprofloxacin in the cell model and showed enhanced antibacterial activity against Pseudomonas aeruginosa. In addition, the formulation displayed a respirable aerosol fraction of 70.5 ± 2.03% of the emitted dose.

Conclusion

Results indicate that the in vitro TSI air interface Calu-3 model is capable of evaluating the fate of nebulised liposomal nanoparticle formulations and support the potential for inhaled liposomal ciprofloxacin to provide a promising treatment for respiratory infections.