Drug Delivery

Metered Dose Inhalers (MDI)

In vitro aerosol, dose, plume, and breathing-interface testing for pressurized inhaler products.

Cascade impactors, Spraytec, APS, high-speed imaging, dose collection, breathing simulation, and HPLC or ELISA quantitation matched to the device.

ISO 17025USP <601>USP <1601>FDA MDI / DPI / nasalReviewed 2026-05-16
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Testing metered dose inhalers

Metered dose inhaler testing shows how the pressurized canister, valve, actuator, formulation, and patient-use interface affect measurable aerosol performance. USP <601>, USP <1601>, and FDA MDI / DPI / nasal guidance provide the core in vitro framework for emitted dose, APSD, plume behavior, and stability-linked change control. The resulting data can inform formulation, device, and regulatory decisions when:

  1. APSD from NGI or Andersen impactors compares MDI formulations, propellants, and actuators under USP <601> and FDA inhalation guidance.
  2. Delivered dose and emitted dose series quantify actuation-to-actuation variability, priming, and end-of-life behavior under USP <601> and ISO 20072.
  3. Spray pattern, plume geometry, and high-speed imaging document actuator or valve changes for FDA comparability and change-control packages.
  4. Breathing simulation evaluates spacers, valved holding chambers, and actuation timing with USP <601> dose collection and FDA use-condition framing.
  5. Stability pulls track APSD, plume, dose, assay, and device function under ICH Q1A storage or ASTM D4169 distribution conditioning.

MDI testing is useful when device output, patient coordination, formulation drift, or actuator changes could alter delivered performance. Before samples arrive, the protocol defines the device setup, actuation sequence, collection method, assay, and acceptance logic.

In vitro test menu for MDI programs

MDI programs often combine aerosol sizing, dose measurement, imaging, breathing-interface testing, modeling, and stability work. The test set depends on the development stage, comparator strategy, and regulatory question.

Test method options

MethodStrengthsTradeoffAligned with
Submission-grade APSD and emitted dose package
  • Cascade impactor plus dose collection quantifies MMAD, GSD, fine-particle dose, and emitted dose under USP <601>.
  • HPLC or ELISA recovery controls connect stage mass to active-specific data for FDA inhalation submissions.
Higher setup and assay burden than screening; best after the formulation, actuator, and collection flow are selected.
USP <601>FDA MDI / DPI / nasal
Dose uniformity and valve delivery series
  • Multi-actuation sequences measure delivered dose, emitted dose, shot weight, priming, and end-of-life behavior under USP <601>.
  • Device-level repeats separate valve, actuator, formulation, and operator effects for ISO 20072 design-verification decisions.
Collection adapters and actuation automation must fit the canister and actuator geometry before meaningful comparisons can start.
USP <601>USP <1601>ISO 20072
Plume geometry and high-speed imaging
  • Laser sheet and high-speed imaging resolve spray pattern, plume angle, duration, and breakup for FDA change-control studies.
  • Controlled distance and trigger timing isolate actuator or formulation effects from operator technique.
Imaging endpoints describe plume behavior, not active mass; pair with dose or APSD data when claims require it.
FDA MDI / DPI / nasal
Breathing-interface and spacer evaluation
  • Programmable profiles test coordination, spacers, valved holding chambers, and mouthpiece interfaces with USP <601> collection logic.
  • Adult and pediatric profile sweeps support FDA use-condition comparisons without changing the active assay.
Results depend on profile assumptions, fixture leakage, and collection geometry; those assumptions must be declared up front.
USP <601>FDA MDI / DPI / nasal
Stability and accelerated aging performance pulls
  • Conditioned pulls track dose, APSD, plume, assay, and actuator function across ICH Q1A storage timepoints.
  • Distribution conditioning can add ASTM D4169 stress before aerosol performance testing when package handling is the question.
Study duration follows storage and pull timing; analytical scheduling should be planned before conditioning begins.
ICH Q1AASTM D4169
CFD-supported airflow and deposition study
  • Modeling estimates airflow, aerosol transport, and mouthpiece deposition to guide fixture design under FDA engineering rationale.
  • Bench PSD, plume, or dose data provide validation points so model outputs remain tied to measured behavior.
CFD supports interpretation and design choices; it does not replace compendial dose or APSD measurement.
FDA MDI / DPI / nasal

Setup configurations

Each MDI study is configured around the device state, collection endpoint, and regulatory use case. The same inhaler may need different fixtures for APSD, plume imaging, spacer evaluation, or stability pulls. Before the first collection run, study planning defines the actuation sequence, flow control, environmental conditions, assay recovery plan, and replicate structure.

Device interfaces

Actuator holders, USP induction ports, mouthpiece adapters, spacers, valved holding chambers, and custom fixtures matched to the canister and actuator geometry.

Flow & actuation profiles

Collection flow, breath profile, actuation force, stroke, timing, canister orientation, priming, repriming, shake procedure, and shot interval documented per run.

Sample numbers

Device count, canister count, shot count, and beginning/middle/end-of-life pulls sized to the decision, assay sensitivity, and expected device variability.

Media & handling

Coated plates, filters, extraction solvents, storage conditions, and chain of custody set for the active, propellant residue, and collection matrix.

Environmental controls

Temperature, RH, storage orientation, aging condition, and use-period handling logged when formulation or actuator behavior may shift with conditioning.

Quality frame for MDI testing

MDI studies operate within a documented quality system anchored to the compendial and regulatory references most often applied to inhalation products, from initial method setup through final reporting.

  • ISO 17025AccreditedLaboratory competence, calibration traceability, method control, and uncertainty contributors.
  • USP <601>AccreditedInhalation aerosols and sprays, including APSD and delivered-dose performance tests.
  • USP <1601>AlignedInhalation product characterization language used where it fits the study.
  • FDA MDI / DPI / nasalAlignedCMC expectations for product quality attributes and device change control.

