InhalationAPSDQualityChecker

Inhalation APSD Quality Checker — Control of Aerodynamic Particle Size Distribution (APSD)

ℹ️  Utility checks critical parameters of inhaler aerosol cloud (USP <601> / Ph. Eur. 2.9.18):
   • Fine Particle Dose (FPD): particles <5 µm
   • Mass Median Aerodynamic Diameter (MMAD): distribution median
   • Geometric Standard Deviation (GSD): distribution width

⚠️  CRITICAL: Large particles (>5 µm) deposit in the oropharynx and do not treat lungs!
   Too small particles (<1 µm) may be exhaled back.

Usage:
 InhalationAPSDQualityChecker.exe                            → demo mode (console output)
 InhalationAPSDQualityChecker.exe input.csv output.json      → evaluate your data

Input format:
BatchNumber,LargeParticleMassMcg,FineParticleDoseMcg,MMAD,GSD,TotalRecoveredDoseMcg

Example:
 INHAL-APSD-2026-001,80.0,45.0,2.8,1.8,130.0

— WHY IS THIS NEEDED?
For inhalation products (MDI, DPI), treatment efficacy depends on the fraction of dose reaching the lungs.
• Impactors (Andersen Cascade Impactor, Next Generation Impactor) separate particles by aerodynamic diameter.
• FPD (Fine Particle Dose) is the amount of drug with particle size <5 µm (or <2 µm for alveoli).
• MMAD shows the average particle size. Optimal range is 1-5 µm.
• GSD shows spray homogeneity.
• These parameters are surrogate markers of clinical efficacy and are required by regulators (FDA/EMA).

⚠️  CRITICAL:
• FPD must be within strictly established product specification limits.
• MMAD must ensure deposition in the target respiratory zone.
• Losses in the apparatus must be minimal, and total Recovery should be within 75-125% of labeled dose.
• Test is performed at standard airflow (e.g., 60 L/min or 30 L/min depending on inhaler resistance).

Key features:
• Calculation and verification of FPD, MMAD, GSD.
• Assessment of particle profile suitability for lung delivery.
• Support for cascade impactor data.

Critical parameters:
• FPD: Within Specified Range (e.g., 40-50 mcg)
• MMAD: Within Specified Range (e.g., 2.5-3.5 µm)
• GSD: Typically < 2.5

💡 Usage tips:
1. Use appropriate impactor (ACI or NGI) depending on inhaler type.
2. Calibrate flow meters before each test.
3. Apply silicone coating to impactor cups to prevent particle bounce.
4. Perform at least 3-5 replicates for statistical reliability.
5. Analyze data using log-normal distribution method to calculate MMAD and GSD.

⚠️ Note: APSD does not measure chemical stability, but is a key Physical Critical Quality Attribute (CQA) directly affecting drug bioavailability in the lungs.