Archive for the ‘Lung Deposition’
Large particles or droplets delivered from inhaler devices will be deposited in the oropharynx, possibly contributing to unwanted side effects, but making no contribution to clinical efficacy. The addition of baffles to inhaler devices reduces oropharyngeal deposition, but may also reduce drug delivery to the lungs. Modification of the RESPIMAT by addition of a baffle in the mouthpiece reduced oropharyngeal deposition from 26.2 to 7.8% of the dose, and reduced whole lung deposition from 44.6 to 29.5%, with the overall effect that targeting of delivered drug to the lungs was improved by the baffle. http://asthma-inhalers-online.com Here This improvement in the selectivity of drug delivery for the RESPIMAT with baffle could result in a reduction in both the local and systemic side effects of high dose inhaled corticosteroids. Read the rest of this entry »
In contrast to the MDI, where drug particles leave the canister at a very high speed and initially are of relatively large particle size (mass median diameter, 15 to 20 |Jim), the RESPIMAT soft mist inhaler generates a slow, gentle release of particles, a high proportion of which are respirable (<5 jmm), and which patients may find easier to inhale in clinical practice. These features of the device suggest that lung deposition may be improved, which has been confirmed by the results of the present studies. The mean whole lung deposition of fenoterol and flunisolide delivered by the RESPIMAT device was similar (39.2% and 44.6% of the metered dose, respectively) More info order antibiotics online. Such high values of whole lung deposition have only rarely been reported previously with other aerosol delivery devices. Lung deposition >25% of the metered dose has been reported for the Turbuhaler, an MDI containing a propellant-soluble radiolabel and an MDI plus Nebuhaler spacer. The whole lung deposition of fenoterol delivered by MDI (11.0%) was similar to the lung deposition from MDIs obtained in other studies. Read the rest of this entry »
In the fenoterol study, only a small percentage of the metered dose from each device was detected in the exhaled air (ie, on the exhalation filter and nose plugs) as shown in Table 3. However, the mean percentage of the dose in exhaled air for the RESPIMAT device was significantly greater than that for the MDI (p<0.02) and the MDI with Aerochamber (p<0.01).
For the subjects receiving flunisolide via the MDI with spacer, the mean percentage of the dose detected in the exhaled air was very low (0.4%). In comparison, both the RESPIMAT and the RESPIMAT with baffle deposited a significantly greater proportion of the dose in the exhaled air (mean 12.4% and 7.4%, respectively; p<0.01) as shown in Table 4. Read the rest of this entry »
In the fenoterol study, the mean oropharyngeal deposition was significantly lower for the RESPIMAT compared with the MDI (37.1% vs 71.7%, respectively; p<0.01) (Table 3). However, the use of the Aerochamber with the MDI reduced the mean oropharyngeal deposition of fenoterol to 3.6%, which was significantly lower than that for the RESPIMAT or the MDI alone (p<0.01).
The mean oropharyngeal deposition of flunisolide delivered via the RESPIMAT was 26.2%, which was similar to that for the MDI with spacer (31.2%). However, modification of the RESPIMAT by the addition of a baffle significantly reduced oropharyngeal deposition of flunisolide to a mean of 7.8%, as shown in Table 4. buy asthma inhalers online
Deposition on the Dosing Apparatus
The mean percentage of the fenoterol dose deposited on the RESPIMAT mouthpiece was significantly greater than that on the MDI actuator (21.9% vs 16.7%, respectively; p<0.05), but was much less than that deposited in the Aerochamber and the MDI actuator to which it was attached (86.2%; p<0.01), as shown in Table 3. Read the rest of this entry »
As shown in Table 1, the demographic characteristics of the patients in both studies were similar. A total of 12 subjects (5 male, 7 female), with a mean age of 27.4 years and normal lung function (mean FEV1, 106% predicted), completed the fenoterol study, whereas 12 subjects (6 male, 6 female), with a mean age of 27.3 years and a mean FEV1 of 97% predicted completed the flunisolide study. buy zyrtec online
The mean parameters of inhalation for the two studies given in Table 2 show that subjects inhaled slowly at a rate between 25 and 35 L/min and had a breath-holding pause of approximately 10 s. Read the rest of this entry »
Immediately following inhalation of the radiolabeled aerosol, images of the posterior and anterior views of the chest and abdomen, a right lateral view of the oropharynx, the dosing apparatus (including wipings from the outer surface of the RESPIMAT nozzle and surrounding plastic casing, baffle, actuator, spacer, and mouthpiece), the nose plugs, and exhalation filter were recorded using a gamma camera (General Electric Maxicamera), connected to a data processing system (Bartec Micas V). Read the rest of this entry »
Radiolabeling of Inhalers
The RESPIMAT and MDI devices that delivered fenoterol or flunisolide were radiolabeled by the addition of the radionuclide “mTc using methods as previously described. These methods were validated in vitro using a high-precision multistage liquid impinger and demonstrated that the radiolabeling procedure did not alter the particle size distribution of either fenoterol or flunisolide in the RESPIMAT or MDI, and confirmed that “mTc is an accurate marker for the in vivo distribution of fenoterol or flunisolide inhaled from both devices. Each metered dose delivered 10 MBq “mTc in addition to the drug substance. antibiotics online
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