Key data outputs & reporting

MDI programs receive endpoint-specific datasets that connect the device setup with measured performance. Depending on the endpoints, these datasets include APSD tables, emitted-dose statistics, plume images, breathing-profile dose data, assay recovery, and QA/QC controls. Reports are organized for development review, method justification, comparability packages, or interpretation of stability trends. When a program includes predicate comparisons, model validation, or storage pulls, extended deliverables provide the supporting appendices.

Primary outputs

  • APSD stage mass, MMAD, GSD, fine-particle dose or fraction, impactor recovery, and active-specific assay results where applicable.
  • Delivered dose, emitted dose, shot weight, priming or end-of-life statistics, with mean, SD, and %RSD by condition.
  • Spray pattern, plume angle, plume width, plume duration, high-speed image observations, and actuator-to-actuator comparisons.
  • Breathing-profile or spacer data, including inhaled dose by profile, fixture notes, actuation timing, and interface controls.

Deliverables

#FormatContents
01PDF reportProtocol summary, setup, controls, deviations, results, and interpretation limits.
02CSV / XLSX datasetsStage mass, dose statistics, plume metrics, and assay tables.
03Images / videoSpray pattern files, plume frames, overlays, and high-speed video exports.
Extended deliverables · multi-arm comparability · stability · predicate studies
  • Comparability appendix — Side-by-side APSD, dose, and plume summaries for reference, predicate, or design-change review.
  • Stability trend pack — Timepoint tables and figures showing dose, APSD, plume, assay, and device-function drift.
  • Model validation notes — CFD assumptions, boundary conditions, and measured data used to ground airflow or deposition outputs.

QA / QC & data integrity

Each MDI study includes a QA/QC plan matched to the selected endpoints, assay, and regulatory frame. Controls run alongside sample collection so the dose, plume, and particle data remain traceable from sample receipt through the final report. Method deviations, invalid runs, and sources of uncertainty are documented rather than buried in summary tables.

Blanks, background checks, comparator devices, or reference runs defined by endpoint and collection train.

Flow meters, balances, impactor stages, imaging scales, timers, and actuation fixtures checked or calibrated before use.

Assay controls for HPLC, ELISA, qPCR, or ddPCR, including calibration standards and recovery checks when required.

Chain of custody for devices, canisters, collected stages, filters, extracts, raw files, and analyst observations.

Predefined acceptance criteria, replicate rules, deviation handling, and outlier logic included in the protocol.

Why ARE Labs

ARE Labs connects technical topics to practical study design, method selection, controlled aerosol work, and reportable evidence without turning technical pages into sales pages.

Reviewed byJamie Balarashti (25 yrs - cascade & inhalation methods) - Weston Schaper (7 yrs - real-time sizing & nanoparticle work)
QualityDocumented study records
900+Studies Performed
17+Years in operation
300+Clients supported

Common questions

These answers address the questions MDI development and regulatory teams commonly raise while scoping a study: which endpoints belong together, how devices and actuations are counted, how spacers or breathing profiles affect the setup, and what documentation the program will receive. Most MDI studies also involve at least one custom decision about the fixture, actuation procedure, or assay. Resolving those details during study planning helps keep the method aligned with the intended use of the data.

Q.Which MDI test should I start with?
A.Begin with the decision the data need to support. APSD characterizes aerodynamic performance; dose testing measures output consistency; plume imaging shows how the actuator behaves; and breathing simulation evaluates delivery under defined use conditions. Many programs combine two or more endpoints.
Q.Can ARE Labs test spacers or valved holding chambers?
A.Yes. MDI studies can include spacers, valved holding chambers, mouthpiece adapters, mannequins, or custom fixtures. The protocol defines the breathing profile, actuation timing, collection geometry, and analytical endpoint for the selected interface.
Q.How many inhalers or actuations are needed?
A.The number of devices, canisters, shots, and replicates depends on expected variability, the dose-life stage, assay sensitivity, and whether the work is for screening or submission support. We define these counts during protocol development.
Q.What data will I receive?
A.Deliverables can include APSD tables, dose statistics, plume metrics, images or videos, breathing-profile dose data, assay results, documented deviations, QA/QC records, and a written report.
Q.Can this support FDA documentation?
A.Testing can support product development, method justification, comparability, stability, and regulatory documentation. It does not include clinical studies, full submission management, product approval, or certification.

Standards & guidance

ARE Labs aligns MDI test programs with the compendial, consensus, and regulatory references used to characterize inhalation products. Accredited scopes are reported as accredited; other references are followed as aligned or conformant where applicable. The rows below list the standards and guidance clusters most often cited for MDI aerosol performance, delivered dose, breathing-interface work, CFD rationale, and stability support.

Inhalation & Drug Delivery - Accredited

USP <601>

Inhalation aerosols and sprays: APSD, delivered dose, and performance quality testsView standard ->Inhalation & Drug Delivery - Aligned

USP <1601>

Inhalation product characterization language used for dose and performance studiesView standard ->QA & Regulatory - Aligned

FDA MDI / DPI / nasal

Quality considerations for inhalation products, comparability, device changes, and CMC supportView standard ->Inhalation & Drug Delivery - Aligned

ISO 20072

Aerosol drug delivery device design verification and dose delivery characteristicsView standard ->QA & Regulatory - Aligned

ICH Q1A

Stability storage conditions, pull timing, and trend interpretation for drug productsView standard ->Packaging & Stability - Aligned

ASTM D4169

Distribution-cycle conditioning before post-stress aerosol performance evaluationView standard ->

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