• Login
    View Item 
    •   UMB Digital Archive
    • School, Graduate
    • Theses and Dissertations All Schools
    • View Item
    •   UMB Digital Archive
    • School, Graduate
    • Theses and Dissertations All Schools
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of UMB Digital ArchiveCommunitiesPublication DateAuthorsTitlesSubjectsThis CollectionPublication DateAuthorsTitlesSubjects

    My Account

    LoginRegister

    Statistics

    Display statistics

    Use of simulated inhaled volumes, flow rates and flow rate ramps to evaluate in vitro dry powder inhaler performance

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Find Full text
    Author
    Chavan, Varsha S.
    Advisor
    Dalby, Richard N.
    Date
    2001
    Type
    dissertation
    
    Metadata
    Show full item record
    Abstract
    Dry Powder Inhalers (DPIs) utilize a patient's inspiratory maneuver to entrain and deaggregate a powder forming an inhalation aerosol. United States Pharmacopoeia (USP) DPI methods replicate the peak rate a patient might achieve, but do not account for how this peak is approached. This research developed a simple, robust system to simulate different rates of rise (ramps) to a final peak inspiratory flow rate. Ramps were programmed to reach 30, 60, 90 and 120 L/min over 100 ms, 500 ms, 1, 2 and 3 s. Using this computerized system, it was demonstrated that peak flow rate, the rate at which that flow rate was achieved and carrier particle size, influenced powder emptying from three passive DPIs. Generally, powder emptying increased as ramp steepness increased---this being most evident at 30 L/min. Greater emptying was usually facilitated by larger carrier particles using all ramps and peak flows. The USP method of instantaneous peak flow rate generation produced more emptying than even the steepest ramp, and may therefore overestimate powder emptying during use. While maximized powder emptying is a prerequisite of optimized dose delivery, a meaningful determination of Fine Particle Fraction (FPF), the fraction of the aerosolized output likely to reach the lungs, is more critical to therapeutic outcome. A semi-automated system was developed permitting ramped air flow through a DPI while maintaining a relatively constant air flow through an inertial impactor. This system suggested that a steeper rate of rise in air flow elicited a higher FPF compared to a shallower ramp at test flow rates of 30 and 60 Umin. FPF determined by the USP method was higher than the ramp method at these flow rates. There were no significant differences in FPF when a 2 and 4 L inhaled volume were compared. This research highlights the limitations of two existing compendial tests when applied to therapeutic aerosols generated from DPIs, and provides a basis and apparatus for evaluating in vitro DPI performance more realistically. It also illustrates the potential dangers in using in vitro tests to infer in vivo performance in the absence of valid correlations.
    Description
    University of Maryland, Baltimore. Pharmaceutical Sciences. Ph.D. 2001
    Keyword
    Health Sciences, Pharmacy
    Identifier to cite or link to this item
    http://hdl.handle.net/10713/1190
    Collections
    Theses and Dissertations School of Pharmacy
    Theses and Dissertations All Schools

    entitlement

     
    DSpace software (copyright © 2002 - 2023)  DuraSpace
    Quick Guide | Policies | Contact Us | UMB Health Sciences & Human Services Library
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.