Output and aerosol properties of 5 nebulizer/compressor systems with arformoterol inhalation solution.

BACKGROUND: Arformoterol, the (R,R) isomer of formoterol, is approved as an inhalation solution for the treatment of bronchoconstriction in patients with chronic obstructive pulmonary disease. Multiple nebulizer systems are commercially available. Different nebulizers can differ significantly in drug output, which may impact drug delivery and clinical efficacy. This study compared the aerosol properties of arformoterol delivered via 5 commonly used nebulizer systems for the home-care market. METHODS: The delivered dose of arformoterol inhalation solution (15 microg/2 mL) was collected in a glass Dreschel-type apparatus. The delivered amount in fine-droplet fraction was assessed with an Andersen cascade impactor, and droplet size (average median diameter and average percent<5 microm) was evaluated via laser diffraction. Compressor flow rate measurements were taken after 1 min and 6 min by placing the flow meter in line with each system. RESULTS: The Pari LC Plus, Updraft II Opti-Neb, and NebuTech systems delivered similar amounts of the 15-microg nominal dose (from 23% to 25%). The Pari LC Star and Sidestream systems delivered slightly higher doses (31% and 35%, respectively). The nebulizer/compressor systems differed somewhat with respect to droplet size. The NebuTech delivered the lowest fine-droplet fraction (61%) via Andersen cascade impactor, and the smallest percent of droplets<5 microm (40%) via laser diffraction. The Pari LC Star and Sidestream delivered the highest fine-droplet fraction (100% and 93%, respectively), and the greatest percent of droplets<5 microm (84% and 88%). The fine-droplet fractions for the Updraft II Opti-Neb and Pari LC Plus were 93% and 89%, respectively, and the percent of droplets<5 microm was about 67%. Compressor flow rates ranged from 3.2 L/min (Pari LC Plus) to 5.4 L/min (NebuTech). CONCLUSIONS: The results of this study demonstrate that the choice of nebulizer/compressor system can influence the aerosol properties of arformoterol inhalation solution and should be considered when prescribing nebulized medications.

The influence of breathing pattern during nebulization on the delivery of arformoterol using a breath simulator.

BACKGROUND: Patients with obstructive airway conditions, including chronic obstructive pulmonary disease (COPD), use nebulizers for drug delivery. Tidal breathing patterns employed by patients during nebulized drug delivery may vary. It is unclear whether different breathing patterns affect the emitted quantity of nebulized drug. This in vitro study evaluated whether different tidal breathing patterns that encompass a range that could be observed in COPD patients influence the emitted amount of nebulized arformoterol. METHODS: Breath-simulation experiments used a Pari LC Plus nebulizer in combination with the Duraneb 3000 portable aerosol system. Four breathing patterns that could represent a range of tidal volumes and inspiratory and expiratory times observed in patients with COPD were studied. The amount of arformoterol on the inspiratory and expiratory filters, and the residual amount in the nebulizer bowl were determined via high-pressure liquid chromatography. Results are expressed as a percent of the nominal dose (15 microg in 2 mL). RESULTS: The total amount of arformoterol on the inspiratory filter increased with a longer inspiratory phase of tidal breathing (ranging from 8.0% to 13.1%), while the expiratory filter dose remained similar (7.9% to 8.7%). The total emitted dose (expiratory and inspiratory amounts combined) for all patterns was 16.0% to 21.1% of the nominal dose. Retained arformoterol amount (not emitted) ranged from 55.9% to 62.3% of the nominal dose. CONCLUSIONS: These breath-simulation experiments suggest that only about 20% of the nominal 15-microg arformoterol dose was emitted from the nebulizer apparatus with each of the 4 tidal breathing patterns studied, and that a longer inspiratory phase was associated with greater inhaled dose.

Taste masking microspheres for orally disintegrating tablets.

The purpose of this study was to evaluate the potential of microspheres for taste masking when incorporated into orally disintegrating tablets. The microspheres were produced by spray drying a mixture of the model compound (famotidine) with taste masking material. The spray process was optimized using a central composite design for two variables to obtain microspheres with desirable characteristics. Then the microspheres were mixed with other excipients to form orally disintegrating tablets. The optimal spray-drying process parameters were 34mg/ml for solid concentration and 7ml/min for feed rate. The drug encapsulation efficiency of the spray-dried microspheres ranges from of 37.59 to 61.56%, with a mean diameter of less than 10microm size and low moisture content (less than 4%). Results from an evaluation by a panel of six human volunteers demonstrated that the orally disintegrating tablets with taste masking microspheres improved the taste significantly. Furthermore, an in vivo study in rats showed that the microspheres neither decrease the bioavailability nor retard the release of famotidine significantly. In conclusion, spray-dried microspheres can effectively mask the bitter taste of the active pharmaceutical ingredients in combination with the orally disintegrating tablets.