Agilent AccuSizer 780/SIS Laser Particle Size Analyzer with Single Particle Optical Sensing (SPOS) Technology

Overview

The Agilent AccuSizer 780/SIS Laser Particle Size Analyzer is a high-precision, laboratory-grade instrument engineered for quantitative particle characterization using Single Particle Optical Sensing (SPOS) technology. Unlike ensemble-based laser diffraction systems, SPOS detects and sizes individual particles as they pass through a focused laser beam—enabling direct counting, volumetric distribution calculation, and high-resolution detection of low-abundance submicron and micron-scale particulates. This principle delivers true number-weighted distributions with exceptional sensitivity to outliers and trace aggregates—critical for quality control in biopharmaceuticals, injectables, vaccines, and advanced colloidal formulations. The system’s fully enclosed fluidic architecture minimizes ambient contamination and ensures consistent hydrodynamic conditions during analysis, supporting regulatory-compliant workflows under current Good Manufacturing Practice (cGMP) and USP / guidelines.

Key Features

• Single Particle Optical Sensing (SPOS) detection platform delivering absolute particle count per size bin, not inferred statistical estimates
• Modular syringe-based sampling with user-selectable volumes (0.5–50 mL), enabling precise volume delivery and minimal sample waste
• Patented auto-dilution module capable of dynamically adjusting sample concentration in real time—eliminating manual dilution errors and extending dynamic range across orders of magnitude
• Sealed, cleanable flow path design compliant with ISO 21501-4 for light scattering particle counters; supports routine cleaning validation and reduced carryover risk
• Configurable channel resolution (32 to 512 bins) allows optimization between speed and granularity—ideal for method development and stability-indicating assays
• FDA-cleared instrumentation (original PSS AccuSizer platform) with documented 510(k) clearance history for use in regulated biologics manufacturing environments

Sample Compatibility & Compliance

The AccuSizer 780/SIS accommodates both aqueous and non-aqueous suspensions, emulsions, protein therapeutics, liposomal dispersions, and sterile-filtered parenteral solutions. Its wet dispersion capability integrates with optional ultrasonic probes and peristaltic pumps for gentle deagglomeration without shear-induced artifact generation. Dry dispersion is supported via auxiliary aerosol modules for specific powder applications requiring inert gas transport. The system meets ASTM E2456–22 (Standard Guide for Light Scattering Instruments Used for Particle Sizing) and aligns with ICH Q5A(R2) recommendations for subvisible particle assessment in biopharmaceutical products. Data integrity is maintained through audit-trail-enabled operation, supporting compliance with FDA 21 CFR Part 11 and EU Annex 11 requirements when deployed with validated software configurations.

Software & Data Management

Instrument control, acquisition, and reporting are managed via AccuSizer Software v5.x—a Windows-based application validated for GxP environments. It provides real-time visualization of raw pulse height histograms, cumulative/differential distributions (number-, volume-, and surface-area-weighted), and statistical summaries (D10, D50, D90, span, % >5 µm, etc.). Export formats include CSV, PDF, XML, and proprietary .ACS files compatible with third-party statistical process control (SPC) platforms. All user actions—including parameter changes, calibration events, and report generation—are logged with timestamps, operator IDs, and electronic signatures where enabled. Raw data files retain full metadata (instrument ID, date/time, syringe volume, dilution factor, flow rate), ensuring full traceability from measurement to final release documentation.

Applications

• Subvisible particle quantification in monoclonal antibody formulations and mRNA-LNP therapeutics per USP and Ph. Eur. 2.9.19
• Stability monitoring of lyophilized reconstituted products across accelerated and real-time storage conditions
• Filter validation studies assessing pore integrity and particle shedding from sterilizing-grade membranes
• Raw material qualification of excipients (e.g., polysorbates, phospholipids) for particulate burden
• Process characterization of homogenization, microfluidization, and tangential flow filtration unit operations
• Comparability assessments following manufacturing site transfers or formulation changes

FAQ

What distinguishes SPOS from laser diffraction in particle sizing?
SPOS counts and sizes each particle individually using pulse-height analysis, yielding absolute number concentrations and high-resolution distributions—especially critical below 10 µm. Laser diffraction reports ensemble-averaged intensity distributions, which are less sensitive to rare large particles and cannot resolve multimodal populations with overlapping signals.
Can the AccuSizer 780/SIS analyze undiluted samples?
Yes—the integrated auto-dilution system enables direct analysis of concentrated suspensions (up to 10⁶ particles/mL) by performing on-the-fly dilution to maintain optimal coincidence error thresholds (<5%).
Is the system compatible with GLP/GMP audit requirements?
When operated with validated software settings, electronic signature controls, and documented calibration/maintenance records, the AccuSizer 780/SIS supports full audit readiness for regulatory inspections including FDA pre-approval and EMA GMP audits.
How is system suitability verified before sample analysis?
Users perform daily verification using NIST-traceable polystyrene latex (PSL) standards at multiple sizes (e.g., 3.0 µm, 10 µm, 25 µm); acceptance criteria include ±5% size accuracy, CV ≤3% for repeated injections, and pulse height linearity across the calibrated range.
Does Agilent provide IQ/OQ/PQ documentation support?
Agilent offers comprehensive qualification packages—including Installation Qualification (IQ), Operational Qualification (OQ), and Performance Qualification (PQ) protocols—alongside certified reference materials and on-site validation assistance for regulated laboratories.