ViscosityRheologyQualityChecker

Viscosity & Rheology Quality Checker — Control of Viscosity and Rheology

ℹ️  Utility assesses rheological parameters of pharmaceutical liquids, gels, and ointments according to USP <911>:
     • Dynamic Viscosity (cP or mPa·s) — resistance to flow
     • Shear Rate (1/s) — measurement condition (critical for non-Newtonian fluids)
     • Yield Stress (Pa) — stress required to initiate flow (for ointments/suspensions)
     • Flow Behavior: Newtonian, Pseudoplastic (shear-thinning), Dilatant, Plastic
     • Strict temperature control (±0.5°C)

⚠️  CRITICAL: Viscosity depends exponentially on temperature! Temperature deviation >0.5°C invalidates the result.
     Change in flow behavior (e.g., from pseudoplastic to Newtonian) indicates irreversible structure breakdown.

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

Input format:
BatchNumber,ProductName,Viscosity_cP,ShearRate_1_per_s,YieldStress_Pa,Temperature_C,FlowBehavior,Density_g_cm3

Example:
  VISC-2026-GEL-001,Carbomer Gel 1%,25000.0,10.0,15.0,25.0,Pseudoplastic,1.01

— WHY IS THIS NEEDED?
Viscosity affects processability (filling, pumping), suspension stability (sedimentation), and consumer properties (spreadability of cream, ease of application).
For eye drops and nasal sprays, viscosity is critical for mucosal contact time.

⚠️  CRITICAL:
• Measurement Condition: For non-Newtonian fluids (gels, creams), viscosity depends on shear rate. Always specify shear rate or spindle/speed.
• Temperature: Measurements must be performed in a thermostated cell.
• Yield Stress: Presence of yield stress prevents ointment from dripping off skin or particles from settling in suspension during storage.
• Thixotropy: If viscosity depends on shear time, this must be accounted for in the method.

Key features:
• Viscosity check considering shear rate
• Yield stress control for structured systems
• Flow behavior identification
• Strict temperature control
• Generation of reports for R&D and QC departments, and LIMS LabWare
• Compliance with USP <911> and Ph. Eur. 2.2.10

Critical parameters:
• Viscosity: within specification (product-dependent)
• Temperature: 25.0 ± 0.5°C (or other specified)
• Yield Stress: ≥ specified minimum (if applicable)
• Flow Behavior: strict compliance (e.g., Pseudoplastic)

💡 Usage tips:
1. Method Selection: Use coaxial cylinders for low-viscosity liquids, cone-plate or parallel plates for high-viscosity ointments.
2. Degassing: Air bubbles in sample distort results. Degas sample before measurement.
3. Recovery Time: For thixotropic gels, allow sample to rest after loading into cell before starting measurement.
4. Calibration: Regularly check instrument with standard fluids of known viscosity (silicone oils).
5. Cleaning: Thoroughly clean geometry between measurements; residues of previous sample cause huge errors.

⚠️ Note: Rheology is not just a single viscosity number, but the material's behavior under deformation. This utility helps control key points of this behavior to ensure quality.