Immediate-Release Tablets
- Smaller particles (e.g., d90 < 100 µm) to enhance dissolution and absorption, leading to rapid onset of action.
Controlled-Release Tablets
- Moderate to larger particles (e.g., d90 > 150 µm) to slow dissolution and provide sustained drug release over time.
Oral Suspensions
- Fine particles (e.g., d90 < 50 µm) to maintain uniform dispersion and prevent sedimentation for stable suspensions.
Inhalation Formulations
- Very fine particles (1-5 µm) to ensure efficient delivery of the API to deep lung regions.
Topical Creams/Ointments
- Fine particles (e.g., d90 < 10 µm) to achieve a smooth, homogeneous distribution without grittiness.
Injectables (Parenterals)
- Very fine particles (< 5 µm) to ensure complete dissolution or provide low-irritation suspensions with minimal embolism risk.
Practical Steps for PSD Optimization
- Understand the drug’s BCS class to determine whether solubility or permeability limits bioavailability, and adjust PSD accordingly.
- Match PSD with the formulation type and desired pharmacokinetic profile (e.g., immediate vs. sustained release).
- Optimize manufacturing processes to support good flow properties and uniform blending without compromising dissolution.
- Conduct experimental trials to identify the optimal PSD that balances dissolution, bioavailability, and manufacturability.
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Resource Person: Moinuddin Syed. Ph.D, PMP